Myelin Oligodendrocyte Glycoprotein Antibody-Positive Optic Neuritis: Clinical Characteristics, Radiologic Clues, and Outcome

Possible clinical role of MOG antibody testing in children presenting with acute neurological symptoms

The differential diagnosis between acquired inflammatory demyelinating syndromes of the central nervous system (CNS), such as multiple sclerosis (MS), neuromyelitis optica spectrum disorders (NMOSD) and acute disseminated encephalomyelitis (ADEM) can be very challenging at onset. Apart from cerebrospinal fluid oligoclonal bands and anti-aquaporin-4 antibodies (AQP4-Ab), definite diagnostic biomarkers are lacking. Anti-myelin oligodendrocyte glycoprotein antibodies (MOG-Abs) have been increasingly described in children with AQP4-seronegative NMOSD, ADEM and other inflammatory demyelinating CND syndromes; despite partial overlaps with AQP4-Ab disease, a novel "MOG-Ab-disorder" phenotype has been suggested. In this study, we tested the presence of MOG-Ab and AQP4-Ab in 57 children at first onset of acute neurological symptoms; three clinical subgroups were identified: 12 patients had acquired inflammatory demyelinating CNS syndromes, 11 had other autoimmune/immune-mediated disorders of the central and peripheral nervous system and 34 had non-immune-mediated CNS disorders. MOG-Abs were found positive only in a subset of cases in the subgroup with acquired inflammatory demyelinating CNS syndromes (in 2/12 patients, both with non-MS phenotype) and in none of the patients with other autoimmune and immune-mediated disorders of the central and peripheral nervous system or with non-immune-mediated disorders of the CNS.Data from the literature review support clinical and analytical observations.

Update on Pediatric Optic Neuritis

PURPOSE OF REVIEW

The purpose of this review is to provide an update on advances in the understanding of pediatric demyelinating optic neuritis.

RECENT FINDINGS

In the past decade, the disease phenotypes for demyelinating syndromes in children have been more clearly defined. Pediatric optic neuritis may present as a clinically isolated syndrome or in the setting of underlying neurologic disease. In addition to optic neuritis associated with multiple sclerosis or neuromyelitis optica, recent work has identified antibodies to the myelin oligodendrocyte glycoprotein (MOG IgG) as a unique demyelinating cause with distinct features regarding treatment and prognosis. The disease phenotypes for demyelinating pediatric optic neuritis have expanded. Treatment strategies vary and are not universally effective for each cause of demyelinating disease. Accurately distinguishing among these unique clinical syndromes is therefore critical for initiation of appropriate treatment to prevent disability, to maximize visual outcomes, and to provide insight into long-term prognosis.

Optic Neuritis

PURPOSE OF REVIEW

This article discusses the clinical presentation, evaluation, and management of the patient with optic neuritis. Initial emphasis is placed on clinical history, examination, diagnostic testing, and medical decision making, while subsequent focus is placed on examining specific inflammatory optic neuropathies. Clinical clues, examination findings, neuroimaging, and laboratory testing that differentiate autoimmune, granulomatous, demyelinating, infectious, and paraneoplastic causes of optic neuritis are assessed, and current treatments are evaluated.

RECENT FINDINGS

Advances in technology and immunology have enhanced our understanding of the pathologies driving inflammatory optic nerve injury. Clinicians are now able to interrogate optic nerve structure and function during inflammatory injury, rapidly identify disease-relevant autoimmune targets, and deliver timely therapeutics to improve visual outcomes.

SUMMARY

Optic neuritis is a common clinical manifestation of central nervous system inflammation. Depending on the etiology, visual prognosis and the risk for recurrent injury may vary. Rapid and accurate diagnosis of optic neuritis may be critical for limiting vision loss, future neurologic disability, and organ damage. This article will aid neurologists in formulating a systematic approach to patients with optic neuritis.

Case Series: Myelin Oligodendrocyte Glycoprotein-Immunoglobulin G-Related Disease Spectrum

Introduction: Myelin oligodendrocyte glycoprotein-immunoglobulin G (MOG-IgG)-related disease was initially described as a subtype of neuromyelitis optica spectrum disorder (NMOSD) with antibodies against MOG. However, it has recently been described as a separate disease entity with clinical and radiological features that overlap those of multiple sclerosis (MS) and NMOSD; the clinical features of this disease phenotype remain undetermined. We herein report the clinical presentation of nine MOG-IgG-positive patients, not all of whom fulfill the NMOSD criteria, in order to highlight the features and challenges of this condition.

Method: We retrospectively reviewed the records of the London (Ontario) MS clinic to identify patients diagnosed with positive MOG antibodies based on the 2015 NMOSD consensus criteria.

Result: Nine patients were identified, all Caucasian. Seven (78%) were female, and the median age of onset was 41 years (range, 28–69 years); the median Expanded Disability Status Scale score at onset was 3.0 (range, 2.0–4.0). A monophasic course was noted in two (22.2%) patients, while the median number of relapse events was 3 (range 2–5) in 77.8% of the patients. Optic neuritis and transverse myelitis contributed equally as initial manifestations in three individuals (33%), while brainstem relapse was reported in two individuals (22%). The brain magnetic resonance imaging findings were compatible with McDonald's 2010 dissemination in space criteria in three cases (33%). Short myelitis and an (H)-sign were each documented in one patient.

Conclusion: The phenotypes of MOG Ab-positive cases exhibited overlapping features with MS and NMOSD. This finding highlights the importance of screening for anti-MOG in individuals with demyelinating symptoms, in consideration of the possibility of false-positive MOG Ab results.

Effects of the Positive Threshold and Data Analysis on Human MOG Antibody Detection by Live Flow Cytometry

Human autoantibodies targeting myelin oligodendrocyte glycoprotein (MOG Ab) have become a useful clinical biomarker for the diagnosis of a spectrum of inflammatory demyelinating disorders. Live cell-based assays that detect MOG Ab against conformational MOG are currently the gold standard. Flow cytometry, in which serum binding to MOG-expressing cells and control cells are quantitively evaluated, is a widely used observer-independent, precise, and reliable detection method. However, there is currently no consensus on data analysis; for example, seropositive thresholds have been reported using varying standard deviations above a control cohort. Herein, we used a large cohort of 482 sera including samples from patients with monophasic or relapsing demyelination phenotypes consistent with MOG antibody-associated demyelination and other neurological diseases, as well as healthy controls, and applied a series of published analyses involving a background subtraction (delta) or a division (ratio). Loss of seropositivity and reduced detection sensitivity were observed when MOG ratio analyses or when 10 standard deviation (SD) or an arbitrary number was used to establish the threshold. Background binding and MOG ratio value were negatively correlated, in which patients seronegative by MOG ratio had high non-specific binding, a characteristic of serum that must be acknowledged. Most MOG Ab serostatuses were similar across analyses when optimal thresholds obtained by ROC analyses were used, demonstrating the robust nature and high discriminatory power of flow cytometry cell-based assays. With increased demand to identify MOG Ab-positive patients, a consensus on analysis is vital to improve patient diagnosis and for cross-study comparisons to ultimately define MOG Ab-associated disorders.

VENOUS STASIS RETINOPATHY SECONDARY TO MYELIN-OLIGODENDROCYTE GLYCOPROTEIN ANTIBODY-POSITIVE OPTIC NEURITIS

PURPOSE

To report a case of a 38-year-old woman with venous stasis retinopathy secondary to myelin oligodendrocyte glycoprotein-IgG optic neuritis.

METHODS

Observational case report.

RESULTS

We report a unique case of venous stasis retinopathy secondary to myelin oligodendrocyte glycoprotein-IgG optic neuritis with significant optic disc edema, tortuous and dilated retinal venules, and retinal hemorrhages, which resolved promptly with high-dose corticosteroids. The retinal changes were likely secondary to severe inflammation of the optic nerve and optic nerve sheath, which exhibited significant postcontrast enhancement on magnetic resonance imaging. Despite aggressive treatment with high-dose corticosteroids and plasmapheresis, the patient had a significant generalized visual field defect at 6 months.

CONCLUSION

Venous stasis retinopathy may be secondary to myelin oligodendrocyte glycoprotein-IgG optic neuritis due to reduced venous outflow from significant optic nerve edema. This may be a poor prognostic factor and a marker for more severe optic nerve inflammation.

MRI differences between MOG antibody disease and AQP4 NMOSD

BACKGROUND

MOG antibody and AQP4 antibody seropositive diseases are immunologically distinct subtypes of neuromyelitis optica spectrum disorders (NMOSD) with similar clinical presentations. MRI findings can be instrumental in distinguishing MOG antibody disease from AQP4 antibody NMOSD.

OBJECTIVES

The aim of this study is to characterize the neuroradiological differences between MOG antibody disease and AQP4 antibody NMOSD with the aim to distinguish between the two entities.

METHODS

This is a retrospective study of 26 MOG and 25 AQP4 seropositive patients in which MRI features of the brain, spinal cord, and orbit were compared.

RESULTS

The majority of the abnormal findings in the MOG cohort were located on orbital MRIs, while spinal cord magnetic resonance (MR) abnormalities were more common in the AQP4 cohort. Brain abnormalities showed some overlap, but cortical gray/juxtacortical white matter involvement was distinct to MOG patients, while area postrema involvement was a rare feature.

CONCLUSION

Cortical gray/juxtacortical white matter lesions on brain MRI might help distinguish MOG antibody disease from AQP4-positive NMOSD. These findings could be of value in distinguishing the two entities as early as the first presentation.

Clinical Features and Outcomes of Pediatric Monophasic and Recurrent Idiopathic Optic Neuritis

Limited data exist on isolated optic neuritis in children. We report the clinical features and treatment of pediatric subjects with monophasic and recurrent idiopathic optic neuritis. This retrospective cohort study of patients with isolated optic neuritis identified 10 monophasic and 7 recurrent optic neuritis cases. Monophasic optic neuritis patients were older (mean 13.3 ± 4.22) than those with recurrent idiopathic optic neuritis (9.86 ± 3.63). Females represented 50% of monophasic and 85.7% of recurrent idiopathic optic neuritis cases. Patients with monophasic optic neuritis were less likely to have a bilateral onset than recurrent idiopathic optic neuritis (40% vs 57.1%). Only 1 case had oligoclonal bands in the cerebrospinal fluid CSF. Most recurrent idiopathic optic neuritis cases had evidence of anti-myelin oligodendrocyte glycoprotein (MOG) antibodies (5/7). Treatment of recurrent idiopathic optic neuritis cases included intravenous pulse glucocorticosteroids and immunotherapy. We observed differences between recurrent and monophasic idiopathic optic neuritis. Immunosuppression appeared to prevent further relapses in recurrent idiopathic optic neuritis patients. Weaning immunotherapies after several years of quiescence in recurrent idiopathic optic neuritis may be possible, but larger studies are needed.

Neuromyelitis Optica Spectrum Disorder and Other Non-Multiple Sclerosis Central Nervous System Inflammatory Diseases

PURPOSE OF REVIEW

This article reviews the clinical features, diagnostic approach, treatment, and prognosis of central nervous system inflammatory diseases that mimic multiple sclerosis (MS), including those defined by recently discovered autoantibody biomarkers.

RECENT FINDINGS

The discovery of autoantibody biomarkers of inflammatory demyelinating diseases of the central nervous system (aquaporin-4 IgG and myelin oligodendrocyte glycoprotein IgG) and the recognition that, despite some overlap, their clinical phenotypes are distinct from MS have revolutionized this field of neurology. These autoantibody biomarkers assist in diagnosis and have improved our understanding of the underlying disease pathogenesis. This has allowed targeted treatments to be translated into clinical trials, three of which are now under way in aquaporin-4 IgG-seropositive neuromyelitis optica (NMO) spectrum disorder.

SUMMARY

Knowledge of the clinical attributes, MRI findings, CSF parameters, and accompanying autoantibody biomarkers can help neurologists distinguish MS from its inflammatory mimics. These antibody biomarkers provide critical diagnostic and prognostic information and guide treatment decisions. Better recognition of the clinical, radiologic, and laboratory features of other inflammatory MS mimics that lack autoantibody biomarkers has allowed us to diagnose these disorders faster and initiate disease-specific treatments more expeditiously.

Pediatric optic neuritis and anti MOG antibodies: a cohort of Italian patients

BACKGROUND

recent studies reported that anti myelin oligodendrocyte glycoprotein (MOG) antibody (ab) related optic neuritis (ON) tend to have characteristics that differ from seronegative ones. The aim of our study was to investigate the clinical characteristics of pediatric anti-MOG ON by comparing anti MOG-ab-seropositive and seronegative patients with ON.

METHODS

in this retrospective Italian multicentre study, participants were identified by chart review of patients evaluated for acquired demyelinating syndromes of the central nervous system (over the period 2009-2019). We selected patients presenting with ON as their first demyelinating event. Inclusion criteria were age < 18 years at symptoms onset; presentation consistent with ON; negativity of anti-aquaporin 4 antibodies (AQP4). Only patients who were tested for MOG-IgG1-ab with a live cell-based assay were included.

RESULTS

22 patients (10 MOG-ab-positive and 12 MOG-ab-negative) were included. Fundus oculi examination at onset showed disc swelling in 9/10 in the MOG-ab-positive cohort and 2/10 in the seronegative group (P = 0.002). Retinal Fiber Nerve Layer (RFNL) thickness measured by Spectral Domain Optical Coherence Tomography (S-OCT) was increased in the 5/5 MOG-ab-positive patients tested and was normal or reduced in the seronegative patients tested (4/4 patients) (P = 0.024). Visual acuity impairment at onset did not differ significantly between the two groups, but the MOG-ab-positive cohort showed better recovery at follow-up both regarding visual acuity (P = 0.025) and expanded disability status scale (EDSS) (P = 0.013). A final diagnosis of MS was frequent among seronegative patients (6/12, 50%), whereas none of the MOG-ab-positive group received a diagnosis of MS (P = 0.015). Clinical relapse frequency was low in both groups: 2/10 MOG-ab-positive and 2/12 seronegative cases relapsed, with a median follow up of 25 months.

CONCLUSION

optic disc swelling and increased RFNL at baseline are strongly associated with MOG-ab positivity. MOG-ab-positive patients with ON showed better recovery compared to the seronegative ones. The relapse rate was low and did not differ among the two groups.

Clinical and radiologic approach to 'typical' versus antibody-related optic neuritis

PURPOSE OF REVIEW

Optic neuritis is an autoimmune optic neuropathy that has been associated with multiple sclerosis (MS), neuromyelitis optica spectrum disorder (NMOSD), and more recently antimyelin oligodendrocyte glycoprotein (anti-MOG)-positive disorder. At initial presentation, it is often difficult to differentiate these entities given their significant overlap in clinical presentation and MRI findings. This review summarizes the distinguishing clinical and radiological features of MS, NMOSD, and anti-MOG disorders to help clinicians accurately diagnose and manage patients affected by these conditions.

RECENT FINDINGS

Antiaquaporin-4 (AQP4) and more recently anti-MOG antibodies are both associated with central nervous system demyelinating diseases that often initially present with optic neuritis. Serologic testing now allows for a new classification of these overlapping conditions that can help to differentiate 'typical' optic neuritis that is often associated with MS from 'atypical' optic neuritis associated with NMOSD and anti-MOG-positive disorder.

SUMMARY

Optic neuritis associated with MS, NMOSD, and anti-MOG-positive disease can have a similar clinical presentation. However, some clinical and radiologic findings can help clinicians to differentiate these entities so that they can be properly managed to optimize visual prognosis.

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.

Cranial Nerve Imaging and Pathology

This review provides a symptom-driven approach to neuroimaging of disease processes affecting the cranial nerves. In addition to describing characteristic imaging appearances of a disease, the authors emphasize exceptions to the rules and neuroimaging pearls. The focus is on adult neurology although some important pediatric conditions are included. On reviewing this material, the reader should be able to (1) differentiate intra- and extra-axial causes of cranial nerve dysfunction and (2) appropriately use neuroimaging to investigate abnormalities of cranial nerve function.

Prognostic Factors for Recovery of Vision in Canine Optic Neuritis of Unknown Etiology: 26 Dogs (2003-2018)

Optic neuritis (ON) is a recognized condition, yet factors influencing recovery of vision are currently unknown. The purpose of this study was to identify prognostic factors for recovery of vision in canine ON of unknown etiology. Clinical databases of three referral hospitals were searched for dogs with presumptive ON based on clinicopathologic, MRI/CT, and fundoscopic findings. Twenty-six dogs diagnosed with presumptive ON of unknown etiology, isolated (I-ON) and MUE-associated (MUE-ON), were included in the study. Their medical records were reviewed retrospectively, and the association of complete recovery of vision with signalment, clinicopathologic findings, and treatment was investigated. Datasets were tested for normality using the D'Agostino and Shapiro-Wilk tests. Individual datasets were compared using the Chi-squared test, Fisher's exact test, and the Mann-Whitney U-test. For multiple comparisons with parametric datasets, the one-way analysis of variance (ANOVA) was performed, and for non-parametric datasets, the Kruskal-Wallis test was performed to test for independence. For all data, averages are expressed as median with interquartile range and significance set at p < 0.05. Twenty-six dogs met the inclusion criteria. Median follow-up was 230 days (range 21–1901 days, mean 496 days). Six dogs (23%) achieved complete recovery and 20 dogs (77%) incomplete or no recovery of vision. The presence of a reactive pupillary light reflex (p = 0.013), the absence of fundoscopic lesions (p = 0.0006), a younger age (p = 0.038), and a lower cerebrospinal fluid (CSF) total nucleated cell count (TNCC) (p = 0.022) were statistically associated with complete recovery of vision. Dogs with I-ON were significantly younger (p = 0.046) and had lower CSF TNCC (p = 0.030) compared to the MUE-ON group. This study identified prognostic factors that may influence complete recovery of vision in dogs with ON. A larger cohort of dogs is required to determine whether these findings are robust and whether additional parameters aid accurate prognosis for recovery of vision in canine ON.

Update on pediatric optic neuritis

PURPOSE OF REVIEW

To summarize recent developments in the classification, investigation and management of pediatric optic neuritis (PON).

RECENT FINDINGS

A recent surge in interest surrounding antibodies to myelin oligodendrocyte glycoprotein antibody (MOG-Ab) has instigated a paradigm shift in our assessment of children with PON. This serological marker is associated with a broad spectrum of demyelinating syndromes that are clinically and radiologically distinct from multiple sclerosis (MS) and aquaporin-4 antibody positive neuromyelitis optica spectrum disorder (AQP4+NMOSD). Optic neuritis is the most common presenting phenotype of MOG-Ab positive-associated disease (MOG+AD). MOG-Ab seropositivity is much more common in the pediatric population and it predicts a better prognosis than MS or AQP4+NMOSD, except in the subset that exhibit a recurrent phenotype.

SUMMARY

A better grasp of MOG+AD features and its natural history has facilitated more accurate risk stratification of children after a presenting episode of PON. Consequently, the initial investigation of PON has broadened to include serology, along with neuroimaging and cerebrospinal fluid analysis. Acute treatment of PON and chronic immunotherapy is also becoming better tailored to the suspected or confirmed diagnoses of MS, AQP4+NMOSD and MOG+AD.

Imaging in Neuro-ophthalmology

PURPOSE OF REVIEW

This article discusses an approach to imaging in patients with neuro-ophthalmologic disorders, with emphasis on the clinical-anatomic localization of lesions affecting afferent and efferent visual function.

RECENT FINDINGS

Advances in MRI, CT, ultrasound, and optical coherence tomography have changed how neuro-ophthalmic disorders are diagnosed and followed in the modern clinical era.

SUMMARY

The advantages, disadvantages, and indications for various imaging techniques for neuro-ophthalmologic disorders are discussed, with a view to optimizing how these tools can be used to enhance patient care.

MOG-Ab prevalence in optic neuritis and clinical predictive factors for diagnosis

OBJECTIVE

What is the proportion of antibodies to myelin oligodendrocyte glycoprotein (MOG-Ab) in optic neuritis (ON) in adults and what would be the ON presentation for which MOG-Ab should be tested?

METHODS

Multicentric prospective study conducted during 1 year on all patients diagnosed with acute ON in all ophthalmological units in hospitals in a region in western France.

RESULTS

Sixty-five patients were included. MOG-Ab prevalence was 14% (9/65) during an acute ON and 13% (7/55) after exclusion of patients already diagnosed with multiple sclerosis (MS) (8) or MOG+ON (2). Compared with MS and clinically isolated syndrome, MOG+ON had no female preponderance (67% of men in case of MOG+ON and 22% of men in case of MS and clinically isolated syndrome, p<0.05) were more often bilateral (44% vs 3%, p<0.005) and associated with optic disc swelling (ODS) (78% vs 14%, p<0.001). To predict MOG+ON, the positive predictive values (PPVs) of male sex, ODS and bilateral involvement were 29% (95% CI 9% to 48%), 41% (95% CI 18% to 65%) and 40% (95% CI 10% to 70%), respectively, while the negative predictive values (NPV) were 93% (95% CI 86% to 100%), 96% (95% CI 90% to 100%) and 91% (95% CI 83% to 99%), respectively. The combined factor 'ODS or bilateral or recurrent ON' was the best compromise between PPV (31% (95% CI 14% to 48%)) and NPV (100% (95% CI 100% to 100%)).

CONCLUSION

Among ON episodes, MOG-Ab were found in 14% of cases. MOG+ON occurred without female preponderance and was significantly associated with ODS and/or bilateral ON. Testing MOG-Ab only in patients presenting with ODS or bilateral or recurrent ON would limit MOG-Ab tests to fewer than half of all patients without the risk of missing any MOG+ON cases.

Characterization of the human myelin oligodendrocyte glycoprotein antibody response in demyelination

Over recent years, human autoantibodies targeting myelin oligodendrocyte glycoprotein (MOG Ab) have been associated with monophasic and relapsing central nervous system demyelination involving the optic nerves, spinal cord, and brain. While the clinical relevance of MOG Ab detection is becoming increasingly clear as therapeutic and prognostic differences from multiple sclerosis are acknowledged, an in-depth characterization of human MOG Ab is required to answer key challenges in patient diagnosis, treatment, and prognosis. Herein, we investigated the epitope, binding sensitivity, and affinity of MOG Ab in a cohort of 139 and 148 MOG antibody-seropositive children and adults (n = 287 patients at baseline, 130 longitudinal samples, and 22 cerebrospinal fluid samples). MOG extracellular domain was also immobilized to determine the affinity of MOG Ab. MOG Ab response was of immunoglobulin G1 isotype, and was of peripheral rather than intrathecal origin. High affinity MOG Ab were detected in 15% paediatric and 18% adult sera. More than 75% of paediatric and adult MOG Ab targeted a dominant extracellular antigenic region around Proline42. MOG Ab titers fluctuated over the progression of disease, but affinity and reactivity to Proline42 remained stable. Adults with a relapsing course intrinsically presented with a reduced immunoreactivity to Proline42 and had a more diverse MOG Ab response, a feature that may be harnessed for predicting relapse. Higher titers of MOG Ab were observed in more severe phenotypes and during active disease, supporting the pathogenic role of MOG Ab. Loss of MOG Ab seropositivity was observed upon conformational changes to MOG, and this greatly impacted the sensitivity of the detection of relapsing disorders, largely considered as more severe. Careful consideration of the binding characteristics of autoantigens should be taken into account when detecting disease-relevant autoantibodies.

Aquaporin-4 and myelin oligodendrocyte glycoprotein antibodies in immune-mediated optic neuritis at long-term follow-up

OBJECTIVES

To re-evaluate serum samples from our 2007 cohort of patients with single-episode isolated ON (SION), recurrent isolated ON (RION), chronic relapsing inflammatory optic neuropathy (CRION), multiple sclerosis-associated ON (MSON) and neuromyelitis optica (NMO).

METHODS

We re-screened 103/114 patients with available serum on live cell-based assays (CBA) for aquaporin-4 (AQP4)-M23-IgG and myelin-oligodendrocyte glycoprotein (MOG)-α1-IgG. Further testing included oligoclonal bands, serum levels of glial fibrillar acidic and neurofilament proteins and S100B. We show the impact of updated serology on these patients.

RESULTS

Reanalysis of our original cohort revealed that AQP4-IgG seropositivity increased from 56% to 75% for NMO, 5% to 22% for CRION, 6% to 7% for RION, 0% to 7% for MSON and 5% to 6% for SION. MOG-IgG1 was identified in 25% of RION, 25% of CRION, 10% of SION, 0% of MSON and 0% of NMO. As a result, patients have been reclassified incorporating their autoantibody status. Presenting visual acuity was significantly worse in patients who were AQP4-IgG seropositive (p=0.034), but there was no relationship between antibody seropositivity and either ON relapse rate or visual acuity outcome.

CONCLUSIONS

The number of patients with seronegative CRION and RION has decreased due to improved detection of autoantibodies over the past decade. It remains essential that the clinical phenotype guides both antibody testing and clinical management. Careful monitoring of the disease course is key when considering whether to treat with prophylactic immune suppression.

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.

Aquaporin-4 IgG seropositivity is associated with worse visual outcomes after optic neuritis than MOG-IgG seropositivity and multiple sclerosis, independent of macular ganglion cell layer thinning

BACKGROUND

Comparative studies of characteristics of optic neuritis (ON) associated with myelin oligodendrocyte glycoprotein-IgG (MOG-ON) and aquaporin-4-IgG (AQP4-ON) seropositivity are limited.

OBJECTIVE

To compare visual and optical coherence tomography (OCT) measures following AQP4-ON, MOG-ON, and multiple sclerosis associated ON (MS-ON).

METHODS

In this cross-sectional study, 48 AQP4-ON, 16 MOG-ON, 40 MS-ON, and 31 healthy control participants underwent monocular letter-acuity assessment and spectral-domain OCT. Eyes with a history of ON >3 months prior to evaluation were analyzed.

RESULTS

AQP4-ON eyes exhibited worse high-contrast letter acuity (HCLA) compared to MOG-ON (-22.3 ± 3.9 letters; p < 0.001) and MS-ON eyes (-21.7 ± 4.0 letters; p < 0.001). Macular ganglion cell + inner plexiform layer (GCIPL) thickness was lower, as compared to MS-ON, in AQP4-ON (-9.1 ± 2.0 µm; p < 0.001) and MOG-ON (-7.6 ± 2.2 µm; p = 0.001) eyes. Lower GCIPL thickness was associated with worse HCLA in AQP4-ON (-16.5 ± 1.5 letters per 10 µm decrease; p < 0.001) and MS-ON eyes (-8.5 ± 2.3 letters per 10 µm decrease; p < 0.001), but not in MOG-ON eyes (-5.2 ± 3.8 letters per 10 µm decrease; p = 0.17), and these relationships differed between the AQP4-ON and other ON groups (p < 0.01 for interaction).

CONCLUSION

AQP4-IgG seropositivity is associated with worse visual outcomes after ON compared with MOG-ON and MS-ON, even with similar severity of macular GCIPL thinning.

Devic's index case: A critical reappraisal - AQP4-IgG-mediated neuromyelitis optica spectrum disorder, or rather MOG encephalomyelitis?

In 1894, Eugène Devic (1858-1930) and his doctoral student Fernand Gault (1873-1936) reported on a patient with optic neuritis (ON) and myelitis and proposed the name "neuro-myélite optique" for this syndrome. Subsequently, Devic became the eponym of neuromyelitis optica (NMO), which was then referred to as "Devic's syndrome", "Devic's disease" or "Morbus Devic". Thereby, the case became a historical index case of NMO. For many decades little attention was paid to NMO, which most authors considered a clinical variant of multiple sclerosis. However, the discovery of pathogenic antibodies to aquaporin-4 at the beginning of the 21st century revived interest in the syndrome, and AQP4-IgG-positive NMO spectrum disorders (NMOSD) are now studied as prototypical autoimmune diseases. More recently, antibodies to full-length myelin oligodendrocyte glycoprotein (MOG) have been detected in patients with ON as well as in patients with myelitis, some of whom exhibit a clinical phenotype very similar to that described by Devic. This raises the question of whether Devic's patient might have suffered from MOG encephalomyelitis rather than classic NMOSD. In this article, we summarise and discuss the available evidence for and against that hypothesis. We also discuss differential diagnoses and the question whether Devic's patient, who worked as a hatter and had initially been admitted for nervous hyperexcitability and tremor, might have suffered from co-existing erethism ('mad hatter disease'), which is caused by chronic occupational exposure to mercury.

Critical review: Typical and atypical optic neuritis

Typical optic neuritis is an idiopathic demyelinating condition that is often associated with multiple sclerosis. This has been well characterized and has an excellent prognosis. Atypical optic neuritis can result from an inflammatory, infectious, or autoimmune disorder. Differentiating the two types of optic neuritis is paramount and may be challenging early on in the clinical course. This review describes the recent literature describing the pathophysiology, clinical presentation, neuroimaging, and management of these disorders.

The swollen optic nerve: an approach to diagnosis and management

The differential diagnosis of swollen optic nerves differs according to whether the swelling is unilateral or bilateral, or whether visual function is normal or affected. Patients with a unilaterally swollen optic nerve and normal visual function most likely have optic nerve head drusen. Patients with abnormal visual function most likely have demyelinating optic neuritis or non-arteritic anterior ischaemic optic neuropathy. Patients with bilaterally swollen optic nerve heads and normal visual function most likely have papilloedema, and require neuroimaging followed by lumbar puncture. However, if their visual function is affected, the most likely causes are bilateral demyelinating optic neuritis, neuromyelitis optica spectrum disorder and anti-myelin oligodendrocyte glycoprotein optic neuritis: these patients require investigating with contrast-enhanced MRI of the orbits.

Frequency and characteristics of short versus longitudinally extensive myelitis in adults with MOG antibodies: A retrospective multicentric study

OBJECTIVES

We aim to (1) determine the frequency and distinctive features of short myelitis (SM) and longitudinally extensive transverse myelitis (LETM) in a cohort of adults with myelin oligodendrocyte glycoprotein (MOG)-antibody (Ab)-associated myelitis and (2) determine baseline prognostic factors among MOG-Ab-positive patients whose disease started with myelitis.

MATERIAL AND METHODS

We retrospectively analyzed clinical and paraclinical variables from a multicentric French cohort of adults with MOG-Ab-associated myelitis. At last follow-up, patients were classified into two groups according to the severity of the Expanded Disability Status Scale (EDSS) as ⩽2.5 or ⩾3.0.

RESULTS

Seventy-three patients with at least one episode of myelitis over disease course were included; among them, 28 (38.4%) presented with SM at the time of the first myelitis. Motor and sphincter involvement was less frequently observed in SM (51.9% and 48.2%, respectively) than in LETM patients (83.3% and 78.6%, respectively), p = 0.007 and p = 0.017; 61% of LETM patients displayed brain lesions compared to 28.6% in the SM group, p = 0.008, and the thoracic segment was more frequently involved in the LETM (82.2%) than in the SM group (39.3%), p < 0.001. EDSS at last follow-up was higher in LETM (median 3.0 (interquartile range: 2.0-4.0)) compared to SM patients (2.0, (1.0-3.0)), p = 0.042. Finally, a higher EDSS at onset was identified as the only independent risk factor for EDSS ⩾3.0 (odds ratio, 1.40, 95% confidence interval (CI): 1.01-1.95, p = 0.046).

CONCLUSION

SM in MOG-Ab-associated disease is not rare. The severity at onset was the only independent factor related to the final prognosis in MOG-Ab-associated myelitis.

Myelin Oligodendrocyte Glycoprotein Antibody (MOG-IgG)-Positive Optic Perineuritis

Optic perineuritis can be a manifestation of infectious and systemic inflammatory disorders, but the majority of cases are idiopathic. Myelin oligodendrocyte glycoprotein (MOG)-IgG-positive optic neuritis has been reported to be associated with optic nerve sheath enhancement. This report describes two MOG-IgG patients with clinical, radiological and therapeutic response consistent with optic perineuritis. MOG-IgG may account for many cases of previously described idiopathic optic perineuritis. Vision loss with optic nerve sheath enhancement on MRI should prompt testing for MOG-IgG.

Epidemiologic and Clinical Characteristics of Optic Neuritis in Japan

PURPOSE

To elucidate the clinical and epidemiologic characteristics of optic neuritis in Japan.

DESIGN

Multicenter cross-sectional, observational cohort study.

PARTICIPANTS

A total of 531 cases of unilateral or bilateral noninfectious optic neuritis identified in 33 institutions nationwide in Japan.

METHODS

Serum samples from patients with optic neuritis were tested for anti-aquaporin-4 antibodies (AQP4-Abs) and anti-myelin oligodendrocyte glycoprotein antibodies (MOG-Abs) using a cell-based assay and were correlated with the clinical findings.

MAIN OUTCOME MEASURES

Antibody positivity, clinical and radiologic characteristics, and visual outcome.

RESULTS

Among 531 cases of optic neuritis, 12% were AQP4-Ab positive, 10% were MOG-Ab positive, 77% were negative for both antibodies (double-negative), and 1 case was positive for both antibodies. Pretreatment visual acuity (VA) worsened to more than a median 1.0 logarithm of the minimum angle of resolution (logMAR) in all groups. After steroid pulse therapy (combined with plasmapheresis in 32% of patients in AQP4-Ab-positive group), median VA improved to 0.4 logMAR in the AQP4-Ab-positive group, 0 logMAR in the MOG-Ab-positive group, and 0.1 logMAR in the double-negative group. The AQP4-Ab-positive group showed a high proportion of females, exhibited diverse visual field abnormalities, and demonstrated concurrent spinal cord lesions on magnetic resonance imaging (MRI) in 22% of the patients. In the MOG-Ab-positive group, although posttreatment visual outcome was good, the rates of optic disc swelling and pain with eye movement were significantly higher than those in the AQP4-Ab-positive and double-negative groups. However, most cases showed isolated optic neuritis lesions on MRI. In the double-negative group, 4% of the patients had multiple sclerosis. Multivariate logistic regression analysis of all participants identified age and presence of antibodies (MOG-Ab and AQP4-Ab) as significant factors affecting visual outcome.

CONCLUSIONS

The present large-scale cohort study revealed the clinicoepidemiologic features of noninfectious optic neuritis in Japan. Anti-aquaporin-4 antibody-positive optic neuritis has poor visual outcome. In contrast, MOG-Ab positive cases manifested severe clinical findings of optic neuritis before treatment, but few showed concurrent lesions in sites other than the optic nerve and generally showed good treatment response with favorable visual outcome. These findings indicate that autoantibody measurement is useful for prompt diagnosis and proper management of optic neuritis that tends to become refractory.

Clinical characteristics and outcomes of myelin oligodendrocyte glycoprotein antibody-seropositive optic neuritis in varying age groups: A cohort study in China

PURPOSE

To investigate the clinical characteristics and outcomes of myelin oligodendrocyte glycoprotein antibody-seropositive optic neuritis (MOG-ON) in patients with varying ages of onset in China.

METHODS

Patients displaying symptoms of MOG-ON were recruited from the Neuro-ophthalmology Department in the Chinese People's Liberation Army General Hospital from January 2016 to May 2018. They were assigned to one of three subgroups based on age of onset: pediatric (<18 years), young (18-46 years), and middle-aged (>46 years) MOG-ON.

RESULTS

110 patients (188 eyes) were assessed, including 58 pediatric (52.7%), 34 young (30.9%), and 18 middle-aged (16.4%) patients. Of the pediatric patients, 93.9% had good recovery of visual acuity (≥0.5) compared with 79.7% of young patients and 66.7% of middle-aged patients (p < .001). The annual relapse rate was lower in the pediatric group than young and middle-aged groups (0.32 ± 0.50 vs 0.73 ± 0.87 vs 0.49 ± 1.08, p = .036). Six children (10.3%) were diagnosed with acute disseminated encephalomyelitis, while seven young patients (20.6%) were diagnosed with aquaporin-4 antibody seronegative neuromyelitis optica spectrum disorder upon follow-up. The average peripapillary RNFL and macular GCIPL thicknesses were not statistically different between subgroups (p = .996, p = .608). Overall, MRIs of the optic nerve showed perineural enhancement in 52.0% of patients and longitudinal extensive involvement in 87.7%. MRIs also revealed a greater proportion of pediatric patients with intracranial optic nerve involvement than in the other two subgroups (45.4% vs. 21.2% vs. 36.7%, p = .014).

CONCLUSION

Pediatric ON was the most common MOG-ON subgroup. Pediatric patients had different clinical features, including better recovery of visual acuity, lower annual relapse rate, and more intracranial optic nerve involvement than young and middle-aged patients. Additionally, age of onset may be a potential predictor for determining visual prognosis with MOG-ON.

The X factor

A 45-year-old white woman presented with chronic bilateral, painless, progressive, peripheral vision loss. She was found to have bilateral optic atrophy and nonenhancing multifocal white matter lesions on magnetic resonance imaging of the brain. Cerebrospinal fluid analysis showed an elevated level of myelin basic protein. She was diagnosed as having the carrier state of X-linked adrenoleukodystrophy. X-linked adrenoleukodystrophy can mimic the clinical and radiographic features of multiple sclerosis in a female carrier. To our knowledge, this is the first case report of bilateral optic atrophy in a female X-linked adrenoleukodystrophy carrier in the English ophthalmic literature.

Antibodies to myelin oligodendrocyte glycoprotein in chronic relapsing inflammatory optic neuropathy

BACKGROUND/AIMS

To evaluate the status of myelin oligodendrocyte glycoprotein antibodies (MOG-IgG) in chronic relapsing inflammatory optic neuropathy (CRION) and investigate its different clinical characteristics and prognosis.

METHODS

Patients diagnosed with CRION were recruited by the Neuro-ophthalmology Department of the Chinese People's Liberation Army General Hospital from December 2015 to April 2017. Based on antibody status, they were assigned to either the MOG-CRION or seronegative-CRION groups.

RESULTS

A total of 33 patients (38 eyes) were assessed and divided into the following groups: 22 (66.7%) MOG-CRION and 11 (33.3%) seronegative-CRION. The ratio of female to male was 1:1, and 81.8% of total CRION patients were adults (≥18 years). A total of 29 eyes (76.3%) showed severe visual loss (<20/200) during the first optic neuritis episode, and 37 eyes (72.5%) demonstrated good visual recovery (>20/40) during the final follow-up. The mean onset age of MOG-CRION patients was 28 ± 16 years (range 6-62), which was significantly younger than that of seronegative-CRION (45 ± 12 years, range 22-59) (p=0.029). The intraorbital and canalicular segments were highly involved in the orbital MRI of CRION patients. During the final follow-up, MOG-CRION patients had more bilateral involvement (p=0.008) and higher annualised relapse rates compared with the seronegative-CRION patients (p=0.019).

CONCLUSION

CRION was predominantly found in adults with unilateral ON and exhibited a higher rate of seropositive MOG-IgG. MOG-CRION, which may be a disparate subtype of MOG-IgG-induced demyelinating disease that needs further investigation, was found in younger patients at onset, with more bilateral involvement and more relapse tendency.

Myelin Oligodendrocyte Glycoprotein Antibody-Associated Disorders: Toward a New Spectrum of Inflammatory Demyelinating CNS Disorders?

Inflammatory demyelinating CNS syndromes include, besides their most common entity multiple sclerosis (MS), several different diseases of either monophasic or recurrent character—including neuromyelitis optica spectrum disorders (NMOSDs) and acute disseminated encephalomyelitis (ADEM). Early diagnostic differentiation is crucial for devising individual treatment strategies. However, due to overlapping clinical and paraclinical features diagnosis at the first demyelinating event is not always possible. A multiplicity of potential biological markers that could discriminate the different diseases was studied. As the use of autoantibodies in patient management of other autoimmune diseases, is well-established and evidence for the critical involvement of B cells/antibodies in disease pathogenesis in inflammatory demyelinating CNS syndromes increases, antibodies seem to be valuable diagnostic tools. Since the detection of antibodies against aquaporin-4 (AQP-4), the understanding of immunopathogenesis and diagnostic management of NMOSDs has dramatically changed. However, for most inflammatory demyelinating CNS syndromes, a potential antigen target is still not known. A further extensively studied possible target structure is myelin oligodendrocyte glycoprotein (MOG), found at the outermost surface of myelin sheaths and oligodendrocyte membranes. With detection methods using cell-based assays with full-length, conformationally correct MOG, antibodies have been described in early studies with a subgroup of patients with ADEM. Recently, a humoral immune reaction against MOG has been found not only in monophasic diseases, but also in recurrent non-MS diseases, particularly in pediatric patients. This review presents the findings regarding MOG antibodies as potential biological markers in discriminating between these different demyelinating CNS diseases, and discusses recent developments, clinical implementations, and data on immunopathogenesis of MOG antibody-associated disorders.