Myelin oligodendrocyte glycoprotein antibodies in neurological disease

Autoimmune and demyelinating optic neuritis

The knowledge on demyelinating and autoimmune optic neuropathies has experienced a revolution the last decade since the discovery of anti-aquaporin 4 antibody. Improvements in diagnostic techniques, and the finding of new targets, along with advances in neuro-immunology have led to the detection of antibodies related to demyelinating diseases. A review is presented on the classical and new concepts in optic neuritis. The debate on the classification of demyelinating and autoimmune optic neuritis is presented. Furthermore, the updated diagnostic criteria in multiple sclerosis and neuro-myelitis optics are described. Finally, the latest insights into Myelin Oligodendrocyte Glycoprotein (MOG) disorders and chronic-recurring optic neuropathies (CRION) are highlited.

Recent developments in MOG-IgG associated neurological disorders

In the past few years, acquired demyelinating syndromes of the central nervous system associated with antibodies against myelin oligodendrocyte glycoprotein (MOG) have evolved into a new inflammatory disease entity distinct from neuromyelitis optica spectrum disorders or multiple sclerosis. The meticulous clinical description of patients with MOG IgG antibodies (MOG-IgG) has been achieved by development and use of highly specific cell-based assays. MOG-IgG associated disorders comprise a wide spectrum of syndromes ranging from acute disseminated encephalomyelitis predominantly in children to optic neuritis or myelitis mostly in adults. In recent studies, phenotype of MOG-IgG associated disorders has further broadened with the description of cases of brainstem encephalitis, encephalitis with seizures and overlap syndromes with other types of autoimmune encephalitis. In this review, we provide an overview of current knowledge of MOG-IgG associated disorders, describe the clinical presentations identified, highlight differences from neuromyelitis optica spectrum disorders and multiple sclerosis, summarize clinical outcome and concepts of immune treatment, depict the underlying mechanisms of antibody pathogenicity and provide the methodological essentials of MOG-IgG assays.

Postinfectious Acute Disseminated Encephalomyelitis Associated With Antimyelin Oligodendrocyte Glycoprotein Antibody

Myelin oligodendrocyte glycoprotein is a major target of the humoral immune response in children affected by inflammatory demyelinating diseases of the central nervous system. Although myelin oligodendrocyte glycoprotein causes autoimmune encephalitis in different animal models, the relevance of this mechanism in human autoimmune diseases of the central nervous system is unclear. We herein report a child with acute disseminated encephalomyelitis possibly triggered by central nervous system infection of primary herpes simplex virus in the presence of antimyelin oligodendrocyte glycoprotein antibody. A healthy 5-year-old Japanese boy suffered from acute disseminated encephalomyelitis. He was positive for antimyelin oligodendrocyte glycoprotein antibody in both the serum and the cerebrospinal fluid, and herpes simplex virus-1 DNA on polymerase chain reaction of the cerebrospinal fluid. We speculated that the central nervous system infection of primary herpes simplex virus disrupted the blood–brain barrier, and antimyelin oligodendrocyte glycoprotein antibody already present in serum was transferred to the cerebrospinal fluid, resulting in the onset of acute disseminated encephalomyelitis. This might be the mechanism underlying postinfectious acute disseminated encephalomyelitis associated with myelin oligodendrocyte glycoprotein antibody.

Cell-based assays for the detection of MOG antibodies: a comparative study

BACKGROUND

The detection of antibodies to myelin oligodendrocyte glycoprotein (MOG) is fundamental for the identification of MOG antibody-associated disorders (MOGAD), and the differential diagnosis of acquired demyelinating syndromes of the CNS, among which multiple sclerosis (MS). We compared the diagnostic performance of four cell-based assays (CBAs) for their detection.

METHODS

Consecutive sera from 204 patients with 'possible MOGAD' (55), MS (112), and other neurological disorders (OND, 37) were tested for MOG-IgG with a live-CBA with anti-heavy-and-light chain secondary-antibody (LCBA-IgG_H+L), and a live-CBA for IgG₁ (LCBA-IgG₁). A subgroup of 71 patients was additionally tested with a live-CBA with anti-Fcγ secondary-antibody (LCBA-IgG_Fcγ), and a commercial fixed-CBA with anti-Fcγ secondary-antibody (FCBA-IgG_Fcγ)_. RESULTS: Fifty-seven/204 patients (27.9%) were MOG-IgG-positive. Sensitivity was 89.1% (CI:77.8-95.9) and specificity 93.3% (CI:88.0-96.7) for LCBA-IgG_H+L, and 74.6% (CI:61.0-85.3) and 100% (CI:97.6-100) for LCBA-IgG₁. Eighteen of 57 (31%) samples showed discrepant results (all negative on LCBA-IgG₁); of these, three with 'possible MOGAD' showed high-titer MOG-IgG (≥ 1:640), and positivity for MOG-IgG₂, whereas 15/18 had low-titer MOG-IgG (1:160/1:320) and mixed diagnoses (5 'possible MOGAD', 6 MS, 4 OND). In the subgroup analysis, sensitivity was 92.3% (CI:79.1-98.4) and specificity 97.0% (CI:83.8-99.9) for LCBA-IgG_Fcγ, and 87.2% (CI:72.6-95.7) and 97.0% (CI:83.8-99.9) for FCBA-IgG_Fcγ.

CONCLUSIONS

LCBA-IgG₁ showed the highest specificity but can miss MOG-IgG₂ reactivities, whose meaning warrants further investigations. Titration of samples tested with LCBA-IgG_H+L/ IgG_Fcγ is important for meaningful interpretation of the results. In the subgroup analysis, LCBA-IgG_Fcγ yielded the highest accuracy, and FCBA-IgG_Fcγ good specificity, but it was at risk of false-negative results.

Myelin oligodendrocyte glycoprotein-associated disorders are associated with HLA subtypes in a Chinese paediatric-onset cohort

OBJECTIVE

Myelin oligodendrocyte glycoprotein-associated disorders (MOGADs) are a rare new neurological autoimmune disease with unclear pathogenesis. Since a linkage of the disease to the human leucocyte antigen (HLA) has not been shown, we here investigated whether MOGAD is associated with the HLA locus.

METHODS

HLA genotypes of 95 patients with MOGADs, assessed between 2016 and 2018 from three academic centres, were compared with 481 healthy Chinese Han individuals. Patients with MOGADs included 51 paediatric-onset and 44 adult-onset cases. All patients were seropositive for IgG targeting the myelin oligodendrocyte glycoprotein (MOG).

RESULTS

Paediatric-onset MOGAD was associated with the DQB1*05:02-DRB1*16:02 alleles (OR=2.43; OR=3.28) or haplotype (OR=2.84) of HLA class II genes. The prevalence of these genotypes in patients with paediatric-onset MOGAD was significantly higher than healthy controls (p^adj=0.0154; p^adj=0.0221; p^adj=0.0331). By contrast, adult-onset MOGAD was not associated with any HLA genotype. Clinically, patients with the DQB1*05:02-DRB1*16:02 haplotype exhibited significantly higher expanded disability status scale scores at onset (p=0.004) and were more likely to undergo a disease relapse (p=0.030). HLA-peptide binding prediction algorithms and computational docking analysis provided supporting evidence for the close relationship between the MOG peptide subunit and DQB1*05:02 allele. In vitro results indicated that site-specific mutations of the predicted target sequence reduced the antigen-antibody binding, especially in the paediatric-onset group with DQB1*05:02 allele.

CONCLUSIONS

This study demonstrates a possible association between specific HLA class II alleles and paediatric-onset MOGAD, providing evidence for the conjecture that different aetiology and pathogenesis likely underlie paediatric-onset and adult-onset cases of MOGAD.

Comparative Analysis of T-Cell Responses to Aquaporin-4 and Myelin Oligodendrocyte Glycoprotein in Inflammatory Demyelinating Central Nervous System Diseases

Autoantibodies against aquaporin-4 (AQP4-Ab) and myelin oligodendrocyte glycoprotein (MOG-Ab) are associated with rare central nervous system inflammatory demyelinating diseases like neuromyelitis optica spectrum disorders (NMOSD). Previous studies have shown that not only antibodies, but also autoreactive T-cell responses against AQP4 are present in NMOSD. However, no study has yet analyzed the presence of MOG reactive T-cells in patients with MOG antibodies. Therefore, we compared AQP4 and MOG specific peripheral T-cell response in individuals with AQP4-Ab (n = 8), MOG-Ab (n = 10), multiple sclerosis (MS, n = 8), and healthy controls (HC, n = 14). Peripheral blood mononuclear cell cultures were stimulated with eight AQP4 and nine MOG peptides selected from previous studies and a tetanus toxoid peptide mix as a positive control. Antigen-specific T-cell responses were assessed using the carboxyfluorescein diacetate succinimidyl ester proliferation assay and the detection of granulocyte macrophage colony-stimulating factor (GM-CSF), interferon (IFN)-ɤ and interleukin (IL)-4, IL-6, and IL-17A in cell culture supernatants. Additionally, human leukocyte antigen (HLA)-DQ and HLA-DR genotyping of all participants was performed. We classified a T-cell response as positive if proliferation (measured by a cell division index ≥3) was confirmed by the secretion of at least one cytokine. Reactivity against AQP4 peptides was observed in many groups, but the T-cell response against AQP4 p156-170 was present only in patients with AQP4-Ab (4/8, 50%) and absent in patients with MOG-Ab, MS and HC (corrected p = 0.02). This AQP4 p156-170 peptide specific T-cell response was significantly increased in participants with AQP4-Ab compared to those without [Odds ratio (OR) = 59.00, 95% confidence interval-CI 2.70–1,290.86]. Moreover, T-cell responses against at least one AQP4 peptide were also more frequent in participants with AQP4-Ab (OR = 11.45, 95% CI 1.24–106.05). We did not observe any significant differences for the other AQP4 peptides or any MOG peptide. AQP4-Ab were associated with HLA DQB1^*02 (OR = 5.71, 95% CI 1.09–30.07), DRB1^*01 (OR = 9.33, 95% CI 1.50–58.02) and DRB1^*03 (OR = 6.75, 95% CI = 1.19–38.41). Furthermore, HLA DRB1^*01 was also associated with the presence of AQP4 p156-170 reactive T-cells (OR = 31.67, 95% CI 1.30–772.98). To summarize, our findings suggest a role of AQP4-specific, but not MOG-specific T-cells, in NMOSD.

A tearfully painful darkness

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

Value of Area Postrema Syndrome in Differentiating Adults With AQP4 vs. MOG Antibodies

Objectives: To compare the frequency of area postrema syndrome (APS) in adults with anti-aquaporin-4 (AQP4) and anti-myelin oligodendrocyte glycoprotein (MOG) antibodies.

Methods: APS is defined as acute or subacute, single or combined, episodic or constant nausea, vomiting, or hiccups, persisting for at least 48 h, which cannot be attributed to any other etiology. The presence of APS was investigated in 274 adults with AQP4 antibodies and 107 adults with MOG antibodies from 10 hospitals.

Results: The study population comprised Korean adults (≥18 years). At the time of disease onset, 14.9% (41/274) adults with AQP4 antibodies had APS, while none of the participants with MOG antibodies developed APS (p < 0.001). During the course of the disease, 17.2% (47/274) adults with AQP4 antibodies had APS in contrast to 1.9% (2/107) adults with MOG antibodies with APS (p < 0.001).

Conclusions: APS, one of the core clinical characteristics of individuals with AQP4 antibodies, is an extremely rare manifestation in Korean adults with MOG antibodies.

Recent Advances in Antigen-Specific Immunotherapies for the Treatment of Multiple Sclerosis

Multiple sclerosis (MS) is an autoimmune disease of the central nervous system and is considered to be the leading non-traumatic cause of neurological disability in young adults. Current treatments for MS comprise long-term immunosuppressant drugs and disease-modifying therapies (DMTs) designed to alter its progress with the enhanced risk of severe side effects. The Holy Grail for the treatment of MS is to specifically suppress the disease while at the same time allow the immune system to be functionally active against infectious diseases and malignancy. This could be achieved via the development of immunotherapies designed to specifically suppress immune responses to self-antigens (e.g., myelin antigens). The present study attempts to highlight the various antigen-specific immunotherapies developed so far for the treatment of multiple sclerosis (e.g., vaccination with myelin-derived peptides/proteins, plasmid DNA encoding myelin epitopes, tolerogenic dendritic cells pulsed with encephalitogenic epitopes of myelin proteins, attenuated autologous T cells specific for myelin antigens, T cell receptor peptides, carriers loaded/conjugated with myelin immunodominant peptides, etc), focusing on the outcome of their recent preclinical and clinical evaluation, and to shed light on the mechanisms involved in the immunopathogenesis and treatment of multiple sclerosis.

Epidemiology of Pediatric NMOSD in Germany and Austria

Background: Neuromyelitis optica spectrum disorders (NMOSD) are severe inflammatory demyelinating disorders of the central nervous system mainly characterized by recurrent episodes of uni- or bilateral optic neuritis (ON), transverse myelitis (TM) and brainstem syndromes (BS). The majority of adult patients has serum antibodies directed against the water channel protein aquaporin 4 (AQP4-abs). In pediatric patients, AQP4-abs are less, while antibodies against myelin oligodendrocyte glycoprotein (MOG-abs) are more frequently detectable than in adults. Some children with NMOSD have neither AQP4- nor MOG-ab (double-seronegative).

Objective: Evaluation of epidemiological data regarding incidence and prevalence of pediatric NMOSD in Germany and Austria.

Methods: We recruited pediatric NMOSD patients between 1 March 2017 and 28 February 2019 with five different tools: (1) ESPED (Surveillance Unit for Rare Pediatric Disorders in Germany), (2) ESNEK (Surveillance for Rare Neurological Disorders during Childhood), (3) pediatric neurology working group within the Austrian Society of Pediatrics and Adolescent Medicine, (4) BIOMARKER Study and (5) NEMOS (Neuromyelitis optica Study Group). We requested data regarding clinical symptoms, antibody status, therapy regimen and response via a standardized questionnaire.

Results: During the 2-year recruitment period, 46 (both incidental and prevalent) patients with a suspected diagnosis of NMOSD were brought to our attention. Twenty-two of these patients did not fulfill the inclusion criteria. Of the remaining 24 children, 22 had a median age at onset of 11 (range 3–17) years and 16/22 were female (72.7%) (no data in two patients). Sixteen of 24 patients were AQP4-ab positive (67%), 4/24 MOG-ab positive (16.7%), three children were double-seronegative and in one patient no antibody testing was done. We calculated an incidence rate of 0.022 per 100,000 person-years for Germany, while there was no incidental case in Austria during the recruitment period. The prevalence rate was 0.147 and 0.267 per 100,000 persons in Germany and Austria, respectively.

Conclusion: Pediatric NMOSD, with and without associated antibodies, are very rare even considering the different limitations of our study. An unexpected finding was that a considerable proportion of patients was tested neither for AQP4- nor MOG-abs during diagnostic work-up, which should prompt to establish and disseminate appropriate guidelines.

The pathology of central nervous system inflammatory demyelinating disease accompanying myelin oligodendrocyte glycoprotein autoantibody

We sought to define the pathological features of myelin oligodendrocyte glycoprotein (MOG) antibody associated disorders (MOGAD) in an archival autopsy/biopsy cohort. We histopathologically analyzed 2 autopsies and 22 brain biopsies from patients with CNS inflammatory demyelinating diseases seropositive for MOG-antibody by live-cell-based-assay with full length MOG in its conformational form. MOGAD autopsies (ages 52 and 67) demonstrate the full spectrum of histopathological features observed within the 22 brain biopsies (median age, 10 years; range, 1–66; 56% female). Clinical, radiologic, and laboratory characteristics and course (78% relapsing) are consistent with MOGAD. MOGAD pathology is dominated by coexistence of both perivenous and confluent white matter demyelination, with an over-representation of intracortical demyelinated lesions compared to typical MS. Radially expanding confluent slowly expanding smoldering lesions in the white matter as seen in MS, are not present. A CD4+ T-cell dominated inflammatory reaction with granulocytic infiltration predominates. Complement deposition is present in all active white matter lesions, but a preferential loss of MOG is not observed. AQP4 is preserved, with absence of dystrophic astrocytes, and variable oligodendrocyte and axonal destruction. MOGAD is pathologically distinguished from AQP4-IgG seropositive NMOSD, but shares some overlapping features with both MS and ADEM, suggesting a transitional pathology. Complement deposition in the absence of selective MOG protein loss suggest humoral mechanisms are involved, however argue against endocytic internalization of the MOG antigen. Parallels with MOG-EAE suggest MOG may be an amplification factor that augments CNS demyelination, possibly via complement mediated destruction of myelin or ADCC phagocytosis.

Recurrence of clinical events at the same anatomical location in patients with MOG antibody-associated disease

OBJECTIVES

Likelihood of clinical events occurring within the same anatomical location in patients with myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) was retrospectively investigated.

METHODS

A total of 236 clinical events in 90 patients with MOGAD from nine referral hospitals were analyzed via logistic regression, and odds ratios (ORs) were calculated. Anatomical lesion location was divided into four groups; optic nerve, spinal cord, cerebral hemisphere, and brainstem/cerebellum.

RESULTS

At all locations, there was an increased likelihood of a second attack occurring at the same location as the initial event (cerebral hemisphere OR = 22.14, brainstem/cerebellum OR = 18.4, spinal cord OR = 9.1, and optic nerve OR = 7.8). There was an increased likelihood of a third attack occurring at the same location as the initial event in the optic nerve (OR = 14.9), cerebral hemisphere (OR = 11.7), and spinal cord (OR = 6.7). There were positive trends toward a third clinical event occurring at the same location as the first and/or second events if the event was in the optic nerve (OR = 13.5), cerebral hemisphere (OR = 6.9), or spinal cord (OR = 5.7).

CONCLUSIONS

The current study suggests that clinical relapses of MOGAD during early stage tend to recur at the same anatomical locations in the central nervous system.

HLA association in MOG-IgG- and AQP4-IgG-related disorders of the CNS in the Dutch population

Objective

To investigate the possible human leukocyte antigen (HLA) association of both myelin oligodendrocyte glycoprotein (MOG-IgG)-associated diseases (MOGAD) and aquaporin-4 antibody (AQP4-IgG)-positive neuromyelitis optica spectrum disorders (NMOSDs) in the Dutch population with European ancestry to clarify similarities or differences in the immunogenetic background of both diseases.

Methods

Blood samples from patients in the Dutch national MS/NMOSD expert clinic were tested for MOG-IgG and AQP4-IgG using a cell-based assay. HLA Class I and II genotyping was performed in 43 MOG-IgG–seropositive and 42 AQP4-IgG–seropositive Dutch patients with European ancestry and compared with those of 5,604 Dutch healthy blood donors.

Results

No significant HLA association was found in MOG-IgG–seropositive patients. The AQP4-IgG–seropositive patients had a significant higher frequency of HLA-A*01 (61.9% vs 33.7%, OR 3.16, 95% CI, 1.707–5.863, p after correction [pc] = 0.0045), HLA-B*08 (61.9% vs 25.6%, OR 4.66, 95% CI, 2.513–8.643, pc < 0.0001), and HLA-DRB1*03 (51.2% vs 27.6%, OR 2.75, 95% CI, 1.495–5.042, pc = 0.0199) compared with controls.

Conclusions

The present study demonstrates differences in the immunogenetic background of MOGAD and AQP4-IgG–positive NMOSD. The strong positive association with HLA-A*01, -B*08, and -DRB1*03 is suggestive of a role of this haplotype in the etiology of AQP4-IgG–positive NMOSD in patients with European ancestry, whereas in MOGAD no evidence was found for any HLA association in these disorders.

Serum biomarkers in myelin oligodendrocyte glycoprotein antibody-associated disease

Objective

To test the hypothesis that the pattern of serum biomarkers of disease activity and disability in myelin oligodendrocyte glycoprotein antibody–associated disease (MOGAD) will be different from those in neuromyelitis optica spectrum disorder (NMOSD) with anti–aquaporin-4 antibodies (AQP4-Abs).

Methods

Using ultrasensitive single-molecule array assays, we measured neurofilament light chain (NfL), glial fibrillary acidic protein (GFAP), and tau in the sera of consecutive patients with MOGAD (n = 16) and NMOSD with AQP4-Ab (n = 33). Serum biomarker levels were compared between patients in relapse and remission states, and correlations between the levels of these biomarkers and Expanded Disability Status Scale (EDSS) scores were analyzed within each group.

Results

In the MOGAD group, the serum tau level was higher in a relapse state than in a remission state (relapse vs remission: 0.5 [0.4–0.5] vs 0.2 [0.1–0.3] pg/mL, p = 0.027). Both serum levels of NfL and tau correlated with the EDSS score (NfL: r = 0.684, p = 0.003; tau: r = 0.524, p = 0.045). Meanwhile, in the NMOSD group, serum NfL and GFAP levels were higher in a relapse state than in a remission state (relapse vs remission: NfL, 34.8 [12.2–62.3] vs 13.0 [11.3–20.0] pg/mL, p = 0.010; GFAP, 253.8 [150.6–303.0] vs 104.4 [93.9–127.9] pg/mL, p = 0.016). Only the serum GFAP level correlated with the EDSS score (r = 0.485, p = 0.012).

Conclusion

The pattern of serum biomarkers of disease activity and disability in MOGAD showed a distinct feature from those in NMOSD with AQP4-Ab, which implicates different pathogeneses between the 2 diseases.

ANTIBODIES AND RECEPTORS: From Neuromuscular Junction to Central Nervous System

Myasthenia gravis (MG) is a relatively rare neurological disease that is usually associated with antibodies to the acetylcholine receptor (AChR). These antibodies (Abs) cause loss of the AChRs from the neuromuscular junction (NMJ), resulting in muscle weakness that can be life-threatening. Another form of the disease is caused by antibodies to muscle specific kinase (MuSK) that result in impaired AChR clustering and numbers at the NMJ, and may also interfere with presynaptic adaptive mechanisms. Other autoimmune disorders, Lambert Eaton myasthenic syndrome and acquired neuromyotonia, are associated with antibodies to presynaptic voltage-gated calcium and potassium channels respectively. All four conditions can be diagnosed by specific clinical features, electromyography and serum antibody tests, and can be treated effectively by a combination of pharmacological approaches and procedures that reduce the levels of the IgG antibodies. They form the first of a spectrum of diseases in which serum autoantibodies bind to extracellular domains of neuronal proteins throughout the nervous system and lead to constellations of clinical features including paralysis, sensory disturbance and pain, memory loss, seizures, psychiatric disturbance and movement disorders. This review will briefly summarize the ways in which this field has developed, since the 1970s when considerable contributions were made in Ricardo Miledi's laboratory at UCL.

International multicenter examination of MOG antibody assays

OBJECTIVE

To compare the reproducibility of 11 antibody assays for immunoglobulin (Ig) G and IgM myelin oligodendrocyte glycoprotein antibodies (MOG-IgG and MOG-IgM) from 5 international centers.

METHODS

The following samples were analyzed: MOG-IgG clearly positive sera (n = 39), MOG-IgG low positive sera (n = 39), borderline negative sera (n = 13), clearly negative sera (n = 40), and healthy blood donors (n = 30). As technical controls, 18 replicates (9 MOG-IgG positive and 9 negative) were included. All samples and controls were recoded, aliquoted, and distributed to the 5 testing centers, which performed the following antibody assays: 5 live and 1 fixed immunofluorescence cell-based assays (CBA-IF, 5 MOG-IgG, and 1 MOG-IgM), 3 live flow cytometry cell-based assays (CBA-FACS, all MOG-IgG), and 2 ELISAs (both MOG-IgG).

RESULTS

We found excellent agreement (96%) between the live CBAs for MOG-IgG for samples previously identified as clearly positive or negative from 4 different national testing centers. The agreement was lower with fixed CBA-IF (90%), and the ELISA showed no concordance with CBAs for detection of human MOG-IgG. All CBAs showed excellent interassay reproducibility. The agreement of MOG-IgG CBAs for borderline negative (77%) and particularly low positive (33%) samples was less good. Finally, most samples from healthy blood donors (97%) were negative for MOG-IgG in all CBAs.

CONCLUSIONS

Live MOG-IgG CBAs showed excellent agreement for high positive and negative samples at 3 international testing centers. Low positive samples were more frequently discordant than in a similar comparison of aquaporin-4 antibody assays. Further research is needed to improve international standardization for clinical care.

Neuromyelitis optica spectrum disorders and pregnancy: therapeutic considerations

Neuromyelitis optica spectrum disorders (NMOSD) are a type of neurological autoimmune disease characterized by attacks of CNS inflammation that are often severe and predominantly affect the spinal cord and optic nerve. The majority of individuals with NMOSD are women, many of whom are of childbearing age. Although NMOSD are rare, several small retrospective studies and case reports have indicated that pregnancy can worsen disease activity and might contribute to disease onset. NMOSD disease activity seems to negatively affect pregnancy outcomes. Moreover, some of the current NMOSD treatments are known to pose risks to the developing fetus and only limited safety data are available for others. Here, we review published studies regarding the relationship between pregnancy outcomes and NMOSD disease activity. We also assess the risks associated with using disease-modifying therapies for NMOSD during the course of pregnancy and breastfeeding. On the basis of the available evidence, we offer recommendations regarding the use of these therapies in the course of pregnancy planning in individuals with NMOSD.

Binding patterns and functional properties of human antibodies to AQP4 and MOG on murine optic nerve and retina

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune-inflammatory CNS disease affecting spinal cord and optic nerves, mediated by autoantibodies against aquaporin-4 (AQP4) and myelin-oligodendrocyte-glycoprotein (MOG). Effects of those immunoglobulins (Ig) on retina and optic nerve are incompletely understood. We investigated AQP4-IgG and MOG-IgG sera on retina and optic nerve ex vivo and in 2D2 mice, which harbor a transgenic MOG-specific T-cell receptor. Some sera reacted with murine retina and optic nerve showing distinct binding patterns, suggesting different epitopes being targeted in both subgroups. Transfer of total IgG from a MOG-IgG positive patient to 2D2 mice did neither enhance disability nor induce functional or histological alterations in the retina.

A Fulminant Case of Demyelinating Encephalitis With Extensive Cortical Involvement Associated With Anti-MOG Antibodies

Anti-myelin oligodendrocyte glycoprotein (MOG) antibodies (MOG-Abs) are commonly associated with clinical presentations as acute disseminated encephalomyelitis (ADEM) in both adults and children and anti-aquaporin 4 antibody-seronegative neuromyelitis optica spectrum disorder (NMOSD) and related syndromes such as optic neuritis, myelitis, and brainstem encephalitis. Most often, the presence of MOG-Abs is associated with a more benign clinical course and a good response to steroids. Here, we present a case report of a previously healthy 52-year-old female patient with fulminant demyelinating encephalitis, leading to death within a week after the first presenting symptoms from a massive brain edema irresponsive to high-dose intravenous steroids as well as osmotic therapy. The final diagnosis was only made postmortem after serum anti-MOG-Abs results were available. Histopathological analysis of the brain revealed extensive, predominantly cortical demyelinating lesions in the frontal, temporal, and parietal lobes with intracortical, leukocortical, and subpial plaques, associated with pronounced perivenous deposition of activated complement complex as well as features of acute MS characterized by destructive lesions.

MOG encephalomyelitis: distinct clinical, MRI and CSF features in patients with longitudinal extensive transverse myelitis as first clinical presentation

Background

Based on clinical, immunological and histopathological evidence, MOG-IgG-associated encephalomyelitis (MOG-EM) has emerged as a distinct disease entity different from multiple sclerosis (MS) and aquaporin-4-antibody-positive neuromyelitis optica spectrum disorder (NMOSD). MOG-EM is associated with a broader clinical phenotype including optic neuritis, myelitis, brainstem lesions and acute disseminated encephalomyelitis with a substantial clinical and radiological overlap to other demyelinating CNS disorders.

Objective

To evaluate common clinical, MRI and CSF findings, as well as therapy responses in patients with longitudinal extensive transverse myelitis (LETM) as initial clinical presentation of MOG-EM.

Methods

After excluding patients with a known diagnosis of MS, we identified 153 patients with myelitis of which 7 fulfilled the inclusion criteria and were investigated for MRI, CSF and clinical parameters.

Results

Patients with LETM as first clinical presentation of MOG-EM display similar characteristics, namely a lack of gadolinium-enhancement in spinal cord MRI, marked pleocytosis, negative oligoclonal bands, a previous history of infections/vaccinations and response to antibody-depleting treatments for acute attacks and long-term treatment.

Conclusions

We identify common pathological findings in patients with LETM as first clinical presentation of MOG-EM which distinguishes it from other forms of LETM and should lead to testing for MOG-IgG in these cases.

Autoimmune encephalitis management: MS centers and beyond

Traditionally, multiple sclerosis (MS) specialists have been the go-to providers for managing certain treatable non-demyelinating inflammatory or autoimmune central nervous system (CNS) disorders. The advent of increased incidence (mostly due to improved recognition) prompts the question: who should be managing autoimmune encephalitis? These patients are generally first encountered in the hospital, as well as general neurology and subspecialty clinics, such as epilepsy. Autoimmune neurology is a specialty which gives focus to evaluation and treatment of patients with autoimmune encephalitis, among other disorders, and trains neurologists accordingly. Some of those experts are dual trained in both MS and non-MS inflammatory/autoimmune CNS disorders. Many other autoimmune specialists are trained in non-MS care, such as hospital neurology, movement disorders, and epilepsy. General and other subspecialty providers increasingly find the need to be versed in management of autoimmune encephalitis.

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

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

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

PURPOSE

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

METHODS

Observational case report.

RESULTS

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

CONCLUSION

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

Siponimod therapy implicates Th17 cells in a preclinical model of subpial cortical injury

Subpial demyelination is a specific hallmark of multiple sclerosis and a correlate of disease progression. Although the mechanism(s) that mediate pathogenesis in the subpial compartment remain unclear, it has been speculated that inflammation in the overlying meninges may be associated with subpial injury. Here we show that adoptive transfer of proteolipid protein-primed Th17 cells into SJL/J recipient mice induces subpial demyelination associated with microglial/macrophage activation, disruption of the glial limitans, and evidence of an oxidative stress response. This pathology was topologically associated with foci of immune cells in the meninges and occurred in the absence of measurable anti-myelin oligodendrocyte glycoprotein IgM or IgG antibodies. To test the role of brain-infiltrating leukocytes on subpial injury, we modulated sphingosine 1-phosphate (S1P) receptor1,5 activity with BAF312 (siponimod) treatment. Administration of BAF312, even after adoptively transferred T cells had entered the brain, significantly ameliorated clinical experimental autoimmune encephalomyelitis and diminished subpial pathology, concomitant with a selective reduction in the capacity of transferred T cells to make Th17 cytokines. We conclude that sustained subpial cortical injury is associated with the capacity for brain-resident T cells to produce Th17 cytokines, and this pathological process occurs in an S1P receptor1,5-dependent manner.

Autoantibody Diagnostics in Neuroimmunology: Experience From the 2018 Italian Neuroimmunology Association External Quality Assessment Program

Background: Neuroimmunology has impressively expanded in the past decade. Novel assays, especially cell-based assays (CBAs) can detect conformational antibodies (Abs) recognizing antigens in their native conformation. Generally, the availability of in-house and of commercial tests has improved the diagnostics, but introduced demanding laboratory tasks. Hence, standardization and quality controls represent a key step to promote accuracy. We report on the results of the 2018 external quality assessment program (EQAP) organized by the Italian Neuroimmunology Association.

Methods: EQAP regarded 10 schemes, including oligoclonal bands (OCBs), intracellular-neuronal (ICN)-Abs, neuronal-surface (NS)-Abs, aquaporin-4 (AQP4)-Abs, myelin oligodendrocyte glycoprotein (MOG)-Abs, myelin-associated glycoprotein (MAG)-Abs, ganglioside-Abs, acetylcholine-receptor (AChR)-Abs, and muscle-specific-kinase (MuSK)-Abs, and 34 laboratories. Assays were classified as tissue-based assays (TBAs), solid-phase assays (SPAs), liquid-phase assays (LPAs), and CBAs. Thirty-three samples were provided.

Results: Three-quarter of the tests were commercial. Median accuracy for the laboratories was 75% (range 50–100). In 8/10 schemes, at least one sample provided discrepant results. Inter-laboratory “substantial agreement” was found in 6/10 schemes (AChR, MuSK, MAG, AQP4, MOG, and NS-Abs), whereas the worst agreements regarded OCBs and ganglioside-Abs. Both commercial and in-house assays performed better in experienced laboratories.

Conclusions: Assays could be divided in (a) robust commercial tests with substantial inter-laboratory agreement (MAG-Abs; AChR- and MuSK-Abs); commercial/“in-house” tests with (b) partial inter-laboratory agreement (AQP4-Abs, MOG-Abs, NS-Abs, ICN-Abs), and (c) with large inter-laboratory disagreement (OCBs, ganglioside-Abs). This real-life snapshot of the neuroimmunology test performances highlights shortcomings attributable to technician-dependent performances, assay structural limitations, and errors in test interpretations.

Autoimmune encephalitis in children and adolescents

Background

Autoimmune encephalitides with neural and glial antibodies have become an attractive field in neurology because the antibodies are syndrome-specific, explain the pathogenesis, indicate the likelihood of an underlying tumor, and often predict a good response to immunotherapy. The relevance and the management of antibody-associated encephalitides in the pediatric age group are to be discussed.

Main body

Subacutely evolving, complex neuropsychiatric conditions that are otherwise unexplained should raise the suspicion of autoimmune encephalitis. Determination of autoantibodies is the key diagnostic step. It is recommended to study cerebrospinal fluid and serum in parallel to yield highest diagnostic sensitivity and specificity. The most frequently found antibodies are those against the N-methyl-D-asparate receptor, an antigen on the neural cell surface. The second most frequent antibody is directed against glutamic acid decarboxylase 65 kDa, an intracellular protein, often found in chronic conditions with questionable inflammatory activity. Immunotherapy is the mainstay of treatment in autoimmune encephalitides. Steroids, apheresis and intravenous immunoglobulin are first-line interventions. Rituximab or cyclophosphamide are given as second-line treatments. Patients with surface antibodies usually respond well to immunotherapy whereas cases with antibodies against intracellular antigens most often do not.

Conclusion

With few exceptions, the experience in adult patients with autoimmune encephalitides can be applied to patients in the pediatric age range.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Frequency of myelin oligodendrocyte glycoprotein antibody in multiple sclerosis: A multicenter cross-sectional study

Objective

To address the frequency of myelin oligodendrocyte glycoprotein (MOG) antibody (Ab) in an unselected large cohort of adults with MS.

Methods

This is a cross-sectional study in 2 MS expert centers (Lyon and Strasbourg University Hospitals, France) between December 1, 2017, and June 31, 2018. Patients aged ≥18 years with a definite diagnosis of MS according to 2010 McDonald criteria were tested for MOG-Ab by using a cell-based assay (CBA) in Lyon and subsequently included. Positive samples were tested by investigators blinded to the first result with a second assay in a different laboratory (Barcelona, Spain) by using the same plasmid and secondary Ab.

Results

Serum samples from 685 consecutive patients with MS were analyzed for MOG-Ab. Median disease duration at sampling was 11.5 (interquartile range, 5.8–17.7) years, and 72% were women. Two (0.3%) patients resulted to be MOG-Ab-positive. The 2 patients were women aged 42 and 38 at disease onset and were diagnosed with secondary and primary progressive forms of MS, respectively. This positive result was confirmed by the CBA in Barcelona.

Conclusion

Our findings indicate that MOG-Ab are exceptional in MS phenotype, suggesting that the MOG-Ab testing should not be performed in typical MS presentation.

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.

Atypical Pediatric Demyelinating Diseases of the Central Nervous System

PURPOSE OF REVIEW

Pediatric central nervous system demyelinating diseases include multiple sclerosis (MS), neuromyelitis optica spectrum disorder (NMOSD), and acute disseminated encephalomyelitis (ADEM). As diagnostic criteria become more inclusive, the risk of misdiagnosis of atypical demyelinating diseases of rheumatologic, infectious, and autoimmune etiology increases.

RECENT FINDINGS

We review mimics of multiple sclerosis, neuromyelitis optica spectrum disorder, and acute disseminated encephalomyelitis, including rheumatologic diseases: systemic lupus erythematosus and neuro-Behçet disease; infectious diseases: human immunodeficiency virus, progressive multifocal leukoencephalopathy, and subacute sclerosis panencephalitis; and autoimmune diseases including X-linked Charcot-Marie-Tooth disease, chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) and autoimmune glial fibrillary acidic protein (GFAP) encephalopathy. Atypical demyelinating disease may mimic classic neuroinflammatory diseases of the central nervous system. Imaging may meet criteria for a diagnosis of multiple sclerosis, or patients may present with optic neuritis and transverse myelitis consistent with neuromyelitis optica spectrum or myelin oligodendrocyte glycoprotein (MOG) antibody disorders. Through careful history-taking and review of atypical MRI findings, we may avoid misdiagnosis and mistreatment.

Predictive Value of Serum Antibodies and Point Mutations of AQP4, AQP1 and MOG in A Cohort of Spanish Patients with Neuromyelitis Optica Spectrum Disorders

The detection of IgG aquaporin-4 antibodies in the serum of patients with Neuromyelitis optica (NMO) has dramatically improved the diagnosis of this disease and its distinction from multiple sclerosis. Recently, a group of patients have been described who have an NMO spectrum disorder (NMOsd) and who are seronegative for AQP4 antibodies but positive for IgG aquaporin-1 (AQP1) or myelin oligodendrocyte glycoprotein (MOG) antibodies. The purpose of this study was to determine whether AQP1 and MOG could be considered new biomarkers of this disease; and if point mutations in the gDNA of AQP4, AQP1 and MOG genes could be associated with the etiology of NMOsd. We evaluated the diagnostic capability of ELISA and cell-based assays (CBA), and analyzed their reliability, specificity, and sensitivity in detecting antibodies against these three proteins. The results showed that both assays can recognize these antigen proteins under appropriate conditions, but only anti-AQP4 antibodies, and not AQP1 or MOG, appears to be a clear biomarker for NMOsd. CBA is the best method for detecting these antibodies; and serum levels of AQP4 antibodies do not correlate with the progression of this disease. So far, the sequencing analysis has not revealed a genetic basis for the etiology of NMOsd, but a more extensive analysis is required before definitive conclusions can be drawn.

Relevance of antibodies to myelin oligodendrocyte glycoprotein in CSF of seronegative cases

OBJECTIVE

To determine the diagnostic relevance of myelin oligodendrocyte glycoprotein antibodies (MOG-Abs) in CSF of seronegative cases by retrospectively analyzing consecutive time-matched CSF of 80 MOG-Ab-seronegative patients with demyelinating disease.

METHODS

The cohort included 44 patients with NMOSD and related disorders and 36 patients with multiple sclerosis (MS). Two independent neurologists blinded to diagnosis analyzed MOG-Abs by live cell-based immunofluorescence assay with goat anti-human immunoglobulin (Ig) G (whole molecule) antibody. Sera were tested at dilutions of 1:20 and 1:40, and a cutoff of 1:160 was considered for serum positivity. CSF specimens were tested undiluted and at 1:2 dilution with further titrations in case of positivity. Anti-IgG-Fc and anti-IgM-µ secondary antibodies were used to confirm the exclusive presence of MOG-IgG in positive cases. CSF of 13 MOG-Abs seropositive cases and 36 patients with neurodegenerative conditions was analyzed as controls.

RESULTS

Three seronegative cases had CSF MOG-Abs (4% of the whole cohort or 7% of cases excluding patients with MS, in which MOG-Abs seem to lack diagnostic relevance). In particular, 2 patients with neuromyelitis optica spectrum disorder (NMOSD) and 1 with acute disseminated encephalomyelitis had MOG-Abs in CSF. Analysis with anti-IgG-Fc and anti-IgM confirmed the exclusive presence of MOG-IgG in the CSF of these patients. Among the control group, MOG-Abs were detectable in the CSF of 8 of 13 MOG-Ab-seropositive cases and in none of the patients with neurodegenerative disorders.

CONCLUSION

Although serum is the optimal specimen for MOG-Ab testing, analyzing CSF could improve diagnostic sensitivity in seronegative patients. This observation has relevant diagnostic impact and might provide novel insight into the biological mechanisms of MOG-Ab synthesis.

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.

Diagnostic Considerations in Acute Disseminated Encephalomyelitis and the Interface with MOG Antibody

Acute disseminated encephalomyelitis (ADEM) is a common yet clinically heterogenous syndrome characterized by encephalopathy, focal neurologic findings, and abnormal neuroimaging. Differentiating ADEM from other demyelinating disorders of childhood can be difficult and appropriate interpretation of the historical, clinical, and neurodiagnostic components of a patient's presentation is critical. Myelin oligodendrocyte glycoprotein (MOG) antibody-associated diseases are a recently recognized set of disorders, which include ADEM presentations, among other phenotypes. This review article discusses the clinical diagnosis, differential diagnosis, interpretation of data, and treatment/prognosis of this unique syndrome with distinctive review of the spectrum of MOG antibodies.