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At one time considered a possible form of neuromyelitis optica (NMO) spectrum disorder (NMOSD), it is now accepted that myelin oligodendrocyte glycoprotein (MOG) antibody (Ab)-associated disorder (MOGAD) is a distinct entity from either NMO or multiple sclerosis (MS) and represents a broad spectrum of clinical phenotypes. Whereas Abs targeting aquaporin-4 (AQP4) in NMO are pathogenic, the extent that anti-MOG Abs contribute to CNS damage in MOGAD is unclear. Both AQP4-specific Abs in NMO and MOG-specific Abs in MOGAD are predominantly IgG1, a T cell-dependent immunoglobulin (Ig) subclass. Key insights in neuroimmunology and MOGAD pathogenesis have been learned from MOG experimental autoimmune encephalomyelitis (EAE), described 2 decades before the term MOGAD was introduced. MOG-specific T cells are required in MOG EAE, and while anti-MOG Abs can exacerbate EAE and CNS demyelination, those Abs are neither necessary nor sufficient to cause EAE. Knowledge regarding the spectrum of MOGAD clinical and radiologic presentations is advancing rapidly, yet our grasp of MOGAD pathogenesis is incomplete. Understanding both the humoral and cellular immunology of MOGAD has implications for diagnosis, treatment, and prognosis.

Background: Neuromyelitis Optica Spectrum Disorder (NMOSD) is an autoimmune demyelinating disease characterized by recurrent myelitis and optic neuritis. It is associated with high rates of relapse and disability. The main treatment strategies for acute attacks include intravenous methylprednisolone pulse (IVMP) treatment and rescue treatment with plasma exchange (PLEX). Recently, the blockade of neonatal Fc receptor (FcRn)-IgG interaction has gained momentum as a therapeutic strategy. Efgartigimod, the first approved FcRn inhibitor for treating generalized myasthenia gravis, has shown impressive safety, efficacy, and tolerability, and is being regarded as "PLEX in a bottle". Case description: We report a 65-year-old female patient who was diagnosed with anti-AQP4 antibody positive NMOSD. Add-on treatment with efgartigimod to IVMP and intravenous immunoglobulin (IVIG) at the second acute relapse showed favorable results. Conclusion: This case suggests that efgartigimod is a potentially effective add-on therapy in acute attacks of AQP4-IgG-positive NMOSD. [ABSTRACT FROM AUTHOR]

Objectives: The majority of neuromyelitis optica spectrum disorders (NMOSD) patients are seropositive for aquaporin-4 (AQP4)-specific antibodies [also named neuromyelitis optica immunoglobulin G antibodies (NMO-IgG)]. Although NMO-IgG can induce pathological changes in the central nervous system (CNS), the immunological changes in the CNS and peripheral tissue remain largely unknown. We investigated whether NMO-IgG binds to tissue expressing AQP4 and induces immunological changes in the peripheral tissue and CNS. Methods: C57BL/6 female mice were assigned into an NMOSD or control group. Pathological and immunological changes in peripheral tissue and CNS were measured by immunostaining and flow cytometry, respectively. Motor impairment was measured by open-field test. Results: We found that NMO-IgG did bind to astrocyte- and AQP4-expressing peripheral tissue, but induced glial fibrillary acidic protein and AQP4 loss only in the CNS. NMO-IgG induced the activation of microglia and modulated microglia polarization toward the classical (M1) phenotype, but did not affect innate or adaptive immune cells in the peripheral immune system, such as macrophages, neutrophils, Th17/Th1, or IL-10-producing B cells. In addition, NMOSD mice showed significantly less total distance traveled and higher immobility time in the open field. Conclusions: We found that injection of human NMO-IgG led to astrocytopathic lesions with microglial activation in the CNS. However, there were no significant pathological or immunological changes in the peripheral tissues. [ABSTRACT FROM AUTHOR]

Immunogenicity is the propensity of a therapeutic protein to generate an immune response to itself. While reporting of antidrug antibodies (ADAs) is increasing, model‐based analysis of such data is seldom performed. Model‐based characterization of factors affecting the emergence and dissipation of ADAs may inform drug development and/or improve understanding in clinical practice. This analysis aimed to predict ADA dynamics, including the potential influence of individual covariates, following subcutaneous satralizumab administration. Satralizumab is a humanized IgG2 monoclonal recycling IL‐6 receptor antagonist antibody approved for treating neuromyelitis optica spectrum disorder (NMOSD). Longitudinal pharmacokinetic (PK) and ADA data from 154 NMOSD patients in two pivotal Phase 3 studies (NCT02028884, NCT02073279) and PK data from one Phase 1 study (SA‐001JP) in 72 healthy volunteers were available for this analysis. An existing population PK model was adapted to derive steady‐state concentration without ADA for each patient. A mixed hidden Markov model (mHMM) was developed whereby three different states were identified: one absorbing Markov state for non‐ADA developer, and two dynamic and inter‐connected Markov states—transient ADA negative and positive. Satralizumab exposure and body mass index impacted transition probabilities and, therefore, the likelihood of developing ADAs. In conclusion, the mHMM model was able to describe the time course of ADA development and identify patterns of ADA development in NMOSD patients following treatment with satralizumab, which may allow for the formulation of strategies to reduce the emergence or limit the impact of ADA in the clinical setting. [ABSTRACT FROM AUTHOR]

Pro-inflammatory autoantigen-specific CD4+ T helper (auto-Th) cells are central orchestrators of autoimmune diseases (AIDs). We aimed to characterize these cells in human AIDs with defined autoantigens by combining human leukocyte antigen (HLA)-tetramer-based and activation-based multidimensional ex vivo analyses. In aquaporin4-antibody-positive neuromyelitis optica spectrum disorder (AQP4-NMOSD) patients, auto-Th cells expressed CD154, but proliferative capacity and pro-inflammatory cytokines were strongly reduced. Instead, exhaustion-associated co-inhibitory receptors were expressed together with FOXP3, the canonical regulatory T cell (Treg) transcription factor. Auto-Th cells responded in vitro to checkpoint inhibition and provided potent B cell help. Cells with the same exhaustion-like (ThEx) phenotype were identified in soluble liver antigen (SLA)-antibody-autoimmune hepatitis and BP180-antibody-positive bullous pemphigoid, AIDs of the liver and skin, respectively. While originally described in cancer and chronic infection, our data point to T cell exhaustion as a common mechanism of adaptation to chronic (self-)stimulation across AID types and link exhausted CD4+ T cells to humoral autoimmune responses, with implications for therapeutic targeting. [Display omitted] • Auto-Th cells from AID patients have an exhausted-like (ThEx) phenotype • Auto-ThEx cell frequencies are stable for years despite successful therapy • ThEx cells respond to checkpoint inhibition and provide B cell help • ThEx phenotype development during chronic stimulation in vitro is regulated by FOXP3 CD4+ T cells are important contributors to autoimmune disease pathology. Saggau, Bacher et al. characterize autoantigen-specific CD4+ T helper cells in various human autoimmune diseases, revealing features of exhaustion. These findings provide insight into CD4+ T cell exhaustion in the context of chronic stimulation and suggest a role for exhausted autoantigen-specific CD4+ Th cells in promoting humoral autoimmunity. [ABSTRACT FROM AUTHOR]

The blood–brain barrier (BBB) acts as a structural and functional barrier for brain homeostasis. This review highlights the pathological contribution of BBB dysfunction to neuroimmunological diseases, including multiple sclerosis (MS), neuromyelitis optica spectrum disorder (NMOSD), myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD), autoimmune encephalitis (AE), and paraneoplastic neurological syndrome (PNS). The transmigration of massive lymphocytes across the BBB caused by the activation of cell adhesion molecules is involved in the early phase of MS, and dysfunction of the cortical BBB is associated with the atrophy of gray matter in the late phase of MS. At the onset of NMOSD, increased permeability of the BBB causes the entry of circulating AQP4 autoantibodies into the central nervous system (CNS). Recent reports have shown the importance of glucose-regulated protein (GRP) autoantibodies as BBB-reactive autoantibodies in NMOSD, which induce antibody-mediated BBB dysfunction. BBB breakdown has also been observed in MOGAD, NPSLE, and AE with anti-NMDAR antibodies. Our recent report demonstrated the presence of GRP78 autoantibodies in patients with MOGAD and the molecular mechanism responsible for GRP78 autoantibody-mediated BBB impairment. Disruption of the BBB may explain the symptoms in the brain and cerebellum in the development of PNS, as it induces the entry of pathogenic autoantibodies or lymphocytes into the CNS through autoimmunity against tumors in the periphery. GRP78 autoantibodies were detected in paraneoplastic cerebellar degeneration and Lambert–Eaton myasthenic syndrome, and they were associated with cerebellar ataxia with anti-P/Q type voltage-gated calcium channel antibodies. This review reports that therapies affecting the BBB that are currently available for disease-modifying therapies for neuroimmunological diseases have the potential to prevent BBB damage. [ABSTRACT FROM AUTHOR]

Objective: The clinical symptoms of neuromyelitis optica spectrum disorder (NMOSD) and acute cervical spondylotic myelopathy (CSM) may overlap in some cases. This study aimed to investigate the differences in imaging features between NMOSD and CSM in acute myelopathy. Methods: We included 78 patients in this retrospective study, including 28 NMOSD patients and 50 CSM patients. The demographic characteristics and clinical symptoms of the two groups of patients were compared. The T1 signal intensity, length of the spinal cord involved by T2 hyperintensity, degree of intervertebral disc degeneration, proportion of thoracic and lumbar cord involvement, proportion of brain involvement and lesion enhancement rate in magnetic resonance imaging (MRI) were compared between the two groups of patients. The number, length, location on the sagittal image, pattern on the sagittal image, and distribution on the axial image of the lesions in the contrast-enhanced MRI of the two groups were evaluated. Results: There were differences between NMOSD and CSM patients in the proportion of women, the proportion of bowel and bladder symptoms, mRS levels, the length of the spinal cord involved by T2 hyperintensity, degree of intervertebral disc degeneration, the proportion of thoracic and lumbar cord involvement, the proportion of brain involvement, the enhancement rate and number of lesions (p < 0.05). Among NMOSD patients, linear, patchy and ring or semi-ring enhancement were present in 8(30.8%) ,14 (53.8%) and 4(15.4%)patients, respectively, and axial gray and white matter were involved in 17 (65.4%) patients. Among patients with CSM, 9(36.0%) patients showed longitudinal oriented flake, 16 (64.0%) patients showed pancake-like enhancement, and 21 (84.0%) patients showed axial white matter involvement only. The differences in enhancement pattern on sagittal images and axial involvement were statistically significant (p < 0.05). Conclusions: Early differential diagnosis of NMOSD and CSM in acute myelopathy can be made by analyzing images and the number, length, sagittal enhancement pattern, and axial involvement of gadolinium-enhanced lesions. [ABSTRACT FROM AUTHOR]

Importance: B-cell-targeting monoclonal antibodies have demonstrated safety and efficacy in multiple sclerosis or anti-aquaporin-4 IgG positive neuromyelitis optica spectrum disorder. However, these therapies do not facilitate drug-free remission, which may become possible with cell-based therapies, including chimeric antigen receptor (CAR) T cells. CAR T-cell therapy holds promise for addressing other antibody-mediated CNS disorders, e.g., MOG-associated disease or autoimmune encephalitis. Objective: To provide an overview of the current clinical knowledge on CAR T-cell therapy in central nervous system autoimmunity. Evidence review: We searched PubMed, Embase, Google Scholar, PsycINFO, and clinicaltrials.gov using the terms 'CAR T cell' and 'multiple sclerosis/MS' or 'neuromyelitis optica/spectrum diseases/NMOSD' or 'MOG-associated disease/MOGAD 'or' autoimmune encephalitis' or 'neuroimmunology'. Findings: An ongoing phase I clinical trial has indicated the safety and benefits of anti-BCMA CAR T cells in 12 patients with AQP4-IgG seropositive neuromyelitis optica spectrum disorder. Case reports involving two individuals with progressive multiple sclerosis and one patient with stiff-person syndrome demonstrated a manageable safety profile following treatment with anti-CD19 CAR T cells. Recruitment has commenced for two larger studies in MS, and a phase I open-label basket study is underway to evaluate BCMA-directed CAR T cells in various antibody-associated inflammatory diseases, including MOG-associated disease. Preclinical research on NMDA receptor antibody autoimmune encephalitis treated with chimeric autoantibody receptor T cells generated promising data. Conclusions and relevance: There is minimal evidence of the benefits of CAR T-cell therapy in individuals with central nervous system-directed autoimmunity. Nevertheless, multicenter controlled clinical trials with a manageable safety profile appear feasible and are warranted due to very promising case experiences. [ABSTRACT FROM AUTHOR]

Neuromyelitis optica (NMO) spectrum disorder (NMOSD) is a relapsing inflammatory disease of the CNS, characterized by the presence of serum aquaporin 4 (AQP4) autoantibodies (AQP4-IgGs) and core clinical manifestations such as optic neuritis, myelitis, and brain or brainstem syndromes. Some people exhibit clinical characteristics of NMOSD but test negative for AQP4-IgG, and a subset of these individuals are now recognized to have serum autoantibodies against myelin oligodendrocyte glycoprotein (MOG) — a condition termed MOG antibody-associated disease (MOGAD). Therefore, the concept of NMOSD is changing, with a disease spectrum emerging that includes AQP4-IgG-seropositive NMOSD, MOGAD and double-seronegative NMOSD. MOGAD shares features with NMOSD, including optic neuritis and myelitis, but has distinct pathophysiology, clinical profiles, neuroimaging findings (including acute disseminated encephalomyelitis and/or cortical encephalitis) and biomarkers. AQP4-IgG-seronegative NMOSD seems to be a heterogeneous condition and requires further study. MOGAD can manifest as either a monophasic or a relapsing disease, whereas NMOSD is usually relapsing. This Review summarizes the history and current concepts of NMOSD and MOGAD, comparing epidemiology, clinical features, neuroimaging, pathology and immunology. In addition, we discuss new monoclonal antibody therapies for AQP4-IgG-seropositive NMOSD that target complement, B cells or IL-6 receptors, which might be applied to MOGAD in the near future. This Review summarizes the history and current concepts of neuromyelitis optica spectrum disorder (NMOSD) and myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD), including epidemiology, clinical and neuroimaging features and pathophysiology. It also discusses new molecularly targeted therapies for NMOSD that might be also applied to MOGAD in the future. Key points: The concepts of neuromyelitis optica spectrum disorders (NMOSD) and myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) are evolving, with increasing recognition of the similarities and differences between these two diseases. This Review provides a critical comparison of NMOSD and MOGAD, including their history, epidemiology, clinical characteristics, neuroimaging findings and immunological aspects. Antibody testing, biomarkers and neuroimaging have crucial roles in the differential diagnosis of NMOSD and MOGAD. The landscape for acute and disease-modifying therapies for NMOSD and MOGAD, including conventional and new molecularly targeted agents, is advancing and could inform the development of therapies for other antibody-mediated neurological diseases. [ABSTRACT FROM AUTHOR]

Background and objectives: Neuromyelitis optica spectrum disorder (NMOSD) is a group of demyelinating diseases of the nervous system with high relapse rate and high disability rate without treatment, and we aimed to explore the influencing factors related to the recurrence of NMOSD and provide basis for clinical treatment in this study. Methods: Referring to the diagnostic criteria for NMOSD issued in 2015, 259 patients were enrolled. Clinical information, cerebrospinal fluid (CSF) and serum analysis results, brain and spinal cord magnetic resonance imaging (MRI) findings, treatment details, and prognosis were all recorded. Results: 176 (68.00%) participants were found to be AQP4 Ab-positive in serum or CSF, and the relapse rate was 36.67% (95/259). These 259 individuals were separated into two groups: non-release (n = 164) and relapse (n = 95). In terms of EDSS scores at onset, EDSS score after treatment, lesion location, serum creatinine (Cr) and treatment strategy, there were statistical differences between the two groups. Multivariable logistic regression analyses revealed five predictors for recurrence of NMOSD patients within two years: EDSS scores at onset, transverse myelitis, brain/brainstem, Cr, and Rituximab/immunosuppressants. Conclusion: It is essential to explore the risk factors related to recurrence and prevent them to reduce the risk of disability and improve the prognosis, and the recurrence rate of NMOSD may be affected by several factors. [ABSTRACT FROM AUTHOR]

Introduction: Satralizumab, an anti-interleukin-6 receptor antibody, is approved in Japan for relapse prevention in neuromyelitis optica spectrum disorder (NMOSD) and is undergoing post-marketing surveillance (PMS) of clinical use. We aimed to describe the real-world safety and effectiveness of satralizumab in Japanese patients with NMOSD. Methods: This is an ongoing PMS (planned completion: February 2027). This 6-month interim analysis assessed the safety and effectiveness of satralizumab in Japanese patients with NMOSD using data collected from August 2020 to July 2021. Results: Among 570 patients who participated, 523 (91.75%) were female and the mean ± standard deviation (SD) age was 52.4 ± 14.1 years. At baseline, NMOSD expanded disability status scale mean ± SD was 4.19 ± 2.19; 490 (85.96%) patients used glucocorticoids and 277 (48.59%) patients used immunosuppressants concomitantly. Of 570 satralizumab-treated patients, 85 (14.91%) had discontinued satralizumab treatment at 6 months. For the overall adverse drug reactions (ADRs), 76.22 (66.07–87.48) events/100 person-years occurred in 118 (20.70%) patients, and infections occurred in 28 (4.91%) patients. Serious infections occurred in 18 (3.15%) patients, with an event rate of 9.05 (5.80–13.47) events/100 person-years. Of the 24 events of serious infections, respiratory tract infections (29.17%; 7) and urinary tract infections (25.00%; 6) were the most common serious infection events. One fatal ADR (septic shock) suspected to be related to satralizumab was reported. The mean ± SD glucocorticoid dose reduced from 12.28 ± 10.17 mg/day at the index date to 8.11 ± 7.30 mg/day at 6 months. The Kaplan–Meier cumulative relapse-free rate (95% confidence interval) was 94.59% (92.25–96.23) at 6 months. Conclusion: In this study, satralizumab was found to be safe, well tolerated, and effective in patients with NMOSD in routine clinical practice. The results are consistent with those of previous clinical trials. The safety and effectiveness of satralizumab in Japanese patients with NMOSD will be analyzed over the 6-year surveillance period. Trial Registration: UMIN Clinical Trials Registry, UMIN000041047. [ABSTRACT FROM AUTHOR]