MOG-antibody associated demyelinating disease of the CNS: A clinical and pathological study in Chinese Han patients

[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.

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).

White matter plasticity and maturation in human cognition

White matter plasticity likely plays a critical role in supporting cognitive development. However, few studies have used the imaging methods specific to white matter tissue structure or experimental designs sensitive to change in white matter necessary to elucidate these relations. Here we briefly review novel imaging approaches that provide more specific information regarding white matter microstructure. Furthermore, we highlight recent studies that provide greater clarity regarding the relations between changes in white matter and cognition maturation in both healthy children and adolescents and those with white matter insult. Finally, we examine the hypothesis that white matter is linked to cognitive function via its impact on neural synchronization. We test this hypothesis in a population of children and adolescents with recurrent demyelinating syndromes. Specifically, we evaluate group differences in white matter microstructure within the optic radiation; and neural phase synchrony in visual cortex during a visual task between 25 patients and 28 typically developing age-matched controls. Children and adolescents with demyelinating syndromes show evidence of myelin and axonal compromise and this compromise predicts reduced phase synchrony during a visual task compared to typically developing controls. We investigate one plausible mechanism at play in this relationship using a computational model of gamma generation in early visual cortical areas. Overall, our findings show a fundamental connection between white matter microstructure and neural synchronization that may be critical for cognitive processing. In the future, longitudinal or interventional studies can build upon our knowledge of these exciting relations between white matter, neural communication, and cognition.

Mechanisms for lesion localization in neuromyelitis optica spectrum disorders

Purpose of review

Neuromyelitis optica spectrum disorders (NMOSD) are severe inflammatory diseases of the central nervous system (CNS), with the presence of aquaporin 4 (AQP4)-specific serum antibodies in the vast majority of patients, and with the presence of myelin oligodendrocyte glycoprotein (MOG)-specific antibodies in approximately 40% of all AQP4-antibody negative NMOSD patients. Despite differences in antigen recognition, the preferred sites of lesions are similar in both groups of patients: They localize to the spinal cord and to the anterior visual pathway including retina, optic nerves, chiasm, and optic tracts, and – to lesser extent – also to certain predilection sites in the brain.

Recent findings

The involvement of T cells in the formation of NMOSD lesions has been challenged for quite some time. However, several recent findings demonstrate the key role of T cells for lesion formation and localization. Studies on the evolution of lesions in the spinal cord of NMOSD patients revealed a striking similarity of early NMOSD lesions with those observed in corresponding T-cell-induced animal models, both in lesion formation and in lesion localization. Studies on retinal abnormalities in NMOSD patients and corresponding animals revealed the importance of T cells for the very early stages of retinal lesions which eventually culminate in damage to Müller cells and to the retinal nerve fiber layer. Finally, a study on cerebrospinal fluid (CSF) barrier pathology demonstrated that NMOSD immunopathology extends beyond perivascular astrocytic foot processes to include the pia, the ependyma, and the choroid plexus, and that diffusion of antibodies from the CSF could further influence lesion formation in NMOSD patients.

Summary

The pathological changes observed in AQP4-antibody positive and MOG-antibody positive NMOSD patients are strikingly similar to those found in corresponding animal models, and many mechanisms which determine lesion localization in experimental animals seem to closely reflect the human situation.

Brain histopathological study and prognosis in MOG antibody-associated demyelinating pseudotumor

Our objective was to examine the brain biopsies by histopathology and investigate the prognosis of patients with myelin oligodendrocyte glycoprotein antibody‐associated demyelinating pseudotumor. The clinical, MRI, and histological features of two patients with myelin oligodendrocyte glycoprotein antibody‐associated demyelinating pseudotumor were reviewed. Both patients were treated with steroid plus rituximab and followed up. The brain biopsies of both cases revealed T cells, macrophages, and complement‐mediated demyelination, which was in accord with multiple sclerosis‐like pathology. Moreover, both cases showed favorable response to steroid plus rituximab therapy. Our cases add a new variant to the myelin oligodendrocyte glycoprotein‐encephalomyelitis spectrum, which favorably responds to immunotherapy.

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 antibody-associated demyelination: comparison between onset phenotypes

BACKGROUND AND PURPOSE

The aim of this study was to analyse the clinical and prognostic features of myelin oligodendrocyte glycoprotein (MOG) antibody-associated demyelination with different onset phenotypes.

METHODS

A total of 52 MOG-IgG-seropositive patients were divided into four groups: (i) optic neuritis (ON) at onset (MOG-ON⁺ , n = 23), (ii) transverse myelitis (TM) at onset (MOG-TM⁺ , n = 12), (iii) pure brain symptoms at onset (MOG-ON^- -TM^- , n = 14) and (iv) both ON and TM at onset (n = 3). This final group was not included in further analyses. Data were collected through medical records and regular follow-up.

RESULTS

Median age at presentation was 24 (range, 3-63) years in the whole cohort (50% female). MOG-ON^- -TM^- patients had the youngest age of onset across the three groups. Patients with MOG-TM⁺ tended to relapse more frequently and had a longer interval to first relapse than was observed in MOG-ON⁺ and MOG-ON^- -TM^- patients. High MOG-IgG titres were associated with increased cerebrospinal fluid leukocytes. The likelihood of harbouring transient, low MOG-IgG titres was higher in the MOG-TM⁺ group than in the other groups. After a median disease duration of 20 months, most but not all cases had a favourable outcome, with 8% developing severe visual deficit, 2% becoming wheelchair-dependent and 6% developing cognitive impairment. The onset phenotype appeared to be an important predictor of disability type. Having high MOG-IgG titres (odds ratio, 0.168, P = 0.027) or female gender (odds ratio, 0.270, P = 0.067) was associated with a lower likelihood of complete recovery.

CONCLUSIONS

Onset phenotype may influence long-term presentation, MOG-IgG status as well as outcome. Further large and prospective studies are needed to better clarify the clinical implications of the first demyelinating event.

Myelin oligodendrocyte glycoprotein antibodies in neuromyelitis optica spectrum disorder

Neuromyelitis optica spectrum disorder (NMOSD) is a severe inflammatory disease of the central nervous system characterized, in particular, by disabling episodes of optic neuritis and longitudinal extensive transverse myelitis. Its main pathogenic characteristic is the presence of anti-aquaporin-4 antibodies (AQP4-Abs) in the serum of affected patients. However, a proportion of patients with the typical NMOSD phenotype are, in fact, negative (seronegative) for AQP4-Abs and, within this category of patients, a proportion of them instead express antibodies to myelin oligodendrocyte glycoprotein (MOG-Abs). The presence of MOG-Abs in the sera of seronegative NMOSD patients is more frequently associated with monophasic disease and moderate symptom severity, and also appears to predict a better outcome. The present report is a review of the clinical and immunological features of MOG-Ab-positive NMOSD.

Clinical Characteristics of Pediatric Optic Neuritis With Myelin Oligodendrocyte Glycoprotein Seropositive: A Cohort Study

BACKGROUND

The clinical characteristics of patients with pediatric optic neuritis with seropositive myelin oligodendrocyte glycoprotein antibodies in Asia have not been reported.

METHODS

Patients ≤18 years-old with acute-onset optic neuritis were enrolled. Serum myelin oligodendrocyte glycoprotein and aquaporin-4 antibodies were detected and patients were followed for at least six months. The clinical features were evaluated among myelin oligodendrocyte glycoprotein-seropositive optic neuritis, aquaporin-4-seropositive optic neuritis, and double seronegative optic neuritis. Best-corrected visual acuity, thickness of optic disc retinal nerve fiber layer, and macular ganglion cell complex were measured by optical coherence tomography.

RESULTS

Among myelin oligodendrocyte glycoprotein-optic neuritis, aquaporin-4-optic neuritis, and seronegative-optic neuritis, the percentages of best-corrected visual acuity measured better than 0.8 (20/25) at the six-month visit were 89.47%, 33.33%, and 82.26%, respectively, a rate that is significantly better in patients with myelin oligodendrocyte glycoprotein-optic neuritis and seronegative-optic neuritis (P = 0.02). The average peripapillary retinal nerve fiber layers were 58.03 ± 8.73 µm, 64.34 ± 12.88 µm, and 78.12 ± 13.34 µm for the patients with myelin oligodendrocyte glycoprotein-optic neuritis, aquaporin-4-optic neuritis, and seronegative-optic neuritis, respectively, which showed no statistical difference between patients with myelin oligodendrocyte glycoprotein-optic neuritis and aquaporin-4-optic neuritis (P = 0.089), but were both thinner than patients with seronegative-optic neuritis (P = 0.001).

CONCLUSIONS

The recovery of visual acuity in patients with myelin oligodendrocyte glycoprotein-optic neuritis was as good as in patients with seronegative-optic neuritis, and the retinal nerve fiber layer of the optic nerve head showed thinning as severe as that of the patients with aquaporin-4-optic neuritis.

Different features between pediatric-onset and adult-onset patients who are seropositive for MOG-IgG: A multicenter study in South China

BACKGROUND

Immunoglobulin against myelin oligodendrocyte glycoprotein (MOG-IgG) is a potential demyelinating disease-associated autoantibody. Whether clinical features of MOG antibody-associated demyelinating diseases change with age remains unclear.

OBJECT

To investigate the different clinical features between pediatric-onset and adult-onset MOG-IgG-seropositive patients in a relatively large cohort.

METHODS

A total of 816 consecutive patients with suspected demyelinating disease were prospectively enrolled from three tertiary academic centers in South China from February 2016 to December 2016. Sixteen pediatric-onset cases (≤14 years old) and 34 adult-onset cases (>14 years old) seropositive for MOG-IgG were identified. Differences in clinical features between the two groups were investigated.

RESULTS

There was a significant difference in the cumulative incidence of first relapse among the two groups (P = .008). Cerebral symptoms were significantly higher in pediatric-onset patients than in adult-onset patients, either at disease onset (pediatric-onset group, 10/16(62.5%); adult-onset group, 8/34(23.53%); P = .007) or throughout the course of disease (pediatric-onset group, 11/16(68.8%); adult-onset group, 10/34(29.4%); P = .009). Optic nerve symptoms were more common in adult-onset groups, but no significant difference was found between the two groups. A significantly higher rate of pediatric-onset patients (9/16, 56.3%) met the acute disseminated encephalomyelitis criteria compared with adult-onset patients (2/34, 5.9%) (P = .0003), and isolated optic neuritis was mainly diagnosed in adult-onset patients (pediatric-onset group, 2/16(12.5%); adult-onset group, 14/34(41.2%); P = .043). The MOG-IgG titer showed a significant positive correlation with total protein levels in cerebrospinal fluid, but only in adult-onset patients (r = 0.95; P = .0004). On magnetic resonance imaging, extensive white matter lesions were observed in both groups, and the number was much higher in pediatric-onset (7/15, 46.7%) than in adult-onset patients (4/29, 13.8%) (P = .043). At the last follow-up, more pediatric-onset patients (10/16, 62.5%) experienced complete recovery (EDSS 0.0 at last follow up) compared with adult-onset patients (9/34, 26.5%) (P = .014).

CONCLUSIONS

Distinctive features are present between pediatric-onset and adult-onset patients with MOG-IgG. Further studies are required to determine the different underlying pathogenesis of MOG antibody at different ages.

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.

MOG-IgG-Associated Optic Neuritis, Encephalitis, and Myelitis: Lessons Learned From Neuromyelitis Optica Spectrum Disorder

Antibodies against myelin oligodendrocyte glycoprotein (MOG-IgG) have been found in some cases diagnosed as seronegative neuromyelitis optica spectrum disorder (NMOSD). MOG-IgG allowed the identification of a subgroup with a clinical course distinct from that of NMOSD patients who are seropositive for aquaporin-4-IgG antibodies. MOG-IgG is associated with a wider clinical phenotype, not limited to NMOSD, with the majority of cases presenting with optic neuritis (ON), encephalitis with brain demyelinating lesions, and/or myelitis. Therefore, we propose the term MOG-IgG-associated Optic Neuritis, Encephalitis, and Myelitis (MONEM). Depending on the clinical characteristics, these patients may currently be diagnosed with NMOSD, acute disseminated encephalomyelitis, pediatric multiple sclerosis, transverse myelitis, or ON. With specific cell-based assays, MOG-IgG is emerging as a potential biomarker of inflammatory disorders of the central nervous system. We review the growing body of evidence on MONEM, focusing on its clinical aspects.

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.

Clinical features of demyelinating optic neuritis with seropositive myelin oligodendrocyte glycoprotein antibody in Chinese patients

BACKGROUND/AIMS

To investigate the clinical features of Chinese patients with seropositive myelin oligodendrocyte glycoprotein antibody (MOG-Ab) optic neuritis (ON) and patients with seropositive aquaporin-4 antibody (AQP4-Ab) ON.

METHODS

In this retrospective observational study, sera from patients with demyelinating ON were tested for MOG-Ab and AQP4-Ab with a cell-based assay. Clinical characteristics were compared between MOG-Ab-related ON (MOG-ON) and AQP4-Ab-related ON (AQP4-ON), including visual performances, serum autoantibodies and features on MRI.

RESULTS

A total of 109 affected eyes from 65 patients with demyelinating ON (20 MOG-ON and 45 AQP4-ON) were included. The onset age of MOG-ON was younger than AQP4-ON (MOG-ON: 20.2±17.4 years old, AQP4-ON: 35.6±15.7 years old, P=0.001). Onset severity was not different between these two groups (P=0.112), but patients with MOG-ON showed better visual outcomes (P=0.004). Half of the MOG-ON had a relapsing disease course. Nineteen per cent of patients with AQP4-ON presented coexisting autoimmune disorders, but there were no coexisting autoimmune disorders among patients with MOG-ON. Optic nerve head swelling was more prevalent in patients with MOG-ON (P<0.01). Retrobulbar segment involvement of the optic nerve were more common in patients with MOG-ON according to our MRI findings (P<0.01). Patients with MOG-ON showed longitudinally extensive lesion in 30% and chiasm and optic tract involvement in 5%.

CONCLUSIONS

MOG-ON is not rare in Chinese demyelinating patients. It underwent a severe vision loss at onset but had relatively better visual recovery than patients with AQP4-ON. MOG-ON might have an unique pathogenesis different from AQP4-ON.

Clinical characteristics of myelin oligodendrocyte glycoprotein seropositive optic neuritis: a cohort study in Shanghai, China

Qualitative and quantitative visual outcomes of Asian optic neuritis (ON) patients with seropositive myelin oligodendrocyte glycoprotein (MOG) antibodies remain unknown. We retrospectively evaluated a cohort of new-onset ON patients in Shanghai, China between January 2015 and December 2016. Serum MOG and aquaporin-4 (AQP4) antibodies were detected using cell-based assays, and patients were followed-up for at least 6 months. The clinical characteristics and optical coherence tomography (OCT) results were evaluated in the MOG-seropositive optic neuritis (MOG-ON), AQP4-seropositive (AQP4-ON), and double seronegative (Seronegative-ON) patients. Best-corrected visual acuity (BCVA) and peripapillary retinal nerve fiber layer (RNFL) thickness after 6 months of follow-up were compared. Among MOG-ON (n = 49, 64 eyes), AQP4-ON (n = 76, 102 eyes), and Seronegative-ON patients (n = 100, 116 eyes), the percentages of BCVAs better than 0.8 (20/25) at the 6-month visit were 67.19, 19.60, and 72.41%, respectively, which showed no statistical difference between MOG-ON and Seronegative-ON patients (p = 0.198), but were better than the AQP4-ON patients (P = 0.001). The average peripapillary RNFLs measured 6 months after the attack were 58.03 ± 8.73, 64.34 ± 12.88, and 78.12 ± 13.34 μm for the MOG-ON, AQP4-ON, and Seronegative-ON patients, respectively. There was no statistical difference between MOG-ON and AQP4-ON patients (P = 0.089), but both were thinner than Seronegative-ON patients (P = 0.001). The visual acuity in MOG-ON patients was as good as Seronegative-ON patients, whereas the RNFL of the optic nerve head showed a significant thinning as in the AQP4-ON patients.

Pattern Recognition of the Multiple Sclerosis Syndrome

During recent decades, the autoimmune disease neuromyelitis optica spectrum disorder (NMOSD), once broadly classified under the umbrella of multiple sclerosis (MS), has been extended to include autoimmune inflammatory conditions of the central nervous system (CNS), which are now diagnosable with serum serological tests. These antibody-mediated inflammatory diseases of the CNS share a clinical presentation to MS. A number of practical learning points emerge in this review, which is geared toward the pattern recognition of optic neuritis, transverse myelitis, brainstem/cerebellar and hemispheric tumefactive demyelinating lesion (TDL)-associated MS, aquaporin-4-antibody and myelin oligodendrocyte glycoprotein (MOG)-antibody NMOSD, overlap syndrome, and some yet-to-be-defined/classified demyelinating disease, all unspecifically labeled under MS syndrome. The goal of this review is to increase clinicians’ awareness of the clinical nuances of the autoimmune conditions for MS and NMSOD, and to highlight highly suggestive patterns of clinical, paraclinical or imaging presentations in order to improve differentiation. With overlay in clinical manifestations between MS and NMOSD, magnetic resonance imaging (MRI) of the brain, orbits and spinal cord, serology, and most importantly, high index of suspicion based on pattern recognition, will help lead to the final diagnosis.

Cerebral cortical encephalitis followed by recurrent CNS demyelination in a patient with concomitant anti-MOG and anti-NMDA receptor antibodies

We report the case of a patient who initially presented with fever, headache and seizure. MRI revealed a fluid attenuation inversion recovery (FLAIR) high-intensity lesion involving the right temporal, parietal and occipital cortex. Afterwards, the patient developed three recurrent episodes, manifested as brainstem encephalitis, optic neuritis and ADEM-like illness successively, indicating demyelination. Both of his serum anti-MOG and CSF anti-NMDAR antibodies were proved positive by transfected cell based assays. We consider our case to have cortical encephalitis due to certain autoimmune mechanism initially, and then developed MOG-antibody mediated recurrent demyelination in the following episodes.