anti-MOG Antibodies Research Articles

“Novel Psychiatric Manifestations of Anti-MOG Antibody Disease” (P10-5.031)

“Novel Psychiatric Manifestations of Anti-MOG Antibody Disease” (P10-5.031)

Post Infectious Triggered Anti-Myelin Oligodendrocyte Glycoprotein Antibody-Associated Disease (MOGAD) via CMV in an Immunocompetent Host (P10-5.030)

<h3>Objective:</h3> N/A <h3>Background:</h3> A previously healthy, immunocompetent 38-year-old female presented with initial complaints of subacute, waxing and waning high grade fevers, general malaise, and muscle aches for two weeks. Acutely she developed severe lumbar radiculopathy with significant urinary retention and bilateral lower extremity weakness leading to ED presentation. The patient was subsequently admitted with rapidly progressive lower extremity paraplegia and brisk reflexes over a 24-hour span. MRI imaging was notable for longitudinally extensive transverse myelitis (LETM) over continuous cervical and thoracic segments with significant gray matter involvement and left parahippocampal FLAIR hyperintensities Serum subsequently demonstrated positive anti-CMV IgM/IgG antibodies with a PCR load of 61 copies/mL indicative of a CMV infection with low viremia. LP CSF was CMV PCR negative with mildly elevated opening pressures and trace neurotrophic pleocytosis. Given stagnant clinical changes after five days of IV steroids, plasmapheresis was initiated with marked improvements in functional lower extremity strength. Soon afterwards, initial presenting lab work resulted, demonstrating high serum titers (1:2560) of anti-MOG antibodies. <h3>Design/Methods:</h3> N/A <h3>Results:</h3> N/A <h3>Conclusions:</h3> In immunocompetent hosts, CMV infection itself is a rarely described cause of inflammatory myelopathy with only 14 prescribed cases. With both deep gray matter FLAIR hyperintensities and cervical and thoracic LETM, a concomitant para-infectious CMV and new MOGAD is unlikely in our clinical setting. Additionally, systemic findings typically indicative of severe CMV infections such as retinitis, pericarditis/myocarditis, transaminitis, thrombocytopenia, and leukopenia were absent. Given prior reports of sequence similarities between MOG T-cell epitopes and a major capsid protein of CMV, molecular mimicry between antigen presenting cells has been hypothesized. Here we detail a first described case report of a possible post-infectious MOG antibody transverse myelitis triggered presumptively via CMV infection. Furthermore, presenting in an immunocompetent host, our case report highlights a further wrinkle into the pathophysiology and presence of post infectious triggered autoimmunity for MOGAD. <b>Disclosure:</b> Dr. Chen has nothing to disclose. Dr. Kwon has nothing to disclose.

Giant Cell Arteritis with concurrent anti-MOG antibodies: Case Report (P9-5.016)

Giant Cell Arteritis with concurrent anti-MOG antibodies: Case Report (P9-5.016)

Evolution in anti-myelin oligodendrocyte glycoprotein antibody detection and its clinical significance: a narrative review.

Myelin oligodendrocyte glycoprotein (MOG) is a protein exclusively expressing on the surface of myelin sheaths and oligodendrocyte plasma membrane in the central nervous system of mammals, and it has a highly conserved nucleotide and amino acid structure between species. Evidence from animal research support that anti-MOG antibodies (MOG-Abs) are pathogenic antibodies rather than a bystander secondary to myelin destruction. Similarly, immunoglobulin-G against myelin oligodendrocyte glycoprotein (MOG-IgG) is considered a demyelinating disease-associated autoantibody in human beings. In clinical studies, several detection methods, including ELISA, immunoblot, radio immunoprecipitation assays and Cell-based assays (CBAs), have been applied in identifying MOG-Abs in idiopathic inflammatory demyelinating diseases (IIDDs) of human beings. CBAs method is recommended by many proposed diagnostic criterions for MOG-Abs-associated disorders (MOGAD). This method involves transfection of mammalian cells with MOG antigen, binding of MOG-Abs to MOG antigen, binding of secondary antibodies to MOG-Abs and quantification method. However, the reliability for CBAs systems of MOG-Abs detection can be influenced by numerous factors, such as length of MOG antigen, expression vectors, cell lines, secondary antibodies, and read-out systems. In addition, there are controversial results on the studies of IIDDs with MOG-IgG positive. Nowadays, more and more evidence suggests that patients positive for MOG-IgG share common features, but further clinical and laboratory researches are needed to clarify if MOGAD is an independent disease entity. In this review, we intend to summarize the detection methods of MOG-Abs and their sensitivity and specificity to MOGAD in human.

A comparative analysis of demographic, clinical and imaging features of myelin oligodendrocyte glycoprotein antibody positive, aquaporin 4 antibody positive, and double seronegative demyelinating disorders - An Indian tertiary care center prospective study.

The aim of the study was to study the demographical, clinical, radiological features, and outcome of anti-myelin oligodendrocyte glycoprotein (MOG) antibody spectrum disorder and compare these features with patients negative for anti-MOG antibody. MOG antibody-associated disease (MOGAD) and aquaporin-4 (AQP4) antibody-related diseases are immunologically distinct pathologies. Our aim was to compare the clinical and radiological features of MOG antibody-related diseases with AQP4 antibody-related diseases and seronegative demyelinating diseases (Non-multiple sclerosis). This was a prospective and cohort study conducted at an apex tertiary care institute in the northern part of India from Jan 2019 to May 2021. We compared clinical, laboratory, and radiological findings of patients with MOGAD, AQP4 antibody-related diseases, and seronegative demyelinating disease. There were a total of 103 patients - 41 patients of MOGAD, 37 patients of AQP4 antibody-related diseases and 25 seronegative demyelinating disease. Bilateral optic neuritis was the most frequent phenotype in patients with MOGAD (18/41) whereas myelitis was the most common phenotype in the AQP4 (30/37) and seronegative groups (13/25). Cortical, juxtacortical lesions, anterior segment optic neuritis, optic sheath enhancement, and conus involvement in myelitis were radiological findings that separated MOGAD from AQP4 related diseases. Nadir Expanded Disability Status Scale (EDSS) and visual acuity were similar across the groups. Last follow-up EDSS was significantly better in the MOG antibody group as compared to AQP4 antibody group (1 [0-8] vs. 3.5 [0-8]; P = 0.03). Encephalitis, myelitis, and seizures were more common in the younger population (<18 vs. >18 years) in MOGAD (9 vs. 2, P = 0.001; 9 vs. 7, P = 0.03; 6 vs. 0, P = 0.001). We identified several clinical and radiological features that can help physicians to distinguish MOGAD from AQP4-immunoglobulin G+neuromyelitis optica spectrum disorder. Differentiation is vital as treatment response might vary among both groups.

Sentinel seizure heralding Myelin oligodendrocyte glycoprotein (MOG) antibody-associated disease

BackgroundIsolated seizure as a manifestation of myelin oligodendrocyte antibody-associated disease (MOGAD) has rarely been reported previously.Case presentationA 16-year-old-male presented with single episode of left focal onset motor seizure with secondary generalization and impaired awareness, without any other focal neurological deficits. There was a history of right focal onset motor seizure with secondary generalized tonic–clonic seizure and impaired awareness 4 years ago. Neurological examination showed bilateral gaze evoked nystagmus. Brain imaging revealed bilateral superficial and deep white matter lesions including the corpus callosum. Anti-MOG antibody was positive. The patient received steroids and Rituximab therapy without any further recurrence of seizure or any neuro-deficits and gradual improvement in lesion burden in brain imaging.ConclusionsThis case of an adolescent boy with sole manifestation of episodes of focal seizures 4 years apart, finally diagnosed to be a case of MOGAD, not only boosts the evidence of establishing the possibility of MOG antibody-associated autoimmune epilepsy but also reinforces the importance of unexplained seizure as a clinical phenotype in MOGAD.

Two Cases of Juvenile Myelomonocytic Leukemia and Myelin Oligodendrocyte Glycoprotein Antibody-Associated Disease

BackgroundMyelin oligodendrocyte glycoprotein (MOG) antibody-associated disease (MOGAD) is an autoimmune demyelinating disorder that often manifests after infections or vaccinations. We report two patients who developed MOGAD out of eight patients with juvenile myelomonocytic leukemia (JMML) that has never been reported. MethodsWe investigated two patients with JMML who developed MOGAD among 127 patients with leukemia from 2012 to 2021. ResultsPatient 1 was treated for JMML and developed fever and impaired consciousness at two years and one month of age. Magnetic resonance imaging revealed high-intensity lesions in the left frontal and left occipital white matter. The serum anti-MOG antibody test was positive, while the test was negative in the stored serum 45 days before the onset of encephalopathy. He had relapse of MOGAD after steroid therapy and plasmapheresis. Patient 2, who was treated for JMML, became apathetic and mute at three years and seven months of age. Magnetic resonance imaging revealed left frontoparietal subcortical high-intensity lesions. Anti-MOG antibody at the onset of encephalopathy was positive, while it was negative in stored serum 57 days before and 47 days after the onset. ConclusionWe treated two patients who developed MOGAD out of eight patients with JMML and none with MOGAD out of 119 patients with acute lymphocytic leukemia, acute myelocytic leukemia, or chronic myelocytic leukemia. The activated autoimmune process via the RAS pathway abnormality may have led to the formation of the anti-MOG antibody and the onset of MOGAD. MOGAD can occur in children with JMML, and abnormalities of the RAS pathway possibly contribute to its onset.

Anti-MOG Antibody-Associated Unilateral Cortical Encephalitis with Bilateral Meningeal Involvement: A Case Report

A 27-year-old Han Chinese woman presented with fever, headache, lethargy, and difficulty in expression. Magnetic resonance imaging (MRI) detected extensive hyperintensity of the left-sided frontoparietal, temporal, occipital, and insular cortices via fluid-attenuated inversion recovery (FLAIR) imaging. Post-contrast MRI revealed linear enhancement in the frontoparietal, temporal, and occipital sulci bilaterally. The detection of anti-myelin oligodendrocyte glycoprotein (MOG) was positive in the cerebrospinal fluid (CSF) and serum. The patient was diagnosed with anti-MOG antibody-associated unilateral cortical encephalitis with bilateral meningeal involvement. The patient received low doses of intravenous dexamethasone followed by oral prednisone, which was tapered until withdrawal. The treatment significantly improved the patient's symptoms. A one-month follow-up showed that the patient gradually resumed her normal lifestyle. No further relapse was recorded after a one-year follow-up. MRI performed almost a year after the initial symptom onset showed that the FLAIR signal had decreased in the left insular lobe, and the abnormal cortical signal of the FLAIR in the original left frontotemporal occipital lobe had disappeared. Thus, we report a rare case of anti-MOG antibody encephalitis (unilateral cortical encephalitis with bilateral meningeal involvement) in an adult patient. This study provides a reference for the clinical diagnosis and treatment of MOG antibody-associated unilateral cortical encephalitis.

Complement-dependent cytotoxicity of human autoantibodies against myelin oligodendrocyte glycoprotein.

The autoantibody to myelin oligodendrocyte glycoprotein (MOG), a component of the central nervous system myelin, has been identified in a subset of demyelinating diseases. However, there is no convincing evidence to support the direct pathogenic contribution of this autoantibody. To elucidate the role of anti-MOG autoantibodies in human demyelinating disorders, we assessed the effect of autoantibodies on MOG-expressing cells. Mammalian cells expressing the human MOG protein reacted with human anti-MOG autoantibodies in the presence or absence of complement. Sera from 86 patients and 11 healthy sera were used. We analyzed anti-MOG antibody titers, IgG subclass, and their cytotoxic ability in sera from patients with various neurological diseases. Membrane attack complex (MAC) formation was examined by detection of complement C9 or C9neo with western blot or flow cytometry. Among 86 patients, 40 were determined to be MOG-IgG-positive and 46 were negative. Anti-MOG-positive sera, but not -negative sera, caused cell death in MOG-expressing cells. This cytotoxic effect was disappeared after heat inactivation of sera. Importantly, anti-MOG IgG and externally added complement were necessary for sufficient cytotoxic effects. Anti-MOG autoantibodies were histologically colocalized with complement and formed a membrane attack complex consisting of anti-MOG IgG and complement factors. The human MOG antibody specifically killed MOG-expressing cells in vitro in the presence of externally added complement. Membrane attack complexes were formed on the cells, indicating that this autoantibody activated complement-mediated cytotoxicity. Further studies in larger numbers of patients are needed to characterize the role of complement in MOGAD.

Myelin oligodendrocyte glycoprotein antibody-associated disease in children: Are there MRI predictors of relapse?

Background and PurposeMyelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) is increasingly recognized in children. Some children have isolated disease while others relapse. The study evaluates clinical, demographic and imaging features children with positive anti-MOG antibodies comparing to previously reported findings and correlate patterns on MR imaging with a relapsing course in MOGAD. Material and methodsAll pediatrics patients with serum anti-MOG antibodies were reviewed. Demographic, clinical, and imaging data were evaluated. Patients with a relapsing course were compared to those with a single event. We assessed initial MR images of the brain, orbits and spine obtained at the onset of clinical symptoms, whether performed at our institution or elsewhere. ResultsThirty patients were included, fourteen with a single event and sixteen with more than one clinical event. The mean age was 8.1 years, with a mean follow-up of 58 months (range of 0.67 to 238 months). The relapsing patients had a mean of 3.5 relapses (range 2–12). 55% of patients had long segment optic nerve lesions, 53% of patients had cortical or peripheral white matter lesions, and 46% of patients had thalamic lesions. 43% of patients had spinal cord lesions, with 39% involving the central cord and 26% with long segment involvement. The imaging features between the groups were not statistically significant. ConclusionThere were no distinguishing features in relapsing versus non-relapsing patients. In the absence of any predictive characteristics for future relapse, patients should have regular clinical and imaging follow up.

Myelin Basic Protein in Oligodendrocyte-Derived Extracellular Vesicles as a Diagnostic and Prognostic Biomarker in Multiple Sclerosis: A Pilot Study.

Approximately 15% of multiple sclerosis (MS) patients develop a progressive form of disease from onset; this condition (primary progressive-PP) MS is difficult to diagnose and treat, and is associated with a poor prognosis. Extracellular vesicles (EVs) of brain origin isolated from blood and their protein cargoes could function as a biomarker of pathological conditions. We verified whether MBP and MOG content in oligodendrocytes-derived EVs (ODEVs) could be biomarkers of MS and could help in the differential diagnosis of clinical MS phenotypes. A total of 136 individuals (7 clinically isolated syndrome (CIS), 18 PPMS, 49 relapsing remitting (RRMS)) and 70 matched healthy controls (HC) were enrolled. ODEVs were enriched from serum by immune-capture with anti-MOG antibody; MBP and MOG protein cargoes were measured by ELISA. MBP concentration in ODEVs was significantly increased in CIS (p &lt; 0.001), RRMS (p &lt; 0.001) and PPMS (p &lt; 0.001) compared to HC and was correlated with disease severity measured by EDSS and MSSS. Notably, MBP concentration in ODEVs was also significantly augmented in PPMS compared to RRMS (p = 0.004) and CIS (p = 0.03). Logistic regression and ROC analyses confirmed these results. A minimally invasive blood test measuring the concentration of MBP in ODEVs is a promising tool that could facilitate MS diagnosis.

Absence of cortical lesions after the first seizure in a patient with anti-myelin oligodendrocyte glycoprotein-associated cortical encephalitis

A 31-year-old man developed headache and generalized convulsions. At the time of the first seizure, there was no distinct MRI abnormality. He was admitted to the hospital with repeated seizures, left-sided hemiparesis, and left-sided neglect. He had a slight fever, elevated cerebrospinal fluid (CSF) pressure, and increased CSF cell count with predominance of mononuclear cells. A repeat MRI scan on day 8 after the recurrent seizure showed cortical edema in the right cerebral hemisphere on fluid-attenuated inversion recovery (FLAIR), abnormal high signal on DWI, and decreased apparent diffusion coefficient. The patient was diagnosed with aseptic meningoencephalitis and treated with antiviral drugs and methylprednisolone pulse therapy. Serum anti-myelin oligodendrocyte glycoprotein (MOG) antibody was subsequently detected, and prednisolone was added to treat the FLAIR-hyperintense lesions in anti-MOG antibody associated encephalitis with seizures (FLAMES). It is important to identify the clinical picture and typical images of FLAMES to allow early treatment.

Relevance of bright spotty lesions in neuromyelitis optica spectrum disorders (NMOSD): a case series

BackgroundNeuromyelitis optica (NMO), or neuromyelitis optica spectrum disorder (NMOSD), is an autoimmune CNS condition which often has a complex clinical course. Longitudinally extensive transverse myelitis (LETM) is an important and sensitive MRI finding but is not very specific to NMOSD and is seen in other causes of myelitis.Case presentationsWe report 11 NMO cases, all seen in women from 25 to 75 years at the time of diagnosis, with most above 65 years of age. All patients were seropositive for AQP4–IgG antibodies, and none had anti-MOG antibodies. Clinical presentations were diverse, the most common being paralytic and visual changes. In this study, 5 of the 11 seropositive NMO patients (45%) had bright spotty lesion (BSLs) on their MRI spine, as opposed to none (0%) in the control group. BSLs were defined as hyperintense foci of signal abnormality on T2-weighted images compared to the surrounding CSF. Treatment included symptomatic management and immunotherapy; timely management led to improvement in all the cases, with partial recovery seen in most (91%) and complete recovery seen only in one.ConclusionsBSLs are a newly defined spinal MRI finding with high specificity, but low sensitivity for NMOSD. The absence of BSLs in the control group establishes its prolific role in distinguishing NMO from MS, ITM, MOGAD and other forms of myelitis. The main aim of this retrospective case–control study was to determine the diagnostic importance and specificity of bright spotty lesions (BSLs) in NMOSD and its ability to discriminate NMOSD from other causes of LETM.

Anti-myelin Oligodendrocyte Glycoprotein Antibody-Associated Disorder (MOGAD) in a Pediatric Patient with Rare Presentation of a Cerebellar Tumefactive Lesion

Objective NA. Background Anti-myelin oligodendrocyte glycoprotein (MOG) antibodies have been commonly associated with optic neuritis, myelitis, and acute disseminated encephalomyelitis but rarely with tumefactive lesions, especially in children. We report a young child with MOGAD presenting with a tumefactive cerebellar demyelinating lesion. Design/Methods A retrospective chart review Results A 3-year-old developmentally appropriate boy with fever for five days prior presented for gait changes and a self-resolved seizure lasting less than 5 minutes. Neurologic examination showed abnormal finger to nose on the left side, weakness of the left lower extremity and an ataxic gait. The differential at the time was Todd's paralysis versus an intracranial process. MRI showed a non-enhancing, ill-defined T2 hyperintense tumefactive lesion with mass effect within the left cerebellum concerning for tumor, abscess, or demyelination. On EEG, a lack of a well sustained and modulated posterior dominant rhythm and lack of a well-developed anterior to posterior gradient, with moderate background slowing was seen. Cerebrospinal fluid showed 8 white blood cells, 0 red blood cells, 55 mg/dl glucose, 31 mg/dl protein, 0.61 IgG index, and 0 oligoclonal bands. The Mayo Clinic cell-based assay detected anti-MOG IgG antibody in the serum with titer of 1:100. Neurological symptoms gradually improved after steroid pulse therapy. Conclusions This report highlights the novel spectrum of radiologic manifestations associated with MOGAD in pediatric patients and MOGAD should always be considered in the differential diagnosis of tumefactive lesions.

Anti-NMDA receptor encephalitis and MOG-associated demyelination – a case report with long-term follow-up and a systematic review

BackgroundOverlap syndromes of anti-NMDA receptor encephalitis and MOG-mediated demyelination have been reported. In this case we provide a long-term longitudinal follow-up of clinical and imaging characteristics as well as of antibody dynamics.Case presentationWe report a 32-year-old male patient who presented with psychosis, decreased consciousness and movement disorders and was tested positive for anti-NMDA receptor antibodies. Forty-four months after symptom onset and diagnosis of autoimmune encephalitis, he suffered from relapse. At this time, the patient developed anti-MOG and anti-Caspr2 antibodies. Treatment with plasmapheresis, steroids and rituximab eventually led to substantial clinical and radiological improvement. Anti-Caspr2 antibodies persisted, anti-NMDA receptor antibodies decreased, while anti-MOG antibodies turned negative again.ConclusionWe provide long-term longitudinal follow-up of a patient with anti-NMDA receptor encephalitis who developed triple antibody positivity at the time of relapse. Antibody dynamics were associated with clinical disease course.

Childhood Small-Vessel Primary Angiitis of the Central Nervous System: Overlap With MOG-Associated Disease.

Childhood (c) primary angiitis of the central nervous system (PACNS) is a rare condition that most often affects small vessels (SV), is nearly exclusively lymphocytic, and devoid of vessel necrosis. Diagnosis of cSV-PACNS is challenging. We noted possible histological overlap of cSV-PACNS with myelin oligodendrocyte glycoprotein disease (MOGAD) on biopsy, prompting a 10-year retrospective review of our experience. Database-search for brain biopsy cases, age <18 years, performed for an acquired neurological deficit with suspicion of vasculitis, with histological evidence of lymphocytic small-vessel inflammation. We identified 7 patients; 2/7 were serum-positive for anti-MOG antibodies and 1/7 for anti-NMDA antibodies. The remaining 4/7 proved to be idiopathic lymphocytic vasculitis/cSV-PACNS. All 7 showed overlapping features of lymphocytes permeating parenchymal SV walls, vessel wall distortion without fibrinoid necrosis, and absence of microglial clusters or intravascular thrombi. Tissue infarction was confined to a single case of idiopathic lymphocytic vasculitis. Although demyelination was diligently sought, only subtle demyelination was identified in the 2 MOGAD cases and absent in the remainder. There is considerable histological overlap between cSV-PACNS and at least some cases of MOGAD or anti-NMDA-encephalitis; at diagnosis, the differential should include cSV-PACNS but correct classification requires post-biopsy serological testing.

Transverse myelitis following COVID-19: Insights from a multi-center study and systematic literature review

IntroductionWe aimed to provide insights into transverse myelitis (TM) following COVID-19 by analyzing cases treated at tertiary care neurology centers and a systemic review of the literature. MethodsThe retrospective observational multi-center study was conducted at the four university neurology departments in Croatia, Slovenia, Serbia, and Austria. We searched for acute myelitis cases that occurred during or after COVID-19. A systemic review of the literature on COVID-19 and transverse myelitis was performed. ResultsWe identified 76 persons with TM associated with COVID-19, 13 from the multi-center study and 63 from the literature review. Most of the participants (55.6%) had an intermediate latency, 25.4% had short and 19% long latency from COVID-19 symptoms to TM. The clinical presentation consisted of the typical TM signs. More than half of the participants had inflammatory changes in the CSF, with rare patients having intrathecal OCB synthesis and positive serology for anti-MOG or anti-AQP4 antibodies. Persons with autonomic symptoms and CSF pleocytosis were significantly more common to have an intermediate latency of 8 to 21 days from COVID-19 to TM (p = 0.005 and p = 0.003; respectively). According to logistic regression analysis, only participants with lesions evident on spinal cord MRI compared to normal spinal cord MRI had reduced risks for poor recovery. >80% of participants were treated with a combination of corticosteroids and intravenous immunoglobulins or plasma exchange with 73% having incomplete recovery. ConclusionOur study further characterizes clinical, laboratory, and MRI features, as well as treatment of TM associated with COVID-19.

66 Optic neuritis in children

IntroductionOptic neuritis (ON) are rare in children. They are due to inflammation of the optic nerve which results in a sudden drop in visual acuity, or amputation of the visual field. They are often secondary to an infectious disease or vaccination, but they can be part of auto-inflammatory, demyelinating or systemic diseases. The features of optic neuritis in children are different from adults as regards high rate of bilateral involvement, poor visual acuity, and papillitis.AimOur aim is to describe the clinical and therapeutic outcomes of patients diagnosed with optic neuritis in the general pediatrics department at the CHU of Bab el Oued in Algiers.MethodsIt is a retrospective, descriptive study of patients who were treated for optic neuritis in our hospital over a period of three years (January 2018 to April 2021).ResultsThere were 7 cases, 4 girls and 3 boys with F: M of 1.3:1, mean age of 10 years and age range of 6–13 years. The first manifestation was a decrease in visual acuity in all cases, 12 eyes affected, with bilateral involvement in 5 patients. Visual acuity decrease was severe < 3/10 in 80% of cases. The visual field was pathological in 2 cases (narrow, central scotoma). All patients had headaches.Retrobulbar involvement was confirmed by visual evoked potentials in all patients, they showed demyelinating involvement. Three patients presented papillitis.The diagnostic work-up included cerebral imaging which showed old nodular abnormalities of signal of the subcortical white matter in one patient.CSF analysis revealed anti-MOG antibodies in only one case. The infection investigations were negative in all cases except positive COVID 19 serology in one caseThe diagnosis retained in our patients were 2 cases of Behcet's disease, 1 monophasic neuritis, 1 optic neuritis with anti-MOG, 1 CRION, 1 case linked to COVID 19 in the absence of another plausible cause. In one case, no diagnosis was retained.Seventy percent of the patients benefited from treatment with corticosteroids pulse, only 2 did not receive treatment, the short-term evolution was favorable in 5 patients with a total recovery of visual acuity, one patient has evolved into atrophy of the left optic nerve and kept visual acuity low to 1/10 of the left eye.The medium-term evolution was marked by recurrence in 3 patients, 5 episodes in the 2 patients with Behcet's disease and 8 episodes in CRION which required the use of immunosuppressive treatment and biotherapy for Behcet's disease and plasmapheresis for CRION.ConclusionDespite the fact that our small series of patients is not representative, we found similar characteristics described in children in other studies. The average onset age was 10 years, with a female predominance, the severe decrease in visual acuity with frequent bilateral involvement. The diagnosis of ON is clinical and must be considered in any sudden drop in visual acuity. The diagnosis of the underlying pathology is often difficult but it’s important in order to propose an adequate specific treatment. The treatment of children's ON is controversial and usually extrapolated from adults. Most practitioners use corticosteroids pulse. The visual prognosis seems good in children, particularly in the case of bilateral involvement, but depends essentially on the aetiology.

Encephalitis with Extensive Cortical Brain Magnetic Resonance Imaging Changes Secondary to Myelin Oligodendrocyte Glycoprotein Antibody Disease

Patient: Male, 17-month-old Final Diagnosis: Fluid attenuated inversion recovery (FLAIR) imaging showing cortical hyperintense lesions in myelin-oligodendrocyte-glycoprotein (MOG) associated encephalitis with seizures (FLAMES Symptoms: Encephalopathy • fever • left sided weakness • seizures Medication: — Clinical Procedure: Plasmapharesis Specialty: Neurology Objective: Rare disease Background:The relatively new autoimmune disorder, anti-myelin oligodendrocyte glycoprotein (MOG) disease is particularly interesting because of its broad range of presentations. This entity’s appearance on magnetic resonance imaging (MRI) of the brain often makes identifying this disease a challenging process. Younger patients tend to present with an acute disseminated encephalomyelitis picture, with encephalopathy and multifocal neurological signs, while older patients are more likely to present with optic neuritis. We, however, report an atypical case of a patient who presented with encephalopathy, seizures, and significant cortical and subcortical gray matter involvement and was found to have anti-MOG positivity in serum.Case Report:A 17-month-old previously healthy boy presented to Emergency Department with fever, lethargy, vomiting, and left-sided weakness. Eventually, he required intubation due to a prolonged seizure. Continuous electroencephalogram captured several focal seizures, and MRI of the brain showed cortical and subcortical T2 hyperintensities. After extensive laboratory evaluation, he tested positive for anti-MOG antibody. He was empirically started on high-dose intravenous pulse methylprednisolone, followed by plasma exchange, given the poor response to the intravenous steroids. At the 5-month follow-up, the results of the neurological examination had dramatically improved, and MRI findings had largely resolved.Conclusions:This case highlights the importance of suspecting anti-MOG antibody-mediated encephalitis, even while ruling out infectious etiologies, in children presenting with encephalopathy, seizures and MRI abnormalities. Prompt recognition would allow for less delay in treatment and hopefully improve prognosis.

Late onset neuromyelitis optica spectrum disorders (LONMOSD) from a nationwide Portuguese study: Anti-AQP4 positive, anti-MOG positive and seronegative subgroups

IntroductionSeveral neuroimmunological disorders have distinct phenotypes according to the age of onset, as in multiple sclerosis or myasthenia gravis. It is also described that late onset NMOSD (LONMOSD) has a different phenotype. ObjectiveTo describe the clinical/demographic characteristics of the LONMOSD and distinguish them from those with early onset (EONMOSD). MethodsFrom a nationwide Portuguese NMOSD study we analyzed the clinical/demographic characteristics of the LONMOSD. ResultsFrom the 180 Portuguese patients 45 had disease onset after 50 years old, 80% were female. 23 had anti-AQP4 antibodies (51.1%), 13 anti-MOG antibodies (28.9%) and 9 were double seronegative (20.0%). The most common presenting phenotypes in LONMOSD were transverse myelitis (53.3%) and optic neuritis (26.7%), without difference from EONMOSD (p = 0.074). The mean EDSS for LONMOSD was 6.0 (SD=2.8), after a mean follow-up time of 4.58 (SD=4.47) years, which was significantly greater than the mean EDSS of EONMOSD (3.25, SD=1.80)(p = 0.022). Anti-AQP4 antibodies positive LONMOSD patients had increased disability compared to anti-MOG antibodies positive LONMOSD (p = 0.022). The survival analysis showed a reduced time to use a cane for LONMOSD, irrespective of serostatus (p<0.001). ConclusionsLONMOSD has increased disability and faster progression, despite no differences in the presenting clinical phenotype were seen in our cohort.