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Background and Objectives: In multiple sclerosis (MS), immune cells invade the CNS and destroy myelin. Macrophages contribute to demyelination and myelin repair, and their role in each process depends on their ability to acquire specific phenotypes in response to external signals. In this article, we assess whether defects in MS patient macrophage responses may lead to increased inflammation or lack of neuroregenerative effects., Methods: CD14 + CD16 - monocytes from patients with MS and healthy controls (HCs) were activated in vitro to obtain homeostatic-like, proinflammatory, and proregenerative macrophages. Macrophage activation profiles were assessed through RNA sequencing and metabolomics. Surface molecule expression of CD14, CD16, and HLA-DR and myelin phagocytic capacity were evaluated with flow cytometry. Macrophage supernatant capacity to influence oligodendrocyte precursor cell differentiation toward an astrocytic or oligodendroglia fate was also tested., Results: We observed that MS patient monocytes ex vivo recapitulate their preferential activation toward the CD16 + phenotype, a subset of proinflammatory cells overrepresented in MS lesions. Functionally, MS patient macrophages display a decreased capacity to phagocytose human myelin and a deficit of processing myelin after ingestion. In addition, MS patient macrophage supernatant favors astrocytes over oligodendrocyte differentiation when compared with HC macrophage supernatant. Furthermore, even when exposed to homeostatic or proregenerative stimuli, MS patient macrophages uphold a proinflammatory transcriptomic profile with higher levels of cytokine/chemokine. Of interest, MS patient macrophages exhibit a distinct metabolic signature with a mitochondrial energy metabolism blockage. Transcriptomic data are further substantiated by metabolomics studies that reveal perturbations in the corresponding metabolic pathways., Discussion: Our results show an intrinsic defect of MS patient macrophages, reminiscent of innate immune cell memory in MS, lifting macrophage importance in the disease and as potential therapeutic targets.

Background and Objectives: Although rituximab failed to demonstrate a significant effect on disability progression in primary progressive multiple sclerosis (PPMS), ocrelizumab succeeded. Our main objective was to analyze confirmed disability progression (CDP) in a cohort of patients with PPMS treated with anti-CD20 therapies compared with a weighted untreated control cohort., Methods: This was a retrospective study using data from the French MS registry (Observatoire Français de la Sclérose En Plaques). We included patients with PPMS treated or never treated with anti-CD20 therapies from 2016 to 2021, with an Expanded Disability Status Scale score of ≤6.5 at baseline. The primary outcome was time to first CDP. The secondary outcomes were time to first relapse, MRI activity at 2 years, identification of risk factors associated with CDP, and serious infection incidence rates (IIRs). Each outcome was studied using an inverse probability of treatment weighting method. The outcomes were modeled using a weighted proportional Cox model for the time-to-event outcomes and by a logistic regression regarding the MRI activity., Results: A total of 1,184 patients (426 treated and 758 untreated) fulfilled the inclusion criteria. Median age (Q1-Q3) was 56 years (49.3-63.8), and 52.7% were female. Among treated patients, 295 received rituximab, whereas 131 received ocrelizumab. At baseline, anti-CD20-treated patients were younger (median 51.9 vs 58.6 years, Cohen d = 0.683) and had more active disease (54.5 vs 27.8%, Cohen d = 0.562). 91.6% were drug-naive at inclusion. In time to first CDP analysis, no statistical significance was observed (hazard ratio [HR], 1.13; 95% CI 0.93-1.36, p = 0.2113). In time to first relapse analysis, a nonsignificant trend toward fewer patients relapsing in the treated group was observed (HR 0.83; 95% CI 0.48-1.28, p = 0.0809). For MRI activity, no significant difference was found between the 2 groups. Risk factors associated with CDP in the treated group were male sex and MS duration. IIR was 6.67 (95% CI 3.12-14.25) per 100 person-years in the treated group vs 2.67 (95% CI 0.80-8.86) in the untreated group., Discussion: Time to first CDP was not different between anti-CD20 treated and untreated patients with PPMS. Although our study is retrospective and mainly included patients treated by rituximab, our results indicate that there should be a constant evaluation of all available data to ascertain the best risk/benefit ratio for patients with PPMS., Classification of Evidence: This study provides Class III evidence that anti-CD20 therapy of previously untreated patients with PPMS was not superior to no therapy in delaying time to first CDP.

Progressive multiple sclerosis poses a considerable challenge in the evaluation of disease progression and treatment response owing to its multifaceted pathophysiology. Traditional clinical measures such as the Expanded Disability Status Scale are limited in capturing the full scope of disease and treatment effects. Advanced imaging techniques, including MRI and PET scans, have emerged as valuable tools for the assessment of neurodegenerative processes, including the respective role of adaptive and innate immunity, detailed insights into brain and spinal cord atrophy, lesion dynamics and grey matter damage. The potential of cerebrospinal fluid and blood biomarkers is increasingly recognized, with neurofilament light chain levels being a notable indicator of neuro-axonal damage. Moreover, patient-reported outcomes are crucial for reflecting the subjective experience of disease progression and treatment efficacy, covering aspects such as fatigue, cognitive function and overall quality of life. The future incorporation of digital technologies and wearable devices in research and clinical practice promises to enhance our understanding of functional impairments and disease progression. This Review offers a comprehensive examination of these diverse evaluation tools, highlighting their combined use in accurately assessing disease progression and treatment efficacy in progressive multiple sclerosis, thereby guiding more effective therapeutic strategies., (© 2024. Springer Nature Limited.)

Background: Choroid plexus (ChP) enlargement is an emerging radiological biomarker in multiple sclerosis (MS)., Objectives: This study aims to assess ChP volume in a large cohort of patients with radiologically isolated syndrome (RIS) versus healthy controls (HC) and explore its relationship with other brain volumes, disease activity, and biological markers., Methods: RIS individuals were included retrospectively and compared with HC. ChPs were automatically segmented using an in-house automated algorithm and manually corrected., Results: A total of 124 patients fulfilled the 2023 RIS criteria, and 55 HCs were included. We confirmed that ChPs are enlarged in RIS versus HC (mean (±SD) normalized ChP volume: 17.24 (±4.95) and 11.61 (±3.58), respectively, p < 0.001). Larger ChPs were associated with more periventricular lesions (ρ = 0.26; r 2 = 0.27; p = 0.005 for the correlation with lesion volume, and ρ = 0.2; r 2 = 0.21; p = 0.002 for the correlation with lesion number) and lower thalamic volume (ρ = -0.38; r 2 = 0.44; p < 0.001), but not with lesions in other brain regions. Conversely, ChP volume did not correlate with biological markers. No significant difference in ChP volume was observed between subjects who presented or did not have a clinical event or between those with or without imaging disease activity., Conclusions: This study provides evidence that ChP volume is higher in RIS and is associated with measures reflecting periventricular pathology but does not correlate with biological, radiological, or clinical markers of disease activity., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: C.L.-C. received a Neuromod Institute grant for her PhD.VAGR reports fees for traveling from Novartis, Merck, Biogen, and Roche, speaker’s honoraria from Novartis, Sandoz, Merck, Biogen, Roche, consulting fees from Biogen, Merck, Novartis, Janssen, M3 Global Research, and Atheneum Partners, all outside of the submitted work.L. M. has no conflict of interest.E. T. received consulting and lecturing fees, travel grants, or unconditional research support from the following pharmaceutical companies: Actelion, Biogen, BMS, Janssen, Merck, Novartis, Roche, and Teva Pharma.P. L. has no financial conflicts related to this work.C. L. has received speaker or consulting fees from Biogen, Merck, Novartis, Sanofi, and Roche and a research grant (to the institution) from Biogen.H. Z. has no disclosure related to this work. HZ received consulting fees from ALEXION, HORIZON THERAPEUTICS, ROCHE, BIOGEN IDEC, SANOFI, JANSSEN, and research support from ROCHE and NOVARTIS.F. D.D. has no financial conflicts related to this work.E. L.P. has no financial conflicts related to this work.A. S. has no financial conflicts related to this work and has received research grants from The Turkish Multiple Sclerosis Society, The Scientific and Technological Research Council Of Turkiye, and Istanbul University-Cerrahpasa Research Support Funds. He has received consultancy fees from Roche Ltd, Merck-Serono, Biogen Idec/Gen Pharma of Turkiye, Sanofi-Genzyme, Novartis, and Alexion and received honoraria for lectures from Sanofi-Genzyme, Novartis, Roche Ltd., and Teva—registration coverage for attending scientific congresses or symposia from Sanofi-Genzyme and Alexion.M. C. has no conflict of interest.A. YP. has no financial conflicts related to this work.C. J.A. has no conflict of interest with this work.D. T.O. received personal compensation for consulting and advisory services from Biogen, Eisai, EMD Serono, Genentech, Genzyme/Sanofi, Moderna, RVL Pharmaceuticals, Inc., Zenas BioPharma, and research support from EMD Serono/Merck and Novartis. D.T.O. has issued national and international patents and pending patents related to other developed technologies. D.T.O. received royalties for intellectual property licensed by The Board of Regents of The University of Texas System and is also the Founder of Revert Health Inc.B. S. has received personal speaker fees from Janssen, Biogen, Novartis, Merck, and Sanofi, as well as research support (to the institution) from Merck, Roche, and Novartis.C. L-F. has no conflict of interest.

Objective: To evaluate: (1) the distribution of gray matter (GM) atrophy in myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD), aquaporin-4 antibody-positive neuromyelitis optica spectrum disorder (AQP4+NMOSD), and relapsing-remitting multiple sclerosis (RRMS); and (2) the relationship between GM volumes and white matter lesions in various brain regions within each disease., Methods: A retrospective, multicenter analysis of magnetic resonance imaging data included patients with MOGAD/AQP4+NMOSD/RRMS in non-acute disease stage. Voxel-wise analyses and general linear models were used to evaluate the relevance of regional GM atrophy. For significant results (p < 0.05), volumes of atrophic areas are reported., Results: We studied 135 MOGAD patients, 135 AQP4+NMOSD, 175 RRMS, and 144 healthy controls (HC). Compared with HC, MOGAD showed lower GM volumes in the temporal lobes, deep GM, insula, and cingulate cortex (75.79 cm 3 ); AQP4+NMOSD in the occipital cortex (32.83 cm 3 ); and RRMS diffusely in the GM (260.61 cm 3 ). MOGAD showed more pronounced temporal cortex atrophy than RRMS (6.71 cm 3 ), whereas AQP4+NMOSD displayed greater occipital cortex atrophy than RRMS (19.82 cm 3 ). RRMS demonstrated more pronounced deep GM atrophy in comparison with MOGAD (27.90 cm 3 ) and AQP4+NMOSD (47.04 cm 3 ). In MOGAD, higher periventricular and cortical/juxtacortical lesions were linked to reduced temporal cortex, deep GM, and insula volumes. In RRMS, the diffuse GM atrophy was associated with lesions in all locations. AQP4+NMOSD showed no lesion/GM volume correlation., Interpretation: GM atrophy is more widespread in RRMS compared with the other two conditions. MOGAD primarily affects the temporal cortex, whereas AQP4+NMOSD mainly involves the occipital cortex. In MOGAD and RRMS, lesion-related tract degeneration is associated with atrophy, but this link is absent in AQP4+NMOSD. ANN NEUROL 2024;96:276-288., (© 2024 The Author(s). Annals of Neurology published by Wiley Periodicals LLC on behalf of American Neurological Association.)

Importance: Understanding the association between clinically defined relapses and radiological activity in multiple sclerosis (MS) is essential for patient treatment and therapeutic development., Objective: To investigate clinical events identified as relapses but not associated with new T2 lesions or gadolinium-enhanced T1 lesions on brain and spinal cord magnetic resonance imaging (MRI)., Design, Setting, and Participants: This multicenter observational cohort study was conducted between January 2015 and June 2023. Data were extracted on June 8, 2023, from the French MS registry. All clinical events reported as relapses in patients with relapsing-remitting MS were included if brain and spinal cord MRI was performed within 12 and 24 months before the event, respectively, and 50 days thereafter with gadolinium injection., Exposures: Events were classified as relapses with active MRI (RAM) if a new T2 lesion or gadolinium-enhanced T1 lesion appeared on brain or spinal cord MRI or as acute clinical events with stable MRI (ACES) otherwise., Main Outcomes and Measures: Factors associated with ACES were investigated; patients with ACES and RAM were compared regarding Expanded Disability Status Scale (EDSS) course, relapse rate, confirmed disability accrual (CDA), relapse-associated worsening (RAW), progression independent of relapse activity (PIRA), and transition to secondary progressive (SP) MS, and ACES and RAM rates under each disease-modifying therapy (DMT) were estimated., Results: Among 31 885 clinical events, 637 in 608 patients (493 [77.4%] female; mean [SD] age, 35.8 [10.7] years) were included. ACES accounted for 166 (26.1%) events and were more likely in patients receiving highly effective DMTs, those with longer disease duration (odds ratio [OR], 1.04; 95% CI, 1.01-1.07), or those presenting with fatigue (OR, 2.14; 95% CI, 1.15-3.96). ACES were associated with significant EDSS score increases, lower than those found for RAM. Before the index event, patients with ACES experienced significantly higher rates of relapse (relative rate [RR], 1.21; 95% CI, 1.01-1.46), CDA (hazard ratio [HR], 1.54; 95% CI, 1.13-2.11), and RAW (HR, 1.72; 95% CI, 1.20-2.45). Patients with ACES were at significantly greater risk of SP transition (HR, 2.58; 95% CI, 1.02-6.51). Although RAM rate decreased with DMTs according to their expected efficacy, ACES rate was stable across DMTs., Conclusions and Relevance: The findings in this study introduce the concept of ACES in MS, which accounted for one-fourth of clinical events identified as relapses.

Introduction: Recent evidence suggests the blood-to-brain influx rate ( K 1 ) in TSPO PET imaging as a promising biomarker of blood-brain barrier ( BBB ) permeability alterations commonly associated with peripheral inflammation and heightened immune activity in the brain. However, standard compartmental modeling quantification is limited by the requirement of invasive and laborious procedures for extracting an arterial blood input function. In this study, we validate a simplified blood-free methodologic framework for K 1 estimation by fitting the early phase tracer dynamics using a single irreversible compartment model and an image-derived input function ( 1T1K-IDIF )., Methods: The method is tested on a multi-site dataset containing 177 PET studies from two TSPO tracers ([ 11 C]PBR28 and [ 18 F]DPA714). Firstly, 1T1K-IDIF K 1 estimates were compared in terms of both bias and correlation with standard kinetic methodology. Then, the method was tested on an independent sample of [ 11 C]PBR28 scans before and after inflammatory interferon- α challenge, and on test-retest dataset of [ 18 F]DPA714 scans., Results: Comparison with standard kinetic methodology showed good-to-excellent intra-subject correlation for regional 1T1K-IDIF-K 1 ( ρ intra  = 0.93 ± 0.08), although the bias was variable depending on IDIF ability to approximate blood input functions (0.03-0.39 mL/cm 3 /min). 1T1K-IDIF-K 1 unveiled a significant reduction of BBB permeability after inflammatory interferon- α challenge, replicating results from standard quantification. High intra-subject correlation ( ρ  = 0.97 ± 0.01) was reported between K 1 estimates of test and retest scans., Discussion: This evidence supports 1T1K-IDIF as blood-free alternative to assess TSPO tracers' unidirectional blood brain clearance. K 1 investigation could complement more traditional measures in TSPO studies, and even allow further mechanistic insight in the interpretation of TSPO signal., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (Copyright © 2024 Maccioni, Carranza Mellana, Brusaferri, Silvestri, Bertoldo, Schubert, Nettis, Mondelli, Howes, Turkheimer, Bottlaender, Bodini, Stankoff, Loggia and Veronese.)

Introduction: Progressive Multifocal Leukoencephalopathy (PML) is a rare and deadly demyelinating disease caused by JC virus (JCV) replication in the central nervous system. PML occurs exclusively in patients with severe underlying immune deficiencies, including AIDS and hematological malignancies. PML has also emerged as a significant threat to patients on potent new immunosuppressive biologics, including natalizumab in multiple sclerosis., Methods: Here, we developed an IFN-γ release assay (IGRA) that mainly detects JCV-specific effector memory T cells and effectors T cells in the blood., Results: This assay was frequently positive in patients with active PML (with a positive JCV PCR in CSF) of various underlying immunosuppression causes (84% sensitivity). Only 3% of healthy donors had a positive response (97% specificity). The frequency of positivity also increased in multiple sclerosis patients according to the time on natalizumab (up to 36% in patients treated for more than 48 months, who are considered at a higher risk of PML)., Discussion: The results show this assay's frequent or increased positivity in patients with PML or an increased risk of PML, respectively. The assay may help to stratify the risk of PML., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 de Goër de Herve, Dekeyser, Hendel-Chavez, Maillart, Labeyrie, Adams, Moreau, Lubetzki, Papeix, Stankoff, Gasnault and Taoufik.)

Background: Exploring the relationship between oxygen supply and myelin damage would benefit from a simultaneous quantification of myelin and cerebral blood flow (CBF) in the brain's white matter (WM). To validate an analytical method for quantifying both CBF and myelin content in the WM using dynamic [ 11 C]PiB positron emission tomography (PET)., Methods: A test-retest study was performed on eight healthy subjects who underwent two consecutive dynamic [11 C]PiB-PET scans. Three quantitative approaches were compared: simplified reference tissue model 2 (SRTM2), LOGAN graphical model, and standardized uptake value ratio (SUVR). The sensitivity of methods to the size of the region of interest was explored by simulating lesion masks obtained from 36 subjects with multiple sclerosis. Reproducibility was assessed using the relative difference and interclass correlation coefficient. Repeated measures correlations were used to test for cross-correlations between metrics., Results: Among the CBF measures, the relative delivery (R1) of the simplified reference tissue model 2 (SRTM2) displayed the best reproducibility in the white matter, with a strong influence of the size of regions analyzed, the test-retest variability being below 10% for regions above 68 mm 3 in the supratentorial white matter. [ 11 C]PiB PET-derived proxies of CBF demonstrated lower perfusion of white matter compared to grey matter with an overall ratio equal to 1.71 ± 0.09 when the SRTM2-R1 was employed. Tissue binding in the white matter was well estimated by the Logan graphical model through estimation of the distribution volume ratio (LOGAN-DVR) and SRTM2 distribution volume ratio (SRTM2-DVR), with test-retest variability being below 10% for regions exceeding 106 mm 3 for LOGAN-DVR and 300 mm 3 for SRTM2-DVR. SRTM2-DVR provided a better contrast between white matter and grey matter. The interhemispheric variability was also dependent on the size of the region analyzed, being below 10% for regions above 103 mm 3 for SRTM2-R1 and above 110 mm 3 for LOGAN-DVR. Whereas the 1 to 8-minute standardized uptake value ratio (SUVR1-8) showed an intermediary reproducibility for CBF assessment, SUVR0-2 for perfusion or SUVR50-70 for tissue binding showed poor reproducibility and correlated only mildly with SRTM2-R1 and LOGAN-DVR estimations respectively., Conclusions: [ 11 C]PiB PET imaging can simultaneously quantify perfusion and myelin content in WM diseases associated with focal lesions. For longitudinal studies, SRTM2-R1 and DVR should be preferred over SUVR for the assessment of regional CBF and myelin content, respectively., Trial Registration: European Union Clinical Trials Register EUDRACT; EudraCT Number: 2008-004174-40; Date: 2009-03-06; https//www.clinicaltrialsregister.eu ; number 2008-004174-40., (© 2024. The Author(s).)

Background: Respiratory disorders remain incompletely described in multiple sclerosis (MS), even though they are a frequent cause of death., Methods: The objective was to describe respiratory disorders in MS patients with Expanded Disability Status Score (EDSS) ⩾ 6.5. Diaphragm dysfunction was defined by at least two of the seven criteria: clinical signs, inspiratory recruitment of neck muscles during wakefulness, reduced upright vital capacity (VC) < 80%, upright-to-supine VC ⩾ 15% of upright VC, decrease in Maximal Inspiratory Pressure < 60%, phasic activation of inspiratory neck muscles during sleep, and opposition of thoracic and abdominal movements during sleep. Cough weakness was defined by a peak cough flow < 270 L/min and/or need for cough assist. Sleep apnea syndrome was defined by an apnea-hypopnea index ⩾ 15., Results: Notably, 71 MS patients were included: median age 54 [48, 61] years; median disease duration 21.4 [16.0, 31.4] years. Of these, 52 patients had one or more respiratory disorders; diaphragm dysfunction was the most frequent ( n = 34). Patients with diaphragm dysfunction and cough weakness were more disabled. The fatigue score and the cognitive evaluations did not differ between the groups. Five patients required non-invasive ventilation., Conclusion: Respiratory disorders are frequent in severe MS, mostly diaphragm dysfunction. Of interest, instrumental interventions are available to address these disorders., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: No disclosure relevant to the manuscript. E.M. reports research support from Biogen and personal fees for lectures and advisory boards from Alexion, Biogen, Horizon, Janssen, Merck, Novartis, Roche, Sanofi, and Teva. C.Lo. has received consulting, speaker or travel fees from Merck, Roche, Biogen, Novartis, Teva, and Sanofi, and an IIT grant from Biogen. S.R., M.H., E.C., P.L., A.U., and I.A. report no disclosure. B.S. reports research support from Roche, Sanofi, and Merck and personal fees for lectures or advisory boards from Novartis, Sanofi, Biogen, Janssen, and Merck. C.P. reports research personal fees for lectures and advisory boards from Alexion, Biogen, Horizon, Merck, Novartis, Roche, and Sanofi. B.B. reports research support from Biogen and personal fees for lectures and advisory boards from Novartis, Roche, Sanofi, and Merck. C.Lu. reports research support from Merck and participates in advisory boards for Biogen, Merck, Rewind, and Roche. T.S. reports personal fees for consulting and teaching activities from AstraZeneca France, Chiesi France, KPL consulting, Lungpacer Inc., OSO-AI, TEVA France, and Vitalaire; he is a shareholder of startups Hephaï and Austral Dx. C.M.P. reports personal fees from AstraZeneca, Chiesi, ADEP Assistance, SOS Oxygène, ISIS, ResMed, Menarini, GSK, Fisher & Paykel, Vivisol, Air Liquide, Lowenstein, and Orkyn outside the submitted work.

Importance: A recent randomized clinical trial concluded that discontinuing medium-efficacy therapy might be a reasonable option for older patients with nonactive multiple sclerosis (MS), but there is a lack of data on discontinuing high-efficacy therapy (HET). In younger patients, the discontinuation of natalizumab and fingolimod is associated with a risk of rebound of disease activity., Objective: To determine whether discontinuing HET in patients 50 years and older with nonactive MS is associated with an increased risk of relapse compared with continuing HET., Design, Setting, and Participants: This observational cohort study used data from 38 referral centers from the French MS registry (Observatoire Français de la Sclérose en Plaques [OFSEP] database). Among 84704 patients in the database, data were extracted for 1857 patients 50 years and older with relapsing-remitting MS treated by HET and with no relapse or magnetic resonance imaging activity for at least 2 years. After verification of the medical records, 1620 patients were classified as having discontinued HET or having remained taking treatment and were matched 1:1 using a dynamic propensity score (including age, sex, disease phenotype, disability, treatment of interest, and time since last inflammatory activity). Patients were included from February 2008 to November 2021, with a mean (SD) follow-up of 5.1 (2.9) years. Data were extracted in June 2022., Exposures: Natalizumab, fingolimod, rituximab, and ocrelizumab., Main Outcomes and Measures: Time to first relapse., Results: Of 1620 included patients, 1175 (72.5%) were female, and the mean (SD) age was 54.7 (4.8) years. Among the 1452 in the HET continuation group and 168 in the HET discontinuation group, 154 patients in each group were matched using propensity scores (mean [SD] age, 57.7 [5.5] years; mean [SD] delay since the last inflammatory activity, 5.6 [3.8] years; mean [SD] follow-up duration after propensity score matching, 2.5 [2.1] years). Time to first relapse was significantly reduced in the HET discontinuation group compared with the HET continuation group (hazard ratio, 4.1; 95% CI, 2.0-8.5; P < .001) but differed between HETs, with a hazard ratio of 7.2 (95% CI, 2.1-24.5; P = .001) for natalizumab, 4.5 (95% CI, 1.3-15.5; P = .02) for fingolimod, and 1.1 (95% CI, 0.3-4.8; P = .85) for anti-CD20 therapy., Conclusion and Relevance: As in younger patients, in patients 50 years and older with nonactive MS, the risk of relapse increased significantly after stopping HETs that impact immune cell trafficking (natalizumab and fingolimod). There was no significant increase in risk after stopping HETs that deplete B-cells (anti-CD20 therapy). This result may inform decisions about stopping HETs in clinical practice.

Cortical myelin loss and repair in multiple sclerosis (MS) have been explored in neuropathological studies, but the impact of these processes on neurodegeneration and the irreversible clinical progression of the disease remains unknown. Here, we evaluated in vivo cortical demyelination and remyelination in a large cohort of people with all clinical phenotypes of MS followed up for 5 years using magnetization transfer imaging (MTI), a technique that has been shown to be sensitive to myelin content changes in the cortex. We investigated 140 people with MS (37 clinically isolated syndrome, 71 relapsing-MS, 32 progressive-MS), who were clinically assessed at baseline and after 5 years and, along with 84 healthy controls, underwent a 3 T-MRI protocol including MTI at baseline and after 1 year. Changes in cortical volume over the radiological follow-up were computed with a Jacobian integration method. Magnetization transfer ratio was employed to calculate for each patient an index of cortical demyelination at baseline and of dynamic cortical demyelination and remyelination over the follow-up period. The three indices of cortical myelin content change were heterogeneous across patients but did not significantly differ across clinical phenotypes or treatment groups. Cortical remyelination, which tended to fail in the regions closer to CSF (-11%, P < 0.001), was extensive in half of the cohort and occurred independently of age, disease duration and clinical phenotype. Higher indices of cortical dynamic demyelination (β = 0.23, P = 0.024) and lower indices of cortical remyelination (β = -0.18, P = 0.03) were significantly associated with greater cortical atrophy after 1 year, independently of age and MS phenotype. While the extent of cortical demyelination predicted a higher probability of clinical progression after 5 years in the entire cohort [odds ratio (OR) = 1.2; P = 0.043], the impact of cortical remyelination in reducing the risk of accumulating clinical disability after 5 years was significant only in the subgroup of patients with shorter disease duration and limited extent of demyelination in cortical regions (OR = 0.86, P = 0.015, area under the curve = 0.93). In this subgroup, a 30% increase in cortical remyelination nearly halved the risk of clinical progression at 5 years, independently of clinical relapses. Overall, our results highlight the critical role of cortical myelin dynamics in the cascade of events leading to neurodegeneration and to the subsequent accumulation of irreversible disability in MS. Our findings suggest that early-stage myelin repair compensating for cortical myelin loss has the potential to prevent neuro-axonal loss and its long-term irreversible clinical consequences in people with MS., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Guarantors of Brain.)

Purpose: MP2RAGE parameter optimization is redefined to allow more time-efficient MR acquisitions, whereas the T 1 -based synthetic imaging framework is used to obtain on-demand T 1 -weighted contrasts. Our aim was to validate this concept on healthy volunteers and patients with multiple sclerosis, using plug-and-play parallel-transmission brain imaging at 7 T., Methods: A "time-efficient" MP2RAGE sequence was designed with optimized parameters including TI and TR set as small as possible. Extended phase graph formalism was used to set flip-angle values to maximize the gray-to-white-matter contrast-to-noise ratio (CNR). Several synthetic contrasts (UNI, EDGE, FGATIR, FLAWS MIN , FLAWS HCO ) were generated online based on the acquired T 1 maps. Experimental validation was performed on 4 healthy volunteers at various spatial resolutions. Clinical applicability was evaluated on 6 patients with multiple sclerosis, scanned with both time-efficient and conventional MP2RAGE parameterizations., Results: The proposed time-efficient MP2RAGE protocols reduced acquisition time by 40%, 30%, and 19% for brain imaging at (1 mm) 3 , (0.80 mm) 3 and (0.65 mm) 3 , respectively, when compared with conventional parameterizations. They also provided all synthetic contrasts and comparable contrast-to-noise ratio on UNI images. The flexibility in parameter selection allowed us to obtain a whole-brain (0.45 mm) 3 acquisition in 19 min 56 s. On patients with multiple sclerosis, a (0.67 mm) 3 time-efficient acquisition enhanced cortical lesion visualization compared with a conventional (0.80 mm) 3 protocol, while decreasing the scan time by 15%., Conclusion: The proposed optimization, associated with T 1 -based synthetic contrasts, enabled substantial decrease of the acquisition time or higher spatial resolution scans for a given time budget, while generating all typical brain contrasts derived from MP2RAGE., (© 2023 The Authors. Magnetic Resonance in Medicine published by Wiley Periodicals LLC on behalf of International Society for Magnetic Resonance in Medicine.)

Background: Epidemiologic studies on coronavirus disease 2019 (COVID-19) in patients with multiple sclerosis (pwMS) have focused on the first waves of the pandemic until early 2021., Objectives: We aimed to extend these data from the onset of the pandemic to the global coverage by vaccination in summer 2022., Methods: This retrospective, multicenter observational study analyzed COVISEP registry data on reported COVID-19 cases in pwMS between January 2020 and July 2022. Severe COVID-19 was defined as hospitalization or higher severity., Results: Among 2584 pwMS with confirmed/highly suspected COVID-19, severe infection rates declined from 14.6% preomicron wave to 5.7% during omicron wave ( p  < 0.001). Multivariate analysis identified age (odds ratio (OR) = 1.43, 95% confidence interval (CI) = [1.25-1.64] per 10 years), male sex (OR = 2.01, 95% CI = [1.51-2.67]), obesity (OR = 2.36, 95% CI = [1.52-3.68]), cardiac comorbidities (OR = 2.36, 95% CI = [1.46-3.83]), higher Expanded Disability Status Scale (EDSS) scores (OR = 2.09, 95% CI = [1.43-3.06] for EDSS 3-5.5 and OR = 4.53, 95% CI = [3.04-6.75] for EDSS ⩾6), and anti-CD20 therapies (OR = 2.67, 95% CI = [1.85-3.87]) as risk factors for COVID-19 severity. Vaccinated individuals experienced less severe COVID-19, whether on (risk ratio (RR) = 0.64, 95% CI = [0.60-0.69]) or off (RR = 0.32, 95% CI = [0.30-0.33]) anti-CD20., Discussion: In pwMS, consistent risk factors were anti-CD20 therapies and neurological disability, emerging as vital drivers of COVID-19 severity regardless of wave, period, or vaccination status., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: L.J. reports no disclosure. E.J. reports no disclosure. P.L. reports no disclosure. E.M. has received research support from Fondation ARSEP and Biogen Idec, travel funding and/or consulting fees from Alexion, Biogen Idec, BMS, Janssen, Merck, Novartis, Roche, Sanofi-Genzyme, and Teva. J.D.S. reports no disclosure. H.Z. has no disclosure related to this manuscript. Unrelated to this manuscript H.Z. received consulting fees from Biogen Idec, Sanofi, Merck, Novartis, Roche, Horizon Therpaeutics, Alexion, BMS, and Grant Research Support from ROCHE. J.P. reports no disclosure. P.K. reports no disclosure. D.B. reports no disclosure. O.H. has received consulting and lecture fees from Bayer Schering, Merck, Teva, Genzyme, Novartis, Almirall, and Biogen Idec, travel grants from Novartis, Teva, Genzyme, Merck Serono, and Biogen Idec, and research support from Roche, Merck, and Novartis. L.G. has received consulting and/or lecture fees and/or travel funding from Novartis, Merck, Sanofi, BMS, and Biogen. C.B. has received consulting honoraria from Alexion, Sanofi, Merck, Biogen, BMS, Novartis, Roche, and Teva. M.T. reports receiving consulting and lecture fees from Merck, Novartis, and Biogen Idec, travel grants from Sanofi, Merck Serono, and Biogen Idec. S.V. has received lecturing fees, travel grants, and research support from Biogen, BMS-Celgene, Janssen, Merck, Novartis, Roche, Sanofi-Genzyme, and Teva. O.C. reports receiving personal fees from Biogen, Roche, Merck, Novartis, Janssen, and Sanofi and nonfinancial support from Roche, Merck, and Novartis outside the submitted work. A.M. reports no disclosure. D.L. reports receiving grants from Roche, Sanofi, the ARSEP Foundation, the EDMUS Foundation, and the National Agency of Research and receiving personal fees from Biogen, Novartis, Alexion, Merck, and MSD outside the submitted work. E.B. has received honoraria and consulting fees from Alexion, Novartis, Sanofi Aventis, Biogen Idec, Genzyme, Merck, Roche, and Teva. C.L-F. reports no disclosure. B.B. serves on scientific advisory board, has received funding for travel and honoraria from Alexion, Biogen, BMS, Janssen, Merck, Novartis, Sanofi, Roche, and Teva. P.B. reports receiving personal fees from Novartis, Biogen, Merck, BMS, Alexion, and Sanofi outside the submitted work. B.S. reports research support from Roche, Sanofi, and Merck and personal fees for lectures or advisory boards from Novartis, Sanofi, Biogen, Janssen, and Merck. P.C. reports receiving personal fees for board participation from Janssen and Novartis and for board participation and travel from Sanofi and Merck outside the submitted work. E.T. reports receiving personal fees from Biogen, BMS, Janssen, Horizon, Merck, Novartis, and Sanofi outside the submitted work. E.M. reports no disclosure. T.M. reports receiving travel grants and fees for advisory boards from Biogen, Roche, Novartis, Sanofi, and Teva outside the submitted work. F.S. reports receiving consulting and/or lecture fees and/or travel funding from Novartis-Pharma, Biogen, Roche, Sanofi, Linde, and LVL. M.Z. reports receiving expert testimony from Alexion and Novartis, and travel grants from Merck, Roche, and Sanofi Aventis France. C.P. reports receiving honoraria and consulting fees from Alexion, Biogen, Merck, Horizon, and Roche outside the submitted work and serving as president of the Francophone Multiple Sclerosis Society from 2021 to 2024. C.L. has received consulting or travel fees from Biogen, Novartis, Roche, Sanofi, Teva, and Merck Serono, and research grant from Biogen.

Importance: Moderately effective therapies (METs) have been the main treatment in pediatric-onset multiple sclerosis (POMS) for years. Despite the expanding use of highly effective therapies (HETs), treatment strategies for POMS still lack consensus., Objective: To assess the real-world association of HET as an index treatment compared with MET with disease activity., Design, Setting, and Participants: This was a retrospective cohort study conducted from January 1, 2010, to December 8, 2022, until the last recorded visit. The median follow-up was 5.8 years. A total of 36 French MS centers participated in the Observatoire Français de la Sclérose en Plaques (OFSEP) cohort. Of the total participants in OFSEP, only treatment-naive children with relapsing-remitting POMS who received a first HET or MET before adulthood and at least 1 follow-up clinical visit were included in the study. All eligible participants were included in the study, and none declined to participate., Exposure: HET or MET at treatment initiation., Main Outcomes and Measures: The primary outcome was the time to first relapse after treatment. Secondary outcomes were annualized relapse rate (ARR), magnetic resonance imaging (MRI) activity, time to Expanded Disability Status Scale (EDSS) progression, tertiary education attainment, and treatment safety/tolerability. An adapted statistical method was used to model the logarithm of event rate by penalized splines of time, allowing adjustment for effects of covariates that is sensitive to nonlinearity and interactions., Results: Of the 3841 children (5.2% of 74 367 total participants in OFSEP), 530 patients (mean [SD] age, 16.0 [1.8] years; 364 female [68.7%]) were included in the study. In study patients, both treatment strategies were associated with a reduced risk of first relapse within the first 2 years. HET dampened disease activity with a 54% reduction in first relapse risk (adjusted hazard ratio [HR], 0.46; 95% CI, 0.31-0.67; P < .001) sustained over 5 years, confirmed on MRI activity (adjusted odds ratio [OR], 0.34; 95% CI, 0.18-0.66; P = .001), and with a better tolerability pattern than MET. The risk of discontinuation at 2 years was 6 times higher with MET (HR, 5.97; 95% CI, 2.92-12.20). The primary reasons for treatment discontinuation were lack of efficacy and intolerance. Index treatment was not associated with EDSS progression or tertiary education attainment (adjusted OR, 0.51; 95% CI, 0.24-1.10; P = .09)., Conclusions and Relevance: Results of this cohort study suggest that compared with MET, initial HET in POMS was associated with a reduction in the risk of first relapse with an optimal outcome within the first 2 years and was associated with a lower rate of treatment switching and a better midterm tolerance in children. These findings suggest prioritizing initial HET in POMS, although long-term safety studies are needed.

Objective: To determine the prognostic value of persisting neuroinflammation in multiple sclerosis (MS) lesions, we developed a 18 kDa-translocator-protein-positron emission tomography (PET) -based classification of each lesion according to innate immune cell content and localization. We assessed the respective predictive value of lesion phenotype and diffuse inflammation on atrophy and disability progression over 2 years., Methods: Thirty-six people with MS (disease duration 9 ± 6 years; 12 with relapsing-remitting, 13 with secondary-progressive, and 11 with primary-progressive) and 19 healthy controls (HCs) underwent a dynamic [ 18 F]-DPA-714-PET. At baseline and after 2 years, the patients also underwent a magnetic resonance imaging (MRI) and neurological examination. Based on a threshold of significant inflammation defined by a comparison of [ 18 F]-DPA-714 binding between patients with MS and HCs, white matter lesions were classified as homogeneously active (active center), rim-active (inactive center and active periphery), or nonactive. Longitudinal cortical atrophy was measured using Jacobian integration., Results: Patients with MS had higher innate inflammation in normal-appearing white matter (NAWM) and cortex than HCs (respective standardized effect size = 1.15, 0.89, p = 0.003 and < 0.001). Out of 1,335 non-gadolinium-enhancing lesions, 53% were classified as homogeneously-active (median = 17 per patient with MS), 6% rim-active (median = 1 per patient with MS), and 41% non-active (median = 14 per patient with MS). The number of homogenously-active lesions was the strongest predictor of longitudinal changes, associating with cortical atrophy (β = 0.49, p = 0.023) and Expanded Disability Status Scale (EDSS) changes (β = 0.35, p = 0.023) over 2 years. NAWM and cortical binding were not associated to volumetric and clinical changes., Interpretation: The [ 18 F]-DPA-714-PET revealed that an unexpectedly high proportion of MS lesions have a smoldering component, which predicts atrophy and clinical progression. This suggests that following the acute phase, most lesions develop a chronic inflammatory component, promoting neurodegeneration and clinical progression. ANN NEUROL 2023;94:366-383., (© 2023 The Authors. Annals of Neurology published by Wiley Periodicals LLC on behalf of American Neurological Association.)

Purpose of Review: Choroid plexuses (ChPs) are key actors of the blood-to-cerebrospinal-fluid barrier and serve as brain immune checkpoint. The past years have seen a regain of interest about their potential involvement in the physiopathology of neuroinflammatory disorders like multiple sclerosis (MS). This article offers an overview of the recent findings on ChP alterations in MS, with a focus on the imaging tools able to detect these abnormalities and on their involvement in inflammation, tissue damage and repair., Recent Findings: On MRI, ChPs are enlarged in people with MS (PwMS) versus healthy individuals. This size increase is an early event, already detected in presymptomatic and pediatric MS. Enlargement of ChPs is linked to local inflammatory infiltrates, and their dysfunction selectively impacts periventricular damage, larger ChPs predicting the expansion of chronic active lesions, smoldering inflammation and remyelination failure in tissues surrounding the ventricles. ChP volumetry may add value for the prediction of disease activity and disability worsening., Summary: ChP imaging metrics are emerging as possible biomarkers of neuroinflammation and repair failure in MS. Future works combining multimodal imaging techniques should provide a more refined characterization of ChP functional changes, their link with tissue damage, blood to cerebrospinal-fluid barrier dysfunction and fluid trafficking in MS., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

MRI and clinical features of myelin oligodendrocyte glycoprotein (MOG)-antibody disease may overlap with those of other inflammatory demyelinating conditions posing diagnostic challenges, especially in non-acute phases and when serologic testing for MOG antibodies is unavailable or shows uncertain results. We aimed to identify MRI and clinical markers that differentiate non-acute MOG-antibody disease from aquaporin 4 (AQP4)-antibody neuromyelitis optica spectrum disorder and relapsing remitting multiple sclerosis, guiding in the identification of patients with MOG-antibody disease in clinical practice. In this cross-sectional retrospective study, data from 16 MAGNIMS centres were included. Data collection and analyses were conducted from 2019 to 2021. Inclusion criteria were: diagnosis of MOG-antibody disease; AQP4-neuromyelitis optica spectrum disorder and multiple sclerosis; brain and cord MRI at least 6 months from relapse; and Expanded Disability Status Scale (EDSS) score on the day of MRI. Brain white matter T2 lesions, T1-hypointense lesions, cortical and cord lesions were identified. Random forest models were constructed to classify patients as MOG-antibody disease/AQP4-neuromyelitis optica spectrum disorder/multiple sclerosis; a leave one out cross-validation procedure assessed the performance of the models. Based on the best discriminators between diseases, we proposed a guide to target investigations for MOG-antibody disease. One hundred and sixty-two patients with MOG-antibody disease [99 females, mean age: 41 (±14) years, median EDSS: 2 (0-7.5)], 162 with AQP4-neuromyelitis optica spectrum disorder [132 females, mean age: 51 (±14) years, median EDSS: 3.5 (0-8)], 189 with multiple sclerosis (132 females, mean age: 40 (±10) years, median EDSS: 2 (0-8)] and 152 healthy controls (91 females) were studied. In young patients (<34 years), with low disability (EDSS < 3), the absence of Dawson's fingers, temporal lobe lesions and longitudinally extensive lesions in the cervical cord pointed towards a diagnosis of MOG-antibody disease instead of the other two diseases (accuracy: 76%, sensitivity: 81%, specificity: 84%, P < 0.001). In these non-acute patients, the number of brain lesions < 6 predicted MOG-antibody disease versus multiple sclerosis (accuracy: 83%, sensitivity: 82%, specificity: 83%, P < 0.001). An EDSS < 3 and the absence of longitudinally extensive lesions in the cervical cord predicted MOG-antibody disease versus AQP4-neuromyelitis optica spectrum disorder (accuracy: 76%, sensitivity: 89%, specificity: 62%, P < 0.001). A workflow with sequential tests and supporting features is proposed to guide better identification of patients with MOG-antibody disease. Adult patients with non-acute MOG-antibody disease showed distinctive clinical and MRI features when compared to AQP4-neuromyelitis optica spectrum disorder and multiple sclerosis. A careful inspection of the morphology of brain and cord lesions together with clinical information can guide further analyses towards the diagnosis of MOG-antibody disease in clinical practice., (© The Author(s) 2022. Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

In multiple sclerosis, while remarkable progress has been accomplished to control the inflammatory component of the disease, repair of demyelinated lesions is still an unmet need. Despite encouraging results generated in experimental models, several candidates favouring or promoting remyelination have not reached the expected outcomes in clinical trials. One possible reason for these failures is that, in most cases, during preclinical testing, efficacy was evaluated on histology only, while functional recovery had not been assessed. We have generated a Xenopus laevis transgenic model Tg(mbp:GFP-NTR) of conditional demyelination in which spontaneous remyelination can be accelerated using candidate molecules. Xenopus laevis is a classic model for in vivo studies of myelination because tadpoles are translucent. We reasoned that demyelination should translate into loss of sensorimotor functions followed by behavioural recovery upon remyelination. To this end, we measured the swimming speed and distance travelled before and after demyelination and during the ongoing spontaneous remyelination and have developed a functional assay based on the visual avoidance of a virtual collision. Here we show that alteration of these functional and clinical performances correlated well with the level of demyelination and that histological remyelination, assayed by counting in vivo the number of myelinating oligodendrocytes in the optic nerve, translated in clinical-functional recovery. This method was further validated in tadpoles treated with pro-remyelinating agents (clemastine, siponimod) showing that increased remyelination in the optic nerve was associated with functional improvement. Our data illustrate the potential interest of correlating histopathological parameters and functional-clinical parameters to screen molecules promoting remyelination in a simple in vivo model of conditional demyelination., (© The Author(s) 2023. Published by Oxford University Press on behalf of the Guarantors of Brain.)

Background and Objectives: The question of the long-term safety of pregnancy is a major concern in patients with multiple sclerosis (MS), but its study is biased by reverse causation (women with higher disability are less likely to experience pregnancy). Using a causal inference approach, we aimed to estimate the unbiased long-term effects of pregnancy on disability and relapse risk in patients with MS and secondarily the short-term effects (during the perpartum and postpartum years) and delayed effects (occurring beyond 1 year after delivery)., Methods: We conducted an observational cohort study with data from patients with MS followed in the Observatoire Français de la Sclérose en Plaques registry between 1990 and 2020. We included female patients with MS aged 18-45 years at MS onset, clinically followed up for more than 2 years, and with ≥3 Expanded Disease Status Scale (EDSS) measurements. Outcomes were the mean EDSS score at the end of follow-up and the annual probability of relapse during follow-up. Counterfactual outcomes were predicted using the longitudinal targeted maximum likelihood estimator in the entire study population. The patients exposed to at least 1 pregnancy during their follow-up were compared with the counterfactual situation in which, contrary to what was observed, they would not have been exposed to any pregnancy. Short-term and delayed effects were analyzed from the first pregnancy of early-exposed patients (who experienced it during their first 3 years of follow-up)., Results: We included 9,100 patients, with a median follow-up duration of 7.8 years, of whom 2,125 (23.4%) patients were exposed to at least 1 pregnancy. Pregnancy had no significant long-term causal effect on the mean EDSS score at 9 years (causal mean difference [95% CI] = 0.00 [-0.16 to 0.15]) or on the annual probability of relapse (causal risk ratio [95% CI] = 0.95 [0.93-1.38]). For the 1,253 early-exposed patients, pregnancy significantly decreased the probability of relapse during the perpartum year and significantly increased it during the postpartum year, but no significant delayed effect was found on the EDSS and relapse rate., Discussion: Using a causal inference approach, we found no evidence of significantly deleterious or beneficial long-term effects of pregnancy on disability. The beneficial effects found in other studies were probably related to a reverse causation bias., (© 2022 American Academy of Neurology.)

Background: In relapsing-remitting multiple sclerosis (RRMS), early identification of suboptimal responders can prevent disability progression., Objective: We aimed to develop and validate a dynamic score to guide the early decision to switch from first- to second-line therapy., Methods: Using time-dependent propensity scores (PS) from a French cohort of 12,823 patients with RRMS, we constructed one training and two validation PS-matched cohorts to compare the switched patients to second-line treatment and the maintained patients. We used a frailty Cox model for predicting individual hazard ratios (iHRs)., Results: From the validation PS-matched cohort of 348 independent patients with iHR ⩽ 0.69, we reported the 5-year relapse-free survival at 0.14 (95% confidence interval (CI) 0.09-0.22) for the waiting group and 0.40 (95% CI 0.32-0.51) for the switched group. From the validation PS-matched cohort of 518 independent patients with iHR > 0.69, these values were 0.37 (95% CI 0.30-0.46) and 0.44 (95% CI 0.37-0.52), respectively., Conclusions: By using the proposed dynamic score, we estimated that at least one-third of patients could benefit from an earlier switch to prevent relapse.

In multiple sclerosis, spontaneous remyelination is generally incomplete and heterogeneous across patients. A high heterogeneity in remyelination may also exist across lesions within the same individual, suggesting the presence of local factors interfering with myelin regeneration. In this study we explored in vivo the regional distribution of myelin repair and investigated its relationship with neurodegeneration. We first took advantage of the myelin binding property of the amyloid radiotracer 11C-PiB to conduct a longitudinal 11C-PiB PET study in an original cohort of 19 participants with a relapsing-remitting form of multiple sclerosis, followed-up over a period of 1-4 months. We then replicated our results on an independent cohort of 40 people with multiple sclerosis followed-up over 1 year with magnetization transfer imaging, an MRI metrics sensitive to myelin content. For each imaging method, voxel-wise maps of myelin content changes were generated according to modality-specific thresholds. We demonstrated a selective failure of remyelination in periventricular white matter lesions of people with multiple sclerosis in both cohorts. In both the original and the replication cohort, we estimated that the probability of demyelinated voxels to remyelinate over the follow-up increased significantly as a function of the distance from ventricular CSF. Enlarged choroid plexus, a recently discovered biomarker linked to neuroinflammation, was found to be associated with the periventricular failure of remyelination in the two cohorts (r = -0.79, P = 0.0018; r = -0.40, P = 0.045, respectively), suggesting a role of the brain-CSF barrier in affecting myelin repair in surrounding tissues. In both cohorts, the failure of remyelination in periventricular white matter lesions was associated with lower thalamic volume (r = 0.86, P < 0.0001; r = 0.33; P = 0.069, respectively), an imaging marker of neurodegeneration. Interestingly, we also showed an association between the periventricular failure of remyelination and regional cortical atrophy that was mediated by the number of cortex-derived tracts passing through periventricular white matter lesions, especially in patients at the relapsing-remitting stage. Our findings demonstrate that lesion proximity to ventricles is associated with a failure of myelin repair and support the hypothesis that a selective periventricular remyelination failure in combination with the large number of tracts connecting periventricular lesions with cortical areas is a key mechanism contributing to cortical damage in multiple sclerosis., (© The Author(s) 2022. Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Choroid Plexuses (ChP) are structures located in the ventricles that produce the cerebrospinal fluid (CSF) in the central nervous system. They are also a key component of the blood-CSF barrier. Recent studies have described clinically relevant ChP volumetric changes in several neurological diseases including Alzheimer's, Parkinson's disease, and multiple sclerosis (MS). Therefore, a reliable and automated tool for ChP segmentation on images derived from magnetic resonance imaging (MRI) is a crucial need for large studies attempting to elucidate their role in neurological disorders. Here, we propose a novel automatic method for ChP segmentation in large imaging datasets. The approach is based on a 2-step 3D U-Net to keep preprocessing steps to a minimum for ease of use and to lower memory requirements. The models are trained and validated on a first research cohort including people with MS and healthy subjects. A second validation is also performed on a cohort of pre-symptomatic MS patients having acquired MRIs in routine clinical practice. Our method reaches an average Dice coefficient of 0.72 ± 0.01 with the ground truth and a volume correlation of 0.86 on the first cohort while outperforming FreeSurfer and FastSurfer-based ChP segmentations. On the dataset originating from clinical practice, the method reaches a Dice coefficient of 0.67 ± 0.01 (being close to the inter-rater agreement of 0.64 ± 0.02) and a volume correlation of 0.84. These results demonstrate that this is a suitable and robust method for the segmentation of the ChP both on research and clinical datasets., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.)

Background: Progressive multifocal leukoencephalopathy (PML) is a rare and often lethal brain disorder caused by the common, typically benign polyomavirus 2, also known as JC virus (JCV). In a small percentage of immunosuppressed individuals, JCV is reactivated and infects the brain, causing devastating neurological defects. A wide range of immunosuppressed groups can develop PML, such as patients with: HIV/AIDS, hematological malignancies (e.g., leukemias, lymphomas, and multiple myeloma), autoimmune disorders (e.g., psoriasis, rheumatoid arthritis, and systemic lupus erythematosus), and organ transplants. In some patients, iatrogenic (i.e., drug-induced) PML occurs as a serious adverse event from exposure to immunosuppressant therapies used to treat their disease (e.g., hematological malignancies and multiple sclerosis). While JCV infection and immunosuppression are necessary, they are not sufficient to cause PML., Methods: We hypothesized that patients may also have a genetic susceptibility from the presence of rare deleterious genetic variants in immune-relevant genes (e.g., those that cause inborn errors of immunity). In our prior genetic study of 184 PML cases, we discovered 19 candidate PML risk variants. In the current study of another 152 cases, we validated 4 of 19 variants in both population controls (gnomAD 3.1) and matched controls (JCV+ multiple sclerosis patients on a PML-linked drug ≥ 2 years)., Results: The four variants, found in immune system genes with strong biological links, are: C8B , 1-57409459-C-A, rs139498867; LY9 (alias SLAMF3 ), 1-160769595-AG-A, rs763811636; FCN2 , 9-137779251-G-A, rs76267164; STXBP2 , 19-7712287-G-C, rs35490401. Carriers of any one of these variants are shown to be at high risk of PML when drug-exposed PML cases are compared to drug-exposed matched controls: P value = 3.50E-06, OR = 8.7 [3.7-20.6]. Measures of clinical validity and utility compare favorably to other genetic risk tests, such as BRCA1 and BRCA2 screening for breast cancer risk and HLA-B * 15:02 pharmacogenetic screening for pharmacovigilance of carbamazepine to prevent Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis., Conclusion: For the first time, a PML genetic risk test can be implemented for screening patients taking or considering treatment with a PML-linked drug in order to decrease the incidence of PML and enable safer use of highly effective therapies used to treat their underlying disease., Competing Interests: Authors CB and CC are employed by Emerald Lake Safety LLC. Authors EH, ES, PE, and SJ are employed by Population Bio, Inc. Author TR is employed by Richmond Bioinformatics Consulting and author DR is employed by Lytic Solutions, LLC. Authors HW, IK, NS, and RL received funding from PML Screening, LLC to partially offset the costs for collection, and clinical characterization of patient samples used in the research. Authors EH, ES, PE, and YT are inventors of genetic screening methods for PML risk and have issued and pending patents related to this work. Applicants/Assignees on issued patents are: PML Screening, LLC, Newport Beach, CA (US), a joint venture between Population Bio, Inc. and Emerald Lake Safety LLC; Université Paris-Saclay, Gif sur Yvette (FR); The Assistance Publique-Hôpitaux de Paris (APHP), Paris (FR); and The Institut National de la Santé et de la Recherche Médicale (INSERM), Paris (FR). Author IC is a shareholder in Keires AG, Nouscom AG, and PDC*line Pharma. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The authors declare that this study received funding from PML Screening, LLC. The funders had the following involvement with the study: conception and design of the study, laboratory experiments, data analysis and interpretation, and wrote the manuscript., (Copyright © 2022 Hatchwell, Smith, Jalilzadeh, Bruno, Taoufik, Hendel-Chavez, Liblau, Brassat, Martin-Blondel, Wiendl, Schwab, Cortese, Monaco, Imberti, Capra, Oksenberg, Gasnault, Stankoff, Richmond, Rancour, Koralnik, Hanson, Major, Chow and Eis.)

Detecting new lesions is a key aspect of the radiological follow-up of patients with Multiple Sclerosis (MS), leading to eventual changes in their therapeutics. This paper presents our contribution to the MSSEG-2 MICCAI 2021 challenge. The challenge is focused on the segmentation of new MS lesions using two consecutive Fluid Attenuated Inversion Recovery (FLAIR) Magnetic Resonance Imaging (MRI). In other words, considering longitudinal data composed of two time points as input, the aim is to segment the lesional areas, which are present only in the follow-up scan and not in the baseline. The backbone of our segmentation method is a 3D UNet applied patch-wise to the images, and in which, to take into account both time points, we simply concatenate the baseline and follow-up images along the channel axis before passing them to the 3D UNet. Our key methodological contribution is the use of online hard example mining to address the challenge of class imbalance. Indeed, there are very few voxels belonging to new lesions which makes training deep-learning models difficult. Instead of using handcrafted priors like brain masks or multi-stage methods, we experiment with a novel modification to online hard example mining (OHEM), where we use an exponential moving average (i.e., its weights are updated with momentum) of the 3D UNet to mine hard examples. Using a moving average instead of the raw model should allow smoothing of its predictions and allow it to give more consistent feedback for OHEM., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Schmidt-Mengin, Soulier, Hamzaoui, Yazdan-Panah, Bodini, Ayache, Stankoff and Colliot.)

Background and Objectives: To evaluate the rate of return of disease activity after cessation of multiple sclerosis (MS) disease-modifying therapy., Methods: This was a retrospective cohort study from 2 large observational MS registries: MSBase and OFSEP. Patients with relapsing-remitting MS who had ceased a disease-modifying therapy and were followed up for the subsequent 12 months were included in the analysis. The primary study outcome was annualized relapse rate in the 12 months after disease-modifying therapy discontinuation stratified by patients who did, and did not, commence a subsequent therapy. The secondary endpoint was the predictors of first relapse and disability accumulation after treatment discontinuation., Results: A total of 14,213 patients, with 18,029 eligible treatment discontinuation epochs, were identified for 7 therapies. Annualized rates of relapse (ARRs) started to increase 2 months after natalizumab cessation (month 2-4 ARR 0.47, 95% CI 0.43-0.51). Commencement of a subsequent therapy within 2-4 months reduced the magnitude of disease reactivation (mean ARR difference: 0.15, 0.08-0.22). After discontinuation of fingolimod, rates of relapse increased overall (month 1-2 ARR: 0.80, 0.70-0.89) and stabilized faster in patients who started a new therapy within 1-2 months (mean ARR difference: 0.14, -0.01 to 0.29). The magnitude of disease reactivation for other therapies was low but reduced further by commencement of another treatment 1-10 months after treatment discontinuation. Predictors of relapse were a higher relapse rate in the year before cessation, female sex, younger age, and higher EDSS score. Commencement of a subsequent therapy reduced both the risk of relapse (HR 0.76, 95% CI 0.72-0.81) and disability accumulation (0.73, 0.65-0.80)., Discussion: The rate of disease reactivation after treatment cessation differs among MS treatments, with the peaks of relapse activity ranging from 1 to 10 months in untreated cohorts that discontinued different therapies. These results suggest that untreated intervals should be minimized after stopping antitrafficking therapies (natalizumab and fingolimod)., Classification of Evidence: This study provides Class III that disease reactivation occurs within months of discontinuation of MS disease-modifying therapies. The risk of disease activity is reduced by commencement of a subsequent therapy., (© 2022 American Academy of Neurology.)

Background and Objectives: Recent imaging studies have suggested a possible involvement of the choroid plexus (CP) in multiple sclerosis (MS). Here, we investigated whether CP changes are already detectable at the earliest stage of MS, preceding symptom onset., Methods: This study is a retrospective analysis of 27 patients with presymptomatic MS, 97 patients with clinically definite MS (CDMS), and 53 healthy controls (HCs) who underwent a cross-sectional 3T-MRI acquisition; of which, 22 MS, 19 HCs, and 1 presymptomatic MS (evaluated 8 months before conversion to CDMS) also underwent translocator protein (TSPO) 18 F-DPA-714 PET and were included in the analysis. CPs were manually segmented on 3D T1-weighted images for volumetric analysis. CP 18 F-DPA-714 uptake, reflecting inflammation, was calculated as the average standardized uptake value (SUV). Multivariable regressions adjusted for age, sex, and ventricular and brain volume were fitted to test CP volume differences between presymptomatic patients and MS or HCs. For the presymptomatic case who also had 18 F-DPA-714 PET, CP SUV differences with MS and HCs were assessed through Crawford-Howell tests. To provide further insight into the interpretation of 18 F-DPA-714-PET uptake at the CP level, a postmortem analysis of CPs in MS vs HCs was performed to characterize the cellular localization of TSPO expression., Results: Compared with HCs, patients with presymptomatic MS had 32% larger CPs (β = 0.38, p = 0.001), which were not dissimilar to MS CPs ( p = 0.69). Moreover, in the baseline scan of the presymptomatic case who later on developed MS, TSPO PET showed 33% greater CP inflammation vs HCs ( p = 0.04), although no differences in 18 F-DPA-714 uptake were found in parenchymal regions vs controls. CP postmortem analysis identified a population of CD163 + mononuclear phagocytes expressing TSPO in MS, possibly contributing to the increased 18 F-DPA-714 uptake., Discussion: We identified an imaging signature in CPs at the presymptomatic MS stage using MRI; in addition, we found an increased CP inflammation with PET in a single presymptomatic patient. These findings suggest a role of CP imaging as an early biomarker and argue for the involvement of the blood-CSF barrier dysfunction in disease development., Trial Registration Information: APHP-20210727144630, EudraCT-Number: 2008-004174-40; ClinicalTrials.gov: NCT02305264, NCT01651520, and NCT02319382., (Copyright © 2022 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology.)

Objective: To investigate the clinical relevance of individual profiles of cortical and white matter lesion myelin content changes combining magnetisation transfer imaging (MTI) and 11C-PiB-positron emission tomography (PET) in patients with multiple sclerosis (MS)., Methods: MTI and [ 11 C]PiB-PET acquired in 19 patients with MS followed up over 2-4 months and in seven healthy controls (HCs), were employed to generate individual maps of cortical and white matter (WM) lesion myelin content changes, respectively. These maps were used to calculate individual indices of demyelination and remyelination, and to investigate their association with clinical scores., Results: Cortical remyelination ranged between 1% and 5% of the total cortical volume (17%-45% of the cortical volume demyelinated at baseline). WM lesion remyelination ranged between 8% and 22% of the lesional volume. An extensive cortical remyelination was associated with a shorter disease duration (rho = -0.63, p  = 0.01) and, in combination with WM lesion remyelination, explained 68%-70% of the variance of clinical scores ( p  < 0.01)., Conclusion: Our multimodal and multicompartment approach allows us to explore single-patient cortical and WM lesion demyelination and remyelination, and to generate clinically relevant indices of myelin repair. These indices may be used as outcome measures in clinical trials, thus increasing the chance to identify successful promyelinating treatments in patients with MS.

Meningeal lymphatic vessels (MLVs) were identified in the dorsal and caudobasal regions of the dura mater, where they ensure waste product elimination and immune surveillance of brain tissues. Whether MLVs exist in the anterior part of the murine and human skull and how they connect with the glymphatic system and extracranial lymphatics remained unclear. Here, we used light-sheet fluorescence microscopy (LSFM) imaging of mouse whole-head preparations after OVA-A555 tracer injection into the cerebrospinal fluid (CSF) and performed real-time vessel-wall (VW) magnetic resonance imaging (VW-MRI) after systemic injection of gadobutrol in patients with neurological pathologies. We observed a conserved three-dimensional anatomy of MLVs in mice and humans that aligned with dural venous sinuses but not with nasal CSF outflow, and we discovered an extended anterior MLV network around the cavernous sinus, with exit routes through the foramina of emissary veins. VW-MRI may provide a diagnostic tool for patients with CSF drainage defects and neurological diseases., (© 2022 Jacob et al.)

Over the recent years, the treatment of multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD) has evolved very rapidly and a large number of disease-modifying treatments (DMTs) are now available. However, most DMTs are associated with adverse events, the most frequent of which being infections. Consideration of all DMT-associated risks facilitates development of risk mitigation strategies. An international focused workshop with expert-led discussions was sponsored by the European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS) and was held in April 2021 to review our current knowledge about the risk of infections associated with the use of DMTs for people with MS and NMOSD and corresponding risk mitigation strategies. The workshop addressed DMT-associated infections in specific populations, such as children and pregnant women with MS, or people with MS who have other comorbidities or live in regions with an exceptionally high infection burden. Finally, we reviewed the topic of DMT-associated infectious risks in the context of the current SARS-CoV-2 pandemic. Herein, we summarize available evidence and identify gaps in knowledge which justify further research.

Background and Purpose: Lesion remyelination preserves axonal integrity in animal models of multiple sclerosis (MS), but an in vivo demonstration of its protective effect on surrounding tissues in humans is lacking., Methods: Nineteen persons with MS were enrolled in a cohort study and underwent two positron emission tomography (PET)/magnetic resonance imaging (MRI) scans 1-4 months apart. Voxelwise maps of Pittsburgh compound B distribution volume ratio, reflecting myelin content, were used to calculate an index of baseline demyelination, and of dynamic demyelination and remyelination over the follow-up in 549 single white matter lesions. Changes in fractional anisotropy and mean diffusivity, reflecting microstructural damage, were calculated in the proximal and distal 3-mm-thick rings surrounding each lesion, and used to classify perilesional microstructure as "preserved" or "worsening" over the follow-up. Mixed-effect linear models and logistic regressions were employed to investigate whether PET-derived lesional indices were associated with changes in MRI metrics in perilesions, and to identify which of them best predicted the microstructural evolution of perilesions over time., Results: A higher index of remyelination, and a lower index of baseline and dynamic demyelination in lesions were associated with a less severe microstructural deterioration of the corresponding proximal and distal perilesions over time (p-value range: <0.001-0.012), but the index of remyelination was the best predicting variable of perilesional fate. For every extra 1% of remyelination within each lesion, the probability of the corresponding perilesional microstructure remaining preserved over time increased by 39% (odds ratio = 6.62, 95% confidence interval = 2.16-20.32, p < 0.001)., Conclusions: Intralesional remyelination is associated with the microstructural preservation of surrounding tissues, possibly preventing neuroaxonal damage resulting from Wallerian degeneration., (© 2022 European Academy of Neurology.)

"Multiple sclerosis: what therapeutic perspectives? Three phenomena, which may be interrelated, are at the origin of the accumulation of disability in multiple sclerosis: remyelination defect, persistence of chronic microglial inflammation and neuro¬degeneration. Identifying the molecular and cellular mechanisms and being able to follow them in vivo by advanced imaging repre¬sent a major research challenge for the coming years. Several translational pharmacological avenues have already led to clinical trials targeting remyelination, neuroprotection and control of mi¬croglial activation; however, an optimized methodology with rele¬vant endpoints remains to be defined.", Competing Interests: "C. Louapre déclare avoir des liens d’intérêts avec Biogen, Novartis, Merck, Roche, Teva, Sanofi. B. Stankoff déclare avoir des liens d’intérêts avec Roche, Biogen, Novartis, Merck et Sanofi. B. Bodini déclare avoir des liens d’intérêts avec Biogen, Novartis, Merck, Roche et Sanofi."

Background and Objectives: Siponimod is an oral, selective sphingosine-1-phosphate receptor-1/5 modulator approved for treatment of multiple sclerosis., Methods: Mouse MRI was used to investigate remyelination in the cuprizone model. We then used a conditional demyelination Xenopus laevis model to assess the dose-response of siponimod on remyelination. In experimental autoimmune encephalomyelitis-optic neuritis (EAEON) in C57Bl/6J mice, we monitored the retinal thickness and the visual acuity using optical coherence tomography and optomotor response. Optic nerve inflammatory infiltrates, demyelination, and microglial and oligodendroglial differentiation were assessed by immunohistochemistry, quantitative real-time PCR, and bulk RNA sequencing., Results: An increased remyelination was observed in the cuprizone model. Siponimod treatment of demyelinated tadpoles improved remyelination in comparison to control in a bell-shaped dose-response curve. Siponimod in the EAEON model attenuated the clinical score, reduced the retinal degeneration, and improved the visual function after prophylactic and therapeutic treatment, also in a bell-shaped manner. Inflammatory infiltrates and demyelination of the optic nerve were reduced, the latter even after therapeutic treatment, which also shifted microglial differentiation to a promyelinating phenotype., Discussion: These results confirm the immunomodulatory effects of siponimod and suggest additional regenerative and promyelinating effects, which follow the dynamics of a bell-shaped curve with high being less efficient than low concentrations., (Copyright © 2022 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology.)

In France, two therapeutic strategies can be offered after fingolimod (FNG) withdrawal to highly active relapsing-remitting multiple sclerosis (RRMS) patients: natalizumab (NTZ) or anti-CD20. We compared the effectiveness of these two strategies as a switch for FNG within the OFSEP database. The primary endpoint was the time to first relapse. Other outcomes were the relapse rates over 3-month periods, time to worsening the EDSS score, proportion of patients with worsened 24-month MRI, time to treatment discontinuation, and incidence rates of serious adverse events. The dynamics of event rates over time were modeled using multidimensional penalized splines, allowing the possibility to model the effects of covariates in a flexible way, considering non-linearity and interactions. A total of 740 patients were included (337 under anti-CD20 and 403 under NTZ). There was no difference between the two treatments regarding the dynamic of the first occurrence of relapse, with a monthly probability of 5.0% at initiation and 1.0% after 6 months. The rate of EDSS worsening increased in both groups until 6 months and then decreased. No difference in the proportion of patients with new T2 lesions at 24 months was observed. After 18 months of follow-up, a greater risk of NTZ discontinuation was found compared to anti-CD20. This study showed no difference between NTZ and anti-CD20 after the FNG switch regarding the clinical and radiological activity. The effect of these treatments was optimal after 6 months and there was more frequent discontinuation of NTZ after 18 months, probably mainly related to JC virus seroconversions., (© 2022. The American Society for Experimental NeuroTherapeutics, Inc.)

Using a philosophical approach or deductive reasoning, we challenge the dominant clinico-radiological worldview that defines multiple sclerosis (MS) as a focal inflammatory disease of the central nervous system (CNS). We provide a range of evidence to argue that the 'real MS' is in fact driven primarily by a smouldering pathological disease process. In natural history studies and clinical trials, relapses and focal activity revealed by magnetic resonance imaging (MRI) in MS patients on placebo or on disease-modifying therapies (DMTs) were found to be poor predictors of long-term disease evolution and were dissociated from disability outcomes. In addition, the progressive accumulation of disability in MS can occur independently of relapse activity from early in the disease course. This scenario is underpinned by a more diffuse smouldering pathological process that may affect the entire CNS. Many putative pathological drivers of smouldering MS can be potentially modified by specific therapeutic strategies, an approach that may have major implications for the management of MS patients. We hypothesise that therapeutically targeting a state of 'no evident inflammatory disease activity' (NEIDA) cannot sufficiently prevent disability accumulation in MS, meaning that treatment should also focus on other brain and spinal cord pathological processes contributing to the slow loss of neurological function. This should also be complemented with a holistic approach to the management of other systemic disease processes that have been shown to worsen MS outcomes., Competing Interests: Conflict of interest statement: In the last 5 years, Gavin Giovannoni has received compensation for serving as a consultant or speaker for or has received research support from AbbVie, Aslan, Atara Bio, Biogen, BMS-Celgene, GlaxoSmithKline, GW Pharma, Janssens/Actelion, Japanese Tobacco, Jazz Pharmaceuticals, LifNano, Merck & Co, Merck KGaA/EMD Serono, Novartis, Sanofi-Genzyme, Roche/Genentech and Teva. Sanofi Genzyme kindly provided financial support to help adapt and design the figures and for a third party to help coordinate the submission of the manuscript., (© The Author(s), 2022.)

Background: SARS-CoV-2 seroconversion rate after COVID-19 may be influenced by disease-modifying therapies (DMTs) in patients with multiple sclerosis (MS) or neuromyelitis optica spectrum disorders (NMO-SD)., Objective: To investigate the seroprevalence and the quantity of SARS-CoV-2 antibodies in a cohort of patients with MS or NMO-SD., Methods: Blood samples were collected in patients diagnosed with COVID-19 between 19 February 2020 and 26 February 2021. SARS-CoV-2 antibody positivity rates and Ig levels (anti-S IgG titre, anti-S IgA index, anti-N IgG index) were compared between DMTs groups. Multivariate logistic and linear regression models were used to estimate the influence of DMTs and other confounding variables on SARS-CoV-2 serological outcomes., Results: 119 patients (115 MS, 4 NMO, mean age: 43.0 years) were analysed. Overall, seroconversion rate was 80.6% within 5.0 (SD 3.4) months after infection. 20/21 (95.2%) patients without DMT and 66/77 (85.7%) patients on DMTs other than anti-CD20 had at least one SARS-CoV-2 Ig positivity, while this rate decreased to only 10/21 (47.6%) for patients on anti-CD20 (p<0.001). Being on anti-CD20 was associated with a decreased odd of positive serology (OR, 0.07 (95% CI 0.01 to 0.69), p=0.02) independently from time to COVID-19, total IgG level, age, sex and COVID-19 severity. Time between last anti-CD20 infusion and COVID-19 was longer (mean (SD), 3.7 (2.0) months) in seropositive patients compared with seronegative patients (mean (SD), 1.9 (1.5) months, p=0.04)., Conclusions: SARS-CoV-2 antibody response was decreased in patients with MS or NMO-SD treated with anti-CD20 therapies. Monitoring long-term risk of reinfection and specific vaccination strategies in this population may be warranted., Trial Registration Number: NCT04568707., Competing Interests: Competing interests: Dr Louapre has received consulting or travel fees from Biogen, Novartis, Roche, Sanofi, Teva and Merck Serono, and research grant from Biogen, none related to the present work. Dr Ibrahim has no disclosure. Dr Maillart has received consulting and lecturing fees, travel grants, from Ad Scientiam, Biogen, Genzyme, Novartis, Merck Serono, Roche, Sanofi and Teva Pharma and research support from Biogen, Novartis and Roche, none related to the present work. Dr Abdi has no disclosure. Dr Papeix has received consulting or lecture fees from Alexion, Biogen, Medday, Merck, Roche, Novartis and Sanofi, none related to the present work. Professor Stankoff has received fees for advisory boards and lectures from Genzyme, Novartis, Teva and Biogen, and research support from Roche, Genzyme and Merck-Serono none related to the present work. Dr Dubessy has received consulting fees from Merck. Dr Bensa has received consulting or travel fees from Biogen, Genzyme, Novartis, Roche, Sanofi, Teva and Merck Serono, none related to the present work. Professor Creange has received grants and nonfinancial support from Medday, personal fees from Medday, personal fees from Merck, grants from Octapharma, grants and personal fees from Novartis, grants and personal fees from Roche, and grants and personal fees from Biogen, none related to the present work. Dr Chamekh has no disclosure. Professor Lubetzki has received grants and personal fees from Biogen, personal fees from Merck-Serono, personal fees from Roche, personal fees from Rewind, personal fees from Ipsen, none related to the present work. Professor Marcelin has received consulting fees and grants from VIIV Healthcare, Gilead and Merck, none related to the present work. Professor Corvol has served in advisory boards for Air Liquide, Biogen, Biophytis, Denali, Ever Pharma, Idorsia, Prevail Therapeutic, Theranexus, UCB, and received grants from Sanofi and the Michael J Fox Foundation, none related to the present work. Professor Pourcher has received consulting fees from Biogen, Novartis, Roche and Merck Serono none related to the present work., (© Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

Background and Purpose: Diagnostic criteria for adult onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP) due to colony-stimulating factor 1 receptor (CSF1R) mutation have recently been proposed. Our objective was to assess their accuracy in an independent multicenter cohort., Methods: We evaluated the sensitivity and specificity of the diagnostic criteria for ALSP (including the "probable" and "possible" definitions) in a national cohort of 22 patients with CSF1R mutation, and 59 patients with an alternative diagnosis of adult onset inherited leukoencephalopathy., Results: Overall, the sensitivity of the diagnostic criteria for ALSP was 82%, including nine of 22 patients diagnosed as probable and nine of 22 diagnosed as possible. Twenty of the 59 CSF1R mutation-negative leukoencephalopathies fulfilled the diagnostic criteria, leading to a specificity of 66%., Conclusions: Diagnostic criteria for ALSP have an overall limited sensitivity along with a modest specificity. We suggest that in patients suspected of genetic leukoencephalopathy, a comprehensive magnetic resonance imaging pattern-based approach is warranted, together with white matter gene panel or whole exome sequencing., (© 2021 European Academy of Neurology.)

Background: The spread of Coronavirus disease-19 (COVID-19) poses unique challenges in the management of people with multiple sclerosis (PwMS)., Objectives: To collect data about the impact of COVID-19 emergency on access to care for PwMS and on MS treatment practices., Methods: Between March and July 2020, the European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS) promoted an online survey covering patient access to care, management of relapses and visits, disease-modifying therapy (DMT) and experience with COVID-19., Results: Three-hundred and sixty neurologists from 52 countries (68% from Europe) completed the survey. 98% reported COVID-19-related restrictions. Telemedicine was adopted to overcome the limited access to care and was newly activated (73%) or widely implemented (17%). 70% reported changes in DMT management. Interferons and glatiramer were considered safe. Dimethyl fumarate, teriflunomide and fingolimod were considered safe except for patients developing lymphopenia. No modifications were considered for natalizumab in 64%, cladribine in 24%, anti-CD20 in 22% and alemtuzumab in 17%; 18% (for alemtuzumab and cladribine) and 43% (for anti-CD20) considered postponing treatment., Conclusion: The ECTRIMS survey highlighted the challenges in keeping standards of care in clinical practice. Telemedicine clearly needs to be implemented. Gathering data on DMT safety will remain crucial to inform treatment decisions.

Background: Yellow fever vaccine (YFV) is not advised for multiple sclerosis (MS) patients because of the potential risk of post-vaccine relapses., Objective: To assess the risk of relapsing-remitting multiple sclerosis (RR-MS) worsening after YFV., Methods: Non-interventional observational retrospective, exposed/non-exposed cohort study nested in the French national cohort including MS., Results: 128 RR-MS were included. The 1-year annualized relapse rate (ARR) following YFV did not differ between exposed: 0.219 (0.420) and non-exposed subjects: 0.208 (0.521) ( p  = 0.92). Time to first relapse was not different between groups (adjusted hazard ratio (HR) = 1.33; 95% confidence interval (CI) = 0.53-3.30, p = 0.54)., Conclusion: These results suggest that YFV does not worsen the course of RR-MS.

Following the impressive progress in the treatment of relapsing-remitting multiple sclerosis (MS), the major challenge ahead is the development of treatments to prevent or delay the irreversible accumulation of clinical disability in progressive forms of the disease. The substrate of clinical progression is neuro-axonal degeneration, and a deep understanding of the mechanisms that underlie this process is a precondition for the development of therapies for progressive MS. PET imaging involves the use of radiolabelled compounds that bind to specific cellular and metabolic targets, thereby enabling direct in vivo measurement of several pathological processes. This approach can provide key insights into the clinical relevance of these processes and their chronological sequence during the disease course. In this Review, we focus on the contribution that PET is making to our understanding of extraneuronal and intraneuronal mechanisms that are involved in the pathogenesis of irreversible neuro-axonal damage in MS. We consider the major challenges with the use of PET in MS and the steps necessary to realize clinical benefits of the technique. In addition, we discuss the potential of emerging PET tracers and future applications of existing compounds to facilitate the identification of effective neuroprotective treatments for patients with MS., (© 2021. Springer Nature Limited.)

Introduction: Natalizumab has proved to be more effective than fingolimod in reducing disease activity in relapsing-remitting multiple sclerosis (RRMS). Whether this association is universal for all patient groups remains to be determined., Objective: The aim of this study was to compare the relative effectiveness of natalizumab and fingolimod in RRMS subgroups defined by the baseline demographic and clinical characteristics of interest., Methods: Patients with RRMS who were given natalizumab or fingolimod were identified in a merged cohort from three international registries. Efficacy outcomes were compared across subgroups based on patients' sex, age, disease duration, Expanded Disability Status Scale (EDSS) score, and disease and magnetic resonance imaging (MRI) activity 12 months prior to treatment initiation. Study endpoints were number of relapses (analyzed with weighted negative binomial generalized linear model) and 6-month confirmed disability worsening and improvement events (weighted Cox proportional hazards model), recorded during study therapy. Each patient was weighted using inverse probability of treatment weighting based on propensity score., Results: A total of 5148 patients (natalizumab 1989; fingolimod 3159) were included, with a mean ± standard deviation age at baseline of 38 ± 10 years, and the majority (72%) were women. The median on-treatment follow-up was 25 (quartiles 15-41) months. Natalizumab was associated with fewer relapses than fingolimod (incidence rate ratio [IRR]; 95% confidence interval [CI]) in women (0.76; 0.65-0.88); in those aged ≤ 38 years (0.64; 0.54-0.76); in those with disease duration ≤ 7 years (0.63; 0.53-0.76); in those with EDSS score < 4 (0.75; 0.64-0.88), < 6 (0.80; 0.70-0.91), and ≥ 6 (0.52; 0.31-0.86); and in patients with pre-baseline relapses (0.74; 0.64-0.86). A higher probability of confirmed disability improvement on natalizumab versus fingolimod (hazard ratio [HR]; 95% CI) was observed among women (1.36; 1.10-1.66); those aged > 38 years (1.34; 1.04-1.73); those with disease duration > 7 years (1.33; 1.01-1.74); those with EDSS score < 6 (1.21; 1.01-1.46) and ≥ 6 (1.93; 1.11-3.34); and patients with no new MRI lesion (1.73; 1.19-2.51)., Conclusions: Overall, in women, younger patients, those with shorter disease durations, and patients with pre-treatment relapses, natalizumab was associated with a lower frequency of multiple sclerosis relapses than fingolimod. It was also associated with an increased chance of recovery from disability among most patients, particularly women and those with no recent MRI activity., (© 2021. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Background and Objectives: To test whether low concentrations of teriflunomide (TF) could promote remyelination, we investigate the effect of TF on oligodendrocyte in culture and on remyelination in vivo in 2 demyelinating models., Methods: The effect of TF on oligodendrocyte precursor cell (OPC) proliferation and differentiation was assessed in vitro in glial cultures derived from neonatal mice and confirmed on fluorescence-activated cell sorting-sorted adult OPCs. The levels of the 8,9-unsaturated sterols lanosterol and zymosterol were quantified in TF- and sham-treated cultures. In vivo, TF was administered orally, and remyelination was assessed both in myelin basic protein-GFP-nitroreductase ( Mbp:GFP-NTR ) transgenic Xenopus laevis demyelinated by metronidazole and in adult mice demyelinated by lysolecithin., Results: In cultures, low concentrations of TF down to 10 nM decreased OPC proliferation and increased their differentiation, an effect that was also detected on adult OPCs. Oligodendrocyte differentiation induced by TF was abrogated by the oxidosqualene cyclase inhibitor Ro 48-8071 and was mediated by the accumulation of zymosterol. In the demyelinated tadpole, TF enhanced the regeneration of mature oligodendrocytes up to 2.5-fold. In the mouse demyelinated spinal cord, TF promoted the differentiation of newly generated oligodendrocytes by a factor of 1.7-fold and significantly increased remyelination., Discussion: TF enhances zymosterol accumulation in oligodendrocytes and CNS myelin repair, a beneficial off-target effect that should be investigated in patients with multiple sclerosis., (Copyright © 2021 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology.)

Background Choroid plexuses (CPs) have been suggested as a key gateway for inflammation in experimental autoimmune encephalitis, but in vivo evidence of their involvement in multiple sclerosis (MS) is lacking. Purpose To assess CP volumetric and inflammatory changes in patients with MS versus healthy control participants. Materials and Methods This was a secondary analysis of 97 patients (61 with relapsing-remitting MS [RRMS] and 36 with progressive MS) and 44 healthy control participants who participated in three prospective 3.0-T brain MRI studies between May 2009 and September 2017. A subgroup of 37 patients and 19 healthy control participants also underwent translocator protein fluorine 18 ( 18 F)-DPA-714 PET for neuroinflammation. Relapses and disability scores were collected at baseline and over 2 years. CPs were manually segmented on three-dimensional T1-weighted images; other brain volumes were additionally segmented. Volumes were expressed as a ratio of intracranial volume. The 18 F-DPA-714 distribution volume ratio was quantified in parenchymal regions, whereas standardized uptake value was used for CP inflammation. Multivariable linear regression analyses were performed to assess CP volumetric and inflammatory differences between patients with MS and healthy control participants and correlations between CP volume and lesion load, brain volumes, 18 F-DPA-714 uptake, and annualized relapse rate. Results Ninety-seven patients with MS (mean age, 42 years ± 12 [standard deviation]; 49 women) and 44 healthy control participants (mean age, 39 years ± 14; 23 women) underwent MRI. Thirty-seven patients with MS and 19 healthy control participants underwent PET. CPs were 35% larger in patients with MS (mean value, 15.9 × 10 -4 ± 4.5) than in healthy control participants (mean value, 11.8 × 10 -4 ± 3.8; P = .004). Subgroup analysis confirmed greater CP volume in patients with RRMS (mean value, 15.5 × 10 -4 ± 4.6; P = .008) than in healthy control participants. CP enlargement was greater in patients with active lesions at MRI (mean volume, 18.2 × 10 -4 ± 4.9 in patients with lesions that enhanced with gadolinium vs 14.9 × 10 -4 ± 4 in patients with lesions that did not enhance with gadolinium; P < .001) and correlated with white matter lesion load ( r = 0.39; 95% CI: 0.20, 0.55; P < .001) and 18 F-DPA-714 binding in the thalami ( r = 0.44; 95% CI: 0.22, 0.72; P = .04) and normal-appearing white matter ( r = 0.5; 95% CI: 0.20, 0.71; P = .005). Moreover, it correlated with annualized relapse rate in patients with RRMS ( r = 0.37; 95% CI: 0.1, 0.55; P = .005). Finally, patients with MS showed 18.5% higher CP 18 F-DPA-714 uptake than control participants (mean value, 0.778 ± 0.23 vs 0.635 ± 0.15, respectively; P = .01). CP volume in patients with RRMS ( r = 0.57; 95% CI: 0.37, 0.73; P = .009) correlated with higher 18 F-DPA-714 uptake. Conclusion Choroid plexuses (CPs) are enlarged and inflamed in patients with multiple sclerosis (MS), particularly in those with relapsing-remitting MS with inflammatory profiles; CP volumetric analysis could represent an MS imaging marker. © RSNA, 2021 EudraCT no. 2008-004174-40; clinical trial registration nos. NCT02305264 and NCT01651520 Online supplemental material is available for this article.

Background: A delayed onset of treatment effect, termed therapeutic lag, may influence the assessment of treatment response in some patient subgroups., Objectives: The objective of this study is to explore the associations of patient and disease characteristics with therapeutic lag on relapses and disability accumulation., Methods: Data from MSBase, a multinational multiple sclerosis (MS) registry, and OFSEP, the French MS registry, were used. Patients diagnosed with MS, minimum 1 year of exposure to MS treatment and 3 years of pre-treatment follow-up, were included in the analysis. Studied outcomes were incidence of relapses and disability accumulation. Therapeutic lag was calculated using an objective, validated method in subgroups stratified by patient and disease characteristics. Therapeutic lag under specific circumstances was then estimated in subgroups defined by combinations of clinical and demographic determinants., Results: High baseline disability scores, annualised relapse rate (ARR) ⩾ 1 and male sex were associated with longer therapeutic lag on disability progression in sufficiently populated groups: females with expanded disability status scale (EDSS) < 6 and ARR < 1 had mean lag of 26.6 weeks (95% CI = 18.2-34.9), males with EDSS < 6 and ARR < 1 31.0 weeks (95% CI = 25.3-36.8), females with EDSS < 6 and ARR ⩾ 1 44.8 weeks (95% CI = 24.5-65.1), and females with EDSS ⩾ 6 and ARR < 1 54.3 weeks (95% CI = 47.2-61.5)., Conclusions: Pre-treatment EDSS and ARR are the most important determinants of therapeutic lag.

Myelin-oligodendrocyte glycoprotein antibody-associated disease (MOGAD) is a recently identified autoimmune disorder that presents in both adults and children as CNS demyelination. Although there are clinical phenotypic overlaps between MOGAD, multiple sclerosis, and aquaporin-4 antibody-associated neuromyelitis optica spectrum disorder (NMOSD) cumulative biological, clinical, and pathological evidence discriminates between these conditions. Patients should not be diagnosed with multiple sclerosis or NMOSD if they have anti-MOG antibodies in their serum. However, many questions related to the clinical characterisation of MOGAD and pathogenetic role of MOG antibodies are still unanswered. Furthermore, therapy is mainly based on standard protocols for aquaporin-4 antibody-associated NMOSD and multiple sclerosis, and more evidence is needed regarding how and when to treat patients with MOGAD., Competing Interests: Declaration of interests RM reports personal fees from Viela Bio, Roche, and UCB; and non-financial support from Viela Bio, Merck, Biogen, and Roche, outside the submitted work. AC-C reports funding from the Instituto de Salud Carlos III (Spain) JR19/00007. A-KP reports grants from the Swiss National Science Foundation, the European Research Council, the National Multiple Sclerosis Society, the ProPatient Foundation, the Goldschmidt-Jacobson-Foundation, and intramural Funding from the University of Basel and personal fees (used for research) from Biogen. OA reports grants from German Research Foundation, German Ministry of Education and Research, Roche, Novartis, and Biogen; and personal fees from Alexion, Almirall, Biogen, Merck, Novartis, Roche, Sanofi, Teva, and Viela Bio, outside the submitted work. M-PA reports grants Merck, Biogen, Sanofi Genzyme, from Teva, Roche, and Novartis; and person fees from Merck, Biogen, Sanofi Genzyme, from Teva, Roche, and Novartis outside the submitted work. BB reports personal fees from Novartis, outside the submitted work. JB reports personal fees from Roche, Genentech, Viela Bio, Chugai Pharm, Alexion, Novartis, Genzyme, Teva Neuroscience, EMD Serono, Frequency Therapeutics, Equillium, Clene Nanoscience, Mitsubishi-Tanabe, and Reistone Bio; grants from Novartis, EMD Serono, National Institutes of Health, Guthy-Jackson Charitable Foundation, and National Multiple Sclerosis Foundation, outside the submitted work; and has a patent Aquaporumab, issued. FB reports grants from the Australian National Health Research Medical Council and the University of Sydney Research Excellence Initiative; personal fees from Biogen and Merck, outside the submitted work. TC reports consulting fees from Biogen Idec, Novartis, Sanofi, Bayer, Celgene, and Genentech; grants from Novartis, Octave Bioscience, EMD Serono, and Verily Life Sciences; all outside the submitted work. OC reports grants from Spinal Cord Research Foundation, Rosetrees Trust, Progressive Multiple Sclerosis Alliance, Bioclinica and GeNeuro, EU-H2020, UK Multiple Sclerosis Society, National Multiple Sclerosis Society, National Institute for Health Research University College London Hospitals Biomedical Research Centre, and National Institute for Health Research Research Professorship; and serves as a consultant for Merck, Novartis, and Roche; and receives an honorarium from the American Academy of Neurology as Associate Editor of Neurology. KD reports personal fees from Novartis, Biogen, Roche, and Merck; and non-financial support from Novartis, outside the submitted work. KF reports grants from Ministry of Education, Science and Technology of Japan, and Ministry of Health, Wellfare and Labor of Japan, during the conduct of the study; personal fees from Chugai/Roche, Alexion, Viela Bio, AsahiKasei Medical, Mitsubishi Tanabe, Biogen/Eisai, Novartis, Teijin, Bayer, Ono, Nihon Pharmaceutical, and Takeda, outside the submitted work; and personal fees from UCB during the conduct of the study. HJK reports grants from National Research Foundation of Korea, Aprilbio; personal fees from Alexion, Aprilbio, Celltrion, Eisai, HanAll BioPharma, Merck Serono, Novartis, Sanofi Genzyme, Teva-Handok, and Viela Bio. M-IL is funded by the UK National Health Service National Specialised Commissioning Group for Neuromyelitis optica and the UK NIHR Oxford Biomedical Research Centre; has been awarded research grants from The Myaware and University of Oxford; received speaker honoraria or travel grants from Biogen Idec, Novartis, and the Guthy-Jackson Charitable Foundation; and serves on scientific or educational advisory boards for UCB, Argenx, and Viela Bio. MC reports personal fees from Biogen, Merck, Sanofi, Novartis, and Roche; and non-financial support from Merck, Sanofi, and Roche, outside the submitted work. IK reports personal fees from Biogen, Novartis, Merck, Sanofi Genzyme, Roche, Mylan, Alexion, Celgene, Chugai, and IQVIA; and grants from Chugai, outside the submitted work. HL reports personal fees from Biogen, Merck, Roche, Novartis, Sanofi Aventis, and MedDay, outside the submitted work. EM reports personal fees from Roche, Novartis, Sanofi, Bioeq, Merck, and Biogen; and grants from Sanofi, Merck, and Novartis, outside the submitted work. JP reports grants from Merck Serono, Chugai, Medlmmum, Alexion, and ABIDE; personal fees from Merck Serono, Teva, Chugai, MedImmun, Alexion, Novartis, Roche, ABIDE, MedDay, ARGENX, Mitsubushi, UCB, and Viela Bio, outside the submitted work; and has a patent Isis: Diagnosing Multiple Sclerosis, issued, and a patent Know-how from the Numares Collaboration, pending. FP receives honoraria for lecturing, and travel expenses for attending meetings from Guthy-Jackson Foundation, Bayer, Biogen, Merck Serono, Sanofi Genzyme, Novartis, Alexion, Viela Bio, Roche, UCB, Mitsubishi Tanabe, and Celgene; and research funding from the German Ministry for Education and Research, Deutsche Forschungsgemeinschaft, Einstein Foundation, Guthy-Jackson Charitable Foundation, EU FP7 Framework Program, Biogen, Genzyme, Merck Serono, Novartis, Bayer, Alexion, Roche, Parexel and Almirall. AP reports personal fees from Novartis, Heidelberg Engineering, and Zeiss; and grants from Novartis, outside the submitted work; and is part of the steering committee of the OCTiMS study which is sponsored by Novartis and the ANGI network which is sponsored by ZEISS (he has not received honoraria for these activities). AP is supported by the National Institute for Health Research, Biomedical Research Centre based at Moorfields Eye Hospital National Health Service Foundation Trust, and University College London Institute of Ophthalmology. The views expressed are those of the authors and not necessarily those of the NHS, the NIHR, or the UK Department of Health. SP reports grants from Grifols, NIH, Guthy-Jackson Charitable Foundation, Autoimmune Encephalitis Alliance, MedImmune, UCB, and Alexion Pharmaceuticals, outside the submitted work; and has a patent (Patent# 8,889,102, Application#12–678350) Neuromyelitis Optica Autoantibodies as a Marker for Neoplasia, issued, a patent (Patent# 9 891 219B2, Application#12–573942) Methods for Treating Neuromyelitis Optica by Administration of Eculizumab to an individual that is Aquaporin-4 (AQP4)-IgG Autoantibody positive, issued, a patent GFAP-IgG, pending, a patent Septin-5-IgG, pending, a patent MAP1B-IgG, pending, a patent Kelch-like protein 11, pending, and a patent PDE10A, pending. MR reports grants from Euroimmun and Roche, during the conduct of the study; and The University Hospital and Medical University of Innsbruck (Austria; employer of MR) receives payments for antibody assays (MOG, AQP4, and other autoantibodies). DKS reports grants from Conselho Nacional de Desenvolvimento Científico e Tecnológico, Fundação de Amparo à Pesquisa do Estado do Rio Grande do Sul, TEVA, and Merck; and personal fees from TEVA, Merck, Biogen, Roche, and Viela Bio, outside the submitted work. KS reports personal fees from Biogen, Novartis, Merck, Roche, Celgene, and TG Therapeutics; and grants from Merck and Roche, outside the submitted work. AS reports personal fees from F Hoffmann-La Roche, Sanofi-Genzyme, Novartis, Merck-Serono, Teva, and Biogen Idec/Gen Pharma of Turkey; and non-financial support from F Hoffmann-La Roche and Sanofi-Genzyme, outside the submitted work. BS has received research grants from Sanofi-Genzyme, Roche, and Merck-Serono, and personal fees for lectures from Sanofi-Genzyme, Merck-Serono, Teva, Biogen and Novartis. MT reports personal fees from Almirall, Bayer Schering Pharma, Biogen-Idec, Genzyme, Merck-Serono, Novartis, Roche, Sanofi-Aventis, Viela Bio, and Teva Pharmaceuticals; and grants from Biogen-Idec and Genzyme, outside the submitted work. AT reports grants from Roche and personal fees from Roche, Sanofi Genzyme, Novartis, EMD Serono, Teva, and Biogen, outside the submitted work. PW reports personal fees from Alexion, F Hoffmann La-Roche, and BC Neuroimmunology, outside the submitted work; and has a patent Antibodies in Autoimmune Neurology, with royalties paid. EW reports personal fees from DBV, Jazz Pharma, and Emerald, outside the submitted work. BW reports personal fees from RSR, Oxford University, Hospices Civil de Lyon, and MVZ Labor PD Dr Volkmann und Kollegen; personal fees from Viela Bio, Alexion, Roche Group (includes Genentech and Chugai), Mitsubishi Tanabe, and Roivant, outside the submitted work; and has a patent NMO-IgG (AQP4-IgG) for diagnosis of NMOSD, with royalties paid. TD reports grants from Novartis, Biogen, and Roche; and financial compensation to his institution for activities on advisory boards, steering committees, or data safety monitoring boards from Alexion, Actelion, Novartis, Merck, Biogen, Genzyme, GeNeuro, Mitsubishi Pharma, Roche, Celgene, and MedDay. TD's wife is an employee of Novartis and holds stock options of Novartis. SV reports grants from Biogen, MedDay, Merck-Serono, Novartis, Roche, and Sanofi-Genzyme; personal fees from Biogen, Celgene, MedDay, Merck-Serono, Novartis, Roche, Sanofi-Genzyme, and Teva; and non-financial support from Biogen, MedDay, Merck-Serono, Novartis, Roche, and Sanofi-Genzyme, outside the submitted work. BH reports personal fees from Desitin, Novartis, Allergy Care, and TG Therapeutics, outside the submitted work. The other authors declare no competing interests., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

We evaluated the effect of DMTs on Covid-19 severity in patients with MS, with a pooled-analysis of two large cohorts from Italy and France. The association of baseline characteristics and DMTs with Covid-19 severity was assessed by multivariate ordinal-logistic models and pooled by a fixed-effect meta-analysis. 1066 patients with MS from Italy and 721 from France were included. In the multivariate model, anti-CD20 therapies were significantly associated (OR = 2.05, 95%CI = 1.39-3.02, p < 0.001) with Covid-19 severity, whereas interferon indicated a decreased risk (OR = 0.42, 95%CI = 0.18-0.99, p = 0.047). This pooled-analysis confirms an increased risk of severe Covid-19 in patients on anti-CD20 therapies and supports the protective role of interferon., (© 2021 The Authors. Annals of Clinical and Translational Neurology published by Wiley Periodicals LLC on behalf of American Neurological Association.)

Background: Natalizumab and fingolimod were the first preparations recommended for disease breakthrough in priorly treated relapsing-remitting multiple sclerosis. Of three published head-to-head studies two showed that natalizumab is the more effective to prevent relapses and EDSS worsening., Methods: By re-analyzing original published results from MSBase, France, and Denmark using uniform methodologies, we aimed at identifying the effects of differences in methodology, in the MS-populations, and at re-evaluating the differences in effectiveness between the two drugs. We gained access to copies of the individual amended databases and pooled all data. We used uniform inclusion/exclusion criteria and statistical methods with Inverse Probability Treatment Weighting., Results: The pooled analyses comprised 968 natalizumab- and 1479 fingolimod treated patients. The on-treatment natalizumab/fingolimod relapse rate ratio was 0.77 (p=0.004). The hazard ratio (HR) for a first relapse was 0.82 (p=0.030), and the HR for sustained EDSS improvement was 1.4 (p=0.009). There were modest differences between each of the original published studies and the replication study, but the conclusions of the three original studies remained unchanged: in two of them natalizumab was more effective, but in the third there was no difference between natalizumab and fingolimod., Conclusion: The results were largely invariant to the epidemiological and statistical methods but differed between the MS populations. Generally, the advantage of natalizumab was confirmed., (Copyright © 2021 Elsevier B.V. All rights reserved.)