Alterations of brain structural and functional connectivity networks topology and decoupling in pediatric myelin oligodendrocyte glycoprotein antibody-associated disease.

OBJECTIVE: To investigate the alteration in structural and functional connectivity networks (SCN and FCN) as well as their coupling in pediatric myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD), and determine if these properties could serve as potential biomarkers for the disease. MATERIALS AND METHODS: In total of 32 children with MOGAD and 30 age- and sex-matched healthy controls (HC) were employed to construct the SCN and FCN, respectively. The graph-theoretical analyses of the global properties, node properties of the 90 brain nodes, and the structural-functional connectivity (SC-FC) coupling of the two networks were performed. The graph-theoretical properties that exhibited significant differences were analyzed using partial correlation analysis in conjunction with the clinical scales, including the expanded disability status scale (EDSS), modified Rankin scale (mRS), and pediatric cerebral performance category (PCPC) of the MOGAD group. Subsequently, a machine learning model was developed to discriminate between MOGAD and the HC group, aiming to explore the potential of these properties as biomarkers. RESULTS: The SCN of the MOGAD group exhibited aberrant global properties, including an increased characteristic path length (Lp) and a decreased global efficiency (Eg), along with reduced nodal properties such as degree centrality (Dc), nodal efficiency (Ne), and local efficiency in multiple nodes. The FCN of the MOGAD group only exhibited decreased Dc, Ne, and betweenness centrality in two nodes of nodal properties. Besides, MOGAD showed a significant decrease in SC-FC coupling compared to the HC group. The analysis of partial correlation revealed significant correlations between several properties and the scales of EDSS and mRS in the MOGAD group. The machine learning method was used to extract six features and establish the model, achieving a classification accuracy of 82.3% for MOGAD. CONCLUSIONS: Pediatric MOGAD showed a more pronounced impairment in the SCN along with decoupling of SC-FC. Both partial correlation analysis and discriminant modeling suggest that alterations in brain network properties have the potential as biomarkers for assessing brain damage in MOGAD.

A protective effect of lower MHC-II expression in MOGAD.

Myelin oligodendrocyte glycoprotein-antibody-associated disease (MOGAD) is a demyelinating central nervous system disorder. We aimed to uncover immune pathways altered in MOGAD to predict disease progression. Using nanostring nCounter technology, we analyzed immune gene expression in PBMCs from MOGAD patients and compare it with healthy controls (HCs). We found 35 genes that distinguished MOGAD patients and HCs. We then validated those results in a larger cohort including MS and NMOSD patients. Expressions of HLA-DRA was significantly lower in MOGAD patients. This reduction in HLA-DRA, correlated with a monophasic disease course and greater brain volume, enhancing our ability to predict MOGAD progression.

Frequency, characteristics, predictors and treatment of relapsing myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD).

BACKGROUND: Myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) may have a monophasic or relapsing disease course. To date, factors that may predict a relapsing disease course remain largely unknown and only limited data exist regarding the efficacy of different utilized immunotherapy regimens at preventing or reducing relapses. OBJECTIVES: To assess the characteristics, predictors, and immunotherapy of relapsing MOGAD. METHODS: This multicenter retrospective analysis included all MOGAD cases at the University of Florida, Baylor College of Medicine and the University of California San Diego with minimum follow-up time of 6 months. Cox proportional hazards regression analyses, corrected for age and sex, were performed to evaluate hazard ratios (HR) of predictors of a relapsing disease course and to compare relapse hazards for utilized immunotherapies. RESULTS: The majority of included participants (51/79 [64.6 %]) had a relapsing course, and of these individuals, 68.6 % (35/51) experienced their first relapse within the first year. However, 10/51 (19.6 %) participants experienced their first relapse ≥5 years (5-15 years) after the initial presentation. Predictors of a relapsing course were CSF pleocytosis (>150 cells/mm3; HR 3.3 [1.18 - 9.24]; p = 0.023), a pediatric disease onset at age < 9 years (HR 2.69 [1.07-6.75]; p = 0.035), and an initial presentation with the clinical syndrome of meningoencephalitis (HR 3.42 [1.28 - 9.17]; p = 0.015),. In participants with a relapsing course, 13/24 (54.2 %) patients remained relapse-free on rituximab, 4/8 (50 %) on mycophenolate mofetil, and 11/14 (78.6 %) on scheduled immunoglobulins. Patients treated with immunoglobulins had significantly fewer relapses compared to patients treated with other immunotherapies (HR: 0.1 [0.2 - 0.63]; p = 0.014). CONCLUSIONS: In our cohort, the majority of MOGAD patients relapsed. The initial relapse occurred most frequently within the first year, but first relapses also took place over a decade after the initial presentation. Prepubertal onset, severe CSF pleocytosis, and the clinical syndrome of meningoencephalitis may be predictors of a relapsing course. Of the currently available off-label steroid-sparing treatments, scheduled immunoglobulins may be the most effective in relapse prevention.

MOG Antibody-Associated Disease in the Setting of Metastatic Melanoma Complicated by Immune Checkpoint Inhibitor Use.

OBJECTIVES: Myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) is an autoimmune demyelinating disease rarely associated with malignancy. We report the clinical, MRI, immunopathology, and treatment response in a person with MOGAD and melanoma. METHODS: This is a case report of a person with a multidisciplinary evaluation at a tertiary referral center. RESULTS: A 52-year-old man presented with progressive encephalomyelitis that led to identification of metastatic melanoma. Investigations revealed positive MOG-IgG at high titers in serum (1:1,000; normal, <1:20) and CSF (1:4,096; normal, <1:2). MRI demonstrated multifocal T2 lesions with enhancement in the brain and spine. Brain biopsy showed demyelination and inflammation. MOG immunostaining was not present in the tumor tissue. He initially improved with methylprednisolone, plasmapheresis, prolonged oral steroid taper, and cancer-directed treatment with BRAF and MEK 1/2 inhibitors, but then developed bilateral optic neuritis. IV immunoglobulin (IVIG) was initiated. Five months later, he developed metastases and immune checkpoint inhibitor (ICI) treatment was started, which precipitated optic neuritis and myelitis despite IVIG and prednisone. Tocilizumab, an interleukin-6 receptor blocker, was started with excellent and sustained clinical and radiologic response. DISCUSSION: This case revealed a presentation of MOGAD concurrent with melanoma without tumor MOG immunostaining. We highlight tocilizumab as a dual-purpose treatment of MOGAD and the neurologic immune-related adverse effect of ICI.

Cerebrospinal fluid eosinophils in pediatric myelin oligodendrocyte glycoprotein antibody-associated disease.

BACKGROUND: Eosinophils in cerebrospinal fluid (CSF) are an uncommon finding most often associated with parasitic infections, but have also been described in some neuroinflammatory disorders. Eosinophilic infiltration is not thought to be a typical feature of myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD). We aim to describe the rate of CSF eosinophil positivity in a cohort of pediatric MOGAD patients. METHODS: Single-center retrospective chart review of pediatric MOGAD patients. Clinical and laboratory data was collected from the electronic medical record and analyzed. RESULTS: Of 46 pediatric patients with positive serum myelin oligodendrocyte glycoprotein antibody (MOG-IgG) identified, 38 patients fulfilling internationally proposed MOGAD diagnostic criteria were included for analysis. 6 patients with MOGAD were excluded as no CSF data was available, and 2 patients with positive MOG-IgG but diagnosis more consistent with MS were excluded. Median age was 7.3 years, and 19/38 (50 %) were female. Acute disseminated encephalomyelitis (ADEM) was the most common presenting phenotype (23/38, 61 %), and other phenotypes included optic neuritis (10/38, 26 %), transverse myelitis (3/38, 8 %), and neuromyelitis optica spectrum disorder (NMOSD) (2/38, 5 %). 12 of 36 (33 %) patients with all lumbar puncture (LP) data available had CSF eosinophils present, with eosinophil mean of 3 % and range from 1 % to 18 % of CSF while blood cells. CONCLUSION: CSF eosinophils were present in one third of pediatric MOGAD patients, which is a higher rate than previously reported in either MOGAD or aquaporin-4 antibody positive NMOSD cohorts. Understanding the CSF composition of pediatric MOGAD patients helps to facilitate more prompt diagnosis and treatment and may shed light onto underlying pathologic mechanisms of disease with the goal to inform future therapeutic targets.

Seizures in inflammatory demyelinating disorders of the central nervous system.

BACKGROUND: Multiple sclerosis (MS), neuromyelitis optica spectrum disorder (NMOSD), and myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) may be associated with acute symptomatic seizures and chronic epilepsy as well. The clinical features of the seizures and/or accompanying epilepsy seen in each disease group may vary. In this study, we aimed to contribute to the existing literature by describing the clinical features of seizures and epilepsy in our demyelinating patient population. METHODS: We retrospectively analyzed patients who were followed up in our tertiary referral center neurology demyelinating diseases outpatient clinic between 2019 and 2024. Patients who had at least one seizure before, simultaneously, or after the diagnosis of demyelinating disease were included in the study. RESULTS: Among 1735 patients with MS, 40 had experienced at least one epileptic seizure (2.3 %). Thirty patients (1.7 %) had seizures that could not be explained by another factor than MS. When secondary progressive MS (SPMS) and relapsing-remitting MS (RRMS) were compared, the interval between MS-epilepsy diagnosis was longer and seizure recurrence was more in SPMS. However, the prognosis of epilepsy was good in both subtypes. There were 21 patients followed up with antibody-positive neuromyelitis optica spectrum disorder. No patient had a seizure during the follow-up. We identified 56 patients who fulfilled the criteria for MOGAD with high antibody titers. Seizures were observed in three of them (5.4 %). All of them had status epilepticus either at the onset or during the course of the disease. CONCLUSION: Even rare, seizures constitute one of the important clinical features of the inflammatory demyelinating disorders of the central nervous system. The pathophysiologic mechanism underlying seizures in MS is still not clear. Seizures may occur through different mechanisms in patients where seizures are the initial symptom or a sign of relapse and those that occur spontaneously during the progressive course of the disease. Prevalence of status epilepticus was common in MOGAD patients. Given the rarity of the seizures in CNS demyelinating disorders, it is difficult the define clinical and pathophysiological characteristics of accompanying seizures and epilepsy. Future studies conducted on large patient groups will contribute to the existing literature.

Patterns and utility of myelin oligodendrocyte glycoprotein (MOG) antibody testing in cerebrospinal fluid.

BACKGROUND: Myelin oligodendrocyte glycoprotein (MOG) antibody-associated disease (MOGAD) is an idiopathic central nervous system (CNS) demyelinating disease gaining recognition with wider availability of cell-based assay (CBA) testing and recently published diagnostic criteria. However, uncertainty remains regarding the interpretation of antibody titers, particularly cerebrospinal fluid (CSF) MOG antibody titers. METHODS: All MOG IgG CBA results performed by the provincial MitogenDx laboratory in Alberta from July 2017 to July 2023 were retrieved. Chart review was performed in patients with both serum and CSF testing and ≥ 1 positive MOG antibody result. Demographics, antibody titers, clinical and imaging features, treatment, and diagnosis were analyzed based on serum/CSF status. RESULTS: Among 4494 MOG CBA assays, there were 413 CSF samples in 402 patients, and 268 patients had at least one associated serum sample. Mean time between CSF and serum testing was 20.9 days (range 0-870 days), most with testing within 30 days. Five of the 268 patients had serum positive/CSF positive MOG antibodies, 4 with acute disseminated encephalomyelitis and 1 with longitudinally extensive transverse myelitis. Twenty-three patients had serum positive/CSF negative MOG and 13/23 with optic neuritis. CSF MOG antibody positive patients were younger, and more likely to remain MOG seropositive versus CSF negative patients. No seronegative patient had MOG antibodies in CSF. CONCLUSIONS: In province-wide testing, CSF MOG antibodies were rare, only in MOG seropositive patients and none with optic neuritis. Our study does not support a clear role for CSF MOG antibody testing in the majority of patients, although further study is required.

Safety and efficacy of rituximab for relapse prevention in myelin oligodendrocyte glycoprotein immunoglobulin G (MOG-IgG)-associated disorders (MOGAD): A systematic review and meta-analysis.

INTRODUCTION: Myelin oligodendrocyte glycoprotein immunoglobulin G (MOG-IgG)-associated disorders (MOGAD) is neuroimmunological disorder manifesting as episodes of ADEM, optic neuritis, transverse myelitis, brainstem encephalitis, and other CNS manifestations and notably, distinct from multiple sclerosis (MS) and neuromyelitis optica spectrum disorders (NMOSD). Current treatment strategy is high-dose intravenous methylprednisolone followed by maintenance immunotherapy for relapse prevention. The purpose of this study is to systematically create compelling evidence addressing the role of rituximab in relapse prevention among patient with MOGAD. METHODS: This study follows the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guideline. We searched PubMed, Embase, and Google Scholar for English language papers published between 2010 and 2021. Individual study proportions were meta-analyzed to yield the pooled relapse-free patient proportion. Individual studies' mean pre- and post-treatment annualized relapse ratio (ARR) and Expanded Disability Status Scale (EDSS) were used to calculate the overall mean difference. RESULTS: Our meta-analysis includes 13 studies with 238 subjects. After rituximab treatment, 55% (95% CI: 0.49-0.61) of MOGAD patients remained relapse-free. Our study found that after rituximab therapy, ARR was lowered by 1.36 (95% CI 1.02-1.71, p < 0.001). Similarly, we detected a 0.52 (95% CI: 0.08 to 0.96, p = 0.02) difference in EDSS score after starting rituximab medication. Because only a handful of the included studies documented adverse events, the safety profile of rituximab for the treatment of MOGAD could not be effectively determined. CONCLUSION: Our meta-analysis shows that rituximab effectively prevents relapses in MOGAD patients.

Cortical and Subcortical Dysmetabolism Are Dynamic Markers of Clinical Disability and Course in Anti-LGI1 Encephalitis.

BACKGROUND AND OBJECTIVES: This [18F]fluorodeoxyglucose (FDG) PET study evaluates the accuracy of semiquantitative measurement of putaminal hypermetabolism in identifying anti-leucine-rich, glioma-inactivated-1 (LGI1) protein autoimmune encephalitis (AE). In addition, the extent of brain dysmetabolism, their association with clinical outcomes, and longitudinal metabolic changes after immunotherapy in LGI1-AE are examined. METHODS: FDG-PET scans from 49 age-matched and sex-matched subjects (13 in LGI1-AE group, 15 in non-LGI1-AE group, 11 with Alzheimer disease [AD], and 10 negative controls [NCs]) and follow-up scans from 8 patients with LGI1 AE on a median 6 months after immunotherapy were analyzed. Putaminal standardized uptake value ratios (SUVRs) normalized to global brain (P-SUVRg), thalamus (P/Th), and midbrain (P/Mi) were evaluated for diagnostic accuracy. SUVRg was applied for all other analyses. RESULTS: P-SUVRg, P/Th, and P/Mi were higher in LGI1-AE group than in non-LGI1-AE group, AD group, and NCs (all p < 0.05). P/Mi and P-SUVRg differentiated LGI1-AE group robustly from other groups (areas under the curve 0.84-0.99). Mediotemporal lobe (MTL) SUVRg was increased in both LGI1-AE and non-LGI1-AE groups when compared with NCs (both p < 0.05). SUVRg was decreased in several frontoparietal regions and increased in pallidum, caudate, pons, olfactory, and inferior occipital gyrus in LGI1-AE group when compared with that in NCs (all p < 0.05). In LGI1-AE group, both MTL and putaminal hypermetabolism were reduced after immunotherapy. Normalization of regional cortical dysmetabolism associated with clinical improvement at the 6- and 20-month follow-up. DISCUSSION: Semiquantitative measurement of putaminal hypermetabolism with FDG-PET may be used to distinguish LGI1-AE from other pathologies. Metabolic abnormalities in LGI1-AE extend beyond putamen and MTL into other subcortical and cortical regions. FDG-PET may be used in evaluating disease evolution in LGI1-AE. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that semiquantitative measures of putaminal metabolism on PET can differentiate patients with LGI1-AE from patients without LGI1-AE, patients with AD, or NCs.

Interleukin-6 Receptor Blockade in Treatment-Refractory MOG-IgG-Associated Disease and Neuromyelitis Optica Spectrum Disorders.

BACKGROUND AND OBJECTIVES: To evaluate the long-term safety and efficacy of tocilizumab (TCZ), a humanized anti-interleukin-6 receptor antibody in myelin oligodendrocyte glycoprotein-IgG-associated disease (MOGAD) and neuromyelitis optica spectrum disorders (NMOSD). METHODS: Annualized relapse rate (ARR), Expanded Disability Status Scale score, MRI, autoantibody titers, pain, and adverse events were retrospectively evaluated in 57 patients with MOGAD (n = 14), aquaporin-4 (AQP4)-IgG seropositive (n = 36), and seronegative NMOSD (n = 7; 12%), switched to TCZ from previous immunotherapies, particularly rituximab. RESULTS: Patients received TCZ for 23.8 months (median; interquartile range 13.0-51.1 months), with an IV dose of 8.0 mg/kg (median; range 6-12 mg/kg) every 31.6 days (mean; range 26-44 days). For MOGAD, the median ARR decreased from 1.75 (range 0.5-5) to 0 (range 0-0.9; p = 0.0011) under TCZ. A similar effect was seen for AQP4-IgG+ (ARR reduction from 1.5 [range 0-5] to 0 [range 0-4.2]; p < 0.001) and for seronegative NMOSD (from 3.0 [range 1.0-3.0] to 0.2 [range 0-2.0]; p = 0.031). During TCZ, 60% of all patients were relapse free (79% for MOGAD, 56% for AQP4-IgG+, and 43% for seronegative NMOSD). Disability follow-up indicated stabilization. MRI inflammatory activity decreased in MOGAD (p = 0.04; for the brain) and in AQP4-IgG+ NMOSD (p < 0.001; for the spinal cord). Chronic pain was unchanged. Regarding only patients treated with TCZ for at least 12 months (n = 44), ARR reductions were confirmed, including the subgroups of MOGAD (n = 11) and AQP4-IgG+ patients (n = 28). Similarly, in the group of patients treated with TCZ for at least 12 months, 59% of them were relapse free, with 73% for MOGAD, 57% for AQP4-IgG+, and 40% for patients with seronegative NMOSD. No severe or unexpected safety signals were observed. Add-on therapy showed no advantage compared with TCZ monotherapy. DISCUSSION: This study provides Class III evidence that long-term TCZ therapy is safe and reduces relapse probability in MOGAD and AQP4-IgG+ NMOSD.

Clinicoradiological comparative study of Aquaporin-4-IgG seropositive neuromyelitis optica spectrum disorder (NMOSD) and MOG antibody associated disease (MOGAD): A prospective observational study and review of literature.

Neuromyelitis Optica spectrum disorders (NMOSD) are autoimmune inflammatory central nervous system diseases. NMOSD patients typically have recurrent attacks of severe optic neuritis or/and myelitis with majority of them having autoantibodies against the aquaporin-4 (AQP4). In the recent past, a robust association of autoantibodies to full-length human myelin oligodendrocyte glycoprotein (MOG-IgG) with optic neuritis, myelitis and brainstem encephalitis, as well as with acute disseminated encephalomyelitis (ADEM)-like presentations had been demonstrated. MOG-IgG antibody associated disease (MOGAD) is now considered as a disease entity in its own right, distinct from classic MS and from AQP4-IgG-positive NMOSD. Here, we compared the clinical, laboratory, radiological features and treatment outcomes of patients with Aquaporin-4-IgG seropositive NMOSD and MOGAD. Relatively younger age at onset, lesser number of relapses, better response to treatment and favorable clinical outcomes were found in MOGAD group in comparison to AQP4-IgG-positive NMOSD group.

Anti-MAG neuropathy: From biology to clinical management.

The acquired chronic demyelinating neuropathies include a growing number of disease entities that have characteristic, often overlapping, clinical presentations, mediated by distinct immune mechanisms, and responding to different therapies. After the discovery in the early 1980s, that the myelin associated glycoprotein (MAG) is a target antigen in an autoimmune demyelinating neuropathy, assays to measure the presence of anti-MAG antibodies were used as the basis to diagnose the anti-MAG neuropathy. The route was open for describing the clinical characteristics of this new entity as a chronic distal large fiber sensorimotor neuropathy, for studying its pathogenesis and devising specific treatment strategies. The initial use of chemotherapeutic agents was replaced by the introduction in the late 1990s of rituximab, a monoclonal antibody against CD20+ B-cells. Since then, other anti-B cells agents have been introduced. Recently a novel antigen-specific immunotherapy neutralizing the anti-MAG antibodies with a carbohydrate-based ligand mimicking the natural HNK-1 glycoepitope has been described.

Risk factors for idiopathic myelitis at admission and predictors for late diagnostic change.

Immune-mediated myelopathy (IMM) diagnosis is challenging, and its etiology may remain unclear despite extensive investigation. We evaluated diagnostic changes in IMM patients during follow-up. We included 80 patients, 61.3% female, with median follow-up time 62.5 months. Diagnoses at discharge were: 48.8% Multiple Sclerosis-IMM (MS-IMM), 32.5% I-IMM, 11.3% Neuromyelitis Optica Spectrum Disorders-IMM (NMOSD-IMM), 1.3% MOG encephalomyelitis (MOGAD), and 6.2% Others IMM (O-IMM). Twenty-two  patients (27.5%) changed diagnosis (median 15.5  months): 68.8% MS-IMM, 12.5%  NMOSD-IMM, 3.8% MOGAD, 10.0% I-IMM, and 5.0% O-IMM. Most patients that changed diagnosis were I-IMM. Predictive factors for diagnostic change in I-IMM were: autonomous gait (p = 0.029), lesions suggestive of MS (p = 0.039), higher number of lesions (p = 0.043), lesions length < 3 vertebral bodies (p = 0.033), cervical involvement (p = 0.038), and lower EDSS at admission (p = 0.013). Etiologic reclassifications in IMM are common, therefore patients require an appropriate follow-up time to increase diagnostic accuracy.

Evidence for and against subclinical disease activity and progressive disease in MOG antibody disease and neuromyelitis optica spectrum disorder.

Myelin oligodendrocyte glycoprotein antibody disease (MOGAD) and aquaporin-4 IgG seropositive neuromyelitis optica spectrum disorder (AQP4-IgG+ NMOSD) are generally considered to be relapsing disorders, without clinical progression or subclinical disease activity outside of clinical relapses, in contrast to multiple sclerosis (MS). With advances in the diagnosis and treatment of these conditions, prolonged periods of remission without relapses can be achieved, and the question of whether progressive disease courses can occur has re-emerged. In this review, we focus on studies exploring evidence for and against relapse-independent clinical progression and/or subclinical disease activity in patients with MOGAD and AQP4-IgG+ NMOSD.

CNS Demyelinating Attacks Requiring Ventilatory Support With Myelin Oligodendrocyte Glycoprotein or Aquaporin-4 Antibodies.

BACKGROUND AND OBJECTIVE: Severe attacks of myelin oligodendrocyte glycoprotein (MOG) antibody-associated disorder (MOGAD) and aquaporin-4 (AQP4) antibody-positive neuromyelitis optica spectrum disorder (AQP4-NMOSD) may require ventilatory support, but data on episodes are limited, particularly for MOGAD. We sought to compare the frequency, characteristics, and outcomes of MOGAD and AQP4-NMOSD attacks requiring ventilatory support. METHODS: This retrospective descriptive study identified Mayo Clinic patients (January 1, 1996-December 1, 2020) with MOGAD or AQP4-NMOSD and an attack requiring noninvasive or invasive ventilation at Mayo Clinic or an outside facility by searching for relevant terms in their electronic medical record. Inclusion criteria were (1) attack-related requirement for noninvasive (bilevel positive airway pressure or continuous positive airway pressure) or invasive respiratory support (mechanical ventilation); (2) MOG or AQP4 antibody positivity with fulfillment of MOGAD and AQP4-NMOSD clinical diagnostic criteria, respectively; and (3) sufficient clinical details. We collected data on demographics, comorbid conditions, indication for and duration of respiratory support, MRI findings, treatments, and outcomes. The races of those with attacks requiring respiratory support were compared to those without such attacks in MOGAD and AQP4-NMOSD. RESULTS: Attacks requiring ventilatory support were similarly rare in patients with MOGAD (8 of 279, 2.9%) and AQP4-NMOSD (11 of 503 [2.2%]) (p = 0.63). The age at attack (median years [range]) (MOGAD 31.5 [5-47] vs AQP4-NMOSD 43 [14-65]; p = 0.01) and percentage of female sex (MOGAD 3 of 8 [38%] vs AQP4-NMOSD 10 of 11 [91%]; p = 0.04) differed. The reasons for ventilation differed between MOGAD (inability to protect airway from seizure, encephalitis or encephalomyelitis with attacks of acute disseminated encephalomyelitis 5 [62.5%] or unilateral cortical encephalitis 3 [37.5%]) and AQP4-NMOSD (inability to protect airway from cervical myelitis 9 [82%], rhombencephalitis 1 [9%], or combinations of both 1 [9%]). Median ventilation duration for MOGAD was 2 days (range 1-7 days) vs 19 days (range 6-330 days) for AQP4-NMOSD (p = 0.01). All patients with MOGAD recovered, but 2 of 11 (18%) patients with AQP4-NMOSD died of the attack. For AQP4-NMOSD, Black race was overrepresented for attacks requiring ventilatory support vs those without these episodes (5 of 11 [45%] vs 88 of 457 [19%]; p = 0.045). DISCUSSION: Ventilatory support is rarely required for MOGAD and AQP4-NMOSD attacks, and the indications differ. Compared to MOGAD, these attacks in AQP4-NMOSD may have higher morbidity and mortality, and those of Black race were more predisposed, which we suspect may relate to socially mediated health inequality.

Myelin-oligodendrocyte glycoprotein antibody-associated disease.

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.

C3 and C4 complement levels in AQP4-IgG-positive NMOSD and in MOGAD.

While complement-dependent cytotoxicity (CDC) is a known effector mechanism in aquaporin-4-immunoglobulin (Ig)G-positive (AQP4-IgG+) neuromyelitis optica spectrum disorder (NMOSD), the role of CDC in myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) is less clear. We determined complement C3 and C4 plasma concentrations in patients with clinically stable AQP4-IgG+ NMOSD (n = 16), MOGAD (n = 15), early multiple sclerosis (MS, n = 19) and in healthy controls (HC, n = 18). C4 was lower in AQP4-IgG+ NMOSD than in MOGAD, MS and HC (p < 0.05, pairwise comparisons). C3 was lower in AQP4-IgG+ NMOSD than in MS (p = 0.034). These findings suggest subtle complement consumption in clinically stable AQP4-IgG+ NMOSD, but not in MOGAD.

Case Report: Myelin Oligodendrocyte Glycoprotein Antibody-Associated Disorder Masquerading as Multiple Sclerosis: An Under-Recognized Entity?

Myelin oligodendrocyte glycoprotein (MOG) antibody-associated disease (MOGAD) covers a wide spectrum of manifestations and is defined by the presence of MOG seropositivity. However, in a proportion of patients, there may be an overlap in some of the clinical and radiological manifestations between MOGAD and multiple sclerosis (MS). Being wary of this entity is critical to ensure appropriate therapy. Herein, we present a case with recurrent episodes of short-segment myelitis typical for multiple sclerosis, but later diagnosed as MOGAD by MOG antibody seropositivity. This case, along with previous reports, highlights an increasingly recognized subgroup in MOGAD with initial clinical phenotypes suggestive of MS, but later showing a disease course and therapeutic response compatible with MOGAD. Given the potential overlap of some clinical phenotypes in patients with MS and those with MOGAD, we recommend MOG antibody testing in all patients with recurrent short-segment myelitis, conus medullaris involvement, and those who demonstrated steroid dependence.

Aseptic meningitis and leptomeningeal enhancement associated with anti-MOG antibodies: A review.

BACKGROUND: Aseptic meningitis can be caused by autoimmune diseases, such as lupus and sarcoidosis. Aseptic meningitis with leptomeningeal enhancement can be the initial presentation of a neuroinflammatory syndrome associated with antibodies to myelin oligodendrocyte glycoprotein (MOG-abs). MOG-abs is a serum biomarker for MOG-associated disorder (MOG-AD), an acquired demyelinating syndrome that includes features of neuromyelitis optica, multiple sclerosis, optic neuritis, and acute disseminated encephalomyelitis. The purpose of this study is to review cases of aseptic meningitis and leptomeningeal enhancement associated with MOG-abs. METHODS: Systematic review using PubMed, Embase, Ovid MEDLINE, Web of Science Core Collection, and Google Scholar up to December 2020 was performed. Cases of MOG-AD were included if they met the following criteria: 1) Initial clinical presentation of aseptic meningitis; 2) positive leptomeningeal enhancement and 3) MOG-Ab seropositivity. Descriptive statistics were used. This analysis was limited to the cases available in the literature. RESULTS: 11 total cases of aseptic meningitis and leptomeningeal enhancement in setting of MOG-ab were identified. Demyelinating type T2 lesions were also present at time of presentation in 6/11; however, 5/11 of patients had leptomeningeal enhancement alone without demyelinating lesions. All 5 patients required immunotherapy for improvement, including one patient with symptoms for 28 days, with 4/5 receiving steroids and 1/5 receiving intravenous immunoglobulin (IVIG). CONCLUSIONS: Aseptic meningitis with leptomeningeal enhancement can be the initial presenting symptom of MOG-AD. MOG-ab testing should be considered in a patient presenting with aseptic meningitis and leptomeningeal enhancement of unknown etiology.