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.

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.

Neuromyelitis optica spectrum disorders: still evolving and broadening

PURPOSE OF REVIEW

The diagnostic criteria of neuromyelitis optica spectrum disorders (NMOSD) has been revised in the past 20 years and pathological and therapeutic data have been accumulated. This review provides an overview of evolution and broadening of the concept of NMOSD.

RECENT FINDINGS

NMOSD encompassing brain syndrome as well as optic neuritis and acute myelitis is now classified into aquaporine-4 (AQP)-antibody-seropositive and aquaporine-4 (AQP)-antibody-seronegative diseases, detecting more patients earlier than before. Seronegative NMOSD includes cases of myelin oligodendrocyte glycoprotein (MOG)-antibody-seropositive disease with its unique clinical spectrum somewhat different from AQP4-antibody-seropositive NMOSD. Pathologically, NMOSD includes AQP4-antibody-seropositive autoimmune astrocytopathic disease and MOG-antibody-seropositive inflammatory demyelinating disease. Double seronegative group needs further research. Therapeutic options of NMOSD has taken shape and first-ever clinical trials of monoclonal antibodies have been done. In retrospect, relapsing NMO in the studies preceding the discovery of AQP4-antibody had features of AQP4-antibody-seropositive NMO whereas monophasic NMO was similar to AQP4-antibody-seronegative/MOG-antibody-seropositive NMO.

SUMMARY

The clinical, pathological and therapeutic concepts of NMOSD have evolved and broadened over the last two decades following the detection of AQP4 antibodies and MOG antibodies in the patients. Double seronegative NMOSD is a current research focus, but now we may need to reconsider how NMOSD should be defined.

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

OBJECTIVES

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

MATERIAL AND METHODS

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

RESULTS

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

CONCLUSION

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

Brain and spinal MRI features distinguishing MS from different AQP4 antibody serostatus NMOSD at disease onset in a cohort of Latin American patients

OBJECTIVE

We aimed to evaluate magnetic resonance imaging (MRI) previously used criteria (Matthews's criteria, MC) for differentiating multiple sclerosis (MS) from neuromyelitis optica spectrum disorders (NMOSD) in Caucasian and non-Caucasian populations (Argentina, Brazil and Venezuela) with positive (P-NMOSD), negative (N-NMOSD), and unknown (U-NMOSD) aquaporin-4 antibody serostatus at disease onset and to assess the added diagnostic value of spinal cord MRI in these populations.

METHODS

We reviewed medical records, and MRIs were assessed by two blinded evaluators and were scored using MC. Short-segment transverse myelitis (STM) was added as a new criterion. MC sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were determined.

RESULTS

We included 282 patients (MS = 188 and NMOSD = 94). MC applied to the entire cohort showed 97.8% sensitivity, 82.9% specificity, 92.0% PPV, and 95.1% NPV for differentiating MS from NMOSD. A subanalysis applied only to non-Caucasian (MS = 89 and NMOSD = 47) showed 100% sensitivity, 80.8% specificity, 90.8% PPV, and 100% NPV. Similar sensitivity, specificity, PPV, and NPV of MC for MS versus P-NMOSD (n = 55), N-NMOSD (n = 28), and U-NMOSD (n = 21) were observed.

CONCLUSION

MC distinguished MS from NMOSD of all serostatus in a Latin American cohort that included non-Caucasian populations. Addition of STM to MC did not raise the accuracy significantly.

Clinical presentation and prognosis in MOG-antibody disease: a UK study

See de Seze (doi:10.1093/brain/awx292) for a scientific commentary on this article. A condition associated with an autoantibody against MOG has been recently recognized as a new inflammatory disease of the central nervous system, but the disease course and disability outcomes are largely unknown. In this study we investigated clinical characteristics of MOG-antibody disease on a large cohort of patients from the UK. We obtained demographic and clinical data on 252 UK patients positive for serum immunoglobulin G1 MOG antibodies as tested by the Autoimmune Neurology Group in Oxford. Disability outcomes and disease course were analysed in more detail in a cohort followed in the Neuromyelitis Optica Oxford Service (n = 75), and this included an incident cohort who were diagnosed at disease onset (n = 44). MOG-antibody disease affects females (57%) slightly more often than males, shows no ethnic bias and typically presents with isolated optic neuritis (55%, bilateral in almost half), transverse myelitis (18%) or acute disseminated encephalomyelitis-like presentations (18%). In the total Oxford cohort after a median disease duration of 28 months, 47% of patients were left with permanent disability in at least one of the following: 16% patients had visual acuity ≤6/36 in at least one eye, mobility was limited in 7% (i.e. Expanded Disability Status Scale ≥ 4.0), 5% had Expanded Disability Status Scale ≥ 6.0, 28% had permanent bladder issues, 20% had bowel dysfunction, and 21% of males had erectile dysfunction. Transverse myelitis at onset was a significant predictor of long-term disability. In the incident cohort 36% relapsed after median disease duration of 16 months. The annualized relapse rate was 0.2. Immunosuppression longer than 3 months following the onset attack was associated with a lower risk of a second relapse. MOG-antibody disease has a moderate relapse risk, which might be mitigated by medium term immunosuppression at onset. Permanent disability occurs in about half of patients and more often involves sphincter and erectile functions than vision or mobility.

The clinical spectrum and incidence of anti-MOG-associated acquired demyelinating syndromes in children and adults

Objectives:

The aim of this study was to assess the Dutch nationwide incidence of myelin oligodendrocyte glycoprotein (MOG)-IgG-associated acquired demyelinating syndromes (ADS) and to describe the clinical and serological characteristics of these patients.

Methods:

All serum samples for routine diagnostics from February 2014 to December 2017 were sent to the single central reference laboratory for the full-length MOG-IgG cell-based assay (CBA) in the Netherlands. Clinical data from patients known in our National ADS centre were available.

Results:

A total of 1414 samples of 1277 patients were received; of these, 92 patients (7%) were MOG-IgG-seropositive. The mean incidence was 0.16/100,000 people, with higher seropositivity in children (0.31/100,000) than in adults (0.13/100,000). In MOG-IgG-positive patients at the National ADS centre (61/92, 66%), the most common presenting phenotype is acute disseminated encephalomyelitis (ADEM, 56%) in children and optic neuritis (ON, 44%) in adults. Relapsing disease occurred in 9/34 (26%) children and 11/27 (41%) adults during median follow-up of 27.5 months. Patients were tested MOG-IgG-positive >200 months after the initial attack, suggesting an extended time to first relapse (TTFR). Longitudinal analysis of MOG-IgG (25/61, 41%) showed that 67% of the monophasic patients remain seropositive and 60% in relapsing patients. Majority of seronegative patients had no relapses (89%).

Conclusion:

This nationwide study shows that the overall incidence of MOG-IgG-seropositive disorders is 0.16 per 100,000 people. The distribution over the clinical phenotypes differs between adults and children. Seropositivity can be maintained over years even without clinical activity, while seronegative patients generally had no relapses.

MRI findings in pediatric neuromyelitis optica spectrum disorder with MOG antibody: Four cases and review of the literature

BACKGROUND

Myelin oligodendrocyte glycoprotein antibodies (MOG Abs) are frequently detected in pediatric acquired demyelinating syndrome (ADS), and MOG-Ab-positive ADS differs from multiple sclerosis (MS) and aquaporin-4 (AQP4)-Ab-positive neuromyelitis optica spectrum disorder (NMOSD) in terms of age distribution, therapeutic response, and prognosis.

METHODS

Based on medical records, we retrospectively evaluated patients with MOG-Ab-positive NMOSD treated in the acute phase who were followed up in the chronic phase at our hospital from January 2011 to December 2017.

RESULTS

The patients comprised two boys and two girls aged 3-12 (median, 8) years. Peak MOG-Ab titers were 1:2048 to 1:32768 (median, 1:10240), and the relapse rate ranged from 0 to 1.25 times/year (median, 0.59 times/year); no sequelae were observed in any cases. Lesions other than those of optic neuritis were distributed at the cortex in one patient, subcortical white matter in four, deep white matter in three, and brainstem in one, all of which were disseminated lesions. No lesions were found in the corpus callosum, periventricular white matter, diencephalon, and regions adjacent to the third and fourth ventricles. The lesions tended to be asymptomatic, and two patients aged >5 years had well-demarcated lesions.

CONCLUSION

All the patients showed disseminated lesions in the subcortical region to deep white matter, which were different from those found in MS and AQP4-Ab-positive NMOSD and were consistent with the characteristics of brain lesions in MOG-Ab-positive ADS, including other disease types.

Myelinoclastic diffuse sclerosis (Schilder's disease) is immunologically distinct from multiple sclerosis: results from retrospective analysis of 92 lumbar punctures

BACKGROUND

Myelinoclastic diffuse sclerosis (MDS; also termed Schilder's disease) is a rare inflammatory demyelinating disorder of the central nervous system characterised by demyelination of vast areas of the white matter. It is unclear whether MDS is a variant of multiple sclerosis (MS) or a disease entity in its own right.

OBJECTIVE

To compare the cerebrospinal fluid (CSF) features of MDS with those of MS.

METHODS

Retrospective analysis of the CSF profile of all patients with MDS reported in the medical literature between 1960 and 2018.

RESULTS

The most striking finding was a substantial lack of oligoclonal bands (OCBs) in MDS, which were absent in at least 77% (30/39) of all lumbar punctures (LP) in the total cohort and in 86% in the subgroup of patients with normal very long-chain fatty acid serum ratios (VLCFA). Almost all cases published in the past 15 years were negative for OCBs. These findings are in contrast to MS, in which OCBs are present in up to 98% of cases (p < 0.00001 when compared with reference works in MS; both in adult and in pediatric patients). CSF pleocytosis was absent in at least 79% (46/58) of all LP (p < 0.0001 vs. MS) and in 92% (24/26) of LPs in the VLCFA-tested subgroup. CSF total protein levels were elevated in 56% of all LPs (p < 0.0001 vs. MS) and in 63% of LPs in the VLCFA-tested subgroup and were often higher than in typical MS (> 100 mg/dL in 13/22; up to 220 mg/dL). EBV serum antibodies, which are present in virtually all patients with MS, and the so-called MRZ (measles/rubella/zoster) reaction, a highly specific marker of MS, were absent in all of the few patients tested. In addition, we discuss further differences between MS and MDS, taking into account also Schilder's original comprehensive case description from 1912.

CONCLUSION

In the majority of patients diagnosed with MDS, CSF features differ significantly from those typically found in MS and are more similar to those previously reported in patients with myelin oligodendrocyte glycoprotein-immunoglobulin G (IgG)-positive encephalomyelitis, aquaporin-4-IgG-positive neuromyelitis optica spectrum disorders or Baló's concentric sclerosis. Our data suggest that MDS and MS are immunopathologically distinct entities in the majority of cases.

Clinical characteristics of myelin oligodendrocyte glycoprotein antibody neuromyelitis optica spectrum disorder

BACKGROUND

Serological antibodies against myelin oligodendrocyte glycoprotein (MOG) are associated with a relapsing autoimmune demyelinating disease of the central nervous system. Initially identified in the context of acute disseminated encephalomyelitis, persistent seropositivity of MOG antibodies is now recognized as a variant of neuromyelitis optica spectrum disorder (NMOSD).

OBJECTIVES

The aim of the study is to describe the epidemiological and clinical features of MOG antibody positive cases and compare our findings with those previously published.

METHODS

This is a retrospective descriptive study of 23 patients with MOG antibody disease who were cared for at Johns Hopkins Hospital over the period from 2015 to 2018. MOG testing was done at Johns Hopkins using the cell based assay (CBA). We describe their epidemiological and clinical features.

RESULTS

Twenty-three patients were included in the study with a female to male ratio of 2.3:1. The mean age of the cohort was 42.6 years, while the mean age at onset was 37 years. The most frequent initial presentation was optic neuritis, followed by ADEM-like encephalopathic clinical picture and transverse myelitis. Five patients showed a monophasic disease course while the rest experienced a relapsing phenotype. Nine patients (39%) experienced immediate relapses on withdrawal of steroids.

CONCLUSIONS

Our cohort showed clinical characteristics comparable with previously published reports of MOG antibody disease worldwide. Unique features of MOG antibody disease are: high frequency of optic neuritis attacks, good long term neurological recovery and sensitivity to steroid use and withdrawal.

A multicenter comparison of MOG-IgG cell-based assays

Objectives

To compares 3 different myelin oligodendrocyte glycoprotein–immunoglobulin G (IgG) cell-based assays (CBAs) from 3 international centers.

Methods

Serum samples from 394 patients were as follows: acute disseminated encephalomyelitis (28), seronegative neuromyelitis optica (27), optic neuritis (21 single, 2 relapsing), and longitudinally extensive (10 single, 3 recurrent). The control samples were from patients with multiple sclerosis (244), hypergammaglobulinemia (42), and other (17). Seropositivity was determined by visual observation on a fluorescence microscope (Euroimmun fixed CBA, Oxford live cell CBA) or flow cytometry (Mayo live cell fluorescence-activated cell sorting assay).

Results

Of 25 samples positive by any methodology, 21 were concordant on all 3 assays, 2 were positive at Oxford and Euroimmun, and 2 were positive only at Oxford. Euroimmun, Mayo, and Oxford results were as follows: clinical specificity 98.1%, 99.6%, and 100%; positive predictive values (PPVs) 82.1%, 95.5%, and 100%; and negative predictive values 79.0%, 78.8%, and 79.8%. Of 5 false-positives, 1 was positive at both Euroimmun and Mayo and 4 were positive at Euroimmun alone.

Conclusions

Overall, a high degree of agreement was observed across 3 different MOG-IgG CBAs. Both live cell-based methodologies had superior PPVs to the fixed cell assays, indicating that positive results in these assays are more reliable indicators of MOG autoimmune spectrum disorders.

Brain and cord imaging features in neuromyelitis optica spectrum disorders

OBJECTIVES

To validate imaging features able to discriminate neuromyelitis optica spectrum disorders from multiple sclerosis with conventional magnetic resonance imaging (MRI).

METHODS

In this cross-sectional study, brain and spinal cord scans were evaluated from 116 neuromyelitis optica spectrum disorder patients (98 seropositive and 18 seronegative) in chronic disease phase and 65 age-, sex-, and disease duration-matched multiple sclerosis patients. To identify independent predictors of neuromyelitis optica diagnosis, after assessing the prevalence of typical/atypical findings, the original cohort was 2:1 randomized in a training sample (where a multivariate logistic regression analysis was run) and a validation sample (where the performance of the selected variables was tested and validated).

RESULTS

Typical brain lesions occurred in 50.9% of neuromyelitis optica patients (18.1% brainstem periventricular/periaqueductal, 32.7% periependymal along lateral ventricles, 3.4% large hemispheric, 6.0% diencephalic, 4.3% corticospinal tract), 72.2% had spinal cord lesions (46.3% long transverse myelitis, 36.1% short transverse myelitis), 37.1% satisfied 2010 McDonald criteria, and none had cortical lesions. Fulfillment of at least 2 of 5 of absence of juxtacortical/cortical lesions, absence of periventricular lesions, absence of Dawson fingers, presence of long transverse myelitis, and presence of periependymal lesions along lateral ventricles discriminated neuromyelitis optica patients in both training (sensitivity = 0.92, 95% confidence interval [CI] = 0.84-0.97; specificity = 0.91, 95% CI = 0.78-0.97) and validation samples (sensitivity = 0.82, 95% CI = 0.66-0.92; specificity = 0.91, 95% CI = 0.71-0.99). MRI findings and criteria performance were similar irrespective of serostatus.

INTERPRETATION

Although up to 50% of neuromyelitis optica patients have no typical lesions and a relatively high percentage of them satisfy multiple sclerosis criteria, several easily applicable imaging features can help to distinguish neuromyelitis optica from multiple sclerosis. ANN NEUROL 2019;85:371-384.

Treatment Approaches for MOG-Ab-Associated Demyelination in Children

Purpose of review

The purpose of this review is to summarize current understanding regarding the treatment of myelin oligodendrocyte glycoprotein antibody (MOG-Ab)-associated demyelination in children. Emphasis is placed on the unique obstacles we face when predicting the risk of relapse and the important implications of such challenges when planning treatment protocols.

Recent findings

MOG-Abs are consistently identified in a range of acquired demyelinating syndromes (ADS) in adults and children with a clinical phenotype distinct of MS and AQP4-Ab neuromyelitis optica spectrum disorder. Although initially thought to be associated with a benign disease, recent reports of children who are treatment-resistant and developed progressive disability over time raise important questions about how children with relapsing MOG-Ab disease should be managed.

Summary

MOG-Abs are common in children with ADS with both monophasic and relapsing disease courses. Treatment of patients with MOG-Ab-associated demyelination includes management of acute relapses and chronic immunotherapy for those with relapsing disease. Emerging consensus supports distinction of treatment strategies from those typically used for relapsing remitting MS, and several groups debate whether to follow treatment protocols akin to those for AQP4-Ab NMOSD. A key challenge remains predicting the severity of the disease at onset. Collaborative international consensus to derive shared clinical evaluative platforms standardized biological and neuroimaging protocols which can be used clinically, and partnered research programs are required to advance personalized treatment for children with MOG-Ab-associated demyelination.

Radiological characteristics of myelin oligodendrocyte glycoprotein antibody disease

BACKGROUND

MOG antibody disease is an autoimmune disease of the central nervous system (CNS) characterized by the presence of a serological antibody against myelin oligodendrocyte glycoprotein (MOG). MRI is instrumental in distinguishing neuromyelitis optica spectrum disorder (NMOSD) from multiple sclerosis (MS), but MRI features of MOG disease appear to overlap with NMOSD and MS.

OBJECTIVES

In this study we aim to characterize the radiological features of MOG antibody disease and compare the findings with those previously described.

METHODS

This is a retrospective study of 26 MOG positive patients. We aim to describe their brain, spinal and orbital MRI features and compare our findings with those previously reported in the literature.

RESULTS

The majority of the abnormal findings was located on orbital MRIs, with more involvement of the anterior structures and bilateral involvement of the optic nerves. Brain abnormalities were distinct from both NMOSD and MS lesions. Spinal cord was the least affected.

CONCLUSIONS

This is a dedicated radiological study aiming to characterize the features of MOG antibody disease which might aid in the proper investigation of cases presenting with acquired demyelinating disorders.

Neurological update: MOG antibody disease

Myelin oligodendrocyte glycoprotein (MOG) antibody disease (MOG-AD) is now recognised as a nosological entity with specific clinical and paraclinical features to aid early diagnosis. Although no age group is exempt, median age of onset is within the fourth decade of life, with optic neuritis being the most frequent presenting phenotype. Disease course can be either monophasic or relapsing, with subsequent relapses most commonly involving the optic nerve. Residual disability develops in 50-80% of patients, with transverse myelitis at onset being the most significant predictor of long-term outcome. Recent advances in MOG antibody testing offer improved sensitivity and specificity. To avoid misdiagnosis, MOG antibody testing should be undertaken in selected cases presenting clinical and paraclinical features that are felt to be in keeping with MOG-AD, using a validated cell-based assay. MRI characteristics can help in differentiating MOG-AD from other neuroinflammatory disorders, including multiple sclerosis and neuromyelitis optica. Cerebrospinal fluid oligoclonal bands are uncommon. Randomised control trials are limited, but observational open-label experience suggests a role for high-dose steroids and plasma exchange in the treatment of acute attacks, and for immunosuppressive therapies, such as steroids, oral immunosuppressants and rituximab as maintenance treatment.

Neuromyelitis optica spectrum disorders: Features of aquaporin-4, myelin oligodendrocyte glycoprotein and double-seronegative-mediated subtypes

The new diagnostic classification of neuromyelitis optica spectrum disorder (NMOSD) in 2015 highlights the central role of biomarkers, such as antibodies against aquaporin-4 (AQP4-Ab), in diagnosis. Also, in approximately 20-25% of patients without AQP4-Ab (NMOSD^AQP4-) the presence of an antibody directed against myelin oligodendrocyte glycoprotein (MOG) characterizes a specific population of NMOSD patients (NMOSD^MOG+), according to their demographic and clinical data and prognoses. While double-seronegative cases (NMOSD^NEG) have not been fully described, they may correspond to the very first patients with opticospinal demyelination reported by Devic and Gault in 1894. The present report reviews the current knowledge of the pathophysiology and clinical features of NMOSD^AQP4+, NMOSD^MOG+ and NMOSD^NEG patients, and also discusses the relationship between the extended spectrum of MOG disease and NMOSD^MOG+. Finally, the current treatments for acute relapses and relapse prevention are described, with a focus on serological-based therapeutic responses and the promising new therapeutic targets.

Myelin oligodendrocyte glycoprotein (MOG) antibody-associated disease: practical considerations

The field of central nervous system (CNS) inflammatory diseases has recently broadened to include a new condition associated with pathogenic serum antibodies against myelin oligodendrocyte glycoprotein (MOG). This is distinct from multiple sclerosis (MS) and aquaporin-4 (AQP4) antibody neuromyelitis optica spectrum disorders (NMOSD). MOG antibody-associated disease phenotypes are varied and range from classical neuromyelitis optica to acute demyelinating encephalomyelitis and cortical encephalitis. The diagnosis depends on using a reliable, specific and sensitive assay of the antibody. Clinical and imaging features of MOG-associated syndromes overlap with AQP4 antibody NMOSD but can be usually distinguished from MS: in particular, the silent lesions typical of MS that progressively increase lesion volume are rare in MOG antibody disease. The disease can relapse but medium-term immunosuppression appears to be protective. Permanent disability, particularly severe ambulatory and visual disability, is less frequent than in AQP4 antibody NMOSD and usually results from the onset attack. However, sphincter and sexual dysfunction after a transverse myelitis is common. Here we review the practical aspects of diagnosing and managing a patient with MOG antibody-associated disease.

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

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

Diagnosis and Treatment of NMO Spectrum Disorder and MOG-Encephalomyelitis

Neuromyelitis optica spectrum disorders (NMOSD) are autoantibody mediated chronic inflammatory diseases. Serum antibodies (Abs) against the aquaporin-4 water channel lead to recurrent attacks of optic neuritis, myelitis and/or brainstem syndromes. In some patients with symptoms of NMOSD, no AQP4-Abs but Abs against myelin-oligodendrocyte-glycoprotein (MOG) are detectable. These clinical syndromes are now frequently referred to as "MOG-encephalomyelitis" (MOG-EM). Here we give an overview on current recommendations concerning diagnosis of NMOSD and MOG-EM. These include antibody and further laboratory testing, MR imaging and optical coherence tomography. We discuss therapeutic options of acute attacks as well as longterm immunosuppressive treatment, including azathioprine, rituximab, and immunoglobulins.

Retrospective analysis of children with myelin oligodendrocyte glycoprotein antibody-related disorders

BACKGROUND

Knowledge has been expanding on myelin oligodendrocyte glycoprotein (MOG) antibody-associated central nervous system disorders. We delineate the clinical and paraclinical findings and outcome of our pediatric patients with MOG antibody seropositive disease.

METHODS

We retrospectively analyzed the clinical presentation, cerebrospinal fluid findings, magnetic resonance imaging (MRI) studies, course and outcome of children seropositive for anti-MOG IgG.

RESULTS

Total 20 children with neurological symptoms and serum anti-MOG IgG were identified from six centers in Turkey. Median age at onset was 9 years (mean 8.8 ± 5.0 years, range: 1.5-16.5 years). Final diagnoses were acute disseminated encephalomyelitis (ADEM) (n = 5), ADEM + optic neuritis (n = 4), neuromyelitis optica spectrum disorder (NMOSD) (n = 3), myelitis (n = 2), relapsing optic neuritis (n = 2), multiphasic DEM (n = 3), and unclassified relapsing demyelinating disease (n = 1). Seven/20 (35%) children experienced a single episode while 13/20 (65%) had a least one relapse during follow-up. On MRI, subcortical white matter, brainstem, and corpus callosum were preferentially involved regions. Full recovery was observed in 15/20 (75%) children.

CONCLUSION

MOG autoimmunity in children has a wide clinical spectrum, tendency to relapse, and a favourable outcome compared with other relapsing demyelinating diseases.

Pathogenicity of human antibodies against myelin oligodendrocyte glycoprotein

OBJECTIVE

Autoantibodies against myelin oligodendrocyte glycoprotein (MOG) occur in a proportion of patients with inflammatory demyelinating diseases of the central nervous system (CNS). We analyzed their pathogenic activity by affinity-purifying these antibodies (Abs) from patients and transferring them to experimental animals.

METHODS

Patients with Abs to MOG were identified by cell-based assay. We determined the cross-reactivity to rodent MOG and the recognized MOG epitopes. We produced the correctly folded extracellular domain of MOG and affinity-purified MOG-specific Abs from the blood of patients. These purified Abs were used to stain CNS tissue and transferred in 2 models of experimental autoimmune encephalomyelitis. Animals were analyzed histopathologically.

RESULTS

We identified 17 patients with MOG Abs from our outpatient clinic and selected 2 with a cross-reactivity to rodent MOG; both had recurrent optic neuritis. Affinity-purified Abs recognized MOG on transfected cells and stained myelin in tissue sections. The Abs from the 2 patients recognized different epitopes on MOG, the CC' and the FG loop. In both patients, these Abs persisted during our observation period of 2 to 3 years. The anti-MOG Abs from both patients were pathogenic upon intrathecal injection in 2 different rat models. Together with cognate MOG-specific T cells, these Abs enhanced T-cell infiltration; together with myelin basic protein-specific T cells, they induced demyelination associated with deposition of C9neo, resembling a multiple sclerosis type II pathology.

INTERPRETATION

MOG-specific Abs affinity purified from patients with inflammatory demyelinating disease induce pathological changes in vivo upon cotransfer with myelin-reactive T cells, suggesting that these Abs are similarly pathogenic in patients. Ann Neurol 2018;84:315-328.

Neuromyelitis Optica Spectrum Disorders: Spectrum of MR Imaging Findings and Their Differential Diagnosis

Neuromyelitis optica (NMO) is an autoimmune demyelinating disorder for which the aquaporin-4 (AQP4) water channels are the major target antigens. Advances in the understanding of NMO have clarified several points of its pathogenesis, clinical manifestations, and imaging patterns. A major advance was the discovery of the AQP4 antibody, which is highly specific for this disorder. Descriptions of new clinical and radiologic features in seropositive patients have expanded the spectrum of NMO, and the term NMO spectrum disorder (NMOSD) has been adopted. NMOSD is now included in a widening list of differential diagnoses. Acknowledgment of NMOSD imaging patterns and their mimicry of disorders has been crucial in supporting early NMOSD diagnosis, especially for unusual clinical manifestations of this demyelinating disease. This pictorial review summarizes the wide imaging spectrum of NMOSD and its differential diagnosis, as well as its historical evolution, pathophysiology, and clinical manifestations. ^©RSNA, 2018.

Distinct regional brain atrophy pattern in multiple sclerosis and neuropsychiatric systemic lupus erythematosus patients

Differentiation of systemic lupus erythematosus (SLE) from multiple sclerosis (MS) can be challenging, especially when neuropsychiatric (NP) symptoms are accompanied by white matter lesions in the brain. Given the lack of discriminative power of currently applied tools for their differentiation, there is an unmet need for other measures that can aid in distinguishing between the two autoimmune disorders. In this study we aimed at exploring whether brain atrophy measures could serve as markers differentiating MS and SLE. Thirty-seven relapsing-remitting MS and 38 SLE patients with nervous system manifestations, matched according to age and disease duration, underwent 1.5 Tesla magnetic resonance imaging (MRI), including volumetric sequences, and clinical assessment. Voxelwise analysis was performed using ANTS-SyN elastic registration protocol, FSL Randomise and Gamma methods. Cortical and subcortical segmentation was performed with Freesurfer 5.3 pipeline using T1-weighted MPRAGE sequence data. Using MRI volumetric markers of general and subcortical gray matter atrophy and clinical variables, we built a stepwise multivariable logistic diagnostic model to identify MRI parameters that best differentiate MS and SLE patients. We found that the best volumetric predictors to distinguish them were: fourth ventricle volume (sensitivity 0.86, specificity 0.57, area under the curve, AUC 0.77), posterior corpus callosum (sensitivity 0.81, specificity 0.57, AUC 0.68), and third ventricle to thalamus ratio (sensitivity 0.42, specificity 0.84, AUC 0.65). The same classifiers were identified in a subgroup analysis that included patients with a short disease duration. In MS brain atrophy and lesion load correlated with clinical disability, while in SLE age was the main determinant of brain volume. This study proposes new imaging parameters for differential diagnosis of MS and SLE with central nervous system involvement. We show there is a different pattern of atrophy in MS and SLE, and the key structural volumes that are differentially affected include fourth ventricle and posterior section of corpus callosum, followed by third ventricle to thalamus ratio. Different correlation patterns between volumetric and clinical data may suggest that while in MS atrophy is driven mainly by disease activity, in SLE it is mostly associated with age. However, these results need further replication in a larger cohort.

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.

Clinical spectrum and prognostic value of CNS MOG autoimmunity in adults

Objective

To describe clinical and radiologic features associated with myelin oligodendrocyte glycoprotein antibodies (MOG-Ab) in a large French nationwide adult cohort, to assess baseline prognostic features of MOG-Ab-associated diseases after a first acute demyelinating syndrome, and to evaluate the clinical value of MOG-Ab longitudinal analysis.

Methods

Clinical data were obtained from 197 MOG-Ab-positive patients ≥18 years of age. Complete imaging data were available in 108, and 54 serum samples were eligible for longitudinal evaluation. For survival analysis comparison, 169 aquaporin-4 antibody (AQP4-Ab)-positive patients from the NOMADMUS database were included.

Results

Median age at onset was 36.46 (range 18.0–76.8) years, and patients were predominantly white (92.9%) with male:female ratio, 1.1. Clinical phenotype at onset included optic neuritis or myelitis in 90.86%, isolated brainstem or encephalopathy syndromes in 6.6%, and a combination of syndromes in 2.5%. Distinctive brain MRI findings in MOG-Ab-positive patients were thalamic and pontine lesions. Cortical and leptomeningeal lesions were found in 16.3% and 6.1%, respectively. The probability of reaching a first relapse after 2 and 5 years was 44.8% and 61.8%, respectively. MOG-Ab-positive patients were at lower risk at presentation of further clinical relapse (hazard ratio [HR] 0.45, 95% confidence interval [CI] 0.26–0.79) compared to AQP4-Ab-positive individuals. MOG-Ab-positive individuals had a lower risk of reaching Disability Status Scale score of 3.0 (HR 0.46, 95% CI 0.22–0.94) and visual acuity of 20/100 (HR 0.23, 95% CI 0.07–0.72). Finally, MOG-Ab titers were higher at relapse than in remission (p = 0.009).

Conclusion

In adults, MOG-Ab-associated disease extends beyond clinical and radiologic abnormalities in the optic nerve and spinal cord. Despite the relapsing course, the overall visual and motor outcome is better compared with AQP4-Ab-positive patients.

Normal brain imaging accompanies neuroimmunologically justified, autoimmune encephalomyelitis

Objective

To examine cases with a clinical course, signs, and symptoms mimicking MS, but without abnormalities on conventional MRI.

Methods

Among 550 people with a tentative diagnosis of MS or neuromyelitis optica spectrum disorder (NMOSD), we selected patients, who met the 2010 McDonald diagnosis criteria for MS, but did not show abnormal findings on conventional brain and spinal cord MRI. After evaluating their clinical data, we analyzed fractional anisotropy (FA) values in the brain white matter on diffusion tensor MRIs and the frequencies of B-cell subsets in the peripheral blood in the corresponding cases as compared to healthy controls.

Results

Eleven patients (age: 41.1 ± 8.0 years, 9 women and 2 men) met the selection criteria. They were functionally disabled, with a median expanded disability status scale score of 6.0 (2.0–8.0). CSF oligoclonal bands were negative in all cases. IV methylprednisolone and plasmapheresis (PP) were found to be efficacious. Diffusion tensor MRI analysis revealed extensive white matter abnormalities characterized by significantly decreased FA values. The frequency of plasmablasts in the peripheral blood was significantly increased in these patients similar to NMOSD.

Conclusions

The neurologic disabilities in these patients could be ascribed to brain white matter damage, as revealed by MRI analysis, whereas the efficacy of PP and B-cell abnormalities in the patients suggested an autoimmune-mediated pathogenesis. In the differential diagnosis of MS, we propose that this condition be referred to as, “Normal-appearing Imaging-associated, Neuroimmunologically Justified, Autoimmune encephalomyelitis.”

Defining distinct features of anti-MOG antibody associated central nervous system demyelination

Extensive research over the last decades basically failed to identify a common cause of noninfectious inflammatory central nervous system (CNS) demyelinating disease. To a great extent, this may reflect that the group of inflammatory CNS demyelinating disorders likely contains multiple pathogenetically distinct disease entities. Indeed, the greatest success so far in deciphering the pathogenesis of a CNS demyelinating disorder resulted from the discovery of anti-aquaporin (AQP)-4 antibodies (ab), which allowed progressive delineation of neuromyelitis optica (NMO), formerly considered a variant of the most common CNS demyelinating disorder, multiple sclerosis (MS), as a distinct disease. Nowadays, AQP-4⁺ NMO is considered an autoimmune astrocytopathy, in which CNS demyelination occurs only as a consequence of a primary destruction of astrocytes. Delineating these patients concomitantly revealed that not all patients presenting with clinically NMO-suggestive disease phenotype express AQP-4 ab, which created the pathogenetically undefined category of NMO spectrum disorders (NMOSD). Recent investigations discovered that a subgroup of these AQP-4^– NMOSD patients produce an ab response against myelin oligodendrocyte glycoprotein (MOG), a molecule expressed on the outer lamella of the myelin sheath. Using pathophysiologically meaningful cell-based assays, this humoral response is extremely rare in adult MS and absent in classical AQP-4⁺ NMO, sharply differentiating the evolving group from both established disorders. In this review, we summarize available clinical, immunological and histopathological data on patients with MOG⁺ CNS demyelinating disease. By comparing this clearly distinct cohort to AQP-4⁺ NMO as well as MS, we propose that MOG⁺ CNS demyelinating disease represents a distinct novel disease entity. In addition to its diagnostic value, we furthermore provide mechanistic insight on how this peripheral anti-MOG ab response may be of pathogenetic relevance in triggering acute flares of inflammatory CNS demyelination.

MOG-IgG in primary and secondary chronic progressive multiple sclerosis: a multicenter study of 200 patients and review of the literature

Background

Antibodies to human full-length myelin oligodendrocyte glycoprotein (MOG-IgG) as detected by new-generation cell-based assays have recently been described in patients presenting with acute demyelinating disease of the central nervous system, including patients previously diagnosed with multiple sclerosis (MS). However, only limited data are available on the relevance of MOG-IgG testing in patients with chronic progressive demyelinating disease. It is unclear if patients with primary progressive MS (PPMS) or secondary progressive MS (SPMS) should routinely be tested for MOG-IgG.

Objective

To evaluate the frequency of MOG-IgG among patients classified as having PPMS or SPMS based on current diagnostic criteria.

Methods

For this purpose, we retrospectively tested serum samples of 200 patients with PPMS or SPMS for MOG-IgG using cell-based assays. In addition, we performed a review of the entire English language literature on MOG-IgG published between 2011 and 2017.

Results

None of 139 PPMS and 61 SPMS patients tested was positive for MOG-IgG. Based on a review of the literature, we identified 35 further MOG-IgG tests in patients with PPMS and 55 in patients with SPMS; the only reportedly positive sample was positive just at threshold level and was tested in a non-IgG-specific assay. In total, a single borderline positive result was observed among 290 tests.

Conclusion

Our data suggest that MOG-IgG is absent or extremely rare among patients with PPMS or SPMS. Routine screening of patients with typical PPMS/SPMS for MOG-IgG seems not to be justified.

MRI of the first event in pediatric acquired demyelinating syndromes with antibodies to myelin oligodendrocyte glycoprotein

Antibodies against the myelin oligodendrocyte glycoprotein (MOG-Ab) can be detected in various pediatric acquired demyelinating syndromes (ADS). Here, we analyze the spectrum of neuroradiologic findings in children with MOG-Ab and a first demyelinating event. The cerebral and spinal MRI of 69 children with different ADS was assessed in regard to the distribution and characteristics of lesions. Children with acute disseminated encephalomyelitis (n = 36) or neuromyelitis optica spectrum disorder (n = 5) presented an imaging pattern characterized predominantly by poorly demarcated lesions with a wide supra- and infratentorial distribution. Younger children also tended to have poorly defined and widespread lesions. The majority of patients with an isolated optic neuritis (n = 16) only presented small non-specific brain lesions or none at all. A longitudinally extensive transverse myelitis mainly affecting the cervical, and less often so the thoracic, lumbar, and conus regions, was detected in 31 children. The three children of our cohort who were then finally diagnosed with multiple sclerosis had at onset already demarcated white matter lesions as well as transverse myelitis. In conclusion, children with MOG seropositive ADS present disparate, yet characteristic imaging patterns. These patterns have been seen to correlate to the disease entity as well as to age of symptom onset.

Clinical course, therapeutic responses and outcomes in relapsing MOG antibody-associated demyelination

OBJECTIVE

We characterised the clinical course, treatment and outcomes in 59 patients with relapsing myelin oligodendrocyte glycoprotein (MOG) antibody-associated demyelination.

METHODS

We evaluated clinical phenotypes, annualised relapse rates (ARR) prior and on immunotherapy and Expanded Disability Status Scale (EDSS), in 218 demyelinating episodes from 33 paediatric and 26 adult patients.

RESULTS

The most common initial presentation in the cohort was optic neuritis (ON) in 54% (bilateral (BON) 32%, unilateral (UON) 22%), followed by acute disseminated encephalomyelitis (ADEM) (20%), which occurred exclusively in children. ON was the dominant phenotype (UON 35%, BON 19%) of all clinical episodes. 109/226 (48%) MRIs had no brain lesions. Patients were steroid responsive, but 70% of episodes treated with oral prednisone relapsed, particularly at doses <10 mg daily or within 2 months of cessation. Immunotherapy, including maintenance prednisone (P=0.0004), intravenous immunoglobulin, rituximab and mycophenolate, all reduced median ARRs on-treatment. Treatment failure rates were lower in patients on maintenance steroids (5%) compared with non-steroidal maintenance immunotherapy (38%) (P=0.016). 58% of patients experienced residual disability (average follow-up 61 months, visual loss in 24%). Patients with ON were less likely to have sustained disability defined by a final EDSS of ≥2 (OR 0.15, P=0.032), while those who had any myelitis were more likely to have sustained residual deficits (OR 3.56, P=0.077).

CONCLUSION

Relapsing MOG antibody-associated demyelination is strongly associated with ON across all age groups and ADEM in children. Patients are highly responsive to steroids, but vulnerable to relapse on steroid reduction and cessation.

Comparison of myelin oligodendrocyte glycoprotein (MOG)-antibody disease and AQP4-IgG-positive neuromyelitis optica spectrum disorder (NMOSD) when they co-exist with anti-NMDA (N-methyl-D-aspartate) receptor encephalitis

BACKGROUND

Myelin oligodendrocyte glycoprotein (MOG)-antibody (ab) disease and AQP4-IgG-positive neuromyelitis optica spectrum disorder (NMOSD) can co-exist with anti-NMDA (N-methyl-D-aspartate) receptor encephalitis (NMDARe).

OBJECTIVES

To characterize MOG-ab disease and AQP4-IgG-positive NMOSD during NMDARe.

METHODS

We analyzed all the patients with overlapping MOG-ab disease and NMDARe (MNOS) and patients with AQP4-IgG-positive NMOSD and NMDARe (ANOS) in our hospital and compared those data with data from systematically review of previously published reports.

RESULTS

In our cohorts, 11.9% patients with MOG-ab disease and 0.6% patients with NMOSD had overlapping NMDARe (P < 0.01). After treatment with steroids and/or intravenous immunoglobulin (IVIg), the median modified Rankin Scale (mRS) of the MNOS group decreased significantly during attacks associated with or without NMDARe (P < 0.01 for both), while that of the ANOS group did not (attack: P < 0.05; attack associated with NMDARe: P > 0.05). Analyzed together with previously reported cases, 6% patients with MNOS and 40% patients with ANOS also used rituximab or cyclophosphamide after steroids and/or IVIg (P < 0.05) during attacks associated with NMDARe.

CONCLUSION

Compared with NMOSD, MOG-ab disease may more commonly co-exist with NMDARe. MNOS patients respond better to steroids and IVIg than do ANOS patients during attacks associated with NMDARe.

Metabolomics reveals distinct, antibody-independent, molecular signatures of MS, AQP4-antibody and MOG-antibody disease

The overlapping clinical features of relapsing remitting multiple sclerosis (RRMS), aquaporin-4 (AQP4)-antibody (Ab) neuromyelitis optica spectrum disorder (NMOSD), and myelin oligodendrocyte glycoprotein (MOG)-Ab disease mean that detection of disease specific serum antibodies is the gold standard in diagnostics. However, antibody levels are not prognostic and may become undetectable after treatment or during remission. Therefore, there is still a need to discover antibody-independent biomarkers. We sought to discover whether plasma metabolic profiling could provide biomarkers of these three diseases and explore if the metabolic differences are independent of antibody titre. Plasma samples from 108 patients (34 RRMS, 54 AQP4-Ab NMOSD, and 20 MOG-Ab disease) were analysed by nuclear magnetic resonance spectroscopy followed by lipoprotein profiling. Orthogonal partial-least squares discriminatory analysis (OPLS-DA) was used to identify significant differences in the plasma metabolite concentrations and produce models (mathematical algorithms) capable of identifying these diseases. In all instances, the models were highly discriminatory, with a distinct metabolite pattern identified for each disease. In addition, OPLS-DA identified AQP4-Ab NMOSD patient samples with low/undetectable antibody levels with an accuracy of 92%. The AQP4-Ab NMOSD metabolic profile was characterised by decreased levels of scyllo-inositol and small high density lipoprotein particles along with an increase in large low density lipoprotein particles relative to both RRMS and MOG-Ab disease. RRMS plasma exhibited increased histidine and glucose, along with decreased lactate, alanine, and large high density lipoproteins while MOG-Ab disease plasma was defined by increases in formate and leucine coupled with decreased myo-inositol. Despite overlap in clinical measures in these three diseases, the distinct plasma metabolic patterns support their distinct serological profiles and confirm that these conditions are indeed different at a molecular level. The metabolites identified provide a molecular signature of each condition which is independent of antibody titre and EDSS, with potential use for disease monitoring and diagnosis.

Characteristics of pediatric multiple sclerosis: The Turkish pediatric multiple sclerosis database

OBJECTIVE

To document the clinical and paraclinical features of pediatric multiple sclerosis (MS) in Turkey.

METHODS

Data of MS patients with onset before age 18 years (n = 193) were collected from 27 pediatric neurology centers throughout Turkey. Earlier-onset (<12 years) and later-onset (≥12 years) groups were compared.

RESULTS

There were 123 (63.7%) girls and 70 (36.3%) boys aged 4-17 years, median 14 years at disease onset. Family history of MS was 6.5%. The first presentation was polysymptomatic in 55.4% of patients, with brainstem syndromes (50.3%), sensory disturbances (44%), motor symptoms (33.2%), and optic neuritis (26.4%) as common initial manifestations. Nineteen children had facial paralysis and 10 had epileptic seizures at first attack; 21 (11%) were initially diagnosed with acute disseminated encephalomyelitis (ADEM). Oligoclonal bands were identified in 68% of patients. Magnetic resonance imaging revealed periventricular (96%), cortical/juxtacortical (64.2%), brainstem (63%), cerebellum (51.4%), and spinal cord (67%) involvement. Visual evoked potentials (VEP) were abnormal in 52%; serum 25-hydroxyvitamin D levels were low in 68.5% of patients. The earlier-onset group had a higher rate of infection/vaccination preceding initial attack, initial diagnosis of ADEM, longer interval between first 2 attacks, and more disability accumulating in the first 3 years of the disease.

CONCLUSION

Brainstem and cerebellum are common sites of clinical and radiological involvement in pediatric-onset MS. VEP abnormalities are frequent even in patients without history of optic neuropathy. Vitamin D status does not appear to affect the course in early disease. MS beginning before 12 years of age has certain characteristics in history and course.

Clinical spectrum and IgG subclass analysis of anti-myelin oligodendrocyte glycoprotein antibody-associated syndromes: a multicenter study

Anti-myelin oligodendrocyte glycoprotein antibodies (MOG-Ab) recently emerged as a potential biomarker in patients with inflammatory demyelinating diseases of the central nervous system. We here compare the clinical and laboratory findings observed in a cohort of MOG-Ab seropositive and seronegative cases and describe IgG subclass analysis results. Consecutive serum samples referred to Verona University Neuropathology Laboratory for aquaporin-4 (AQP4)-Ab and/or MOG-Ab testing were analysed between March 2014 and May 2017. The presence of AQP4-Ab was determined using a cell-based assay. A live cell immunofluorescence assay was used for the detection of MOG-IgG and IgG subclass analysis. Among 454 analysed samples, 29 were excluded due to AQP4-Ab positivity or to the final demonstration of a disorder not compatible with MOG-Ab. We obtained clinical data in 154 out of 425 cases. Of these, 22 subjects resulted MOG-Ab positive. MOG-Ab positive patients were mainly characterised by the involvement of the optic nerve and/or spinal cord. Half of the cases presented relapses and the recovery was usually partial. Brain MRI was heterogeneous while short lesions were the prevalent observation on spinal cord MRI. MOG-Ab titre usually decreased in non-relapsing cases. In all MOG-IgG positive cases, we observed IgG1 antibodies, which were predominant in most subjects. IgG2 (5/22), IgG3 (9/22) and IgG4 (3/22) antibodies were also detectable. We confirm that MOG-Ab-related syndromes have distinct features in the spectrum of demyelinating conditions, and we describe the possible role of the different IgG subclasses in this condition.

Clinical and imaging correlation in patients with pathologically confirmed tumefactive demyelinating lesions

OBJECTIVES

To characterize clinical and imaging features in patients with pathologically confirmed demyelinating lesions.

METHODS

In this retrospective chart review, we analyzed clinical-radiological-pathological correlations in patients >15years old who underwent brain biopsy at our institution between 2000 and 2015 and had inflammatory demyelination on neuropathology.

RESULTS

Of 31 patients, the mean age was 42years (range 16 to 69years) and 55% were female. All but one of the biopsied lesions were considered tumefactive demyelinating lesions (TDLs) by imaging criteria, measuring >2cm on contrast-enhanced brain MRI. On clinical follow-up, the final diagnosis was a CNS malignancy in 2 patients (6.5%). In patients without malignant tumor, the TDL was solitary in 12 (41%) and multifocal in 17 (59%), with contrast enhancement in all but one case, primarily in an incomplete rim enhancement pattern (75.9%). Of 16 patients with at least 12months of clinical follow-up, 7 (43.8%) had a clinical relapse. Of patients without a prior neurologic history, relapse occurred in 2/7 (29%) in solitary TDL and 2/6 (33%) in multifocal lesions at initial presentation. Recurrent TDLs occurred in 3 patients, all with initially solitary TDLs. Stratifying by CSF analysis, 4 of 6 patients (67%) with either an elevated IgG Index or >2 oligoclonal bands suffered a clinical relapse compared to 2/8 (25%) with non-inflammatory CSF.

CONCLUSIONS

Pathologically confirmed TDLs call for careful clinical correlation, clinical follow-up and imaging surveillance. Although sometimes clinically monophasic, tumefactive demyelinating lesions carried nearly a 45% risk of near-term clinical relapse in our study, even when presenting initially as a solitary mass lesion.