Do Myelin Oligodendrocyte Glycoprotein Antibodies Represent a Distinct Syndrome?

MOG antibody prevalence in adult optic neuritis and clinical predictive factors for diagnosis: A Chinese cohort study

OBJECTIVE

Because AQP4/MOG antibody testing is not available in some parts of the world and there are often delays in obtaining results, it is particularly important to use clinical factors to predict the subtypes of adult optic neuritis (ON).

METHODS

This was a single-center retrospective cohort study.

RESULTS

The final analysis included 249 adult patients presenting with the first ON attack during January 2016 to January 2020. These included 109 (43.8%) AQP4-ON cases, 49 (19.7%) MOG-ON cases, and 91 (36.5%) Seronegative-ON cases. The proportion of optic disk swelling (ODS) and bilateral involvement in MOG-ON group was significantly higher than in the other two subgroups (P = 0.029, 0.001). The MOG-ON group had the best follow-up BCVA (P = 0.003). To predict adult AQP4-ON, unilateral involvement (sensitivity 0.88, NPV 0.77) was the most sensitivity predictors, while neurological history (specificity 0.96, PPV 0.65) and concomitant other autoimmune antibodies (specificity 0.76, PPV 0.65) were the most specific predictors. Using the parallel test 'unilateral or other autoimmune antibodies' increased sensitivity to 0.95, with an optimal NPV of 0.88. To predict adult MOG-ON, the most sensitive clinical characteristics were ODS (sensitivity 0.79, NPV 0.88), and follow-up VA ≤0.1logMAR (sensitivity 0.78, NPV 0.92), whereas the most specific values were prior neurological history or bilateral involvement, with specificities of 0.92 and 0.82, respectively. The sensitivity increased to 0.94, 0.97, and 0.97 when using the parallel clinical factors of 'bilateral or ODS or relapse', 'bilateral or ODS or follow-up VA ≤0.1logMAR', and 'ODS or follow-up VA ≤0.1logMAR', and the corresponding NPV (0.94, 0.97 vs 0.98).

CONCLUSION

The proportion of MOG-ON (19.7%) was less than that of AQP4-ON and Seronegative-ON. Moreover, MOG-ON had a better prognosis and was more likely to be associated with ODS or bilateral involvement. The use of parallel clinical parameters improved the sensitivity for the diagnosis of adult MOG-ON and AQP4-ON.

Neuromyelitis Optica Spectrum Disorders

PURPOSE OF REVIEW

This article reviews the cardinal clinical features, distinct immunopathology, current diagnostic criteria, relapse-related risk factors, emerging biomarkers, and evolving treatment strategies pertaining to neuromyelitis optica spectrum disorders (NMOSD).

RECENT FINDINGS

The discovery of the pathogenic aquaporin-4 (AQP4)-IgG autoantibody and characterization of NMOSD as an autoimmune astrocytopathy have spearheaded the identification of key immunologic therapeutic targets in this disease, including but not limited to the complement system, the interleukin 6 (IL-6) receptor, and B cells. Accordingly, four recent randomized controlled trials have demonstrated the efficacy of three new NMOSD therapies, namely eculizumab, satralizumab, and inebilizumab.

SUMMARY

Currently, NMOSD poses both diagnostic and treatment challenges. It is debated whether individuals who are seropositive for myelin oligodendrocyte glycoprotein (MOG)-IgG belong within the neuromyelitis optica spectrum. This discussion is fueled by disparities in treatment responses between patients who are AQP4-IgG seropositive and seronegative, suggesting different immunopathologic mechanisms may govern these conditions. As our understanding regarding the immune pathophysiology of NMOSD expands, emerging biomarkers, including serum neurofilament light chain and glial fibrillary acidic protein (GFAP), may facilitate earlier relapse detection and inform long-term treatment decisions. Future research focal points should include strategies to optimize relapse management, restorative treatments that augment neurologic recovery, and practical solutions that promote equitable access to approved therapies for all patients with NMOSD.

Update on glial antibody-mediated optic neuritis

Optic neuritis (ON) refers to inflammatory demyelinating lesions of the optic nerve, which can cause acute or subacute vision loss and is a major cause of vision loss in young adults. Much of our understanding of typical ON is from the Optic Neuritis Treatment Trial. Glial autoantibodies to aquaporin-4 immunoglobulin (AQP4-IgG) and myelin oligodendrocyte glycoprotein immunoglobulin (MOG-IgG) are recently established biomarkers of ON that have revolutionized our understanding of atypical ON. The detection of glial antibodies is helpful in the diagnosis, treatment, and follow-up of patients with different types of ON. AQP4-IgG and MOG-IgG screening is strongly recommended for patients with atypical ON. Research on the pathogenesis of NMOSD and MOGAD will promote the development and marketing of targeted immunotherapies. The application of new and efficient drugs, such as the selective complement C5 inhibitor, IL-6 receptor inhibitor, B cell-depleting agents, and drugs against other monoclonal antibodies, provides additional medical evidence. This review provides information on the diagnosis and management of glial antibody-mediated ON.

Vision Prognosis and Associated Factors of Optic Neuritis in Dependence of Glial Autoimmune Antibodies

PURPOSE

To assess the visual prognosis of optic neuritis (ON) in dependence of the glial autoimmune antibody status and associated factors.

DESIGN

Longitudinal observational cohort study.

METHODS

Patients with ON and measurements of serum concentrations of glial autoantibodies were consecutively and longitudinally examined with a minimal follow-up of 3 months. Patients with multiple sclerosis and double seronegative results were excluded.

RESULTS

The study included 529 patients (aquaporin-4 immunoglobulin [AQP4-IgG] seropositive, n = 291; myelin oligodendrocyte glycoprotein immunoglobulin [MOG-IgG] seropositive, n = 112; double-seronegative, n = 126) with 1022 ON episodes (AQP4-IgG seropositive, n = 550; MOG-IgG seropositive, n=254; double-seronegative, n = 218). Prevalence of severe vision loss (best-corrected visual acuity [BCVA] ≤20/200 at the end of follow-up) was higher (P < .001) in the AQP4-IgG group (236/550; 42.9%) than in the seronegative group (68/218; 31.2%) and in the MOG-IgG group (15/254; 5.9%). Prevalence of good vision recovery (BCVA≥20/40) was higher (P < .001) in the MOG-IgG group (229/254; 90.2%) than in the seronegative group (111/218; 50.9%) and in the AQP4-IgG group (236/550; 42.9%). In multivariable logistic analysis, higher prevalence of severe vision loss was associated with AQP4-IgG seropositivity (odds ratio [OR] 1.66; 95% CI 1.14, 2.43; P = .008), male sex (OR 1.97, 95% CI 1.33, 2.93; P < .001), age at ON onset >45 years (OR 1.93, 95% CI 1.35, 2.77; P < .001), nadir vision ≤20/200 (OR 14.11, 95% CI 6.54, 36.93; P < .001), and higher number of recurrences (OR 1.35, 95% CI 1.14, 1.61; P = .001). Higher prevalence of good vision outcome was associated with MOG-IgG seropositivity (OR 8.13, 95% CI 4.82, 14.2; P < .001), age at ON onset <18 years (OR 1.78, 95% CI 1.18, 2.71; P = .006), nadir visual acuity ≥20/40 (OR 4.03; 95% CI 1.45, 14.37; P = .015), and lower number of recurrences (OR 0.60; 95% CI 0.50, 0.72; P < .001).

CONCLUSION

Severe vision loss (prevalence in the AQP4-IgG group, MOG-IgG group, and seronegative group: 42.9%, 5.9%, and 31.2%, respectively) was associated with AQP4-IgG seropositivity, male gender, older age at onset, worse nadir vision, and higher number of recurrences.

The occurrence of myelin oligodendrocyte glycoprotein antibodies in aquaporin-4-antibody seronegative Neuromyelitis Optica Spectrum Disorder: A systematic review and meta-analysis

BACKGROUND

Despite inclusion in neuromyelitis optica spectrum disorders (NMOSD), myelin oligodendrocyte glycoprotein antibody (MOG-Ab)-associated diseases are increasingly recognized as an independent disease entity. In this study, we conducted a systematic review and meta-analysis to comprehensively update the rate of occurrence of MOG-Ab in Aquaporin4 (AQP4)-antibody seronegative NMOSD.

METHODS

We searched PubMed, EMBASE, and Cochrane databases for studies reporting the rates of patients with MOG-Ab in NMOSD. Fixed or random-effects models were used to pool results across studies.

RESULTS

Fourteen studies met the inclusion criteria. Overall, MOG-Abs positive patients comprised 9.3% of all NMO/NMOSD (95% confidence interval [CI] 7.9%-10.8%, I² = 13.1%), 32.5% of all AQP4-Ab seronegative NMO/NMOSD (95% CI 25.7%-39.3%, I² = 45.8%), and 41.6% of AQP4-Ab seronegative NMOSD cases diagnosed by IPND 2015 criteria (95% CI 35.1%-48.2%, I² = 0.0%). The pooled prevalence of MOG-Ab was 31.0% among Asian AQP4-Ab seronegative NMO/NMOSD patients (95% CI 22.1%-39.9% I²=54.1%) and 34.3% in European seronegative NMO/NMOSD (95% CI 21.9%-46.7%, I² = 51.9%).

CONCLUSIONS

This study shows that MOG-Abs represent a substantial proportion of AQP4-Ab seronegative NMOSD patients despite different underlying mechanisms, clinical manifestations, and treatment response, suggesting MOG-Ab screening in AQP4-Ab seronegative NMOSD patients can facilitate accurate diagnoses and treatments.

Clinical Characteristics and Treatment of MOG-IgG-Associated Optic Neuritis

PURPOSE OF REVIEW

Antibodies against myelin oligodendrocyte glycoprotein (MOG) are associated with a unique acquired central nervous system demyelinating disease-termed MOG-IgG-associated disorder (MOGAD)-which has a variety of clinical manifestations, including optic neuritis, transverse myelitis, acute disseminating encephalomyelitis, and brainstem encephalitis. In this review, we summarize the current knowledge of the clinical characteristics, neuroimaging, treatments, and outcomes of MOGAD, with a focus on optic neuritis.

RECENT FINDINGS

The recent development of a reproducible, live cell-based assay for MOG-IgG, has improved our ability to identify and study this disease. Based on contemporary studies, it has become increasingly evident that MOGAD is distinct from multiple sclerosis and aquaporin-4-positive neuromyelitis optica spectrum disorder with different clinical features and treatment outcomes. There is now sufficient evidence to separate MOGAD from other inflammatory central nervous system demyelinating disorders, which will allow focused research on understanding the pathophysiology of the disease. Prospective treatment trials are needed to determine the best course of treatment, and until then, treatment plans must be individualized to the clinical manifestations and severity of disease.

Optic neuritis in the era of biomarkers

The Optic Neuritis Treatment Trial, a landmark study completed in 1991, stratified the risk of multiple sclerosis in patients with optic neuritis. Since that time, unique biomarkers for optic neuritis have been found. The antibody against aquaporin-4 (AQP4)-immunoglobulin G (IgG) discovered in 2004 was found to be both the pathologic cause and a reliable biomarker for neuromyelitis optica spectrum disorders. This finding enabled an expanded definition of the phenotype of neuromyelitis optica spectrum disorder and improved treatment of the disease. Subsequently, myelin oligodendrocyte glycoprotein (MOG) IgG was recognized to be a marker for MOG-IgG-associated disorder, a central demyelinating disease characterized by recurrent optic neuritis, prominent disk edema, and perineural optic nerve enhancement on magnetic resonance imaging. Most multiple sclerosis disease-modifying agents are ineffective for AQP4-IgG-positive neuromyelitis optica spectrum disorder and MOG-IgG-associated disorder. Because there are crucial differences in treatment and prognosis between multiple sclerosis, AQP4-IgG-positive neuromyelitis optica spectrum disorder, and MOG-IgG-associated disorder, ophthalmologists should be aware of these new biomarkers of optic neuritis and incorporate their testing in all patients with atypical optic neuritis.