Myelitis in inflammatory disorders associated with myelin oligodendrocyte glycoprotein antibody and aquaporin-4 antibody: A comparative study in Chinese Han patients

NMOSD and MOGAD: an evolving disease spectrum

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.

MOG-antibody-associated transverse myelitis with the H-sign and unusual MRI enhancement: a case report and literature review

Transverse myelitis is the second most common symptoms in myelin oligodendrocyte antibody-associated diseases (MOGAD), causing obvious clinical manifestation. T2-hyperintense lesions mainly restricted to the gray matter in the spinal cord on axial magnetic resonance imaging, produce the H-sign, which is thought to be the typical finding of MOGAD. Contrast enhancement can be observed in some cases of myelin oligodendrocyte antibody-associated transverse myelitis (MOG-TM). However, reports on the enhancement pattern associated with the H-sign are rarely seen. In this report, we describe a case of pediatric MOG-TM in which the H-sign was observed without enhancement, while the surrounding white matter exhibited enhancement. This pattern contradicts the previously observed gray matter involvement. Then we reviewed the literatures of myelin oligodendrocyte antibody-positive myelitis to focus on the neuroimaging features and discuss the implications of our finding.

Spinal movement disorders in NMOSD, MOGAD, and idiopathic transverse myelitis: a prospective observational study

BACKGROUND

Retrospective studies suggest that spinal movement disorders, especially tonic spasms, are prevalent in NMOSD. However, there have been no prospective studies evaluating spinal movement disorders in NMOSD, MOGAD, and idiopathic transverse myelitis (ITM).

METHODS

Patients referred to a tertiary neuroimmunology clinic for spinal cord demyelination (excluding MS) were evaluated. All patients answered a movement disorders survey and underwent a movement disorder-focused exam. Movement disorders were compared among patients with NMOSD with and without AQP4-IgG, MOGAD, and ITM. Patients with and without involuntary movements were also compared to identify predictors of spinal movement disorders.

RESULTS

Sixty-three patients were evaluated from 2017 to 2021 (71% females, median age 49 years, range 18-72 years, median disease duration 12 months, range 1-408). Of the total, 49% had ITM, 21% had NMOSD without AQP4-IgG, 19% had NMOSD with AQP4-IgG, and 11% had MOGAD. Movement disorders were present in 73% of the total patients and were most frequent in NMOSD with AQP4-IgG (92%) and least frequent in MOGAD (57%). The most frequent spinal movement disorders were tonic spasms (57%), focal dystonia (25%), spinal tremor (16%), spontaneous clonus (9.5%), secondary restless limb syndrome (9.5%), and spinal myoclonus (8%). Multivariate analysis showed that longitudinally extensive myelitis and AQP4-IgG are independent risk factors for the development of spinal movement disorders, while MOG-IgG and African American race were associated with a lower risk of developing these movement disorders.

CONCLUSIONS

Spinal movement disorders are highly prevalent in non-MS demyelinating disorders of the spinal cord. Prevalence rates exceed those reported in MS and retrospective NMOSD studies.

MOG Antibody Disease: Nuances in Presentation, Diagnosis, and Management

PURPOSE OF REVIEW

Myelin oligodendrocyte glycoprotein antibody disease (MOGAD) is a distinct neuroinflammatory condition characterized by attacks of optic neuritis, transverse myelitis, and other demyelinating events. Though it can mimic multiple sclerosis and neuromyelitis optica spectrum disorder, distinct clinical and radiologic features which can discriminate these conditions are now recognized. This review highlights recent advances in our understanding of clinical manifestations, diagnosis, and treatment of MOGAD.

RECENT FINDINGS

Studies have identified subtleties of common clinical attacks and identified more rare phenotypes, including cerebral cortical encephalitis, which have broadened our understanding of the clinicoradiologic spectrum of MOGAD and culminated in the recent publication of proposed diagnostic criteria with a familiar construction to those diagnosing other neuroinflammatory conditions. These criteria, in combination with advances in antibody testing, should simultaneously lead to wider recognition and reduced incidence of misdiagnosis. In addition, recent observational studies have raised new questions about when to treat MOGAD chronically, and with which agent. MOGAD pathophysiology informs some of the relatively unique clinical and radiologic features which have come to define this condition, and similarly has implications for diagnosis and management. Further prospective studies and the first clinical trials of therapeutic options will answer several remaining questions about the peculiarities of this condition.

Clinical analysis of myelin oligodendrocyte glycoprotein antibody-associated disease in a diverse cohort of children: A single-center observational study

BACKGROUND

Prognostic markers for relapse and neurological disability following the first clinical event in children with myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) remain lacking. We investigated the clinical profiles and early prognostic factors associated with relapsing disease or impaired functional outcome in a large single-center cohort of pediatric MOGAD.

METHODS

We retrospectively analyzed the clinical and paraclinical data and treatment outcomes of children with MOGAD seen at Children's Health in Dallas, Texas from 2009 to 2022. Univariate analyses were used to evaluate factors from initial event associated with relapsing disease course and impaired functional outcome (modified Rankin scale [mRS] >1) at final follow-up.

RESULTS

Our cohort comprised of 87 children of diverse race/ethnicity. Presentation with acute disseminated encephalomyelitis (ADEM) was more frequent in children aged ≤8 years and Caucasian background, whereas presentation with optic neuritis was more common in children aged >8 years and other race/ethnicity. 44.3 % (27/61) had relapsing disease course, of whom 48.0 % had multiple relapses. 30.3 % (23/76) had final mRS >1. Children with abnormal electroencephalogram had reduced relapse risk. Children with ADEM presentation, severe disease, low MOG-IgG titer, and central and systemic inflammation (represented by cerebrospinal fluid pleocytosis and serum leukocytosis, respectively) at onset had higher likelihood of final mRS >1.

CONCLUSION

Abnormal electroencephalogram at the first event was associated with reduced relapse risk while disease severity and peripheral inflammation significantly contributed to final neurological disability. Further studies are needed to validate these findings as early risk factors for disability and relapse and to identify optimal treatment strategies.

Delimiting MOGAD as a disease entity using translational imaging

The first formal consensus diagnostic criteria for myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) were recently proposed. Yet, the distinction of MOGAD-defining characteristics from characteristics of its important differential diagnoses such as multiple sclerosis (MS) and aquaporin-4 antibody seropositive neuromyelitis optica spectrum disorder (NMOSD) is still obstructed. In preclinical research, MOG antibody-based animal models were used for decades to derive knowledge about MS. In clinical research, people with MOGAD have been combined into cohorts with other diagnoses. Thus, it remains unclear to which extent the generated knowledge is specifically applicable to MOGAD. Translational research can contribute to identifying MOGAD characteristic features by establishing imaging methods and outcome parameters on proven pathophysiological grounds. This article reviews suitable animal models for translational MOGAD research and the current state and prospect of translational imaging in MOGAD.

Comparison of glial fibrillary acidic protein-immunoglobulin G-associated myelitis with myelin oligodendrocyte glycoprotein-immunoglobulin G-associated myelitis

Objective

Glial fibrillary acidic protein-immunoglobulin G (GFAP-IgG)-associated myelitis and myelin oligodendrocyte glycoprotein-IgG (MOG-IgG)-associated myelitis have rarely been compared. Therefore, this study aimed to explore the clinical, laboratory, and imaging features of them to identify the differences.

Methods

Overall, 14 and 24 patients with GFAP-IgG-and MOG-IgG-associated myelitis, respectively, were retrospectively screened and included in the study.

Results

Among the 14 patients with GFAP-IgG-associated myelitis, the condition was more common in males (71.4%), with a median age of onset of 36.5 years, and more common in adults than in children (35.7%). In contrast, among the 24 patients with MOG-IgG-associated myelitis, the condition was equally divided between males and females, with a median age of onset of 9.5 years and more in children (66.7%) than in adults. The median age of onset of GFAP-IgG-associated myelitis was later than that of the MOG-IgG group. Isolated myelitis was rare in both groups. Elevated cerebrospinal fluid (CSF) protein levels were more prevalent in patients with GFAP-IgG-associated myelitis (64.3%) than in those with MOG-IgG-associated myelitis (16.7%) (p < 0.05), whereas patchy gadolinium enhancement of the cerebral lesion site was less common in patients with GFAP-IgG-associated myelitis than in those with MOG-IgG associated myelitis (p < 0.05). Six patients had a combination of other neurological autoantibodies, the specific mechanism of the overlapping antibodies remains unclear.

Conclusion

Cerebrospinal fluid analysis and gadolinium enhanced MRI examination may help to distinguish the two kinds of myelitis.

Clinical feature and disease outcome in patients with myelin oligodendrocyte glycoprotein antibody-associated disorder: a Chinese study

BACKGROUND

To identify factors associated with relapse risk and disability in myelin oligodendrocyte glycoprotein antibody-associated disorder (MOGAD).

METHOD

Between 2016 and 2021, 186 patients with MOGAD were included in the study. Factors associated with a relapsing course, annualised relapse rate (ARR), recurrent relapses under different maintenance treatments and unfavourable disability outcome were analysed.

RESULTS

MOGAD affects women (53.8%) slightly more often than men. After a median disease duration of 51.0 months, 60.2% (112/186) relapsed, with an overall ARR of 0.5. The ARR (0.6 vs 0.4, p=0.049), median Expanded Disability Status Scale (EDSS) score (1 (range 0-9.5) vs 1 (range 0-3.5), p=0.005) and Visual Functional System Score (VFSS) (0 (range 0-6) vs 0 (range 0-3), p=0.023) at last visit were higher in adults than in children, and time to first relapse was shorter in adults than in children (4.1 (range 1.0-111.0) vs 12.2 (range 1.3-266.8) months, p=0.001). Myelin oligodendrocyte glycoprotein antibody (MOG-ab) persistence over 1 year was associated with a relapsing course (OR 7.41, 95% CI 2.46 to 22.33, p=0.000), while timely maintenance therapy was associated with a lower ARR (p=0.008). More than four attacks (OR 4.86, 95% CI 1.65 to 14.28, p=0.004) and poor recovery from the first attack (OR 75.28, 95% CI 14.45 to 392.05, p=0.000) were associated with an unfavourable outcome (EDSS score ≥2 including VFSS ≥2).

CONCLUSIONS

The results underscored the importance of timely maintenance treatment to prevent further relapses, especially in adult patients with persistently positive MOG-ab and unsatisfactory recovery from the onset attack.

The Potential Pathogenicity of Myelin Oligodendrocyte Glycoprotein Antibodies in the Optic Pathway

BACKGROUND

Myelin oligodendrocyte glycoprotein (MOG) antibody-associated disease (MOGAD) is an acquired inflammatory demyelinating disease with optic neuritis (ON) as the most frequent clinical symptom. The hallmark of the disease is the presence of autoantibodies against MOG (MOG-IgG) in the serum of patients. Whereas the role of MOG in the experimental autoimmune encephalomyelitis animal model is well-established, the pathogenesis of the human disease and the role of human MOG-IgG is still not fully clear.

EVIDENCE ACQUISITION

PubMed was searched for the terms "MOGAD," "optic neuritis," "MOG antibodies," and "experimental autoimmune encephalomyelitis" alone or in combination, to find articles of interest for this review. Only articles written in English language were included and reference lists were searched for further relevant papers.

RESULTS

B and T cells play a role in the pathogenesis of human MOGAD. The distribution of lesions and their development toward the optic pathway is influenced by the genetic background in animal models. Moreover, MOGAD-associated ON is frequently bilateral and often relapsing with generally favorable visual outcome. Activated T-cell subsets create an inflammatory environment and B cells are necessary to produce autoantibodies directed against the MOG protein. Here, pathologic mechanisms of MOG-IgG are discussed, and histopathologic findings are presented.

CONCLUSIONS

MOGAD patients often present with ON and harbor antibodies against MOG. Furthermore, pathogenesis is most likely a synergy between encephalitogenic T and antibody producing B cells. However, to which extent MOG-IgG are pathogenic and the exact pathologic mechanism is still not well understood.

Diagnosis of myelin oligodendrocyte glycoprotein antibody-associated disease: International MOGAD Panel proposed criteria

Serum antibodies directed against myelin oligodendrocyte glycoprotein (MOG) are found in patients with acquired CNS demyelinating syndromes that are distinct from multiple sclerosis and aquaporin-4-seropositive neuromyelitis optica spectrum disorder. Based on an extensive literature review and a structured consensus process, we propose diagnostic criteria for MOG antibody-associated disease (MOGAD) in which the presence of MOG-IgG is a core criterion. According to our proposed criteria, MOGAD is typically associated with acute disseminated encephalomyelitis, optic neuritis, or transverse myelitis, and is less commonly associated with cerebral cortical encephalitis, brainstem presentations, or cerebellar presentations. MOGAD can present as either a monophasic or relapsing disease course, and MOG-IgG cell-based assays are important for diagnostic accuracy. Diagnoses such as multiple sclerosis need to be excluded, but not all patients with multiple sclerosis should undergo screening for MOG-IgG. These proposed diagnostic criteria require validation but have the potential to improve identification of individuals with MOGAD, which is essential to define long-term clinical outcomes, refine inclusion criteria for clinical trials, and identify predictors of a relapsing versus a monophasic disease course.

[Clinical features and modern diagnostic criteria of the disease associated with myelin oligodendrocyte glycoprotein antibody disease]

Demyelinating disease of the central nervous system associated with antibodies to myelin oligodendrocyte glycoprotein (MOGAD) has been proposed to be distinguished from neuromyelitis optica spectrum disorders (NMOSD) into a separate nosological form. The basis for the recognition of nosological independence was the presence of clinical features of this disease and the detection of a specific biomarker in the blood serum of patients - IgG class antibodies to MOG. The article summarizes the current data on the clinical and radiological phenotypes of MOGAD in children and adults and the features of the course of the disease. The requirements for the laboratory diagnosis of the disease and diagnostic criteria for MOGAD proposed by an international group of experts in 2023 are given.

Comparison on the effect of seven drugs to prevent relapses of neuromyelitis optica spectrum disorders: A modeling analysis of literature aggregate data

BACKGROUND

Neuromyelitis optica spectrum disorders (NMOSD) is an immune-mediated demyelinating disease of the central nervous system. This study aimed to perform a comprehensive comparison of the effect of seven drugs to prevent relapses of NMOSD.

METHOD

A literature search was conducted using public databases. Clinical studies on the seven drugs (eculizumab, inebilizumab, satralizumab, rituximab, tocilizumab, azathioprine, and mycophenolate mofetil) to prevent relapses of NMOSD were identified. A time-course model was established using the time to first relapse as the primary endpoint, in order to evaluate the long-term effect of each drug in preventing relapse.

RESULTS

Twenty-four trials, including 2207 patients, were included in the model analysis. The results showed that monoclonal antibody therapy could significantly prolong the time to first relapse. Among all seven drugs, eculizumab can most significantly prevent patient from relapse. The estimated proportion of relapse-free patients treated with eculizumab was 98.9% at 24 months.

CONCLUSION

Based on the construction of a time-course pharmacodynamic model, this study made a comprehensive quantitative comparison of seven drugs for the treatment of NMOSD for the first time. These results can not only serve as a quantitative supplement for the rational use of drugs in clinical practice but also provide a pharmacodynamic reference for clinical trial design and decision making in the future.

Clinical and Radiological Features of Myelin Oligodendrocyte Glycoprotein-Associated Myelitis in Adults

Antibodies against myelin oligodendrocyte glycoprotein (MOG-IgG) have recently been established as a biomarker for MOG-antibody-associated disease (MOGAD), which is a distinct demyelinating disease of the central nervous system. Among the diverse clinical phenotypes of MOGAD, myelitis is the second-most-common presentation in adults, followed by optic neuritis. While some features overlap, there are multiple reports of distinctive clinical and radiological features of MOG-IgG-associated myelitis, which are useful for differentiating MOGAD from both multiple sclerosis and neuromyelitis optica spectrum disorder. In this review we summarize the clinical and radiographic characteristics of MOG-IgG-associated myelitis with a particular focus on adult patients.

Efficacy of azathioprine, mycophenolate mofetil, and rituximab in the treatment of neuromyelitis optica spectrum disorder and analysis of prognostic factors

OBJECTIVE

The study aims to compare the efficacies of the immunosuppressants most commonly prescribed for patients with neuromyelitis optica spectrum disorder (NMOSD). The predictors, which might be associated with relapse and disability in NMOSD, were also analyzed.

METHODS

This retrospective study included NMOSD patients treated with azathioprine (AZA), mycophenolate mofetil (MMF), and rituximab (RTX). The annual relapse rate (ARR) and the incidence rates of adverse events were compared. Cox proportional-hazards model calculated the potential predictors of NMOSD relapse and disability.

RESULTS

A total of 83 patients were included. The median treatment time of AZA group (n = 34), MMF group (n = 20), and RTX group (n = 29) were 19.5, 15.5, and 12 months, respectively. ARR of the three groups reduced significantly after treatment. In the three groups, 55.9%, 50%, and 79.3% of patients, respectively, were free from relapse. However, the difference among the three groups was of no statistical significance, possibly due to the small sample size. During the treatment, 32.4%, 15%, and 24.1% of patients experienced adverse events in the AZA group, MMF group, and RTX group, respectively. Additionally, the multivariate Cox analyses indicated that history of a severe attack and disease duration were associated with the risk of relapse after immunotherapy. Late-onset (≥ 50 years old) NMOSD patients were probably more susceptible to motor disability, and those with optic neuritis at onset were more likely to develop visual disability.

CONCLUSIONS

AZA, MMF, and low-dose RTX were all effective in reducing the relapse rate in NMOSD. The age at onset, disease duration, history of severe attacks, and primary syndromes might be significant prognostic predictors in NMOSD.

Comparisons of clinical phenotype, radiological and laboratory features, and therapy of neuromyelitis optica spectrum disorder by regions: update and challenges

Neuromyelitis optica spectrum disorder (NMOSD) is an inflammatory demyelinating disease of the central nervous system (CNS) associated with autoantibody (ab) to aquaporin-4 (AQP4). There is obvious variation between regions and countries in the epidemiology, clinical features and management in NMOSD. Based on published population-based observation and cohort studies, the different clinical pattern of NMOSD has been seen in several geographical regions and some of these patients with NMOSD-like features do not fully meet the current diagnostic criteria, which is needed to consider the value of recently revised diagnostic criteria. At present, all treatments applied in NMOSD have made great progress, however, these treatments failed in AQP4 ab negative and refractory patients. Therefore, it is necessary to turn into an innovative idea and to open a new era of NMOSD treatment to develop novel and diverse targets and effective therapeutic drugs in NMOSD and to conduct the trails in large clinical samples and case-control studies to confirm their therapeutic effects on NMOSD in the future, which still remain a challenge.