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

[Aquaporin 4 antibody-positive neuromyelitis optica spectrum disorders and myelin oligodendrocyte glycoprotein antibody-associated encephalomyelitis. A brief review]

Aquaporin 4 (AQP4) immunoglobulin (Ig)G-associated neuromyelitis optica spectrum disorders (NMOSD) and myelin oligodendrocyte glycoprotein immunoglobulin (Ig)G-associated encephalomyelitis (MOG-EM, also termed MOG antibody-associated disease, MOGAD) are important autoimmune differential diagnoses of multiple sclerosis (MS), which differ from MS with respect to optimum treatment and prognosis. AQP4 IgG-positive NMOSD take a relapsing course in virtually all cases and MOG-EM in at least 80% of adult cases. Both diseases can quickly lead to permanent disability if left untreated, although MOG-EM is associated with a better overall long-term prognosis. Antibody testing must be carried out by means of so-called cell-based assays. A number of red flags have been defined that must be checked prior to making a diagnosis of NMOSD or MOG-EM. Acute attacks are treated using high-dose glucocorticoids and plasma exchange or immunoadsorption. Rituximab and other immunosuppressants are used off-label for attack prevention. Recently, eculizumab, a C5 complement inhibitor, has been approved in the European Union (EU) for the treatment of patients with AQP4 IgG-positive NMOSD. This article gives a brief overview of the clinical and paraclinical features, pathology, treatment and prognosis of these rare disorders.

New Therapeutic Landscape in Neuromyelitis Optica

Purpose of review

This review discusses the current treatment trends and emerging therapeutic landscape for patients with neuromyelitis optica spectrum disorder (NMOSD).

Recent findings

Conventional immune suppressive therapies, such as B cell depletion, have been used for long-term treatment. However, the availability of recent FDA-approved and investigational drugs has made therapeutic choices for NMOSD more complex.

Summary

Recent randomized clinical trials have shown that eculizumab, inebilizumab, and satralizumab are efficacious therapies for AQP4 seropositive NMOSD. These therapies may not have the same benefit in patients with seronegative NMOSD, including MOG-associated disease, and further investigation is required in this population. Reliable biomarkers to guide therapy decisions are urgently needed. There is a plethora of promising investigational therapies currently in the pipeline with exciting and novel mechanisms of action.

Serum Biomarkers in Neuro-Ophthalmology: When to Test

Discovery and characterization of serologic biomarkers has revolutionized the diagnostic framework of systemic and paraneoplastic autoimmune neuro-ophthalmic diseases. Expanding recognition of the multiple ocular and visual manifestations of these conditions highlights the important role of the referring provider in identifying potential cases. Increasing ease of access to serologic testing also enables these practitioners to initiate the diagnostic work-up in suspected cases. We aimed to provide an update on the current knowledge surrounding and use of relevant autoimmune biomarkers by correlating specific clinical neuro-ophthalmic manifestations with autoantibody biomarkers. The utility of select biomarkers for myasthenia gravis, neuromyelitis optica spectrum disorder, myelin oligodendrocyte glycoprotein-IgG-associated disorder, opsoclonus-myoclonus syndrome, anti-collapsin-response mediator protein-5 optic neuropathy, and glial fibrillary acidic protein-IgG-associated disease are discussed with particular focus on the clinical contexts in which to consider testing.

Neuromyelitis optica spectrum disorder and myelin oligodendrocyte glycoprotein associated disorder-optic neuritis: a comprehensive review of diagnosis and treatment

Optic neuritis (ON) is the most common cause of acute optic neuropathy in patients younger than 50 years of age and is most frequently idiopathic or associated with multiple sclerosis. However, the discovery of aquaporin-4 immunoglobulin G (IgG) and myelin oligodendrocyte glycoprotein (MOG)-IgG as biomarkers for two separate central nervous system inflammatory demyelinating diseases has revealed that neuromyelitis optica spectrum disorder (NMSOD) and MOG-IgG-associated disease (MOGAD) are responsible for clinically distinct subsets of ON. NMOSD-ON and MOGAD-ON both demonstrate tendencies for bilateral optic nerve involvement and often exhibit a relapsing course with the potential for devastating long-term visual outcomes. Early and accurate diagnosis is therefore essential. This review will summarize the current understanding of the clinical spectra of NMOSD and MOGAD, the radiographic and serological findings which support their diagnoses, and the current evidence behind various acute and long-term therapeutic strategies for ON related to these conditions. A particular emphasis is placed on a number of recent multi-centre randomized placebo-controlled trials, which provide the first level I evidence for long-term treatment of NMOSD.

Myelin oligodendrocyte glycoprotein antibody-associated disorders: clinical spectrum, diagnostic evaluation, and treatment options

Inflammatory or immune-mediated demyelinating central nervous system (CNS) syndromes include a broad spectrum of clinical phenotype and different overlapping diseases. Antibodies against myelin oligodendrocyte glycoprotein (MOG-Ab) have been found in some cases of these demyelinating diseases, particularly in children. MOG-Ab is associated with a wider clinical phenotype not limited to neuromyelitis optica spectrum disorder, with most patients presenting with optic neuritis, acute disseminated encephalomyelitis (ADEM) or ADEM-like encephalitis with brain demyelinating lesions, and/or myelitis. Using specific cell-based assays, MOG-Ab is becoming a potential biomarker of inflammatory demyelinating disorders of the CNS. A humoral immune reaction against MOG was recently found in monophasic diseases and recurrent/multiphasic clinical progression, particularly in pediatric patients. This review summarizes the data regarding MOG-Ab as an impending biological marker for discriminating between these diverse demyelinating CNS diseases and discusses recent developments, clinical applications, and findings regarding the immunopathogenesis of MOG-Ab-associated disorders.

Clinical phenotype, radiological features, and treatment of myelin oligodendrocyte glycoprotein-immunoglobulin G (MOG-IgG) optic neuritis

PURPOSE OF REVIEW

To review the clinical characteristics, radiological manifestations and treatment of myelin oligodendrocyte glycoprotein (MOG)-immunoglobulin G (IgG) optic neuritis.

RECENT FINDINGS

Serum antibodies to MOG have recently been found to be a biomarker of MOG-IgG-associated disorder (MOGAD), a demyelinating disease distinct from both multiple sclerosis (MS) and aquaporin-4-IgG neuromyelitis optica spectrum disorder (AQP4-IgG-positive NMOSD). The phenotype of MOGAD is broad and includes optic neuritis, transverse myelitis, and acute demyelinating encephalomyelitis (ADEM). Optic neuritis is the most common presentation in adults, whereas ADEM is the most common presentation in children. Clinical characteristics suggestive of MOG-IgG optic neuritis include recurrent optic neuritis, prominent disc edema, and perineural enhancement of the optic nerve on magnetic resonance imaging. Although the nadir of vision loss is severe with MOG-IgG optic neuritis, the recovery is typically better than AQP4-IgG optic neuritis and therefore has a favorable overall prognosis. Patients with relapsing disease will often need chronic immunotherapy. Rituximab, azathioprine, mycophenolate mofetil, and monthly intravenous immune globulin are the most commonly utilized treatments.

SUMMARY

MOGAD is a unique entity that is separate from both MS and AQP4-IgG-positive NMOSD. Recognition of the clinical and radiologic features allow for the correct diagnosis. Future randomized trials will determine the optimal treatment for MOGAD.

Neuromyelitis optica spectrum disorder and myelin oligodendrocyte glycoprotein IgG associated disorder: A comprehensive neuro-ophthalmic review

Neuromyelitis optica spectrum disorder (NMOSD) is an antibody-mediated inflammatory disease of the central nervous system that involves the optic nerves, spinal cord, and often other specific brain regions such as area postrema of the medulla. NMOSD was formerly classified as a variant of multiple sclerosis (MS), given the similar symptomatology and relapsing course but is now considered to have distinct clinical, paraclinical, immunological and prognostic features. The discovery of aquaporin 4 (AQP4) immunoglobulin G (IgG) has improved the ability to diagnose NMOSD. AQP4-IgG targets the astrocytic AQP4 water channel leading to complement activation and increased blood-brain barrier permeability. Accurate and early diagnosis is crucial as timely treatment may result in mitigation of long-term disability. Myelin oligodendrocyte glycoprotein (MOG)-IgG associated disorder (MOGAD) is a distinct nosologic entity, which has been more recently described. Its clinical spectrum partly overlaps that of seronegative NMOSD and MS. Although it is considered to have fewer relapses and better prognosis than NMOSD, the clinical course and outcome of MOGAD has not been fully characterized.

MRI Characteristics of NMO, MOG and MS Related Optic Neuritis

Acute isolated optic neuritis can be the initial presentation of demyelinating inflammatory central nervous system disease related to multiple sclerosis (MS), neuromyelitis optica (NMO) or myelin oligodendrocyte glycoprotein antibody disease (MOG-AD). In addition to the well-characterized brain and spinal cord imaging features, important and characteristic differences in the radiologic appearance of the optic nerves in these disorders are being described, and magnetic resonance imaging (MRI) of the optic nerves is becoming an essential tool in the differential diagnosis of optic neuritis. Whereas typical demyelinating optic neuritis is a relatively mild and self-limited disease, atypical optic neuritis in NMO and MOG-AD is potentially much more vision-threatening and merits a different treatment approach. Thus, differentiation based on MRI features may be particularly important during the first attack of optic neuritis, when antibody status is not yet known. This review discusses the optic nerve imaging in the major demyelinating disorders with an emphasis on clinically relevant differences that can help clinicians assess and manage these important neuro-ophthalmic disorders. It also reviews the utility of optic nerve MRI as a prognostic indicator in acute optic neuritis.

The role of optical coherence tomography in the diagnosis of afferent visual pathway problems: A neuroophthalmic perspective

Optical coherence tomography (OCT) is a noninvasive ocular imaging technique that has become a standard tool in neuroophthalmic practice. Specifically, OCT captures retinal manifestations of neuroaxonal injury caused by lesions along anterior and posterior regions of the afferent visual pathway, in patients presenting with vision loss. More recently, the advent of OCT angiography (OCTA) has enabled evaluation of the choroidal and retinal microvasculature, thus informing our understanding regarding vascular mechanisms associated with optic nerve and retinal injuries. Much of our longitudinal experience with OCT in the field of neuroophthalmology has been acquired from the study of optic neuritis (ON) caused by inflammatory disorders of the central nervous system (CNS). Over the past two decades, OCT has emerged as a surrogate endpoint for CNS neuroaxonal injury in multiple sclerosis (MS) research trials. On a more pragmatic level, OCT is used in the clinical arena to diagnose ON associated with: MS, neuromyelitis optica spectrum disorder (NMOSD), and myelin oligodendrocyte glycoprotein (MOG) antibody associated disease (MOGAD). Subsequent advancements in swept-source (SS) and enhanced depth imaging (EDI) have established OCT as the new "gold standard" in the diagnosis of optic disc drusen. Recent studies have highlighted pathognomonic OCT features that distinguish cases of true papilledema from pseudopapilledema, in patients presenting with undifferentiated optic disc elevation. Preoperative OCT measures of neuroaxonal integrity have shown prognostic value in predicting postoperative visual outcomes for patients with compressive anterior visual pathway lesions. Finally, OCT is indispensable in differentiating optic neuropathies from retinal diseases in patients with visual loss and a nondiagnostic fundus examination. An in-depth discussion regarding the technical aspects of OCT is beyond the scope of this chapter. Instead, we wish to highlight the value OCT brings to the diagnosis and management of common neuroophthalmic conditions, with emphasis on optic neuropathies and retinal disorders.

Progression pattern of neurological disability with respect to clinical attacks in anti-MOG antibody-associated disorders

The progression pattern of neurological disability among patients with anti-myelin oligodendrocyte glycoprotein antibody-associated disorders (MOGAD) was evaluated. Neurological disability was evaluated annually for 408 person-years in 50 patients. More than 30% of the patients had clinical relapses in the first 5 years. Disability progression independent of relapse activity (PIRA) was not seen, whereas a stepwise disability progression was observed after clinical attacks in some instances. Disability worsening was more frequent after relapses than after the onset episode (p < 0.01). Similar to patients with anti-aquaporin-4 antibodies, attack-related stepwise disability progression without PIRA is typical in MOGAD, suggesting the importance of relapse prevention.

Anti-MOG associated disorder-Clinical and radiological characteristics compared to AQP4-IgG+ NMOSD-A single-center experience

BACKGROUND

The discovery of two immunoglobulin G (IgG) antibodies against aquaporin 4 (anti-AQP4) and myelin oligodendrocyte glycoprotein (anti-MOG) has led to the distinction of the disorders anti-AQP4 immunoglobulin G positive neuromyelitis spectrum disorder (AQP4-IgG+ NMOSD) and anti-MOG associated disorder (MOGAD). Different clinical and radiological features have been proposed to distinguish these two demyelinating CNS diseases.

METHODS

This is a single-center retrospective review at the University of Florida (UF) including all patients with the diagnostic code ICD G36 ("other acute disseminated demyelination") from October 2015 to January 2020 (n=141) and all charts included in the clinical NMOSD database of the UF Division of Neuroimmunology (n=36). A total of 151 cases were reviewed for presence of anti-MOG and anti-AQP4 antibodies and NMOSD diagnostic criteria. Differences in MOGAD and AQP4-IgG+ NMOSD were compared.

RESULTS

Of the 151 reviewed patient charts, 11 were consistent with MOGAD and 43 with AQP4-IgG+ NMOSD. Patients with MOGAD were significantly younger at symptom onset compared to patients with AQP4-IgG+ NMOSD (14 [1-33] years vs. 37 [6-82] years; p=0.005). In comparison with AQP4-IgG+ NMOSD, optic neuritis in MOGAD was more frequently associated with bilateral optic nerve involvement: (6/11 [54.5%] vs. 6/43 [13.9%]; p=0.009) and fundoscopic presence of optic disc edema (5/11 [45.5%] vs. 3/43 [7%]; p=0.006). Perineuritis was a common radiological feature in MOGAD (present in 4 cases). In case of myelitis, there was more frequent involvement of the conus medullaris in MOGAD (4/11 [36.4%] vs. 2/43 [4.7%]; p=0.012). Symptomatic cerebral syndrome with supratentorial white matter lesions was seen in MOGAD patients with pediatric onset (pediatric onset: 4/6 [66.7%] vs. adult onset: 0/5 [0%]. In MOGAD, evidence for combined central and peripheral demyelination and increased intracranial pressure was present in one patient each. A preceding inciting event (illness/postpartum) was more frequently identifiable in MOGAD (4/11 [36.4%] vs. 4/43 [7%]; p=0.045). Disability as calculated on the Expanded Disability Status Scale was less severe in MOGAD compared to AQP-IgG+ NMOSD (most severe presentation: 5 [2-7] vs. 7 [1-10]; p=0.015; most recent assessment: 2 [0-5] vs. 5 [0-10]; p=0.045) and patients were more likely to respond to treatment of acute attacks with corticosteroids and/or plasmapheresis (Clinical Global Impression-Global Change scale: 1 [1-4] vs. 3 [1-6]; p=0.001).

INTERPRETATION

The study confirms that simultaneous bilateral optic neuritis, presence of optic disc edema, transverse myelitis with conus involvement and a less severe disease course are distinctive features of MOGAD.

A multi-center case series of sarcoid optic neuropathy

OBJECTIVE

The diagnosis of sarcoid optic neuropathy is time-sensitive, as delayed treatment risks irreversible vision loss. We sought to analyze its characteristics and outcomes.

METHODS

We performed a multi-center retrospective study of sarcoid optic neuropathy among 5 USA medical centers. Inclusion criteria were: 1) clinical optic neuropathy; 2) optic nerve/sheath enhancement on neuroimaging; 3) pathological confirmation of systemic or nervous system sarcoidosis.

RESULTS

Fifty-one patients were included. The median onset age of sarcoid optic neuropathy was 50 years (range, 17-70 years) and 71% were female. The median visual acuity at nadir in the most affected eye was 20/80 (range, 20/20 to no-light-perception). Thirty-four of 50 (68%) patients had radiologic evidence of other nervous system involvement and 20 (39%) patients had symptoms/signs of other cranial nerve dysfunction. Cerebrospinal fluid analysis revealed an elevated white blood cell count in 22 of 31 (71%) patients (median: 14/μL; range: 1-643/μL). Pathologic confirmation of sarcoidosis was by biopsy of systemic/pulmonary site, 34 (67%); optic nerve/sheath, 9 (18%); or other nervous system region, 8 (16%). Forty patients improved with treatment (78%), 98% receiving corticosteroids and 65% receiving steroid-sparing immunosuppressants, yet 11/46 patients (24%) had a visual acuity of 20/200 or worse at last follow-up.

CONCLUSIONS

Sarcoid optic neuropathy frequently occurs with other clinical and radiologic abnormalities caused by neurosarcoidosis and diagnostic confirmation occasionally requires optic nerve/sheath biopsy. Improvement with treatment is common but most patients have some residual visual disability. Improved recognition and a more expeditious diagnosis and treatment may spare patients from permanent vision loss.

MOG-IgG- versus AQP4-IgG-Positive Optic Neuritis in Thailand: Clinical Characteristics and Long-Term Visual Outcomes Comparison

Purpose

To compare demographic data, clinical and radiological characteristics, treatment, and long-term visual outcomes between myelin oligodendrocyte glycoprotein autoantibody-positive optic neuritis (MOG-IgG + ON) and aquaporin-4 autoantibody-positive optic neuritis (AQP4-IgG + ON) in Thailand.

Patients and Methods

We included individuals who were diagnosed with either MOG-IgG + ON or AQP4-IgG + ON over an 11-year period. Demographic data, clinical and radiological characteristics at ON presentation, treatment, and long-term visual outcomes were retrospectively collected.

Results

There were 16 patients (28 eyes) and 43 patients (59 eyes) in the MOG-IgG + ON and AQP4-IgG + ON groups, respectively. AQP4-IgG + ON occurred predominantly in female patients whereas MOG-IgG + ON-affected female patients and male patients equally (p < 0.001). Prior or concurrent non-ON demyelinating events were more often observed at AQP4-IgG + ON onset (p < 0.001). At ON presentation, bilaterality and the presence of optic disc edema were predominantly found in the MOG-IgG + ON group (bilaterality: 80% vs 8%, MOG-IgG + ON vs AQP4-IgG + ON patients, respectively (p < 0.001); presence of optic disc edema: 92.3% vs 36.6%, MOG-IgG + ON- vs AQP4-IgG + ON-affected eyes, respectively (p < 0.001)). There was no statistically significant difference in age at ON onset, nadir visual acuity (VA), presence of pain, segmental enhancement, and total enhanced segments of the anterior visual pathways. At the last follow-up, immunosuppressive drugs were used more often in the AQP4-IgG + ON group (43.7% vs 74.4%, MOG-IgG + ON vs AQP4-IgG + ON, respectively; p < 0.027). Remarkably better final VA was achieved in MOG-IgG + ON-affected eyes (median: 0.0 vs 0.4 logMAR, MOG-IgG + ON- vs AQP4-IgG + ON-affected eyes, respectively; p < 0.001).

Conclusion

Compared with AQP4-IgG + ON, MOG-IgG + ON tended to present with bilaterality and optic disc edema and demonstrated better visual outcomes.

Population-Based Incidence of Optic Neuritis in the Era of Aquaporin-4 and Myelin Oligodendrocyte Glycoprotein Antibodies

PURPOSE

To re-evaluate the population-based incidence of optic neuritis in the era of aquaporin-4-immunoglobulin G (AQP4-IgG) and myelin oligodendrocyte glycoprotein (MOG)-IgG, which are biomarkers of optic neuritis that is distinct from multiple sclerosis (MS). Over the past 15 years, 2 new biomarkers have been discovered that allow for further characterization of the cause of atypical optic neuritis: AQP4-IgG and MOG-IgG.

DESIGN

Retrospective, population-based cohort.

SETTING

population-based.

PARTICIPANTS

all residents of Olmsted County, Minnesota, with optic neuritis diagnosed between January 1, 2000, and December 31, 2018.

METHODS

The Rochester Epidemiology Project database was used to identify patients. Sera were tested for AQP4-IgG and MOG-IgG by using a live-cell-based flow cytometry assay. Main outcome measurements were the incidence and cause of optic neuritis.

RESULTS

Optic neuritis was diagnosed in 110 patients, providing an annual incidence of 3.9 per 100,000. The final diagnosis was MS in 57%, idiopathic in 29%, MOG-IgG-associated disorder in 5%, AQP4-IgG-seropositive neuromyelitis optic spectrum disorder (NMOSD) in 3%, infectious type in 2%, sarcoidosis in 2%, seronegative NMOSD in 1%, and medication-related in 1%. All 3 patients positive for AQP4-IgG had more than 1 optic neuritis attack, 2 with residual no light perception vision in at least 1 eye. Among MOG-IgG-positive patients, 4 of 6 patients had recurrent optic neuritis, and all 6 had a final visual acuity of 20/30 or better.

CONCLUSIONS

At a population level, AQP4-IgG and MOG-IgG account for 9% of optic neuritis and are associated with recurrent attacks, but MOG-IgG optic neuritis has a better visual outcome than AQP4-IgG optic neuritis.

Silent New Brain MRI Lesions in Children with MOG-Antibody Associated Disease

Anti-myelin oligodendrocyte glycoprotein immunoglobulin G (MOG-IgG) antibodies are associated clinically with either a monophasic or relapsing disease course. We investigated the frequency and clinical importance of acquired asymptomatic brain magnetic resonance imaging (MRI) lesions in a prospective incident cohort of 74 MOG-IgG positive children with serial MRI scans over a median of 5 years from presentation. Silent new lesions were detected in 14% of MOG-IgG positive participants, most commonly within the first months post-onset, with a positive predictive value for clinically relapsing disease of only 20%. Detection of asymptomatic lesions alone need not prompt initiation of chronic immunotherapy. ANN NEUROL 2021;89:408-413.

Variability of cerebrospinal fluid findings by attack phenotype in myelin oligodendrocyte glycoprotein-IgG-associated disorder

BACKGROUND

The variability in cerebrospinal fluid (CSF) findings of myelin oligodendrocyte glycoprotein-IgG-associated disorder (MOGAD) is not fully elucidated.

OBJECTIVE AND METHODS

We retrospectively analyzed 203 attack-associated CSFs from Mayo Clinic patients (2000-2019) with MOGAD.

RESULTS

White-blood-cell (>5/mm³) elevation was less with clinically isolated optic neuritis (23%), compared to myelitis, brain/brainstem attacks, or combinations thereof (>70%), p<0.0001. CSF pleocytosis in optic neuritis was more common in patients with coexisting asymptomatic brain and/or spine MRI T2-lesions (53%) than in those without (16%), p=0.005. Abnormal CSF oligoclonal bands ranged from 1% (optic neuritis) to 18% (brain/brainstem attacks). CSF pleocytosis was less common after immunotherapy.

CONCLUSIONS

CSF findings in MOGAD vary by attack phenotype and preceding treatment.

Efficacy for the Annual Relapse Rate after the Immunosuppressive Therapy in Patients Associated with Anti-AQP4 or Anti-MOG Antibody-Positive Optic Neuritis

Purpose

Although oral prednisolone is the first-line treatment for preventing recurrent optic neuritis (ON) after the completion of acute-phase treatment, especially anti-aquaporin 4 (AQP4) antibody-positive ON, and anti-myelin oligodendrocyte glycoprotein (MOG) antibody-positive ON, some patients experience relapses. Immunosuppressants could be effective in reducing the recurrence rate for neuromyelitis optica spectrum disorder and MOG antibody-related diseases, but there have been few studies addressing this issue focusing on the changes in ophthalmic parameters. The objective of the study was to analyze the impact of off-label uses of immunosuppressants to reduce recurrent ON.

Design

Retrospective observational study, clinical case series.

Methods

We reviewed the medical charts of 11 cases (22 eyes) who underwent immunosuppressive therapy in Kobe University Hospital and compared the annualized relapse rate (ARR) before and after immunosuppressive therapy. We also evaluated the dosage of prednisolone, complications of immunosuppressants, and other visual functional ophthalmologic parameters.

Results

Eleven cases in total had AQP4 antibody (9 cases) and/or MOG antibody (3 cases). One case was double positive for these antibodies. Nine patients received azathioprine and two received mycophenolate mofetil as an initial immunosuppressive therapy. The median duration of immunosuppressant treatment was 2.8 years. The median ON ARR before immunosuppressive therapy was 0.33, and this decreased significantly to 0 after the therapy (p = 0.02). The dose of prednisolone was reduced from 17.8 ± 7.1 mg/day before to 5.8 ± 2.2 mg/day after immunosuppressive therapy (p < 0.01). Although two patients presented with mild elevation of liver enzymes and nausea, all patients were able to continue taking the immunosuppressants.

Conclusions

Immunosuppressants can potentially decrease relapses and steroid dosage in patients with anti-AQP4 or MOG antibody-positive ON without severe adverse events and the exacerbation of visual acuities.

Anti-MOG-associated demyelinating disorders: two sides of the same coin

BACKGROUND

Anti-myelin oligodendrocyte glycoprotein antibody-associated disorders (MOGAD) are new emerging diseases with heterogeneous course, treatment, response, and prognosis.

CASE REPORT

We herein present 2 cases with antibodies to MOG, one with a cerebellar/brainstem monophasic syndrome which partially improved after treatment, and the other with an optic neuritis onset then relapsed with cortical encephalitis and presented a subsequent complete recovery. We further discuss elements possibly associated with disease heterogeneity and influencing treatment choices.

CONCLUSIONS

MOGAD is an extremely variable disease which can relapse and accumulate disability over time. An early diagnosis and correct timely treatment is fundamental to improve clinical outcome.

Biomarkers in Rare Demyelinating Disease of the Central Nervous System

Rare neurological diseases are a heterogeneous group corresponding approximately to 50% of all rare diseases. Neurologists are among the main specialists involved in their diagnostic investigation. At the moment, a consensus guideline on which neurologists may base clinical suspicion is not available. Moreover, neurologists need guidance with respect to screening investigations that may be performed. In this respect, biomarker research has emerged as a particularly active field due to its potential applications in clinical practice. With respect to autoimmune demyelinating diseases of the Central Nervous System (CNS), although these diseases occur in the frame of organ-specific autoimmunity, pathology of the disease itself is orchestrated among several anatomical and functional compartments. The differential diagnosis is broad and includes, but is not limited to, rare neurological diseases. Multiple Sclerosis (MS) needs to be differentially diagnosed from rare MS variants, Acute Disseminated Encephalomyelitis (ADEM), the range of Neuromyelitis Optica Spectrum Disorders (NMOSDs), Myelin Oligodendrocyte Glycoprotein (MOG) antibody disease and other systemic inflammatory diseases. Diagnostic biomarkers may facilitate timely diagnosis and proper disease management, preventing disease exacerbation due to misdiagnosis and false treatment. In this review, we will describe advances in biomarker research with respect to rare neuroinflammatory disease of the CNS.

Beyond Giant Cell Arteritis and Takayasu's Arteritis: Secondary Large Vessel Vasculitis and Vasculitis Mimickers

PURPOSE OF REVIEW

To provide an overview of mimickers of large vessel vasculitis (LVV), by the main presenting manifestation, i.e., systemic, vascular, and cranial manifestations.

RECENT FINDINGS

The main differential diagnoses in patients with giant cell arteritis (GCA) and Takayasu arteritis (TAK) presenting with systemic manifestations (i.e., fever, anorexia, weight loss, night sweats, arthralgia/myalgia, and/or increased inflammatory indexes) are neoplastic, infectious, or other inflammatory conditions. In patients with vascular manifestations (such as peripheral ischemia, vascular stenoses, or aneurysms), atherosclerosis and non-inflammatory vascular diseases should be excluded. In those presenting with predominant cranial symptoms (i.e., temporal headache, jaw claudication, scalp tenderness, transient or permanent vision loss), other causes of headache, cerebrovascular accidents, optic neuropathy, and neuromuscular syndromes need to be considered. The diagnosis of LVV maybe challenging, especially when patients present with atypical or incomplete clinical forms. In these cases, a multidisciplinary approach is strongly recommended.

E.U. paediatric MOG consortium consensus: Part 1 - Classification of clinical phenotypes of paediatric myelin oligodendrocyte glycoprotein antibody-associated disorders

Over the past few years, increasing interest in the role of autoantibodies against myelin oligodendrocyte glycoprotein (MOG-abs) as a new candidate biomarker in demyelinating central nervous system diseases has arisen. MOG-abs have now consistently been identified in a variety of demyelinating syndromes, with a predominance in paediatric patients. The clinical spectrum of these MOG-ab-associated disorders (MOGAD) is still expanding and differs between paediatric and adult patients. This first part of the Paediatric European Collaborative Consensus emphasises the diversity in clinical phenotypes associated with MOG-abs in paediatric patients and discusses these associated clinical phenotypes in detail. Typical MOGAD presentations consist of demyelinating syndromes, including acute disseminated encephalomyelitis (ADEM) in younger, and optic neuritis (ON) and/or transverse myelitis (TM) in older children. A proportion of patients experience a relapsing disease course, presenting as ADEM followed by one or multiple episode(s) of ON (ADEM-ON), multiphasic disseminated encephalomyelitis (MDEM), relapsing ON (RON) or relapsing neuromyelitis optica spectrum disorders (NMOSD)-like syndromes. More recently, the disease spectrum has been expanded with clinical and radiological phenotypes including encephalitis-like, leukodystrophy-like, and other non-classifiable presentations. This review concludes with recommendations following expert consensus on serologic testing for MOG-abs in paediatric patients, the presence of which has consequences for long-term monitoring, relapse risk, treatments, and for counselling of patient and families. Furthermore, we propose a clinical classification of paediatric MOGAD with clinical definitions and key features. These are operational and need to be tested, however essential for future paediatric MOGAD studies.

Differences in Clinical Features of Myelin Oligodendrocyte Glycoprotein Antibody-Associated Optic Neuritis in White and Asian Race

PURPOSE

To determine whether clinical features and visual outcomes of myelin oligodendrocyte glycoprotein antibody-associated optic neuritis (MOG-ON) differ between White and Asian subjects.

DESIGN

Multicenter retrospective cohort.

METHODS

This was a multicenter study of 153 subjects who were White or Asian with a history of adult-onset (age 18 years or older) optic neuritis (ON) and positive MOG-IgG serology by cell-based assay. Subjects were enrolled from 2 unpublished cohorts (January 2017-November 2019) and 9 published cohorts with case-level data available (2012-2018). Subjects with alternative etiologies of demyelinating disease and positive or lack of aquaporin-4-IgG serology result were excluded. The main outcome measurements were clinical features and final visual outcomes.

RESULTS

Of the 153 subjects who were White (n = 80) or Asian (n = 73) included in the study, 93 (61%) were women, mean age of onset was 40.8 ± 14.9 years, and median follow-up was 35.2 months (range: 1-432 months); all of these characteristics were similar between White and Asian subjects. White subjects were more likely to have recurrent ON (57 [71%] vs 20 [27%]; P = .001) and extra-optic nerve manifestations (35 [44%] vs 8 [11%]; P = .001). Optic disc swelling, neuroimaging findings, presenting visual acuity (VA), treatment, and final VA did not differ according to subjects' race. Despite the high prevalence of severe visual loss (<20/200) during nadir, most subjects had good recovery of VA (>20/40) at final examination (51/77 [66%] White subjects vs 52/70 [74%] Asian subjects).

CONCLUSION

White subjects with MOG-ON were more likely to have recurrent disease and extra-optic nerve manifestations. Visual outcomes were similar between White and Asian subjects.

E.U. paediatric MOG consortium consensus: Part 2 - Neuroimaging features of paediatric myelin oligodendrocyte glycoprotein antibody-associated disorders

Imaging plays a crucial role in differentiating the spectrum of paediatric acquired demyelinating syndromes (ADS), which apart from myelin oligodendrocyte glycoprotein antibody associated disorders (MOGAD) includes paediatric multiple sclerosis (MS), aquaporin-4 antibody neuromyelitis optica spectrum disorders (NMOSD) and unclassified patients with both monophasic and relapsing ADS. In contrast to the imaging characteristics of children with MS, children with MOGAD present with diverse imaging patterns which correlate with the main demyelinating phenotypes as well as age at presentation. In this review we describe the common neuroradiological features of children with MOGAD such as acute disseminated encephalomyelitis, optic neuritis, transverse myelitis, AQP4 negative NMOSD. In addition, we report newly recognized presentations also associated with MOG-ab such as the 'leukodystophy-like' phenotype and autoimmune encephalitis with predominant involvement of cortical and deep grey matter structures. We further delineate the features, which may help to distinguish MOGAD from other ADS and discuss the future role of MR-imaging in regards to treatment decisions and prognosis in children with MOGAD. Finally, we propose an MRI protocol for routine examination and discuss new imaging techniques, which may help to better understand the neurobiology of MOGAD.

Anti-myelin oligodendrocyte glycoprotein antibody-positive coursing with optic neuritis: Imaging and clinical implications

A 9-year-old boy was admitted to our institution with acute onset of bilateral blurry vision. Physical examination revealed bilateral papilledema. Cerebrospinal fluid analysis and comprehensive metabolic panel were normal. Magnetic resonance imaging (MRI) of the brain showed extensive bilateral optic nerve inflammation with post-contrast gadolinium enhancement on T1-weighted sequence. The involvement was limited to the anterior segments of the optic nerves sparing chiasma and optic tracts. Anti-aquaporin-4 antibody (AQP4) was negative while anti-myelin oligodendrocyte glycoprotein antibody (MOG) was positive. After intravenous methylprednisolone, his vision dramatically improved. The patient was discharged with only mildly impaired visual acuity, 2 weeks after admission. Follow-up brain MRI and MOG assay after 3 months were within normal limits.

Neuromyelitis optica

Neuromyelitis optica (NMO; also known as Devic syndrome) is a clinical syndrome characterized by attacks of acute optic neuritis and transverse myelitis. In most patients, NMO is caused by pathogenetic serum IgG autoantibodies to aquaporin 4 (AQP4), the most abundant water-channel protein in the central nervous system. In a subset of patients negative for AQP4-IgG, pathogenetic serum IgG antibodies to myelin oligodendrocyte glycoprotein, an antigen in the outer myelin sheath of central nervous system neurons, are present. Other causes of NMO (such as paraneoplastic disorders and neurosarcoidosis) are rare. NMO was previously associated with a poor prognosis; however, treatment with steroids and plasma exchange for acute attacks and with immunosuppressants (in particular, B cell-depleting agents) for attack prevention has greatly improved the long-term outcomes. Recently, a number of randomized controlled trials have been completed and the first drugs, all therapeutic monoclonal antibodies, have been approved for the treatment of AQP4-IgG-positive NMO and its formes frustes.

MRI characteristics of MOG-Ab associated disease in adults: An update

Our knowledge of the radiological spectrum of myelin oligodendrocyte glycoprotein antibody associated disease (MOGAD) is growing rapidly. An update on the radiological features of the disease, and its evolution is thus necessary. Magnetic resonance imaging (MRI) has an increasingly important role in the differential diagnosis of MOGAD particularly from aquaporin-4 antibody-positive neuromyelitis optica spectrum disorder (AQP4-NMOSD), and multiple sclerosis (MS). Differentiating these conditions is of prime importance because the management is different between the three inflammatory diseases, and thus could prevent further attack-related disability. Therefore, identifying the MRI features suggestive of MOGAD has diagnostic and prognostic implications. We herein review optic nerve, spinal cord and the brain MRI findings from MOGAD adult patients, and compare them to AQP4-NMOSD and MS.

AQP4-IgG and MOG-IgG Related Optic Neuritis-Prevalence, Optical Coherence Tomography Findings, and Visual Outcomes: A Systematic Review and Meta-Analysis

Background: Optic neuritis (ON) is a cardinal manifestation of multiple sclerosis (MS), aquaporin-4 (AQP4)-IgG-, and myelin oligodendrocyte glycoprotein (MOG)-IgG-associated disease. However, the prevalence of AQP4-IgG seropositivity and MOG-IgG seropositivity in isolated ON is unclear, and studies comparing visual outcomes and optical coherence tomography (OCT)-derived structural retinal measures between MS-ON, AQP4-ON, and MOG-ON eyes are limited by small sample sizes. Objectives: (1) To assess the prevalence of AQP4-IgG and MOG-IgG seropositivity among patients presenting with isolated ON; (2) to compare visual outcomes and OCT measures between AQP4-ON, MOG-ON, and MS-ON eyes. Methods: In this systematic review and meta-analysis, a total of 65 eligible studies were identified by PubMed search. Statistical analyses were performed with random effects models. Results: In adults with isolated ON, AQP4-IgG seroprevalence was 4% in non-Asian and 27% in Asian populations, whereas MOG-IgG seroprevalence was 8 and 20%, respectively. In children, AQP4-IgG seroprevalence was 0.4% in non-Asian and 15% in Asian populations, whereas MOG-IgG seroprevalence was 47 and 31%, respectively. AQP4-ON eyes had lower peri-papillary retinal nerve fiber layer (pRNFL; -11.7 μm, 95% CI: -15.2 to -8.3 μm) and macular ganglion cell + inner plexiform layer (GCIPL; -9.0 μm, 95% CI: -12.5 to -5.4 μm) thicknesses compared with MS-ON eyes. Similarly, pRNFL (-11.2 μm, 95% CI: -21.5 to -0.9 μm) and GCIPL (-6.1 μm, 95% CI: -10.8 to -1.3 μm) thicknesses were lower in MOG-ON compared to MS-ON eyes, but did not differ between AQP4-ON and MOG-ON eyes (pRNFL: -1.9 μm, 95% CI: -9.1 to 5.4 μm; GCIPL: -2.6 μm, 95% CI: -8.9 to 3.8 μm). Visual outcomes were worse in AQP4-ON compared to both MOG-ON (mean logMAR difference: 0.60, 95% CI: 0.39 to 0.81) and MS-ON eyes (mean logMAR difference: 0.68, 95% CI: 0.40 to 0.96) but were similar in MOG-ON and MS-ON eyes (mean logMAR difference: 0.04, 95% CI: -0.05 to 0.14). Conclusions: AQP4-IgG- and MOG-IgG-associated disease are important diagnostic considerations in adults presenting with isolated ON, especially in Asian populations. Furthermore, MOG-IgG seroprevalence is especially high in pediatric isolated ON, in both non-Asian and Asian populations. Despite a similar severity of GCIPL and pRNFL thinning in AQP4-ON and MOG-ON, AQP4-ON is associated with markedly worse visual outcomes.

Ophthalmic manifestations of myelin oligodendrocyte glycoprotein-IgG-associated disorder other than optic neuritis: a systematic review

Background/Aims

Optic neuritis (ON) is the primary ophthalmic manifestation of myelin oligodendrocyte glycoprotein-IgG-associated disorder (MOGAD), but numerous reports have expanded the visual manifestations of this condition. The goal of this study was to synthesise the extensive literature on this topic to help ophthalmologists understand when testing for MOG-IgG should be considered.

Method

A systematic review of the English-language literature was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and searches were conducted using Ovid MEDLINE (from January 1, 1948 to April 1, 2020) and Ovid EMBASE (from January 1, 1947 to April 1, 2020). Inclusion criteria included studies describing non-isolated ON ophthalmic manifestations where cell-based assays were used for the detection of MOG antibodies.

Results

Fifty-one articles representing 62 patients with a median age of 32.0 (range 2–65), female gender (51%) and follow-up of 20.0 months (range: 1–240) were included. Twenty-nine patients had non-isolated ON afferent visual manifestations: uveitis, peripheral ulcerative keratitis, acute macular neuroretinopathy, neuroretinitis, venous stasis retinopathy, large preretinal macular haemorrhage, orbital inflammatory syndrome, orbital apex syndrome, optic perineuritis, papilloedema and homonymous visual field defects. Incomplete recovery of ON was associated with a case of Leber’s hereditary optic neuropathy. Efferent ophthalmic manifestations included cranial neuropathies, internuclear ophthalmoplegia, central nystagmus, saccadic intrusions and ocular flutter. Cranial nerve involvement was secondary to enhancement of the cisternal portion or brainstem involvement. All included cases were treated with corticosteroids with 31% of cases requiring additional immunosuppressive therapy.

Conclusions

MOGAD has been associated with various afferent and efferent ophthalmic manifestations apart from isolated ON. Awareness of these findings may result in earlier diagnosis and treatment.

Myelin Oligodendrocyte Glycoprotein Antibody-Associated Optic Neuritis in Canada

OBJECTIVE

To describe clinical characteristics of Canadian patients with myelin-oligodendrocyte glycoprotein immunoglobulin-G optic neuritis (MOG-IgG ON).

METHODS

Retrospective observational case series of MOG-IgG seropositive patients with ON referred to tertiary neuro-ophthalmology practices. Outcome measures included clinical characteristics, radiologic findings, and visual outcomes.

RESULTS

Forty-six eyes of 30 patients were included. Twenty-three (76.7%) were women, mean onset age was 40.7 years (range 16-77), and most were Caucasian. Seventeen (56.7%) presented with their first ON episode. Sixteen (53.3%) had bilateral eye involvement. Isolated ON without associated neurological symptoms occurred in 90.0%. In 22 patients with acute ON (seen within 1 month of onset), presenting mean visual acuity (VA) was 20/258 (logMAR 1.11), mean deviation (MD) on Humphrey visual fields was -16.90 ± 10.83 dB, and peripapillary retinal nerve fiber layer (RNFL) thickness on ocular coherence tomography (OCT) was 164.23 ± 46.53 um. Orbital magnetic resonance imaging (MRI) within 1 month of symptom onset for 19 patients demonstrated orbital optic nerve enhancement in 11 (57.9%) and perineural enhancement in 11 (57.9%). Brain MRI was normal in 28 (93.3%) patients. Twenty out of 22 patients with acute presentation were treated with high-dose glucocorticoids and 5 with plasma exchange in addition to corticosteroids. Long-term immunosuppression was utilized in 9 (30%) out of all 30 patients. Final VA was 20/30 (logMAR 0.18), MD was -7.17 ± 8.85 dB, and RNFL thickness was 72.15 ± 20.16 um.

CONCLUSION

MOG-IgG ON in Canada has a variable presentation with most patients having substantial initial vision loss with good recovery. This is the largest characterization of the disease in Canada to date.

MOG-IgG1 and co-existence of neuronal autoantibodies

BACKGROUND

The presence of co-existent neuronal antibodies (neuronal-IgG) in patients with myelin oligodendrocyte glycoprotein immunoglobulin G (MOG-IgG1) is not yet well understood.

OBJECTIVES

The aim of this study was to investigate the co-existence of a broad range of neuronal-IgG in MOG-IgG1+ patients.

METHODS

MOG-IgG1+ patients were tested for 17 neuronal-IgGs in cerebrospinal fluid (CSF) and serum including NMDA-R-IgG, AMPA-R-IgG, GABAB-R-IgG, LGI1-IgG, CASPR2-IgG, GABAA-R-IgG, GAD65-IgG, mGLUR1-IgG, DPPX-IgG, CRMP5-IgG, amphiphysin-IgG, PCA1,2,Tr, and ANNA1,2,3. Clinical and radiological features of MOG-IgG1+ with NMDA-R-IgG in CSF were compared to a control cohort of MOG-IgG1+ patients without NMDA-R-IgG.

RESULTS

A total of 376 MOG-IgG1+ patients underwent testing for neuronal-IgGs. Serum testing for neuronal-IgGs (113 adults, 142 children) identified one child with NMDA-R-IgG (0.7%), one child with CASPR2-IgG (0.7%), one adult with LGI1-IgG (0.9%) and one adult with GABAA-R-IgG (0.9%). CSF testing for neuronal-IgGs (97 adults, 169 children) identified seven children (4%) and seven adults (7%) with NMDA-R-IgG, and one adult with GABAA-R-IgG (1%). The MOG-IgG1+/NMDA-R-IgG+ patients had a median age of 17 (range: 2-39) years. Features associated with MOG-IgG1+/NMDA-R-IgG+ included encephalopathy (p = 0.001), seizures (p = 0.045), and leptomeningeal enhancement (p = 0.045).

CONCLUSION

NMDA-R-IgG was the most frequently detected neuronal-IgG to co-exist with MOG-IgG1. MOG-IgG1+/NMDA-R-IgG+ patients most often presented with encephalopathy and seizures. Testing for MOG-IgG1 and NMDA-R-IgG may be warranted in patients with encephalopathy and inflammatory demyelinating syndromes.

Understanding Pediatric Neuroimmune Disorder Conflicts: A Neuroradiologic Approach in the Molecular Era

Neuroimmune disorders in children are a complex group of inflammatory conditions of the central nervous system with diverse pathophysiologic mechanisms and clinical manifestations. Improvements in antibody analysis, genetics, neuroradiology, and different clinical phenotyping have expanded knowledge of the different neuroimmune disorders. The authors focus on pediatric-onset myelin oligodendrocyte glycoprotein (MOG) antibody-associated disease, which is a new entity in the spectrum of inflammatory demyelinating diseases, distinct from both multiple sclerosis (MS) and anti-aquaporin-4 (AQP4) antibody neuromyelitis optica spectrum disorders (NMOSDs). The authors review the importance of an optimized antibody-detection assay, the frequency of MOG antibodies in children with acquired demyelinating syndrome (ADS), the disease course, the clinical spectrum, proposed diagnostic criteria, and neuroimaging of MOG antibody-associated disease. Also, they outline differential diagnosis from other neuroimmune disorders in children according to the putative primary immune mechanism. Finally, they recommend a diagnostic algorithm for the first manifestation of ADS or relapsing ADS that leads to four demyelinating syndromes: MOG antibody-associated disease, AQP4 antibody NMOSDs, MS, and seronegative relapsing ADS. This diagnostic approach provides a framework for the strategic role of neuroradiology in diagnosis of ADS and decision making, to optimize patient care and treatment outcome in concert with clinicians. Online supplemental material is available for this article. ^©RSNA, 2020.

[Myelin oligodendrocyte glycoprotein immunoglobulin G-associated encephalomyelitis]

The article discusses the role of myelin oligodendrocyte glycoprotein immunoglobulin G (MOG-IgG) in demyelinating diseases of the central nervous system. Clinical phenotypes of demyelinating syndromes associated with MOG-IgG that are currently included into neuromyelitis optica spectrum disorders (NMOSD) are described. However, it has been shown that encephalomyelitis associated with MOG-IgG (MOG-EM) has certain clinical, radiological, immunological and histopathological features that make it possible to single out these syndromes into a separate nosological form. We provide International recommendations that establish indications for testing MOG-IgG using cell-based assay. We discuss epidemiological issues and classification challenges of the disease. Various approaches to treatment and prevention of relapses of MOG-EM are analyzed.

Resolution of myelin oligodendrocyte glycoprotein (MOG)-IgG optic neuritis without treatment

BACKGROUND

Patients with MOG-IgG optic neuritis tend to present with severely comprised visual function during the acute phase of the disease. Treatment with corticosteroids is almost always used in the acute period to aid in visual recovery and there is limited data on the natural history without treatment.

METHODS

We present the case of a 45-year-old woman who developed right eye pain worse with eye movements and mildly blurred vision and was found to have optic disk edema with peripapillary hemorrhages. Her visual acuity was 20/20 and she had several depressed points on Humphrey visual field testing. Magnetic resonance imaging of the brain was normal and the orbits revealed very mild enhancement of the optic nerve/optic nerve sheath. MOG-IgG was positive in the serum (medium positivity). She was observed without treatment, the pain resolved and she felt her vision returned to normal within 2 months of onset.

CONCLUSIONS

MOG-IgG optic neuritis may present with relatively preserved visual function even at its nadir. Observation may be a reasonable strategy for these patients.

Pain in NMOSD and MOGAD: A Systematic Literature Review of Pathophysiology, Symptoms, and Current Treatment Strategies

Neuromyelitis optica spectrum disorders (NMOSDs) and myelin oligodendrocyte glycoprotein-antibody-associated disease (MOGAD) are autoimmune inflammatory disorders of the central nervous system (CNS). Pain is highly prevalent and debilitating in NMOSD and MOGAD with a severe impact on quality of life, and there is a critical need for further studies to successfully treat and manage pain in these rare disorders. In NMOSD, pain has a prevalence of over 80%, and pain syndromes include neuropathic, nociceptive, and mixed pain, which can emerge in acute relapse or become chronic during the disease course. The impact of pain in MOGAD has only recently received increased attention, with an estimated prevalence of over 70%. These patients typically experience not only severe headache, retrobulbar pain, and/or pain on eye movement in optic neuritis but also neuropathic and nociceptive pain. Given the high relevance of pain in MOGAD and NMOSD, this article provides a systematic review of the current literature pertaining to pain in both disorders, focusing on the etiology of their respective pain syndromes and their pathophysiological background. Acknowledging the challenge and complexity of diagnosing pain, we also provide a mechanism-based classification of NMOSD- and MOGAD-related pain syndromes and summarize current treatment strategies.

Differences in morphology and visual function of myelin oligodendrocyte glycoprotein antibody and multiple sclerosis associated optic neuritis

Background

Myelin oligodendrocyte glycoprotein immunoglobulin G associated optic neuritis (MOG-ON) is a recently described entity. Recent studies have shown that MOG-ON has a more severe clinical presentation than classic optic neuritis (ON).

Objective

This study aimed to define morphological characteristics of MOG-ON, correlate these with clinical characteristics and compare them with multiple sclerosis associated ON (MS-ON) and healthy controls (CTRL).

Methods

In a retrospective study, we included MOG-ON and MS-ON patients seen between 2011 and 2018 at the University Hospital Bern. Data from clinical examination, perimetry, and optical coherence tomography (OCT) were analyzed.

Results

A total of 66 eyes of 43 patients were included; 22 MS-ON and 33 CTRL eyes were sex- and age-matched to 11 MOG-ON eyes. We found significantly worse visual acuity at nadir, but better recovery and thinner global peripapillary retinal nerve fiber layer thickness in MOG-ON patients compared to MS-ON patients. Both groups exhibited irregular thinning of the macular ganglion cell layer. Furthermore, the visual acuity and visual field parameters correlated to retinal layer thickness only in MOG-ON eyes.

Conclusion

In comparison to MS-ON, MOG-ON is associated with more prominent acute vision loss and more pronounced global thinning of the pRNFL. Both entities result in similar final visual acuity and atrophy of the macular ganglion cell layer.

Steroid-sparing maintenance immunotherapy for MOG-IgG associated disorder

OBJECTIVE

Myelin oligodendrocyte glycoprotein-immunoglobulin G (MOG-IgG) associated disorder (MOGAD) often manifests with recurrent CNS demyelinating attacks. The optimal treatment for reducing relapses is unknown. To help determine the efficacy of long-term immunotherapy in preventing relapse in patients with MOGAD, we conducted a multicenter retrospective study to determine the rate of relapses on various treatments.

METHODS

We determined the frequency of relapses in patients receiving various forms of long-term immunotherapy for MOGAD. Inclusion criteria were history of ≥1 CNS demyelinating attacks, MOG-IgG seropositivity, and immunotherapy for ≥6 months. Patients were reviewed for CNS demyelinating attacks before and during long-term immunotherapy.

RESULTS

Seventy patients were included. The median age at initial CNS demyelinating attack was 29 years (range 3-61 years; 33% <18 years), and 59% were female. The median annualized relapse rate (ARR) before treatment was 1.6. On maintenance immunotherapy, the proportion of patients with relapse was as follows: mycophenolate mofetil 74% (14 of 19; ARR 0.67), rituximab 61% (22 of 36; ARR 0.59), azathioprine 59% (13 of 22; ARR 0.2), and IV immunoglobulin (IVIG) 20% (2 of 10; ARR 0). The overall median ARR on these 4 treatments was 0.3. All 9 patients treated with multiple sclerosis (MS) disease-modifying agents had a breakthrough relapse on treatment (ARR 1.5).

CONCLUSION

This large retrospective multicenter study of patients with MOGAD suggests that maintenance immunotherapy reduces recurrent CNS demyelinating attacks, with the lowest ARR being associated with maintenance IVIG therapy. Traditional MS disease-modifying agents appear to be ineffective. Prospective randomized controlled studies are required to validate these conclusions.

Visual field loss and structure-function relationships in optic neuritis associated with myelin oligodendrocyte glycoprotein antibody

BACKGROUND

A paradoxical discrepancy between severe peripapillary retinal nerve fiber layer (pRNFL) atrophy and good visual outcome had been reported in patients with myelin oligodendrocyte glycoprotein-immunoglobulin G (MOG-IgG)-associated optic neuritis (ON). However, only visual acuity (VA) was assessed.

OBJECTIVES

To study visual field (VF) outcomes of patients with MOG-IgG-associated ON and evaluate the correlation between functional eye outcome and retinal structural changes assessed by optical coherence tomography.

METHODS

The records of 32 patients with MOG-IgG-associated ON who underwent ophthalmological examination at least 12 months after ON onset were reviewed. Degree of VF disability was determined by mean deviation (MD).

RESULTS

At final assessment (median, 35 months), 4.2% of 48 affected eyes (AE) had VA ⩽ 0.1, 40% had abnormal MD, and among AE with final VA ⩾ 1.0, 31% had mild to moderate damage. Thinning of the inner retinal layers was significantly correlated with MD impairment. Analysis demonstrated a threshold of pRNFL thickness (50 µm), below which MD was significantly worse (mean, -2.27 dB vs -17.72 dB; p = 0.0003). ON relapse was significantly associated with poor visual outcome assessed by MD.

CONCLUSION

Functional impairment measured with VF is not rare, and MD assessment better reflects actual structural damage.

High association of MOG-IgG antibodies in children with bilateral optic neuritis

BACKGROUND

Bilateral optic neuritis (bilON) is a rare clinical presentation often thought to be associated with relapsing disorders such as neuromyelitis optica spectrum disorders (NMOSD) or multiple sclerosis (MS).

OBJECTIVE

To characterize the clinical, radiological phenotype and antibody status of children presenting with bilON.

MATERIAL AND METHODS

Retrospective multicenter study on children with bilON age <18 years with a first episode aquired demyelinating syndrome (ADS), cMRI, AQP4- and serum MOG-antibody status and follow-up data were collected.

RESULTS

30 patients (f:m = 15:15, median age 8.0y) with bilON met the inclusion criteria. 22/30 (73%) were MOG-positive (median: 1:1280, range: 1:160-1:1520). No patient showed AQP4-abs. 4/30 patients (13%), all with high MOG-abs titers, had recurrent episodes. No patient developed MS. Improvement after IVMP was observed in most patients (26/30; 87%). Outcome was favorable with no sequelae in 22/30 patients. Serial MOG-abs titers tested in 15/22 patients decreased to a median of 1:160 (range: 0-1:640) over a period of 31 months (range: 2-141 months) in 14/15 (93%) patients. MR imaging showed a predominantly anterior affection of the visual system in seropositive patients with bilateral intraorbital lesions in 68% (15/22), compared to 25% in MOG-negative patients (2/8).

CONCLUSION

Pediatric bilON is associated with high MOG-abs titers in combination with anterior involvement of the visual system. Despite severe loss of vision, the majority of patients shows distinct recovery after IVMP.

Myelin oligodendrocyte glycoprotein antibody-associated diffuse orbital inflammation

An 87-year-old man presented with a 2-day history of painful bilateral visual loss. On examination, exophthalmos, lid edema, chemosis, and optic disc edema, on the left side only, were found. Visual acuity was 4/10 OD and no light perception OS. Magnetic resonance imaging (MRI) revealed bilateral optic neuritis and a diffuse and severe infiltration of the intra- and extraconal fat on the left. Laboratory testing was negative except for serum myelin oligodendrocyte glycoprotein (MOG) antibodies. This presentation adds a new variant to the MOG-associated disease spectrum. Testing for MOG antibodies should be considered in patients presenting with diffuse orbital inflammation and optic neuritis.

Effects of Varying Intranasal Treatment Regimens in ST266-Mediated Retinal Ganglion Cell Neuroprotection

INTRODUCTION

Previous studies have shown that intranasally administered ST266, a novel biological secretome of amnion-derived multipotent progenitor cells containing multiple growth factors and anti-inflammatory cytokines, attenuated visual dysfunction and prevented retinal ganglion cell (RGC) loss in experimental optic neuritis. Long-term effects and dose escalation studies examined here have not been reported previously.

METHODS

Optic neuritis was induced in the multiple sclerosis model experimental autoimmune encephalomyelitis (EAE). EAE and control mice were treated once or twice daily with intranasal placebo/vehicle or ST266 beginning after onset of optic neuritis for either 15 days or continuously until sacrifice. Visual function was assessed by optokinetic responses (OKRs). RGC survival and optic nerve inflammation and demyelination were measured.

RESULTS

Both once and twice daily continuous intranasal ST266 treatment from disease onset to 56 days after EAE induction significantly increased OKR scores, decreased RGC loss, and reduced optic nerve inflammation and demyelination compared with placebo (saline, nonspecific protein solution, or cell culture media)-treated EAE mice. ST266 treatment given for just 15 days after disease onset, then discontinued, only delayed OKR decreases, and had limited effects on RGC survival and optic nerve inflammation 56 days after disease induction.

CONCLUSIONS

ST266 is a potential neuroprotective therapy to prevent RGC damage, and intranasal delivery warrants further study as a novel mechanism to deliver protein therapies for optic neuropathies. Results suggest that once daily ST266 treatment is sufficient to sustain maximal benefits and demonstrate that neuroprotective effects promoted by ST266 are specific to the combination of factors present in this complex biologic therapy.

A tearfully painful darkness

A 70-year-old woman presented with new onset of left eye and facial pain. Ophthalmic and neurological examinations, magnetic resonance imaging brain, erythrocyte sedimentation rate, and C-reactive protein were unrevealing. A few days later, she developed vision loss in her left eye. Examination revealed decreased visual acuity with a relative afferent pupillary defect in the left eye and a diffuse mild swelling of the left optic nerve head. Repeat magnetic resonance imaging showed T2 hyperintensity and enhancement of the intraorbital optic nerve and surrounding tissues with no other intracranial abnormalities. Serum studies showed elevated myelin oligodendrocyte glycoprotein IgG titer. She was treated with IV methylprednisolone 1000 mg daily for 3 days and was discharged on prolonged prednisone taper with return of vision to baseline.