MOG-IgG in NMO and related disorders: a multicenter study of 50 patients. Part 2: Epidemiology, clinical presentation, radiological and laboratory features, treatment responses, and long-term outcome

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.

Pattern Visually Evoked Potentials in Japanese Girl With Optic Neuritis and Seropositive to Anti-myelin Oligodendrocyte Glycoprotein (MOG) Antibody

Purpose: To describe a Japanese girl with unilateral optic neuritis who was seropositive for the anti-myelin-oligodendrocyte glycoprotein (MOG). Serial recordings of the pattern visual evoked potentials (pVEPs) were made to follow the dynamic changes of the disease activity.

Observations: A 5-year-old girl developed a sudden reduction of vision and deep ocular pain in her right eye. On examination at our university hospital, the best-corrected visual acuity (BCVA) was light perception, and a swelling of the optic disc and tortuous vessels at the posterior pole of the right eye were observed. MRI demonstrated that her right optic nerve was hyperintense on short TI inversion recovery (STIR) sequence. A diagnosis of right papillitis was made, and she was treated with steroid pulse therapy followed by a gradual tapering of oral prednisolone. The visual acuity decreased to no light perception and plasmapheresis combined with high-dose intravenous immunoglobulin therapy was performed. The decimal visual acuity rapidly improved and recovered to 1.2, and no recurrence was observed for at least 1 year. On day 19, she was found to be anti-MOG antibody positive and anti-Aquaporin 4 antibody negative. pVEPs were recorded during the course of the disease process which showed the dynamic changes of the physiology of the visual pathways. The implicit times of the N75 and P100 components were prolonged in the right eye in the acute phase. The right visual acuity remained at 1.2 for at least 1 year, but the implicit times of the N75 and P100 components of the pVEPs of the right eye were still prolonged compared to left eye.

Conclusion: Our findings indicate a positive relationship between the anti-MOG antibodies-positivity and the prolonged pVEPs. Further analyses of the pVEPs and other clinical findings of the optic neuritis are needed to establish the clinical significance of the anti-MOG antibodies positivity and optic neuritis for the diagnosis, treatment, and prognosis for this disease.

The history of neuromyelitis optica. Part 2: 'Spinal amaurosis', or how it all began

Neuromyelitis optica (NMO) was long considered a clinical variant of multiple sclerosis (MS). However, the discovery of a novel and pathogenic anti-astrocytic serum autoantibody targeting aquaporin-4 (termed NMO-IgG or AQP4-Ab), the most abundant water channel protein in the central nervous system, led to the recognition of NMO as a distinct disease entity in its own right and generated strong and persisting interest in the condition. NMO is now studied as a prototypic autoimmune disorder, which differs from MS in terms of immunopathogenesis, clinicoradiological presentation, optimum treatment, and prognosis. While the history of classic MS has been extensively studied, relatively little is known about the history of NMO. In Part 1 of this series we focused on the late 19th century, when the term 'neuromyelitis optica' was first coined, traced the term's origins and followed its meandering evolution throughout the 20th and into the 21st century. Here, in Part 2, we demonstrate that the peculiar concurrence of acute optic nerve and spinal cord affliction characteristic for NMO caught the attention of physicians much earlier than previously thought by re-presenting a number of very early cases of possible NMO that date back to the late 18th and early 19th century. In addition, we comprehensively discuss the pioneering concept of 'spinal amaurosis', which was introduced into the medical literature by ophthalmologists in the first half of the 19th century.

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.

High-dose intravenous methylprednisolone in juvenile non-infectious uveitis: A retrospective analysis

Non-infectious uveitis is associated with visual impairment and blindness. Non-biologic treatment for non-infectious uveitis is not based on strong evidence. A retrospective chart review was conducted to investigate treatment response to high-dose intravenous methylprednisolone (IVMP) in children with non-infectious uveitis. Fifty-six patients (93 eyes affected) were included. In 29% uveitis was associated with juvenile idiopathic arthritis. Uveitis predominately affected the anterior segment, was bilateral and recurrent. Complications were common and included visual loss, synechiae, cataract and/or retinal lesions. Patients received up to 5 IVMP at monthly intervals. Visual acuity improved at 3 and 6 months. Anterior chamber cells, synechiae, keratic precipitates, papillary and/or macular edema improved at 3 months. Children treated with ≥3 IVMP (vs 1 IVMP) experienced trends towards fewer relapses, fewer cataracts and less frequently required treatment with biologic agents. High-dose IVMP induce rapid improvement in children with non-infectious uveitis. Prospective randomized trials are required to confirm results.

Co-occurrence of Anti-N-Methyl-D-Aspartate Receptor Encephalitis and Anti-myelin Oligodendrocyte Glycoprotein Inflammatory Demyelinating Diseases: A Clinical Phenomenon to Be Taken Seriously

Background: Anti-N-methyl-D-aspartate receptor (NMDAR) immunoglobulin G antibodies which exist on myelin sheaths, composed of oligodendrocytes, especially target GluN1 subunits and are highly characteristic of anti-NMDAR encephalitis which is a newly recognized autoimmune encephalitis (AE) characterized by psychiatric symptoms, behavioral abnormalities, seizures, cognitive impairment and other clinical symptoms. Myelin oligodendrocyte glycoprotein (MOG) is a type of protein which is expressed on the surface of oligodendrocytes and myelin in the central nervous system. Anti-MOG antibodies cause demyelination. In some rare reported cases, these two types of antibodies have been found to co-exist, but the underlying mechanisms remain unknown.

Case presentation: Here we report cases of 4 inpatients (median age 31.5 years, age range 27–43 years) from The Second Xiangya Hospital of Central South University between March 2018 and April 2019. Two of the cases were first diagnosed as anti-NMDAR encephalitis and had developed visual impairments in the course of the dosage reduction during corticosteroid therapy. They were found at the time, to have anti-MOG antibody-positive CSF and/or serum. Another patient was diagnosed with anti-MOG inflammatory demyelinating diseases (IDDs) when he tested double positive for both anti-NMDAR and anti-MOG antibodies early in the course of his illness. Over the course of the dosage reduction during corticosteroid therapy, his symptoms deteriorated; however, anti-MOG antibody levels elevated while anti-NDMAR antibody levels remained low. The other patient had initially developed psychiatric symptoms and limb weakness. She was also double positive for anti-NMDAR and anti-MOG antibodies early in the course of her illness. However, over the course of the dosage reduction during corticosteroid therapy, her symptoms worsened and levels of both antibodies elevated.

Conclusion: Anti-NMDAR and anti-MOG antibodies may coexist in rare cases. In addition, anti-NMDAR encephalitis and anti-MOG inflammatory demyelinating diseases may occur either simultaneously or in succession. Thus, when a patient is diagnosed with either of these two diseases, but exhibits symptoms of the other disease, the possibility of co-occurrence with both these diseases should be considered and the appropriate antibodies should be accurately detected to enable prompt selection of appropriate treatments by the physicians.

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.

Quantitative brain lesion distribution may distinguish MOG-ab and AQP4-ab neuromyelitis optica spectrum disorders

OBJECTIVES

Antibodies to myelin oligodendrocyte glycoprotein (MOG-ab) and antibodies to aquaporin-4 (AQP4-ab) have been suggested to play roles in commonly separated subsets of patients with neuromyelitis optica spectrum disorder (NMOSD) phenotypes. The aim of this study is to quantitatively delineate and compare the brain lesion distributions of AQP4-ab-positive and MOG-ab-positive patients.

METHODS

Fifty-seven and twenty-eight clinical MRI scans were collected from fifty-two AQP4-ab-positive and twenty-four MOG-ab-positive patients, respectively. T2 lesions were segmented manually on each axial FLAIR image. Probabilistic lesion distribution maps were created for each group after spatial normalization. Lobe-wise and voxel-wise quantitative comparisons of the two distributions were performed. A classification model based on the lesion distribution features was constructed to differentiate the two patient groups.

RESULTS

Infratentorial and supratentorial brain lesions were found in both AQP4-ab-positive and MOG-ab-positive patients, with large inter-group overlap mainly in deep white matter (WM). In comparison with those in the AQP4 group, the brain lesions of the MOG-ab-positive patients had a larger size, dispersed distribution, and higher probabilities in the cerebellum, pons, midbrain, and GM and juxtacortical WM in temporal, sublobar, frontal, and parietal lobes. The area under the receiver operating characteristic curve of the lesion-distribution-based classification model was 0.951.

CONCLUSIONS

MOG-ab-positive and AQP4-ab-positive groups showed similar but quantitatively different brain lesion distributions. These results may help clinicians in considering MOG versus AQP4 in initial diagnosis, and add rationale for sending corresponding serologic testing.

KEY POINTS

• Brain lesion distributions of AQP-ab-positive and MOG-ab-positive NMOSD patients • Larger size, dispersed distribution, higher lesion probabilities in the cerebellum, pons, midbrain, and GM and juxtacortical WM in the MOG group • The lesion-distribution-based classification model differentiates the two groups with AUC = 0.951.

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.

Brain Atrophy in Relapsing Optic Neuritis Is Associated With Crion Phenotype

Background and objective: Chronic relapsing inflammatory optic neuritis (CRION) is one of the more common phenotypes related to myelin oligodendrocyte glycoprotein antibodies (MOG-Abs). The absence of specific biomarkers makes distinguishing between CRION and relapsing inflammatory ON (RION) difficult. A recent work has suggested a widespread affectation of the central nervous system in CRION patients. In order to search for a potential CRION marker we have measured brain atrophy in a cohort of patients, stratified by phenotypes: CRION, RION, multiple sclerosis with a history of optic neuritis (MS-ON), and MOG-Abs status. Methods: A cross-sectional study was conducted in 31 patients (seven CRION, 11 RION, and 13 MS-ON). All patients were tested for MOG and aquaporin-4 antibodies (AQ4-Abs). Clinical data were collected. Brain atrophy was calculated by measuring the brain parenchyma fraction (BPF) with Neuroquant® software. Results: Four of seven CRION patients and one of 11 RION patients were positive for MOG-Abs (p = 0.046) and no MS-ON patients tested positive to MOG-Abs. All patients were negative to AQ4-Abs. The BPF was lower in patients with CRION than patients with RION (70.6 vs. 75.3%, p = 0.019) and similar to that in MS-ON patients. Conclusions: Brain atrophy in idiopathic inflammatory relapsing ON is present in patients with the CRION phenotype. Data from this study reflect that the optic nerve is a main target involved in these patients but not the only one. Our results should be further investigated in comprehensive and prospective studies.

Dimethyl Fumarate Was Ineffective but Not Harmful for a Patient with Myelin Oligodendrocyte Glycoprotein Antibody Disease

We treated a myelin oligodendrocyte glycoprotein (MOG) antibody disease patient who had been prescribed dimethyl fumarate because she was thought to have been suffering from multiple sclerosis (MS). Mild optic neuritis relapsed at one year and four months after the administration of dimethyl fumarate. Therefore, dimethyl fumarate was ineffective for preventing relapse of MOG antibody disease. However, dimethyl fumarate for MOG antibody disease was not harmful compared with when disease-modifying drugs (DMDs) of MS were used for anti-aquaporin-4 antibody-positive neuromyelitis optica. If MS patients repeat relapses even after the start of DMDs, a differential diagnosis including MOG antibody disease should be made.

MOG-IgG myelitis coexisting with systemic lupus erythematosus in the post-partum setting

BACKGROUND

Longitudinally extensive transverse myelitis (LETM) accompanying systemic lupus erythematosus (SLE) is often due to coexisting aquaporin-4-IgG seropositive neuromyelitis optica spectrum disorder but has not been associated with myelin oligodendrocyte glycoprotein-IgG (MOG-IgG).

OBJECTIVE AND METHODS

Case report at an academic medical center.

RESULTS

A 32-year-old woman developed severe transverse myelitis (paraplegia) shortly after SLE onset in the post-partum period. Magnetic resonance imaging (MRI) revealed an LETM, cerebrospinal fluid showed marked inflammation, and testing for infections was negative. Serum live-cell-based assay for MOG-IgG was positive but aquaporin-4-IgG was negative.

CONCLUSION

In patients with SLE and LETM, MOG-IgG testing should be considered, in addition to AQP4-IgG.

Identification of circulating MOG-specific B cells in patients with MOG antibodies

OBJECTIVE

To identify circulating myelin oligodendrocyte glycoprotein (MOG)-specific B cells in the blood of patients with MOG antibodies (Abs) and to determine whether circulating MOG-specific B cells are linked to levels and epitope specificity of serum anti-MOG-Abs.

METHODS

We compared peripheral blood from 21 patients with MOG-Abs and 26 controls for the presence of MOG-specific B cells. We differentiated blood-derived B cells in vitro in separate culture wells to Ab-producing cells via engagement of Toll-like receptors 7 and 8. We quantified the anti-MOG reactivity with a live cell-based assay by flow cytometry. We determined the recognition of MOG epitopes with a panel of mutated variants of MOG.

RESULTS

MOG-Ab-positive patients had a higher frequency of MOG-specific B cells in blood than controls, but MOG-specific B cells were only detected in about 60% of these patients. MOG-specific B cells in blood showed no correlation with anti-MOG Ab levels in serum, neither in the whole group nor in the untreated patients. Epitope analysis of MOG-Abs secreted from MOG-specific B cells cultured in different wells revealed an intraindividual heterogeneity of the anti-MOG autoimmunity.

CONCLUSIONS

This study shows that patients with MOG-Abs greatly differ in the abundance of circulating MOG-specific B cells, which are not linked to levels of MOG-Abs in serum suggesting different sources of MOG-Abs. Identification of MOG-specific B cells in blood could be of future relevance for selecting patients with MOG-Abs for B cell-directed therapy.

CNS inflammatory demyelinating disorders: MS, NMOSD and MOG antibody associated disease

Although Multiple Sclerosis is the most common central nervous system (CNS) inflammatory demyelinating disorder, other CNS inflammatory disorders should be included as diagnostic considerations. Neuromyelitis Optica Spectrum Disorder (NMOSD) and myelin oligodendrocyte glycoprotein (MOG) antibody-associated disease are less common but share some clinical characteristics, such as optic neuritis and myelitis, which can make a specific diagnosis challenging. However, these disorders have distinctive and generally different clinical phenotypes, prognosis and management. It is imperative to distinguish each from one another, especially since the treatments (not discussed in this review) can be different. The advent of reliable testing for anti-aquaporin-4 for NMOSD and anti-MOG antibodies has helped significantly; however, diagnosis can remain challenging, especially in sero-negative cases. Clinical indicators are important to guide diagnostic work-up. Careful review of the history, neurological exam, imaging, and/or spinal fluid results are essential to making an accurate diagnosis. In this review, we will examine the clinical presentation, diagnosis, and natural history of these inflammatory CNS disorders.

Comparison of Clinical Outcomes of Transverse Myelitis Among Adults With Myelin Oligodendrocyte Glycoprotein Antibody vs Aquaporin-4 Antibody Disease

Importance

Recognizing the differences between transverse myelitis (TM) associated with myelin oligodendrocyte glycoprotein (MOG) antibody (Ab) disease vs aquaporin-4 (AQP4)-Ab disease and prognosticating patients within each group may be an important factor for better clinical treatment for these respective patients.

Objectives

To compare the clinical and radiological findings of the first TM episode in patients with MOG-Ab disease vs patients with AQP4-Ab disease and to assess factors associated with worse outcomes and relapse risk.

Design, Setting, and Participants

This retrospective cross-sectional study used data collected from the Oxford Neuromyelitis Optica Service database, a national service that serves the south of England, including detailed clinical data, and high-quality imaging from within 4 weeks of the first TM episode from patients with MOG-Ab disease or AQP4-Ab disease and a confirmed history of TM from April 2018 to January 2019. Data analyses were conducted from February 2019 to April 2019.

Main Outcomes and Measures

Onset features of each condition measured using the Expanded Disability Status Scale (EDSS) score, time to an EDSS score of 6, time to relapse, and residual sphincter dysfunction at least 6 months after the first TM episode and at last follow-up.

Results

The total cohort included 115 adult patients, including 46 patients with MOG-Ab disease and 69 patients with AQP4-Ab disease. Patients with AQP4-Ab disease, compared with patients with MOG-Ab disease, tended to be older at onset of disease (mean [SD] age, 48.5 [14.9] years vs 33.7 [1.2] years) and female (57 [83%] women vs 24 [52%] women). Transverse myelitis occurred at onset of disease for 32 patients (70%) with MOG-Ab disease and 57 patients (78%) with AQP4-Ab disease. Onset severity did not differ between groups. An acute disseminated encephalomyelitis-like presentation occurred at the time of the TM in 4 patients (9%) with MOG-Ab disease but no patients with AQP4-Ab disease. Compared with patients with AQP4-Ab disease, patients with MOG-Ab disease were more likely to have short cord lesions (22 patients [48%] vs 10 patients [15%]; P < .001) and multiple cord lesions (18 patients [39%] vs 7 patients [10%]; P < .001). Approximately 50% of patients with MOG-Ab disease had only short cord lesions when the TM occurred as a relapse. Median (range) recovery EDSS score was lower in patients with MOG-Ab disease than patients with AQP4-Ab disease (1.8 [1.0-8.0] vs 3.0 [1.0-8.0]). Persistent bladder dysfunction associated with an increased prevalence of conus lesions occurred more frequently in patients with MOG-Ab disease than in patients with AQP4-Ab disease (27 patients [59%] vs 33 patients [48%]). Long-term catheter requirement was roughly equal between groups (9 patients [20%] vs 16 patients [23%]). Relapses after TM occurred in 17 patients with MOG-Ab disease (37%) and 36 patients with AQP4-Ab disease (52%). Concomitant brainstem lesions in patients with MOG-Ab disease were associated with a higher mean (SD) EDSS score at recovery (3.5 [2.3] vs 1.4 [0.9]; P < .001). In patients with AQP4-Ab disease, those younger than 50 years were more likely to relapse (27 of 36 patients aged <50 years [75%] vs 9 of 33 patients aged ≥50 years [27%]; P < .001) and those 50 years and older were more likely to reach an EDSS score of 6 (19 of 33 patients aged ≥50 years [58%] vs 11 of 36 patients aged <50 years [31%]; P = .03).

Conclusions and Relevance

This study found that in patients who experienced a TM episode, short and multiple lesions at onset were more common in those with MOG-Ab disease than among those with AQP4-Ab disease. The presence of a brainstem lesion at the time of a TM episode in patients with MOG-Ab disease was associated with a worse recovery. In patients with AQP4-Ab disease, those 50 years and older at disease onset had more disability, and those younger than 50 years at disease onset had more relapses.

Long-term outcome of a group of Japanese children with myelin-oligodendrocyte glycoprotein encephalomyelitis without preventive immunosuppressive therapy

INTRODUCTION

There is increasing evidence that immunosuppressive therapy is essential for reducing disease activity and avoiding further attacks in patients positive for anti-myelin-oligodendrocyte glycoprotein (MOG) antibodies. However, to date, no placebo-controlled trial has been published.

OBJECTIVE

We aimed to evaluate the long-term outcome and anti-MOG antibody titers of seropositive Japanese pediatric patients without long-term immunosuppressive therapy.

METHODS

Of 11 consecutive patients positive for anti-MOG antibodies seen at Tohoku University Hospital from 1992 to 2013, 5 patients did not receive preventive long-term immunosuppressive treatment and had been followed up longitudinally (more than 60 months).

RESULTS

The follow-up periods were 68-322 months (median, 150 months). The expanded disability status scale scores of all patients were 0 at the last observation. Three patients were negative for the antibody at the last follow-up, and the titers of the two patients whose anti-MOG antibodies were positive at the last follow-up were lower than at the first examinations. The interval to the second attack in three patients was 1-124 months (median, 33 months). Acute attacks were treated with methylprednisolone pulse therapy (four patients) or intravenous immunoglobulin (one patient). All patients achieved full recovery after acute therapy. Oral corticosteroid was tapered over a period of 6-26 weeks (median, 17 weeks).

CONCLUSIONS

We reported our experience with very long-term follow-up of 5 Japanese pediatric patients with anti-MOG antibody-positive disease who did not receive long-term immunosuppressive therapy. Persistent positivity to anti-MOG antibody in some patients suggests the necessity for long-term follow up despite infrequent relapse.

Transient MOG antibody seroconversion associated with immunomodulating therapy

Immunoglobulin G (IgG) autoantibodies targeting myelin oligodendrocyte glycoprotein (MOG) have recently been associated with autoimmune CNS demyelination. We present the case of a 35-year-old patient who was seronegative for MOG-IgG (as confirmed by means of three independent immunoassays) during two corticosteroid-responsive attacks of brainstem encephalitis and optic neuritis, respectively, but turned positive for MOG-IgG under treatment with interferon-beta (IFN-beta), which was commenced 6 months after onset of the first attack. MOG-IgG serum levels declined after therapy was switched to glatiramer acetate. The fact that seroconversion was first observed under treatment with IFN-beta is in accordance with previous evidence suggesting a role of IFN-beta in disease exacerbation in antibody-mediated disorders.

Atypical presentation of MOG-related disease: Slowly progressive behavioral and personality changes following a seizure

BACKGROUND

Myelin Oligodendrocyte Glycoprotein (MOG) antibodies-related disease is mainly presented with acute disseminated encephalomyelitis (ADEM), recurrent optic neuritis, and neuromyelitis optica spectrum disorders (NMOSDs), however the complete clinical spectrum has not yet been defined. We describe an unusual presentation of MOG- related disease. A previously well 10-year-old girl admitted with a focal onset seizure. Neurological examination, electroencephalography, and brain magnetic resonance imaging (MRI) were normal. Following seizure episode she developed gradually increased behavioral and personality changes during a period of 2.5 months. Neurological examination was unremarkable except for drowsiness and minimal ataxia on tandem walking. Repeated brain MRI revealed hazy and poorly demarcated lesions with gadolinium enhancement in the basal ganglia, supratentorial white matter, cerebral peduncles, cerebellum, and servical spinal cord. Cerebrospinal fluid analyses (CSF) revealed 10 lymphocytes /µL, normal protein concentration and IgG index, and negative oligoclonal bands. Auto-antibodies against N-methyl-d-aspartate receptor and CASPR2 in CSF, and antibodies against aquaporin 4 in serum were negative. Analysis with a cell-based assay identified high serum titer of MOG antibodies (1:320). Following IVIG therapy, the patient showed complete clinical recovery within a week with no further relaps for the following 6-month period.

CONCLUSION

Slowly progressive behavioral and personality changes following a seizure may be a manifestation of MOG-related disease in children.

The imbalance between regulatory and memory B cells accompanied by an increased number of circulating T-follicular helper cells in MOG-antibody-associated demyelination

OBJECTIVE

To explore the alteration of T and B lymphocyte subsets proportions in myelin oligodendrocyte glycoprotein (MOG)-antibody-associated demyelination.

METHODS

19 MOG-antibody-positive, 25 AQP4-antibody-positive and 25 double-negative NMOSD patients in the acute phase of the diseases were included in the study, as well as 29 healthy controls. The frequencies of different lymphocyte subsets, including CD19⁺CD27⁺ memory B cells, CD19⁺CD24^hiCD38^hi, and CD19⁺CD5⁺CD1d^hi regulatory B cells, IFN-γexpressing B cells, IL-10 expressing B cells and CD4⁺CXCR5⁺ICOS⁺T-follicular helper cells (T_FH) were measured via flow cytometry and compared among the four groups.

RESULTS

The frequencies of CD19⁺CD24^hiCD38^hi, CD19⁺CD5⁺CD1d^hi regulatory B cells as well as the IL-10 expressing B cells were significantly lower in the MOG-antibody-associated demyelination compared to the healthy controls, whereas the frequencies of CD19⁺CD27⁺ memory B cells were significantly higher in the MOG-antibody-positive group. The frequencies of T_FH were significantly higher in the MOG-antibody-positive group as compared to the healthy controls. No significant difference was detected in the above mentioned lymphocytic profile between the MOG-antibody-positive and the AQP4-antibody-positive groups.

CONCLUSIONS

The immuno-regulatory functions of B cells were significantly impaired whereas T_FH cells were markedly increased in the acute phase of MOG-antibody-associated demyelination. Despite having distinct clinical features, MOG-antibody-associated demyelination shared a similar lymphocytic profile with AQP4-antibody-positive NMOSD in the acute relapse phase.

Prevalence of Myelin Oligodendrocyte Glycoprotein and Aquaporin-4-IgG in Patients in the Optic Neuritis Treatment Trial

Importance

Autoantibodies to aquaporin-4 (AQP4) and myelin oligodendrocyte glycoprotein (MOG) are recently established biomarkers of autoimmune optic neuritis whose frequency and accompanying phenotype, especially for MOG-IgG, are still being characterized. The Optic Neuritis Treatment Trial (ONTT) was a well-known randomized clinical trial in optic neuritis; therefore, knowledge of the serostatus and accompanying phenotype of these patients would be useful to determine the frequency of these antibodies in patients presenting with typical monocular optic neuritis and their outcomes.

Objectives

To determine the AQP4-IgG and MOG-IgG serostatus of patients within the ONTT and describe the clinical features of seropositive patients.

Design, Setting, and Participants

In this follow-up study of the randomized clinical trial, ONTT, conducted between July 1, 1988, and June 30, 1991, analysis of serum for AQP4-IgG and MOG-IgG was performed from January 1 to April 30, 2017. A total of 177 patients from the ONTT with acute optic neuritis and serum available for analysis were enrolled from 13 academic referral centers.

Interventions

Analysis of serum for AQP4-IgG and MOG-IgG was performed at Mayo Clinic Neuroimmunology Laboratory in 2017 with a flow cytometry, live cell, AQP4- and MOG-transfected cell-based assay.

Main Outcomes and Measures

Aquaporin-4-IgG and MOG-IgG serostatus.

Results

Of the 177 patients in the study (135 women and 42 men; mean [SD] age, 32.8 [6.9] years), 3 were positive for MOG-IgG (1.7%) and none were positive for AQP4-IgG. All 3 patients positive for MOG-IgG had disc edema at presentation. Two patients later had a single episode of recurrent optic neuritis. All 3 patients had complete recovery of visual acuity, and none were corticosteroid dependent, although peripheral visual field loss persisted in 1 patient. None of the 3 patients positive for MOG-IgG had demyelinating lesions on magnetic resonance imaging scans, and none had developed multiple sclerosis at the 15-year follow-up.

Conclusions and Relevance

Frequency of MOG-IgG was rare in the ONTT, and AQP4-IgG was not found in patients in the ONTT. Characteristics of patients positive for MOG-IgG in the ONTT support the previously described phenotype of MOG-IgG optic neuritis. Myelin oligodendrocyte glycoprotein-related disease appears to be a different entity than multiple sclerosis. Overall, AQP4-IgG and MOG-IgG may be less common in isolated optic neuritis than previously reported.

Seizures and Encephalitis in Myelin Oligodendrocyte Glycoprotein IgG Disease vs Aquaporin 4 IgG Disease

Importance

Antibodies to myelin oligodendrocyte glycoprotein IgG (MOG-IgG) are increasingly detected in patients with non-multiple sclerosis-related demyelination, some of whom manifest a neuromyelitis optica (NMO) phenotype. Cortical involvement, encephalopathy, and seizures are rare in aquaporin 4 antibody (AQP4-IgG)-related NMO in the white European population. However, the authors encountered several patients with seizures associated with MOG-IgG disease.

Objective

To compare incidence of seizures and encephalitis-like presentation, or both between AQP4-IgG-positive and MOG-IgG-positive patients.

Design, Setting, and Participants

Retrospective case series of all patients who were seropositive for MOG-IgG (n = 34) and the last 100 patients with AQP4-IgG disease (NMO spectrum disorder) seen in the NMO service between January 2013 and December 2016, and analysis was completed January 4, 2017. All patients were seen in a tertiary neurological center, The Walton Centre NHS Foundation Trust in Liverpool, England.

Main Outcomes and Measures

The difference in seizure frequency between the AQP4-IgG-positive and MOG-IgG-positive patient groups was determined.

Results

Thirty-four patients with MOG-IgG disease (20 female) with a median age at analysis of 30.5 years (interquartile range [IQR], 15-69 years), and 100 AQP4-IgG-positive patients (86 female) with a median age at analysis of 54 years (IQR, 12-91 years) were studied. Most patients were of white race. Five of the 34 patients with MOG-IgG (14.7%) had seizures compared with 1 patient with AQP4-IgG (2-sided P < .008, Fisher test). On magnetic resonance imaging, all 5 MOG-IgG-positive patients had inflammatory cortical brain lesions associated with the seizures. In 3 of the 5 MOG-IgG-positive patients, seizures occurred as part of the index event. Four of the 5 presented with encephalopathy and seizures, and disease relapsed in all 5 patients. Four of these patients were receiving immunosuppressant medication at last follow-up, and 3 continued to take antiepileptic medication. In contrast, the only AQP4-IgG-positive patient with seizures had a diagnosis of complex partial epilepsy preceding the onset of NMO by several years and experienced no encephalitic illness; her magnetic resonance imaging results demonstrated no cortical, subcortical, or basal ganglia involvement.

Conclusions and Relevance

Patients with MOG-IgG-associated disease were more likely to have seizures and encephalitis-like presentation than patients with AQP4-IgG-associated disease.

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.

Intradermal vaccination prevents anti-MOG autoimmune encephalomyelitis in macaques

Background

Autoimmune demyelinating diseases (ADD) are a major cause of neurological disability due to autoreactive cellular and humoral immune responses against brain antigens. A cure for chronic ADD could be obtained by appropriate immunomodulation.

Methods

We implemented a preclinical scheme to foster immune tolerance to myelin oligodendrocyte glycoprotein (MOG), in a cynomolgus-macaque model of experimental autoimmune encephalomyelitis (EAE), in which administration of recombinant human MOG (rhMOG) elicits brain inflammation mediated by MOG-autoreactive CD4⁺ lymphocytes and anti-MOG IgG. For immunotherapy, we used a recombinant antibody (Ab) directed against the dendritic cell-asialoglycoprotein receptor (DC-ASGPR) fused either to MOG or a control antigen PSA (prostate-specific antigen).

Findings

rhMOG and the anti-DC-ASGPR-MOG were respectively detected in CD1a⁺ DCs or CD163⁺ cells in the skin of macaques. Intradermal administration of anti-DC-ASGPR-MOG, but not control anti-DC-ASGPR-PSA, was protective against EAE. The treatment prevented the CD4⁺ T cell activation and proinflammatory cytokine production observed in controls. Moreover, the administration of anti-DC-ASGPR-MOG induced MOG-specific CD4⁺CD25⁺FOXP3⁺CD39⁺ regulatory lymphocytes and favoured an upsurge in systemic TGFβ and IL-8 upon rhMOG re-administration in vivo.

Interpretation

We show that the delivery of an anti-DC-ASGPR-MOG allows antigen-specific adaptive immune modulation to prevent the breach of immune tolerance to MOG. Our findings pave the way for therapeutic vaccines for long-lasting remission to grave encephalomyelitis with identified autoantigens, such as ADD associated with anti-MOG autoantibodies.

Fund

Work supported by the French ANR (ANR-11-INBS-0008 and ANR-10-EQPX-02-01), NIH (NIH 1 R01 AI 105066), the Baylor Scott and White Healthcare System funding and Roche Research Collaborative grants.

Collaborative International Research in Clinical and Longitudinal Experience Study in NMOSD

Objective

To develop a resource of systematically collected, longitudinal clinical data and biospecimens for assisting in the investigation into neuromyelitis optica spectrum disorder (NMOSD) epidemiology, pathogenesis, and treatment.

Methods

To illustrate its research-enabling purpose, epidemiologic patterns and disease phenotypes were assessed among enrolled subjects, including age at disease onset, annualized relapse rate (ARR), and time between the first and second attacks.

Results

As of December 2017, the Collaborative International Research in Clinical and Longitudinal Experience Study (CIRCLES) had enrolled more than 1,000 participants, of whom 77.5% of the NMOSD cases and 71.7% of the controls continue in active follow-up. Consanguineous relatives of patients with NMOSD represented 43.6% of the control cohort. Of the 599 active cases with complete data, 84% were female, and 76% were anti-AQP4 seropositive. The majority were white/Caucasian (52.6%), whereas blacks/African Americans accounted for 23.5%, Hispanics/Latinos 12.4%, and Asians accounted for 9.0%. The median age at disease onset was 38.4 years, with a median ARR of 0.5. Seropositive cases were older at disease onset, more likely to be black/African American or Hispanic/Latino, and more likely to be female.

Conclusions

Collectively, the CIRCLES experience to date demonstrates this study to be a useful and readily accessible resource to facilitate accelerating solutions for patients with NMOSD.

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.

[Neuroimmunology and rheumatology: overlap and differential diagnoses]

Multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD) are chronic inflammatory diseases of the central nervous system (CNS). They may cause inflammation in the brain, spinal cord and optic nerve. Both conditions must be differentiated from CNS manifestations of other systemic autoimmune diseases such as systemic lupus erythematosus (SLE), Sjögren's syndrome, autoinflammtory diseases and sarcoidosis, since amongst others myelitis and optic nerve inflammation may also occur in these conditions. Nevertheless, coexistence of MS or NMOSD with rheumatic disorders such as SLE or Sjögren's syndrome has also been reported especially in NMOSD. Since the therapeutic approach is different it is important to determine a clear diagnosis. In addition some drugs used in rheumatic disease such as anti-tumor necrosis factor biologics may induce inflammatory disease of the CNS and should be avoided in MS. An interdisciplinary approach between neuroimmunology and rheumatology is important for optimal care and treatment in such patients.

Different magnetic resonance imaging features between MOG antibody- and AQP4 antibody-mediated disease: A Chinese cohort study

Few studies have compared radiological features obtained on magnetic resonance imaging (MRI) between myelin oligodendrocyte glycoprotein antibody (MOG-ab)- and aquaporin 4 antibody (AQP4-ab)-positive patients. In this study, 77 MOG-ab and 92 AQP4-ab patients were enrolled. The results demonstrated that the brain MRI-based incidence of subcortical white matter lesions was higher in MOG-ab patients (p < .000) than in AQP4-ab patients and that the former therefore had a higher incidence of periventricular lesions (p = .003). The posterior limb of the internal capsule was more prone to lesions in MOG-ab patients (p = .019). Large lesions and U- or S-shaped lesions were also more frequent in MOG-ab (p < .000 and p = .013, respectively). Half of the MOG-ab patients had spinal cord involvement, and 36.5% presented with longitudinally extensive transverse myelitis (LETM). However, among the MOG-ab and AQP4-ab patients with spinal attack, there was no significant difference in the proportion with LETM (p = .057). In conclusion, a higher proportion of MOG-ab patients than AQP4-ab patients had brain lesions in white matter. Among MOG-ab patients who had an attack in the spinal cord, 65.5% also had LETM during the disease course. Conus medullaris lesions were rare in Chinese MOG-ab patients.

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.

Review: Recent advances in the understanding of the pathophysiology of neuromyelitis optica spectrum disorder

Neuromyelitis optica is an autoimmune inflammatory disorder of the central nervous system that preferentially targets the spinal cord and optic nerve. Following the discovery of circulating antibodies against the astrocytic aquaporin 4 (AQP4) water channel protein, recent studies have expanded our knowledge of the unique complexities of the pathogenesis of neuromyelitis optica and its relationship with the immune response. This review describes and summarizes the recent advances in our understanding of the molecular mechanisms underlying neuromyelitis optica disease pathology and examines their potential as therapeutic targets. Additionally, we update the most recent research by proposing major unanswered questions regarding how peripheral AQP4 antibodies are produced and their entry into the central nervous system, the causes of AQP4-IgG-seronegative disease, why peripheral AQP4-expressing organs are spared from damage, and the impact of this disease on pregnancy.

Immune-Mediated Myelopathies

PURPOSE OF REVIEW

This article reviews the clinical presentation, diagnostic evaluation, and management of immune-mediated myelopathies.

RECENT FINDINGS

The discovery of several neural autoantibodies and their antigenic targets has revolutionized the investigation and treatment of immune-mediated myelopathies. Detection of these serologic biomarkers can support or establish a diagnosis of an autoimmune myelopathy, and, in the case of paraneoplastic syndromes, indicate the likely presence of an underlying malignancy. Distinctive lesion patterns detected on spinal cord or brain MRI narrow the differential diagnosis in patients with acute or subacute inflammatory myelopathies, including those not associated with autoantibody markers.

SUMMARY

Immune-mediated myelopathies usually present acutely or subacutely and have a broad differential diagnosis. A systematic diagnostic approach using data from the clinical setting and presentation, MRI lesion patterns, CSF data, and autoantibody markers can differentiate these disorders from noninflammatory myelopathies, often with precise disease classification. This, in turn, provides prognostic information, especially whether the disorder is likely to relapse, and facilitates therapeutic decision making. Diagnostic accuracy informs selection of acute immunotherapy aimed at arresting and reversing recent neurologic injury and, when necessary, selection of long-term treatment for prevention of disease progression or relapse.

[MOG encephalomyelitis: international recommendations on diagnosis and antibody testing]

Over the past few years, new-generation cell-based assays have demonstrated a robust association of autoantibodies to full-length human myelin oligodendrocyte glycoprotein (MOG-IgG) with (mostly recurrent) optic neuritis, myelitis and brainstem encephalitis, as well as with acute disseminated encephalomyelitis (ADEM)-like presentations. Most experts now consider MOG-IgG-associated encephalomyelitis (MOG-EM) a disease entity in its own right, immunopathogenetically distinct from both classic multiple sclerosis (MS) and aquaporin-4 (AQP4)-IgG-positive neuromyelitis optica spectrum disorders (NMOSD). Owing to a substantial overlap in clinicoradiological presentation, MOG-EM was often unwittingly misdiagnosed as MS in the past. Accordingly, increasing numbers of patients with suspected or established MS are currently being tested for MOG-IgG. However, screening of large unselected cohorts for rare biomarkers can significantly reduce the positive predictive value of a test. To lessen the hazard of overdiagnosing MOG-EM, which may lead to inappropriate treatment, more selective criteria for MOG-IgG testing are urgently needed. In this paper, we propose indications for MOG-IgG testing based on expert consensus. In addition, we give a list of conditions atypical for MOG-EM ("red flags") that should prompt physicians to challenge a positive MOG-IgG test result. Finally, we provide recommendations regarding assay methodology, specimen sampling and data interpretation, and propose for the first time diagnostic criteria for MOG-EM.

Optical coherence tomography in myelin-oligodendrocyte-glycoprotein antibody-seropositive patients: a longitudinal study

Background

Serum antibodies against myelin-oligodendrocyte-glycoprotein (MOG-IgG) are detectable in a proportion of patients with acute or relapsing neuroinflammation. It is unclear, if neuro-axonal damage occurs only in an attack-dependent manner or also progressively. Therefore, this study aimed to investigate longitudinally intra-retinal layer changes in eyes without new optic neuritis (ON) in MOG-IgG-seropositive patients.

Methods

We included 38 eyes of 24 patients without ON during follow-up (F/U) [median years (IQR)] 1.9 (1.0–2.2) and 56 eyes of 28 age- and sex-matched healthy controls (HC). The patient group’s eyes included 18 eyes without (Eye^ON-) and 20 eyes with history of ON (Eye^ON+). Using spectral domain optical coherence tomography (OCT), we acquired peripapillary retinal nerve fiber layer thickness (pRNFL) and volumes of combined ganglion cell and inner plexiform layer (GCIP), inner nuclear layer (INL), and macular volume (MV). High-contrast visual acuity (VA) was assessed at baseline.

Results

At baseline in Eye^ON-, pRNFL (94.3 ± 15.9 μm, p = 0.36), INL (0.26 ± 0.03 mm³, p = 0.11), and MV (2.34 ± 0.11 mm³, p = 0.29) were not reduced compared to HC; GCIP showed thinning (0.57 ± 0.07 mm³; p = 0.008), and VA was reduced (logMAR 0.05 ± 0.15 vs. − 0.09 ± 0.14, p = 0.008) in comparison to HC. Longitudinally, we observed pRNFL thinning in models including all patient eyes (annual reduction − 2.20 ± 4.29 μm vs. − 0.35 ± 1.17 μm, p = 0.009) in comparison to HC. Twelve Eye^ON- with other than ipsilateral ON attacks ≤ 6 months before baseline showed thicker pRNFL at baseline and more severe pRNFL thinning in comparison to 6 Eye^ON- without other clinical relapses.

Conclusions

We observed pRNFL thinning in patients with MOG-IgG during F/U, which was not accompanied by progressive GCIP reduction. This effect could be caused by a small number of Eye^ON- with other than ipsilateral ON attacks within 6 months before baseline. One possible interpretation could be a reduction of the swelling, which could mean that MOG-IgG patients show immune-related swelling in the CNS also outside of an attack’s target area.

Electronic supplementary material

The online version of this article (10.1186/s12974-019-1521-5) contains supplementary material, which is available to authorized users.

Pharmacotherapy for Neuromyelitis Optica Spectrum Disorders: Current Management and Future Options

Neuromyelitis optica (NMO) is an inflammatory and demyelinating disease of the central nervous system. Although the prevalence of NMO is low, the rapid and severe impairment observed in patients has led to extensive development of research in the fields of diagnostic criteria and therapy in the past 15 years. With improved understanding of the pathophysiology of NMO and the role of aquaporin-4 (AQP4) or myelin oligodendrocyte glycoprotein antibodies, numerous therapeutic approaches have been proposed and are currently undergoing evaluation. In this review, we describe the rationale for existing therapeutics and their benefit/risk ratio. We also discuss the pharmacological and clinical interest of future approaches targeting, among others, B or T cells, the blood-central nervous system barrier, complement, polynuclear cells, AQP4-antibody linkage and AQP4 activity. The numerous agents under development are the result of a major collaborative effort all over the world. After the considerable progress on diagnosis, we are now close to class I evidence for a therapeutic effect of several drugs in NMO spectrum disorders, most notably with the anti-interleukin-6 receptor antibody (satralizumab) and anti-complement-5 antibody (eculizumab).

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.

Evaluation of treatment response in adults with relapsing MOG-Ab-associated disease

Background

Myelin oligodendrocyte glycoprotein antibodies (MOG-Ab) are related to several acquired demyelinating syndromes in adults, but the therapeutic approach is currently unclear. We aimed to describe the response to different therapeutic strategies in adult patients with relapsing MOG-Ab-associated disease.

Methods

This is a retrospective study conducted in France and Spain including 125 relapsing MOG-Ab patients aged ≥ 18 years. First, we performed a survival analysis to investigate the relapse risk between treated and non-treated patients, performing a propensity score method based on the inverse probability of treatment weighting. Second, we assessed the annualised relapse rates (ARR), Expanded Disability Status Scale (EDSS) and visual acuity pre-treatment and on/end-treatment.

Results

Median age at onset was 34.1 years (range 18.0–67.1), the female to male ratio was 1.2:1, and 96% were Caucasian. At 5 years, 84% (95% confidence interval [CI], 77.1–89.8) patients relapsed. At the last follow-up, 66 (52.8%) received maintenance therapy. Patients initiating immunosuppressants (azathioprine, mycophenolate mophetil [MMF], rituximab) were at lower risk of new relapse in comparison to non-treated patients (HR, 0.41; 95CI%, 0.20–0.82; p = 0.011). Mean ARR (standard deviation) was reduced from 1.05(1.20) to 0.43(0.79) with azathioprine (n = 11; p = 0.041), from 1.20(1.11) to 0.23(0.60) with MMF (n = 11; p = 0.033), and from 1.08(0.98) to 0.43(0.89) with rituximab (n = 26; p = 0.012). Other immunosuppressants (methotrexate/mitoxantrone/cyclophosphamide; n = 5), or multiple sclerosis disease-modifying drugs (MS-DMD; n = 9), were not associated with significantly reduced ARR. Higher rates of freedom of EDSS progression were observed with azathioprine, MMF or rituximab.

Conclusion

In adults with relapsing MOG-Ab-associated disease, immunosuppressant therapy (azathioprine, MMF and rituximab) is associated with reduced risk of relapse and better disability outcomes. Such an effect was not found in the few patients treated with MS-DMD.

Electronic supplementary material

The online version of this article (10.1186/s12974-019-1525-1) contains supplementary material, which is available to authorized users.

Epidemiology of neuromyelitis optica spectrum disorder in Denmark (1998-2008, 2007-2014)

Epidemiological studies of the uncommon disorder neuromyelitis optica spectrum disorder (NMOSD) may be difficult to interpret because of the evolving nature of diagnostic criteria, differences in the definition and accuracy of NMOSD diagnosis, the completeness of case ascertainment, and variability in assays for the disease-specific biomarker aquaporin-4 (AQP4)-IgG. A sub-group of patients with the clinical syndrome NMOSD lack detectable AQP4-IgG and in these cases an accurate diagnosis requires precise diagnostic algorithms and longitudinal follow-up. Consecutive sets of criteria for NMO/NMOSD have been introduced during the two last decades. Such criteria need validation in different populations. Detection of other autoantibodies, such as IgG specific for myelin oligodendrocyte glycoprotein or for glial fibrillary acidic protein in a sub-group of AQP4-IgG-negative NMOSD patients, has improved over the past decade and may lead to overlap of the clinical syndromes/phenotypes. This review begins by summarizing current knowledge on the widening clinical spectrum of NMOSD. Subsequently, we describe two epidemiological studies from Denmark carried out in two different decades (1998-2008 and 2007-2014) and comment on the differences in study design, patient ascertainment, and interpretation of results. These factors may explain some of the observed differences, reflecting the complexity and providing a clear example of this development.

[Longitudinally extensive transverse myelitis involving fifteen vertebral bodies positive for anti-myelin oligodendrocyte glycoprotein (MOG) antibody: a case report]

A 16-year-old male with no previous medical history developed sudden fever and urinary dysfunction. He was admitted to our hospital due to bilateral leg weakness and sensory disturbance on the third day of weakness onset. A sagittal T₂-weighted image displayed a longitudinal extensive lesion of transverse myelitis in the spinal column from the upper cervical (C2) to the thoracic region (Th9). The patient was diagnosed with autoimmune myelitis and treated with four courses of intravenous methylprednisolone (1 g/day for three consecutive days per week). This improved his signs, and his serum sample tested negative for anti-aquaporin-4 (AQP-4) antibody but positive for anti-myelin oligodendrocyte glycoprotein (MOG) antibody in cell-based assays. We report this case of longitudinally extensive transverse myelitis involving fifteen vertebral bodies positive for anti-MOG antibody.

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.

Neuromyelitis Optica Spectrum Disorder and Anti-MOG Syndromes

Neuromyelitis optica spectrum disorder (NMOSD) and anti-myelin oligodendrocyte glycoprotein (anti-MOG) syndromes are immune-mediated inflammatory conditions of the central nervous system that frequently involve the optic nerves and the spinal cord. Because of their similar clinical manifestations and habitual relapsing course they are frequently confounded with multiple sclerosis (MS). Early and accurate diagnosis of these distinct conditions is relevant as they have different treatments. Some agents used for MS treatment may be deleterious to NMOSD. NMOSD is frequently associated with antibodies which target aquaporin-4 (AQP4), the most abundant water channel in the CNS, located in the astrocytic processes at the blood-brain barrier (BBB). On the other hand, anti-MOG syndromes result from damage to myelin oligodendrocyte glycoprotein (MOG), expressed on surfaces of oligodendrocytes and myelin sheaths. Acute transverse myelitis with longitudinally extensive lesion on spinal MRI is the most frequent inaugural manifestation of NMOSD, usually followed by optic neuritis. Other core clinical characteristics include area postrema syndrome, brainstem, diencephalic and cerebral symptoms that may be associated with typical MRI abnormalities. Acute disseminated encephalomyelitis and bilateral or recurrent optic neuritis are the most frequent anti-MOG syndromes in children and adults, respectively. Attacks are usually treated with steroids, and relapses prevention with immunosuppressive drugs. Promising emerging therapies for NMOSD include monoclonal antibodies and tolerization.

Cognitive Impairment in Neuromyelitis Optica Spectrum Disorders: A Review of Clinical and Neuroradiological Features

Neuromyelitis optica spectrum disorders (NMOSD) are mostly relapsing autoimmune inflammatory disorders of the central nervous system (CNS) with optic neuritis, myelitis, and brainstem syndromes as clinical hallmarks. With a reported prevalence of up to 70%, cognitive impairment is frequent, but often unrecognized and an insufficiently treated burden of the disease. The most common cognitive dysfunctions are decline in attention and memory performance. Magnetic resonance imaging can be used to access structural correlates of neuropsychological disorders. Cognitive impairment is not only a highly underestimated symptom in patients with NMOSD, but potentially also a clinical correlate of attack-independent changes in NMOSD, which are currently under debate. This article reviews cognitive impairment in NMOSD and discusses associations between structural changes of the CNS and cognitive deficits.

The Glycosylation Site of Myelin Oligodendrocyte Glycoprotein Affects Autoantibody Recognition in a Large Proportion of Patients

Autoantibodies to myelin oligodendrocytes glycoprotein (MOG) are found in a fraction of patients with inflammatory demyelination and are detected with MOG-transfected cells. While the prototype anti-MOG mAb 8-18C5 and polyclonal anti-MOG responses from different mouse strains largely recognize the FG loop of MOG, the human anti-MOG response is more heterogeneous and human MOG-Abs recognizing different epitopes were found to be pathogenic. The aim of this study was to get further insight into details of antigen-recognition by human MOG-Abs focusing on the impact of glycosylation. MOG has one known N-glycosylation site at N31 located in the BC loop linking two beta-sheets. We compared the reactivity to wild type MOG with that toward two different mutants in which the neutral asparagine of N31 was mutated to negatively charged aspartate or to the neutral alanine. We found that around 60% of all patients (16/27) showed an altered reactivity to one or both of the mutations. We noted seven different patterns of recognition of the two glycosylation-deficient mutants by different patients. The introduced negative charge at N31 enhanced recognition in some, but reduced recognition in other patients. In 7/27 patients the neutral glycosylation-deficient mutant was recognized stronger. The folding of the extracellular domain of MOG with the formation of beta-sheets did not depend on its glycosylation as seen by circular dichroism. We determined the glycan structure of MOG produced in HEK cells by mass spectrometry. The most abundant glycoforms of MOG expressed in HEK cells are diantennary, contain a core fucose, an antennary fucose, and are decorated with α2,6 linked Neu5Ac, while details of the glycoforms of MOG in myelin remain to be identified. Together, we (1) increase the knowledge about heterogeneity of human autoantibodies to MOG, (2) show that the BC loop affects recognition in about 60% of the patients, (3) report that all patients recognized the unglycosylated protein backbone, while (4) in about 20% of the patients the attached sugar reduces autoantibody binding presumably via steric hindrance. Thus, a neutral glycosylation-deficient mutant of MOG might enhance the sensitivity to identify MOG-Abs.