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Autoimmune encephalitis (AE) can be classified into antibody-defined subtypes, which can manifest with immunotherapy-responsive movement disorders sometimes mimicking non-inflammatory etiologies. In the elderly, anti-leucin-rich-glioma-inactivated-1 (LGI1) and contactin-associated-protein-like-2 (CASPR2) antibody-associated diseases compose a relevant fraction of AE. Patients with LGI1 autoantibodies are known to present with limbic encephalitis and additionally faciobrachial dystonic seizures (FBDS) may occur. However, the clinical spectrum of CASPR2 autoantibody-associated disorders is more diverse including limbic encephalitis, Morvan`s syndrome, peripheral nerve hyperexcitability syndrome, ataxia, pain and sleep disorders. Reports on unusual, sometimes isolated and immunotherapy-responsive movement disorders in CASPR2-autoantibody associated syndromes have caused substantial concern regarding necessity of autoantibody-testing in patients with movement disorders. Therefore, we aimed to systematically assess their prevalence and manifestation in patients with CASPR2 autoimmunity. This international, retrospective cohort study included patients with CASPR2 autoimmunity from participating expert centers in Europe. Patients with ataxia and/or movement disorders were analyzed in detail using questionnaires and video recordings. We recruited a comparator group with anti-leucin-rich-glioma-inactivated-1 (LGI1) encephalitis from the GENERATE network. Characteristics were compared according to serostatus. We identified 164 patients with CASPR2 autoantibodies. Of these, 149 (90.8%) had only CASPR2- and 15 (9.1%) both CASPR2- and LGI1-autoantibodies. Compared to 105 patients with LGI1 encephalitis, patients with CASPR2 autoantibodies more often had movement disorders and/or ataxia (35.6% versus 3.8%; p

Autoimmune Encephalitis (AE) spans a group of non-infectious inflammatory conditions of the central nervous system due to an imbalanced immune response. Aiming to elucidate the pathophysiological mechanisms of AE, we applied an unsupervised proteomic approach to analyze the cerebrospinal fluid (CSF) protein profile of AE patients with autoantibodies against N-methyl-D-aspartate receptor (NMDAR) (n = 9), leucine-rich glioma-inactivated protein 1 (LGI1) (n = 9), or glutamate decarboxylase 65 (GAD65) (n = 8) compared to 9 patients with relapsing-remitting multiple sclerosis as inflammatory controls, and 10 patients with somatic symptom disorder as non-inflammatory controls. We found a dysregulation of the complement system, a disbalance between pro-inflammatory and anti-inflammatory proteins on the one hand, and dysregulation of proteins involved in synaptic transmission, synaptogenesis, brain connectivity, and neurodegeneration on the other hand to a different extent in all AE subtypes compared to non-inflammatory controls. Furthermore, elevated levels of several proteases and reduction in protease inhibitors could be detected in all AE subtypes compared to non-inflammatory controls. Moreover, the different AE subtypes showed distinct protein profiles compared to each other and inflammatory controls which may facilitate future identification of disease-specific biomarkers. Overall, CSF proteomics provides insights into the complex pathophysiological mechanisms of AE, including immune dysregulation, neuronal dysfunction, neurodegeneration, and altered protease function.

Here, we describe the clinical phenotype of SARS-CoV-2-related CNS disease and evaluate the SARS-CoV-2 antibody index as a tool to differentiate between a direct (viral) and indirect etiology. Out of >4000 hospitalized patients with COVID-19, we included 13 patients with neurological symptoms with suspicion of neuroinflammation. On clinical grounds, eight were classified as having a possible/probable relationship between neurological symptoms and COVID-19. A clinically distinctive phenotype of brainstem and cerebellar symptoms was seen in 6/8 patients. As we found a positive SARS-CoV-2 antibody index in 3/5 patients, indicating specific intrathecal SARS-CoV-2 IgG production, a direct link with SARS-CoV-2 is likely.

Objectives: It is assumed that autoimmune limbic encephalitis (ALE) demonstrates distinct neuropsychological manifestations with differential responses to immunotherapy according to which associated autoantibody (AAB), if any, is identified. Towards investigating whether this is the case, this study aims to summarize respective findings from the primary literature on ALE with AABs binding to cell surface neural antigens and ALE with AABs against intracellular neural antigens. Methods: We chose ALE with AABs against leucine-rich, glioma inactivated protein 1 (LGI1) and contactin-associated protein-like 2 (CASPR2) as the most frequent cell surface membrane antigens, and ALE with AABs to Embryonic Lethal, Abnormal Vision, Like 1 (ELAVL) proteins (anti-Hu) and glutamic acid decarboxylase 65 (GAD65) as the most frequent intracellular neural antigens. The PubMed and Scopus databases were searched on March 1st, 2021 for neuropsychological test and -screening data from patients with ALE of these AAB-types. Findings were reviewed according to AAB-type and immunotherapy status and are presented in a review section and are further statistically evaluated and presented in a meta-analysis section in this publication. Results: Of the 1304 initial hits, 32 studies on ALE with AABs against LGI1, CASPR2, and GAD65 reporting cognitive screening data could be included in a review. In ALE with AABs against LGI1, CASPR2 and GAD65, memory deficits are the most frequently reported deficits. However, deficits in attention and executive functions including working memory, fluency, and psychological function have also been reported. This review shows that ALE patients with AABs against both LGI1 and CASPR2 show higher percentages of neuropsychological deficits compared to ALE patients with AABs against GAD65 before and after initiation of immunotherapy. However, the methodologies used in these studies were heterogenous, and longitudinal studies were not comparable. Moreover, 21 studies including ALE patients with AABs against LGI1 and GAD65 were also suitable for meta-analysis. No suitable study on ALE with AABs against ELAVL proteins could be identified. Meta-Analyses could be executed for cognitive screening data and only partially, due to the small number of studies. However, in statistical analysis no consistent effect of AAB or immunotherapy on performance in cognitive screening tests could be found. Conclusion: Currently, there is no definite evidence supporting the notion that different AAB-types of ALE exhibit distinct neuropsychological manifestations and respond differently to immunotherapy. Overall, we could not identify evidence for any effect of immunotherapy on cognition in ALE. More systematic, in-depth and longitudinal neuropsychological assessments of patients with different AAB-types of ALE are required in the future to investigate these aspects.

The objective of this paper is to evaluate available evidence for each step in autoimmune encephalitis management and provide expert opinion when evidence is lacking. The paper approaches autoimmune encephalitis as a broad category rather than focusing on individual antibody syndromes. Core authors from the Autoimmune Encephalitis Alliance Clinicians Network reviewed literature and developed the first draft. Where evidence was lacking or controversial, an electronic survey was distributed to all members to solicit individual responses. Sixty-eight members from 17 countries answered the survey. The most popular bridging therapy was oral prednisone taper chosen by 38% of responders while rituximab was the most popular maintenance therapy chosen by 46%. Most responders considered maintenance immunosuppression after a second relapse in patients with neuronal surface antibodies (70%) or seronegative autoimmune encephalitis (61%) as opposed to those with onconeuronal antibodies (29%). Most responders opted to cancer screening for 4 years in patients with neuronal surface antibodies (49%) or limbic encephalitis (46%) as opposed to non-limbic seronegative autoimmune encephalitis (36%). Detailed survey results are presented in the manuscript and a summary of the diagnostic and therapeutic recommendations is presented at the conclusion.

ObjectiveTo study survival and to characterize long-term functional impairments and health-related quality of life (HRQOL) of patients with Lambert-Eaton myasthenic syndrome (LEMS).MethodsIn this observational study, survival of patients with LEMS, separately for nontumor (NT) and small cell lung cancer (SCLC), was compared to that of the Dutch general population and patients with SCLC. Disease course in patients with LEMS was recorded retrospectively. Several scales for functional impairments and health-related quality of life were assessed.ResultsWe included 150 patients with LEMS. Survival was similar to that of the general population in 65 patients with NT-LEMS. Tumor survival was significantly longer in 81 patients with SCLC-LEMS compared to patients with non-LEMS SCLC (overall median survival 17 vs 7.0 months, p < 0.0001). At diagnosis, 39 (62%) of 63 patients with complete follow-up data were independent for activities of daily living, improving to 85% at the 1-year follow-up. The physical HRQOL composite score (55.9) was significantly lower than in the general population (76.3, p < 0.0001) and comparable to that of patients with myasthenia gravis (60.5). The mental HRQOL composite score was 71.8 in patients with LEMS, comparable to that of the general population (77.9, p = 0.19) and patients with myasthenia gravis (70.3).ConclusionsThis study shows that patients with NT-LEMS have normal survival. Patients with SCLC-LEMS have an improved tumor survival, even after correction for tumor stage. A majority of patients with LEMS report a stable disease course and remain or become independent for self-care after treatment.

This scientific commentary refers to ‘Seronegative autoimmune encephalitis: clinical characteristics and factors associated with outcomes’ by Lee et al. (https://doi.org/10.1093/brain/awac166).

Background and ObjectivesAnti-IgLON5 disease is a recently described neurologic disease that shares features of autoimmunity and neurodegeneration. Abnormal movements appear to be frequent and important but have not been characterized and are underreported. We describe the frequency and types of movement disorders in a series of consecutive patients with this disease.MethodsIn this retrospective, observational study, the presence and phenomenology of movement disorders were assessed with a standardized clinical questionnaire. Available videos were centrally reviewed by 3 experts in movement disorders.ResultsSeventy-two patients were included. In 41 (57%), the main reason for initial consultation was difficulty walking along with one or several concurrent movement disorders. At the time of anti-IgLON5 diagnosis, 63 (87%) patients had at least 1 movement disorder with a median of 3 per patient. The most frequent abnormal movements were gait and balance disturbances (52 patients [72%]), chorea (24 [33%]), bradykinesia (20 [28%]), dystonia (19 [26%]), abnormal body postures or rigidity (18 [25%]), and tremor (15 [21%]). Other hyperkinetic movements (myoclonus, akathisia, myorhythmia, myokymia, or abdominal dyskinesias) occurred in 26 (36%) patients. The craniofacial region was one of the most frequently affected by multiple concurrent movement disorders (23 patients [32%]) including dystonia (13), myorhythmia (6), chorea (4), or myokymia (4). Considering any body region, the most frequent combination of multiple movement disorders consisted of gait instability or ataxia associated with craniofacial dyskinesias or generalized chorea observed in 31 (43%) patients. In addition to abnormal movements, 87% of patients had sleep alterations, 74% bulbar dysfunction, and 53% cognitive impairment. Fifty-five (76%) patients were treated with immunotherapy, resulting in important and sustained improvement of the movement disorders in only 7 (13%) cases.DiscussionMovement disorders are a frequent and leading cause of initial neurologic consultation in patients with anti-IgLON5 disease. Although multiple types of abnormal movements can occur, the most prevalent are disorders of gait, generalized chorea, and dystonia and other dyskinesias that frequently affect craniofacial muscles. Overall, anti-IgLON5 disease should be considered in patients with multiple movement disorders, particularly if they occur in association with sleep alterations, bulbar dysfunction, or cognitive impairment.

Background Increment of compound muscle action potential amplitude is a diagnostic hallmark of Lambert‐Eaton myasthenic syndrome (LEMS). Making a diagnosis can be challenging, therefore, a proper cutoff for abnormal increment is highly relevant for improved recognition of this rare disease. Methods We determined the sensitivity and specificity of 60% and 100% cutoff values in all consecutive patients who underwent increment testing in our hospital from 1999 to 2016. Results We included 156 patients, 63 with LEMS and 93 without LEMS. Sensitivity of a 60% cutoff for increment testing was 77.8% (95% confidence interval 65.5%–87.3%) and 58.7% (45.6%–71.0%) for 100%. Specificity was 98.9% (94.2%–100%) and 100% (96.1%–100%) using a threshold of 60% and 100%, respectively. Conclusions Lowering the cutoff value for abnormal increment to 60% greatly increases sensitivity to diagnose LEMS without an overt loss in specificity.

ObjectiveTo clinically characterize patients with anti-metabotropic glutamate receptor (mGluR) 1 encephalitis, to identify prognostic factors, and to study the immunoglobulin G (IgG) subclasses and effects of antibodies on neuronal mGluR1 clusters.MethodsClinical information on new and previously reported patients was reviewed. Antibodies to mGluR1 and IgG subclasses were determined with brain immunohistochemistry and cell-based assays, and their effects on mGluR1 clusters were studied on rat hippocampal neurons.ResultsEleven new patients were identified (10 adults, 1 child);4 were female. In these and 19 previously reported cases (n = 30, median age 55 years), the main clinical manifestation was a subacute cerebellar syndrome that in 25 (86%) patients was associated with behavioral/cognitive changes or other neurologic symptoms. A tumor was found in 3 of 26 (11%). Brain MRI was abnormal in 7 of 19 (37%) at onset and showed cerebellar atrophy in 10 of 12 (83%) at follow-up. Twenty-five of 30 (83%) patients received immunotherapy. Follow-up was available for 25: 13 (52%) had clinical stabilization; 10 (40%) showed significant improvement; and 2 died. At the peak of the disease, patients with bad outcome at 2 years (modified Rankin Scale score > 2, n = 7) were more likely to have higher degree of initial disability, as reflected by a worse Scale for Assessment and Rating of Ataxia score, and more frequent need of assistance to walk. Antibodies to mGluR1 were mainly IgG1 and caused a significant decrease of mGluR1 clusters in cultured neurons.ConclusionsAnti-mGluR1 encephalitis manifests as a severe cerebellar syndrome, often resulting in long-term disability and cerebellar atrophy. The antibodies are pathogenic and cause significant decrease of mGluR1 clusters in cultured neurons.

Nodding syndrome has been suggested to be triggered by neurotoxic leiomodin-1 auto-antibodies cross-reacting with Onchocerca volvulus. Here, we screened serum and CSF samples of persons with nodding syndrome and other forms of onchocerciasis-associated epilepsy (OAE) and African and European controls for leiomodin-1 antibodies by a cell-based assay (CBA) and Western blot (WB). These samples were also investigated for the presence of auto-antibodies cross-reacting with rat brain tissue by immunohistochemistry (IHC). Additionally, IHC was used to detect the leiomodin-1 protein in post-mortem brain samples of persons with OAE who died. Leiomodin-1 antibodies were detected by CBA in 6/52 (12%) and by WB in 23/54 (43%) persons with OAE compared to in 14/61 (23%) (p = 0.113) and 23/54 (43%) (p = 0.479) of controls without epilepsy. Multivariable exact logistic regression did not show an association between O. volvulus infection or epilepsy status and the presence of leiomodin-1. Leiomodin-1 antibodies were not detected in 12 CSF samples from persons with OAE or in 16 CSF samples from persons with acute-onset neurological conditions, as well as not being detected in serum from European controls. Moreover, the leiomodin-1 protein was only detected in capillary walls in post-mortem brain tissues and not in brain cells. IHC on rat brain slides with serum samples from persons with OAE or controls from persons with or without O. volvulus infection revealed no specific staining pattern. In conclusion, our data do not support OAE to be an autoimmune disorder caused by leiomodin-1 antibodies.

ObjectiveThe contemporary diagnosis of paraneoplastic neurologic syndromes (PNSs) requires an increasing understanding of their clinical, immunologic, and oncologic heterogeneity. The 2004 PNS criteria are partially outdated due to advances in PNS research in the last 16 years leading to the identification of new phenotypes and antibodies that have transformed the diagnostic approach to PNS. Here, we propose updated diagnostic criteria for PNS.MethodsA panel of experts developed by consensus a modified set of diagnostic PNS criteria for clinical decision making and research purposes. The panel reappraised the 2004 criteria alongside new knowledge on PNS obtained from published and unpublished data generated by the different laboratories involved in the project.ResultsThe panel proposed to substitute “classical syndromes” with the term “high-risk phenotypes” for cancer and introduce the concept of “intermediate-risk phenotypes.” The term “onconeural antibody” was replaced by “high risk” (>70% associated with cancer) and “intermediate risk” (30%–70% associated with cancer) antibodies. The panel classified 3 levels of evidence for PNS: definite, probable, and possible. Each level can be reached by using the PNS-Care Score, which combines clinical phenotype, antibody type, the presence or absence of cancer, and time of follow-up. With the exception of opsoclonus-myoclonus, the diagnosis of definite PNS requires the presence of high- or intermediate-risk antibodies. Specific recommendations for similar syndromes triggered by immune checkpoint inhibitors are also provided.ConclusionsThe proposed criteria and recommendations should be used to enhance the clinical care of patients with PNS and to encourage standardization of research initiatives addressing PNS.

Systemic autoimmune disorders occur more frequently in patients with epilepsy than in the general population, suggesting shared disease mechanisms. The risk of epilepsy is elevated across the spectrum of systemic autoimmune disorders but is highest in systemic lupus erythematosus and type 1 diabetes mellitus. Vascular and metabolic factors are the most important mediators between systemic autoimmune disorders and epilepsy. Systemic immune dysfunction can also affect neuronal excitability, not only through innate immune activation and blood–brain barrier dysfunction in most epilepsies but also adaptive immunity in autoimmune encephalitis. The presence of systemic autoimmune disorders in subjects with acute seizures warrants evaluation for infectious, vascular, toxic and metabolic causes of acute symptomatic seizures, but clinical signs of autoimmune encephalitis should not be missed. Immunosuppressive medications may have antiseizure properties and trigger certain drug interactions with antiseizure treatments. A better understanding of mechanisms underlying the co-existence of epilepsy and systemic autoimmune disorders is needed to guide new antiseizure and anti-epileptogenic treatments. This review aims to summarize the epidemiological evidence for systemic autoimmune disorders as comorbidities of epilepsy, explore potential immune and non-immune mechanisms, and provide practical implications on diagnostic and therapeutic approach to epilepsy in those with comorbid systemic autoimmune disorders.

Aside from well-characterized immune-mediated ataxias with a clear trigger and/or association with specific neuronal antibodies, a large number of idiopathic ataxias are suspected to be immune mediated but remain undiagnosed due to lack of diagnostic biomarkers. Primary autoimmune cerebellar ataxia (PACA) is the term used to describe this later group. An International Task Force comprising experts in the field of immune ataxias was commissioned by the Society for Research on the Cerebellum and Ataxias (SRCA) in order to devise diagnostic criteria aiming to improve the diagnosis of PACA. The proposed diagnostic criteria for PACA are based on clinical (mode of onset, pattern of cerebellar involvement, presence of other autoimmune diseases), imaging findings (MRI and if available MR spectroscopy showing preferential, but not exclusive involvement of vermis) and laboratory investigations (CSF pleocytosis and/or CSF-restricted IgG oligoclonal bands) parameters. The aim is to enable clinicians to consider PACA when encountering a patient with progressive ataxia and no other diagnosis given that such consideration might have important therapeutic implications.

ObjectiveAntibodies against glutamic acid decarboxylase 65 (anti-GAD65) are associated with a number of neurologic syndromes. However, their pathogenic role is controversial. Our objective was to describe clinical and paraclinical characteristics of anti-GAD65 patients and analyze their response to immunotherapy.MethodsRetrospectively, we studied patients (n = 56) with positive anti-GAD65 and any neurologic symptom. We tested serum and CSF with ELISA, immunohistochemistry, and cell-based assay. Accordingly, we set a cutoff value of 10,000 IU/mL in serum by ELISA to group patients into high-concentration (n = 36) and low-concentration (n = 20) groups. We compared clinical and immunologic features and analyzed response to immunotherapy.ResultsClassical anti–GAD65-associated syndromes were seen in 34/36 patients with high concentration (94%): stiff-person syndrome (7), cerebellar ataxia (3), chronic epilepsy (9), limbic encephalitis (9), or an overlap of 2 or more of the former (6). Patients with low concentrations had a broad, heterogeneous symptom spectrum. Immunotherapy was effective in 19/27 treated patients (70%), although none of them completely recovered. Antibody concentration reduction occurred in 15/17 patients with available pre- and post-treatment samples (median reduction 69%; range 27%–99%), of which 14 improved clinically. The 2 patients with unchanged concentrations showed no clinical improvement. No differences in treatment responses were observed between specific syndromes.ConclusionMost patients with high anti-GAD65 concentrations (>10,000 IU/mL) showed some improvement after immunotherapy, unfortunately without complete recovery. Serum antibody concentrations' course might be useful to monitor response. In patients with low anti-GAD65 concentrations, especially in those without typical clinical phenotypes, diagnostic alternatives are more likely.

ObjectiveTo construct a grading score that predicts neurologic function 1 year after diagnosis of anti-NMDA receptor (NMDAR) encephalitis.MethodsThree hundred eighty-two patients with detailed information and functional status at 1 year were studied. Factors associated with poor status (defined as modified Rankin Scale score ≥3) were identified and incorporated into a multivariate logistic regression model. This model was used to develop a 5-point prediction score, termed the anti-NMDAR Encephalitis One-Year Functional Status (NEOS) score.ResultsIntensive care unit admission (p < 0.001), treatment delay >4 weeks (p = 0.012), lack of clinical improvement within 4 weeks (p < 0.001), movement disorder (p = 0.001), central hypoventilation (p < 0.001), elevated CSF white blood cell count (p < 0.001), elevated CSF protein level (p = 0.027), and abnormal MRI (p = 0.002) were associated with 1-year functional status in univariate analysis. Intensive care unit admission, treatment delay >4 weeks, lack of clinical improvement within 4 weeks, abnormal MRI, and CSF white blood cell count >20 cells/μL were independent predictors for outcome in multivariate regression modeling. These 5 variables were assigned 1 point each to create the NEOS score. NEOS score strongly associated with the probability of poor functional status at 1 year (3% for 0 or 1 point to 69% for 4 or 5 points, p < 0.001).ConclusionsThe NEOS score accurately predicts 1-year functional status in patients with anti-NMDAR encephalitis. This score could help estimate the clinical course following diagnosis and may aid in identifying patients who could benefit from novel therapies.

ObjectiveThe aims of this study were (1) to describe the incidence of autoimmune encephalitis (AIE) and acute disseminated encephalomyelitis (ADEM) in children, (2) to validate the currently used clinical criteria to diagnose AIE, and (3) to describe pitfalls in the diagnosis of pediatric autoimmune (AI) and inflammatory neurologic disorders.MethodsThis study cohort consists of 3 patient categories: (1) children with antibody-mediated AIE (n = 21), (2) children with ADEM (n = 32), and (3) children with suspicion of an AI etiology of their neurologic symptoms (n = 60). Baseline and follow-up clinical data were used to validate the current guideline to diagnose AIE. In addition, patient files and final diagnoses were reviewed.ResultsOne-hundred three of the 113 included patients fulfilled the criteria of possible AIE. Twenty-one children had antibody-mediated AIE, of whom 19 had anti-N-methyl-D-aspartate receptor (NMDAR), 1 had anti–α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor, and 1 had anti–leucine-rich glioma-inactivated protein 1 encephalitis. Finally, 34 children had ADEM, and 2 children had Hashimoto encephalopathy. Mean incidence rates were 1.54 children/million (95% CI 0.95–2.35) for antibody-mediated AIE and 2.49 children/million (95% CI 1.73–3.48) for ADEM. Of the other 48 children, treating physicians' diagnoses were reviewed. In 22% (n = 6) of children initially diagnosed as having an AI/inflammatory etiology (n = 27), no support for AI/inflammation was found.ConclusionBesides anti-NMDAR encephalitis and ADEM, other AIEs are rare in children. The current guideline to diagnose AIE is also useful in children. However, in children with nonspecific symptoms, it is important to review data critically, to perform complete workup, and to consult specialized neuroinflammatory centers.

Item does not contain fulltext OBJECTIVE: This nationwide study gives a detailed description of the clinical features and long-term outcome of anti-leucine-rich glioma-inactivated 1 (LGI1) encephalitis. METHODS: We collected patients prospectively from October 2013, and retrospectively from samples sent to our laboratory from January 2007. LGI1 antibodies were confirmed with both cell-based assay and immunohistochemistry. Clinical information was obtained in interviews with patients and their relatives and from medical records. Initial MRI and follow-up MRI were revised blindly. Neuropsychological assessment was performed in those patients with follow-up over 2 years. RESULTS: Annual incidence in the Netherlands was 0.83/million. A total of 34/38 patients had a limbic encephalitis. Subtle focal seizures (66%, autonomic or dyscognitive) and faciobrachial dystonic seizures (FBDS, 47%) mostly occurred before onset of memory disturbance. Later in the disease course, 63% had tonic-clonic seizures. Initial MRI showed hippocampal T2 hyperintensity in 74% of the patients. These lesions evolved regularly into mesial temporal sclerosis (44%). Substantial response to immunotherapy was seen in 80%, with early response of seizures and slow recovery of cognition. At follow-up >/=2 years, most surviving patients reported mild residual cognitive deficit with spatial disorientation. A total of 86% had persistent amnesia for the disease period. Relapses were common (35%) and presented up to 8 years after initial disease. Two-year case fatality rate was 19%. CONCLUSIONS: Anti-LGI1 encephalitis is a homogenous clinical syndrome, showing early FBDS and other focal seizures with subtle clinical manifestations, followed by memory disturbances. Better recognition will lead to earlier diagnosis, essential for prompt start of treatment. Long-term outcome of surviving patients is mostly favorable, but relapses are common.

Anti-NMDA receptor (anti-NMDAR) encephalitis is a treatment-responsive autoimmune encephalitis, first described in 2007.1 Ovarian teratomas are found in one-third of the patients.2 The clinical features of this disorder vary between patients and age groups and usually include abnormal (psychiatric) behavior or cognitive dysfunction, speech dysfunction (pressured speech, verbal reduction, and mutism), seizures, movement disorders, dyskinesias, or rigidity/abnormal postures, decreased level of consciousness, autonomic dysfunction, or central hypoventilation.2 Cerebellar ataxia has been described as a symptom during the first months of the disease, especially in young children, in combination with other symptoms.2,3 It is extremely rare as the initial symptom, especially in adults. We report a case of a female adult with anti-NMDAR encephalitis presenting with cerebellar ataxia associated with recurrent mature ovarian teratomas. The authors thank J.J. Oudejans, pathologist, Tergooi, Blaricum, The Netherlands, and C.E. de Boer, physiatrist, Tergooi, Blaricum, The Netherlands, for their advice on this case.

Objective:To report the main syndrome of dipeptidyl-peptidase–like protein 6 (DPPX) antibody–associated encephalitis, immunoglobulin G (IgG) subclass, and the antibody effects on DPPX/Kv4.2 potassium channels.Methods:A retrospective analysis of new patients and cases reported since 2013 was performed. IgG subclass and effects of antibodies on cultured neurons were determined with described techniques.Results:Nine new patients were identified (median age 57 years, range 36–69 years). All developed severe prodromal weight loss or diarrhea followed by cognitive dysfunction (9), memory deficits (5), CNS hyperexcitability (8; hyperekplexia, myoclonus, tremor, or seizures), or brainstem or cerebellar dysfunction (7). The peak of the disease was reached 8 months (range 1–54 months) after onset. All patients had both IgG4 and IgG1 DPPX antibodies. In cultured neurons, the antibodies caused a decrease of DPPX clusters and Kv4.2 protein that was reversible on removal of the antibodies. Considering the current series and previously reported cases (total 39), 67% developed the triad: weight loss (median 20 kg; range 8–53 kg)/gastrointestinal symptoms, cognitive-mental dysfunction, and CNS hyperexcitability. Outcome was available from 35 patients (8 not treated with immunotherapy): 60% had substantial or moderate improvement, 23% had no improvement (most of them not treated), and 17% died. Relapses occurred in 8 of 35 patients (23%) and were responsive to immunotherapy.Conclusions:DPPX antibodies are predominantly IgG1 and IgG4 and associate with cognitive-mental deficits and symptoms of CNS hyperexcitability that are usually preceded by diarrhea, other gastrointestinal symptoms, and weight loss. The disorder is responsive to immunotherapy, and this is supported by the reversibility of the antibody effects in cultured neurons.

To the Editor: Balamuthia mandrillaris is a free-living ameba that has a worldwide distribution in soil and was first reported in 1990 (1). Approximately 200 B. mandrillaris meningoencephalitis cases have been described, mostly from warm climate areas in South America. Its prevalence in the United States is estimated to be 1 case/year (2). However, B. mandrillaris meningoencephalitis has not been reported in Africa, and only 4 cases have been reported in Europe (3–6). Transmission occurs through the respiratory tract or the skin or by organ transplant, and the incubation period varies from weeks to months after primary infection (7). After an indolent, subacute phase with aspecific symptoms, the amebae invade the central nervous system, and illness rapidly progresses, leading almost invariably to death (7). Because B. mandrillaris is difficult to detect in soil, its specific geographic distribution around the world is unknown and is estimated on the basis of where illnesses have been reported (7). This report addresses fatal B. mandrillaris meningoencephalitis in a woman from the Netherlands who had visited The Gambia. In December 2013, a previously healthy 61-year-old white woman in the Netherlands sought care for fever, headaches, and muscle pains she had experienced for 1 week. That year, she had traveled 4 times to The Gambia, the last visit being 1 month before her hospitalization (Technical Appendix Table 1). After she returned from her visit in September 2013, fatigue, diarrhea, fever, and pustular skin lesions on her back and lower extremities developed. A wound swab culture showed Staphylococcus aureus, for which she was treated successfully with oral clarithromycin and topical fucidin ointment. On admission in December, her physical and neurologic examination results were unremarkable. Malaria was excluded; because of persisting headaches, a cerebral computed tomography scan without contrast was performed but showed no abnormalities. In the following days, high fevers, altered mental status, and nuchal rigidity without focal neurologic deficits developed. Cerebrospinal fluid (CSF) examination showed mononuclear pleocytosis, highly elevated protein levels, and low glucose levels (Technical Appendix Table 2). Serial cerebral computed tomography and magnetic resonance imaging scans showed development of an asymmetric hydrocephalus and diffuse leptomeningeal and subependymal contrast enhancement, especially around the brainstem, without signs of intracerebral mass lesions (Technical Appendix Figure). Presumed diagnosis was tuberculous meningitis, and she was treated with tuberculostatic drugs (isoniazid, rifampin, pyrazinamide, and ethambutol) combined with intravenous acyclovir, ceftriaxone, and co-trimoxazole for other infectious causes of meningoencephalitis. Despite external lumbar and ventricular (both lateral ventricles and fourth ventricle) CSF drainage, her neurologic condition deteriorated. Multiple cranial nerve palsies developed, and she became comatose and died 11 days after admission. Informed consent for postmortem examination was obtained, and macroscopic pathologic examination showed uncal and cerebellar herniation caused by increased intracranial pressure. Microscopic brain tissue examination showed signs of acute granulomatous inflammation, multiple hemorrhagic infarctions, and angiitis in the presence of numerous amebic trophozoites and cysts (Figure), which showed granulomatous hemorrhagic necrotic amebic meningoencephalitis. Real-time PCR and subsequent sequencing on brain biopsy and CSF specimens showed B. mandrillaris to be the causative ameba (8,9). Figure Postmortem pathologic findings for woman in the Netherlands who died of Balamuthia mandrillaris meningoencephalitis after returning from travel to The Gambia. A) Macroscopic coronal central section scan showing hemorrhagic necrotizing lesions of the subependymal, ... The infection could have been acquired in The Gambia or the Netherlands because the patient had intensive soil contact in The Gambia, where she frequently cultivated land, and in the Netherlands, where she worked in glass horticulture. She may have been infected through the skin after contact with contaminated soil, but her skin lesions were atypical for B. mandrillaris, and postmortem examinations failed to identify B. mandrillaris except in the central nervous system. The lack of reported B. mandrillaris cases from Africa might indicate a low number of postmortem examinations and little access to advanced diagnostics, rather than a low environmental prevalence of B. mandrillaris. The few reported cases in Europe might be related to lack of awareness and to clinical signs and symptoms that mimic tuberculous meningitis: a lymphocytic pleocytosis with an elevated protein level and a low glucose level in CSF, together with a hydrocephalus and subependymal and leptomeningeal contrast enhancement on magnetic resonance imaging (10). Also, B. mandrillaris meningoencephalitis imaging findings are often nonspecific, including cerebral edema, hydrocephalus, multiple space-occupying and ring-enhancing lesions, leptomeningeal enhancement, or formation of mycotic aneurysms (2). Furthermore, amebic trophozoites are seldom detected in CSF by microscopy (2,3). Consequently, B. mandrillaris meningoencephalitis could be underdiagnosed, especially where this infection has no or only sporadic reports. B. mandrillaris should be considered in refractory or unexplained cases of meningoencephalitis, even outside the Americas and in immunocompetent patients. Detecting B. mandrillaris by PCR in CSF seems most likely to enable early diagnosis and timely treatment. However, appropriate therapy is not well defined; success has been sparsely reported with the simultaneous use of azoles, flucytosine, pentamidine, sulfazidine, macrolide antimicrobial drugs, phenothiazines, and miltefosine (2,7,10). Technical Appendix. Timeline of relevant events, laboratory investigations during hospitalization, and imaging results for Dutch traveler who died of Balamuthia mandrillaris meningoencephalitis after returning from The Gambia. Click here to view.(248K, pdf)

Objective: To report a large cohort of patients with antibodies against contactin-associated protein-like 2 (Caspr2) and provide the clinical spectrum of this disorder. Methods: Serum and CSF samples were assessed at 2 neuroimmunology centers in Barcelona and Rotterdam. Patients were included if Caspr2 antibodies were confirmed with 2 independent techniques, including brain immunohistochemistry and cell-based assay. Clinical information was obtained by the authors or provided by treating physicians after patients9 informed consent. Results: Median age at symptom onset was 66 years. Of 38 patients, 34 were male. Median time to nadir of disease was 4 months (in 30% >1 year). The most frequent syndromes included limbic encephalitis (42%) and Morvan syndrome (29%). Seventy-seven percent of the patients had ≥3 of the following symptoms: encephalopathy (cognitive deficits/seizures), cerebellar dysfunction, peripheral nervous system hyperexcitability, dysautonomia, insomnia, neuropathic pain, or weight loss. A tumor, mostly thymoma, occurred in 19% of the patients. Immunoglobulin G4 subclass antibodies were present in all patients; 63% also had immunoglobulin G1 antibodies. Treatment response occurred in 93% of the patients and 25% had clinical relapses. Conclusions: Caspr2 antibodies associate with a treatable disorder that predominantly affects elderly men. The resulting syndrome may vary among patients but it usually includes a set of well-established symptoms. Recognition of this spectrum of symptoms and consideration of the protracted clinical course are important for early diagnosis of this disorder. Prompt immunotherapy and tumor therapy (if needed) often result in improvement.

Purpose SOX1 antibodies are common in small-cell lung carcinoma (SCLC) with and without paraneoplastic syndrome (PNS) and can serve as serological tumor marker. Addition of other antibodies might improve its diagnostic power. We validated an enzyme-linked immunosorbent assay (ELISA) to assess the diagnostic value of serum antibodies in SCLC and Lambert-Eaton myasthenic syndrome (LEMS). Clinical outcome with respect to SOX antibodies was evaluated, as the SOX-related antitumor immune response might help to control the tumor growth. Patients and Methods We used recombinant SOX1, SOX2, SOX3, SOX21, HuC, HuD, or HelN1 proteins in an ELISA to titrate serum samples and validated the assay by western blot. We tested 136 consecutive SCLC patients, 86 LEMS patients (43 with SCLC), 14 patients with SCLC and PNS (paraneoplastic cerebellar degeneration or Hu syndrome), 62 polyneuropathy patients, and 18 healthy controls. Results Our ELISA was equally reliable as western blot. Forty-three percent of SCLC patients and 67% of SCLC-LEMS patients had antibodies to one of the SOX or Hu proteins. SOX antibodies had a sensitivity of 67% and a specificity of 95% to discriminate between LEMS with SCLC and nontumor LEMS. No difference in survival was observed between SOX positive and SOX negative SCLC patients. Conclusion SOX antibodies are specific serological markers for SCLC. Our assay is suitable for high throughput screening, detecting 43% of SCLC. SOX antibodies have diagnostic value in discriminating SCLC-LEMS from nontumor LEMS, but have no relation to survival in patients with SCLC.

A 20-year-old woman developed anti–NMDA receptor (NMDAR) encephalitis with psychosis, dysphagia, hemiparesis, generalized dystonia, cortical blindness, and status epilepticus. IgG NMDAR antibodies were present in serum and CSF (figure). She was successfully treated with IV immunoglobulin (IVIg), plasmapheresis, and carbamazepine. She relapsed 1.5 years later and was treated regularly with IVIg and carbamazepine since that time. She became pregnant 2.5 years after the relapse. There were some remaining cognitive deficits, but she had been stable since the relapse. At 37 weeks of gestation a boy was born, weighing 2.5 kg. At birth, he responded little to manual stimulation and had respiratory insufficiency. The Moro, rooting, grasp, sucking, and swallowing reflexes were decreased or absent but his muscle tone was normal. He did not respond to venous cannulation. The infant remained lethargic and required supplemental oxygen and gastric tube feeding. He received IV antibiotics for 3 days. At day 6 he opened his eyes for the first time and slowly started bottle drinking. Because the infant improved after several days, no lumbar puncture was performed. By day 10 his feeding problems had resolved.

Objective: Significant immunological alterations have been observed in women with first-onset affective psychosis during the postpartum period. Recent studies have highlighted the possibility that a subset of patients with first-onset severe psychiatric episodes might suffer from undiagnosed autoimmune encephalitis. Therefore, the authors performed a three-step immunohistochemistry-based screening for CNS autoantibodies in a large cohort of patients with postpartum psychosis and matched postpartum comparison subjects. Method: Ninety-six consecutive patients with postpartum psychosis and 64 healthy postpartum women were included. Screening for antibodies in patient serum was performed using immunohistochemistry. Samples showing any staining were further examined by immunocytochemistry using live hippocampal neurons and cell-based assays to test for anti-N-methyl-D-aspartate (NMDA) receptor antibodies. Cell-based assays for all other known CNS antigens were performed in those samples with immunocytochemistry labeling but negative for NMDA receptor antibodies. Results: Four patients (4%) with neuropil labeling suggestive for extracellular antigen reactivity were identified. Serum samples from all four patients showed clear extracellular labeling of live hippocampal neurons. Two women had the specific stainingpattern characteristic for anti-NMDA receptor antibody positivity, which was confirmed by cell-based assays. Neither patient with anti-NMDA receptor antibody positivity had evidence of an ovarian teratoma. The other two patients tested negative by cell-based assays for all known CNS antigens. None of the matched postpartum comparison subjects had confirmed neuronal surface antibodies. The two patients with anti-NMDA receptor antibodies both showed extrapyramidal symptoms following initiation of treatment with low-dose haloperidol. Conclusions: In patients with acute psychosis during the postpartum period, systematic screening for anti-NMDA receptor autoantibodies should be considered. The acute onset of severe atypical psychiatric symptoms in young female patients should raise the index of suspicion for anti-NMDA receptor encephalitis, particularly in the setting of neurological symptoms, including extrapyramidal side effects of antipsychotic treatment.

We appreciate the comments of Dr. Chen. Our study was focused on the clinical picture associated with Caspr2 antibodies, showing a spectrum of symptoms that do not conform to specific syndromes but were present in most of the patients, leading to the terminology “Caspr2 core symptoms.”1 In some patients, Caspr2 antibodies associate with the syndrome described by Morvan.

Anti-N-methyl D-aspartate receptor (NMDAR) encephalitis is a severe neuropsychiatric disorder that associates with prominent memory and behavioural deficits. Patients' antibodies react with the N-terminal domain of the GluN1 (previously known as NR1) subunit of NMDAR causing in cultured neurons a selective and reversible internalization of cell-surface receptors. These effects and the frequent response to immunotherapy have suggested an antibody-mediated pathogenesis, but to date there is no animal model showing that patients' antibodies cause memory and behavioural deficits. To develop such a model, C57BL6/J mice underwent placement of ventricular catheters connected to osmotic pumps that delivered a continuous infusion of patients' or control cerebrospinal fluid (flow rate 0.25 µl/h, 14 days). During and after the infusion period standardized tests were applied, including tasks to assess memory (novel object recognition in open field and V-maze paradigms), anhedonic behaviours (sucrose preference test), depressive-like behaviours (tail suspension, forced swimming tests), anxiety (black and white, elevated plus maze tests), aggressiveness (resident-intruder test), and locomotor activity (horizontal and vertical). Animals sacrificed at Days 5, 13, 18, 26 and 46 were examined for brain-bound antibodies and the antibody effects on total and synaptic NMDAR clusters and protein concentration using confocal microscopy and immunoblot analysis. These experiments showed that animals infused with patients' cerebrospinal fluid, but not control cerebrospinal fluid, developed progressive memory deficits, and anhedonic and depressive-like behaviours, without affecting other behavioural or locomotor tasks. Memory deficits gradually worsened until Day 18 (4 days after the infusion stopped) and all symptoms resolved over the next week. Accompanying brain tissue studies showed progressive increase of brain-bound human antibodies, predominantly in the hippocampus (maximal on Days 13-18), that after acid extraction and characterization with GluN1-expressing human embryonic kidney cells were confirmed to be against the NMDAR. Confocal microscopy and immunoblot analysis of the hippocampus showed progressive decrease of the density of total and synaptic NMDAR clusters and total NMDAR protein concentration (maximal on Day 18), without affecting the post-synaptic density protein 95 (PSD95) and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors. These effects occurred in parallel with memory and other behavioural deficits and gradually improved after Day 18, with reversibility of symptoms accompanied by a decrease of brain-bound antibodies and restoration of NMDAR levels. Overall, these findings establish a link between memory and behavioural deficits and antibody-mediated reduction of NMDAR, provide the biological basis by which removal of antibodies and antibody-producing cells improve neurological function, and offer a model for testing experimental therapies in this and similar disorders. This work was supported by the National Institutes of Health RO1NS077851 (J.D.), RO1MH094741 (R.B-G. and J.D.), Fundació La Marató de TV3 #101530 (J.D.), Fondo de Investigaciones Sanitarias/Instituto Carlos III (FIS PI11/01780 J.D.), ErasmusMC fellowship (M.T.), and Forschungsförderungsfonds Hamburg-Eppendorf FL)

Introduction: Lambert–Eaton myasthenic syndrome (LEMS) is a rare autoimmune disorder of the neuromuscular junction. Antibody-mediated functional loss of voltage-gated calcium channels (VGCCs) on the presynaptic surface results in reduced neurotransmitter release. Muscle weakness starts in the proximal limbs and is accompanied by autonomic failure and areflexia. About 50 – 60% of the patients have small-cell lung cancer (SCLC), with antibodies produced in reaction to VGCC on tumor cells. In non-tumor LEMS, an autoimmune reaction causes antibody production. Knowledge of the pathophysiology of antibody production in SCLC-LEMS and non-tumor LEMS and a detailed understanding of the neuromuscular junction and its dysfunction in LEMS is needed for drug development. Areas covered: This review gives an overview of the clinical symptoms, diagnosis and pathophysiology of LEMS. Current treatment options and results of recent research on newly developed symptomatic treatment are described. Expert opinion: Extensive se...

Summary Background Increasing evidence suggests that seizures and status epilepticus can be immune-mediated. We aimed to describe the clinical features of a new epileptic disorder, and to establish the target antigen and the effects of patients' antibodies on neuronal cultures. Methods In this observational study, we selected serum and CSF samples for antigen characterisation from 140 patients with encephalitis, seizures or status epilepticus, and antibodies to unknown neuropil antigens. The samples were obtained from worldwide referrals of patients with disorders suspected to be autoimmune between April 28, 2006, and April 25, 2013. We used samples from 75 healthy individuals and 416 patients with a range of neurological diseases as controls. We assessed the samples using immunoprecipitation, mass spectrometry, cell-based assay, and analysis of antibody effects in cultured rat hippocampal neurons with confocal microscopy. Findings Neuronal cell-membrane immunoprecipitation with serum of two index patients revealed GABA A receptor sequences. Cell-based assay with HEK293 expressing α1/β3 subunits of the GABA A receptor showed high titre serum antibodies (>1:160) and CSF antibodies in six patients. All six patients (age 3–63 years, median 22 years; five male patients) developed refractory status epilepticus or epilepsia partialis continua along with extensive cortical-subcortical MRI abnormalities; four patients needed pharmacologically induced coma. 12 of 416 control patients with other diseases, but none of the healthy controls, had low-titre GABA A receptor antibodies detectable in only serum samples, five of them also had GAD-65 antibodies. These 12 patients (age 2–74 years, median 26·5 years; seven male patients) developed a broader spectrum of symptoms probably indicative of coexisting autoimmune disorders: six had encephalitis with seizures (one with status epilepticus needing pharmacologically induced coma; one with epilepsia partialis continua), four had stiff-person syndrome (one with seizures and limbic involvement), and two had opsoclonus-myoclonus. Overall, 12 of 15 patients for whom treatment and outcome were assessable had full (three patients) or partial (nine patients) response to immunotherapy or symptomatic treatment, and three died. Patients' antibodies caused a selective reduction of GABA A receptor clusters at synapses, but not along dendrites, without altering NMDA receptors and gephyrin (a protein that anchors the GABA A receptor). Interpretation High titres of serum and CSF GABA A receptor antibodies are associated with a severe form of encephalitis with seizures, refractory status epilepticus, or both. The antibodies cause a selective reduction of synaptic GABA A receptors. The disorder often occurs with GABAergic and other coexisting autoimmune disorders and is potentially treatable. Funding The National Institutes of Health, the McKnight Neuroscience of Brain Disorders, the Fondo de Investigaciones Sanitarias, Fundacio la Marato de TV3, the Netherlands Organisation for Scientific Research (Veni-incentive), the Dutch Epilepsy Foundation.

Summary Lambert–Eaton myasthenic syndrome (LEMS) is a neuromuscular autoimmune disease that has served as a model for autoimmunity and tumour immunology. In LEMS, the characteristic muscle weakness is thought to be caused by pathogenic autoantibodies directed against voltage-gated calcium channels (VGCC) present on the presynaptic nerve terminal. Half of patients with LEMS have an associated tumour, small-cell lung carcinoma (SCLC), which also expresses functional VGCC. Knowledge of this association led to the discovery of a wide range of paraneoplastic and non-tumour-related neurological disorders of the peripheral and central nervous systems. Detailed clinical studies have improved our diagnostic skills and knowledge of the pathophysiological mechanisms and association of LEMS with SCLC, and have helped with the development of a protocol for early tumour detection.

Sporadic inclusion body myositis is considered to be a slowly progressive myopathy. Long-term follow-up data are, however, not yet available. Follow-up data are important with a view to informing patients about their prognosis and selecting appropriate outcome measures for clinical trials. We performed a follow-up study of 64 patients with sporadic inclusion body myositis who participated in a national epidemiological study in the Netherlands. Case histories were recorded, and manual and quantitative muscle tests as well as laboratory tests were performed at baseline and 12 years (median) after the first out-patient visit. Date and cause of death were recorded for all deceased patients. Forty-six patients died during the follow-up period, two patients chose not to participate and one patient was lost to follow-up. The remaining 15 surviving patients had a mean disease duration of 20 years and were clinically evaluated at the second time point. The mean decline in strength was 3.5 and 5.4% per year according to the manual muscle testing and quantitative muscle testing, respectively. This decline was most pronounced in the lower legs, which were also the weakest extremities. Life expectancy was normal at 81 years, but activities of daily life were clearly restricted. At follow-up, all patients were found to be using a wheelchair, seven of them (47%) being completely wheelchair-bound. Disorders of the respiratory system were the most common cause of death. In three patients, euthanasia was requested and in another three, continuous deep sedation was applied. The fact that end-of-life care interventions were used in six patients (13%) reflects the severe disability and loss of quality of life at the end stage of this disease. Sporadic inclusion body myositis is a chronic progressive disorder, leading to major disabilities at the end stage of the disease due to extensive muscle weakness.

Purpose Approximately one half of patients with Lambert-Eaton myasthenic syndrome (LEMS) have small-cell lung carcinomas (SCLC), aggressive tumors with poor prognosis. In view of its profound impact on therapy and survival, we developed and validated a score to identify the presence of SCLC early in the course of LEMS. Patients and Methods We derived a prediction score for SCLC in LEMS in a nationwide cohort of 107 Dutch patients, and validated it in a similar cohort of 112 British patients. A Dutch-English LEMS Tumor Association Prediction (DELTA-P) score was developed based on multivariate logistic regression. Results Age at onset, smoking behavior, weight loss, Karnofsky performance status, bulbar involvement, male sexual impotence, and the presence of Sry-like high-mobility group box protein 1 serum antibodies were independent predictors for SCLC in LEMS. A DELTA-P score was derived allocating 1 point for the presence of each of the following items at or within 3 months from onset: age at onset ≥ 50 years, smoking at diagnosis, weight loss ≥ 5%, bulbar involvement, erectile dysfunction, and Karnofsky performance status lower than 70. The area under the curve of the receiver operating curve was 94.4% in the derivation cohort and 94.6% in the validation set. A DELTA-P score of 0 or 1 corresponded to a 0% to 2.6% chance of SCLC, whereas scores of 4, 5, and 6 corresponded to chances of SCLC of 93.5%, 96.6%, and 100%, respectively. Conclusion The simple clinical DELTA-P score discriminated patients with LEMS with and without SCLC with high accuracy early in the course of LEMS.

N-glycosylation of the immunoglobulin Fc moiety influences its biological activity by, for example, modulating the interaction with Fc receptors. Changes in IgG glycosylation have been found to be associated with various inflammatory diseases. Here we evaluated for the first time IgG Fc N-glycosylation changes in well-defined antibody-mediated autoimmune diseases, that is, the neurological disorders Lambert-Eaton myasthenic syndrome and myasthenia gravis, with antibodies to muscle nicotinic acetylcholine receptors or muscle-specific kinase. IgGs were purified from serum or plasma by protein A affinity chromatography and digested with trypsin. Glycopeptides were purified and analyzed by MALDI-FTICR-MS. Glycoform distributions of both IgG1 and IgG2 were determined for 229 patients and 56 controls. We observed an overall age and sex dependency of IgG Fc N-glycosylation, which was in accordance with literature. All three disease groups showed lower levels of IgG2 galactosylation compared to controls. In addition, LEMS patients showed lower IgG1 galactosylation. Notably, the galactosylation differences were not paralleled by a difference in IgG sialylation. Moreover, the level of IgG core-fucosylation and bisecting N-acetylglucosamine were evaluated. The control and disease groups revealed similar levels of IgG Fc core-fucosylation. Interestingly, LEMS patients below 50 years showed elevated levels of bisecting N-acetylglucosamine on IgG1 and IgG2, demonstrating for the first time the link of changes in the level of bisecting N-acetylglucosamine with disease.