Brazilian autoimmune encephalitis network (BrAIN): antibody profile and clinical characteristics from a multicenter study.

Background: The frequency of antibodies in autoimmune encephalitis (AIE) may vary in different populations, however, data from developing countries are lacking. To describe the clinical profile of AIE in Brazil, and to evaluate seasonality and predictors of AIE in adult and pediatric patients. Methods: We evaluated patients with possible AIE from 17 centers of the Brazilian Autoimmune Encephalitis Network (BrAIN) between 2018 and 2022. CSF and serum were tested with TBAs and CBAs. Data on clinical presentation, complementary investigation, and treatment were compiled. Seasonality and predictors of AIE in adult and pediatric populations were analyzed. Results: Of the 564 patients, 145 (25.7%) were confirmed as seropositive, 69 (12.23%) were seronegative according to Graus, and 58% received immunotherapy. The median delay to diagnosis confirmation was 5.97 ± 10.3 months. No seasonality variation was observed after 55 months of enrolment. The following antibodies were found: anti-NMDAR (n=79, 54%), anti-MOG (n=14, 9%), anti-LGI1(n=12, 8%), anti-GAD (n=11, 7%), anti-GlyR (n=7, 4%), anti-Caspr2 (n=6, 4%), anti-AMPAR (n=4, 2%), anti-GABA-BR (n=4, 2%), anti-GABA-AR (n=2, 1%), anti-IgLON5 (n=1, 1%), and others (n=5, 3%). Predictors of seropositive AIE in the pediatric population (n=42) were decreased level of consciousness (p=0.04), and chorea (p=0.002). Among adults (n=103), predictors of seropositive AIE were movement disorders (p=0.0001), seizures (p=0.0001), autonomic instability (p=0.026), and memory impairment (p=0.001). Conclusion: Most common antibodies in Brazilian patients are anti-NMDAR, followed by anti-MOG and anti-LGI1. Only 26% of the possible AIE patients harbor antibodies, and 12% were seronegative AIE. Patients had a 6-month delay in diagnosis and no seasonality was found. Findings highlight the barriers to treating AIE in developing countries and indicate an opportunity for cost-effect analysis. In this scenario, some clinical manifestations help predict seropositive AIE such as decreased level of consciousness, chorea, and dystonia among children, and movement disorders and memory impairment among adults.

Clinical Features of COVID-19 on Patients With Neuromyelitis Optica Spectrum Disorders.

BACKGROUND AND OBJECTIVES: To describe the clinical features and disease outcomes of coronavirus disease 2019 (COVID-19) in patients with neuromyelitis optica spectrum disorder (NMOSD). METHODS: The Neuroimmunology Brazilian Study Group has set up the report of severe acute respiratory syndrome (SARS-CoV2) cases in patients with NMOSD (pwNMOSD) using a designed web-based case report form. All neuroimmunology outpatient centers and individual neurologists were invited to register their patients across the country. Data collected between March 19 and July 25, 2020, were uploaded at the REDONE.br platform. Inclusion criteria were as follows: (1) NMOSD diagnosis according to the 2015 International Panel Criteria and (2) confirmed SARS-CoV2 infection (reverse transcription-polymerase chain reaction or serology) or clinical suspicion of COVID-19, diagnosed according to Center for Disease Control / Council of State and Territorial Epidemiologists (CDC/CSTE) case definition. Demographic and NMOSD-related clinical data, comorbidities, disease-modifying therapy (DMT), COVID-19 clinical features, and severity were described. RESULTS: Among the 2,061 pwNMOSD followed up by Brazilian neurologists involved on the registry of COVID-19 in pwNMOSD at the REDONE.br platform, 34 patients (29 women) aged 37 years (range 8-77), with disease onset at 31 years (range 4-69) and disease duration of 6 years (range 0.2-20.5), developed COVID-19 (18 confirmed and 16 probable cases). Most patients exhibited mild disease, being treated at home (77%); 4 patients required admission at intensive care units (severe cases); and 1 patient died. Five of 34 (15%) presented neurologic manifestations (relapse or pseudoexacerbation) during or after SARS-CoV2 infection. DISCUSSION: Most NMOSD patients with COVID-19 presented mild disease forms. However, pwNMOSD had much higher odds of hospitalization and intensive care unit admission comparing with the general Brazilian population. The frequency of death was not clearly different. NMOSD disability, DMT type, and comorbidities were not associated with COVID-19 outcome. SARS-CoV2 infection was demonstrated as a risk factor for NMOSD relapses. Collaborative studies using shared NMOSD data are needed to suitably define factors related to COVID-19 severity and neurologic manifestations.

Anti-GAD Antibody-associated Syndrome Presenting with Limb Myoclonus.

Background: The clinical spectrum of anti-glutamic acid decarboxylase (GAD) antibody-associated neurologic syndromes is expanding, with focal, generalized, and atypical forms. Case Report: We describe a 59-year-old female showing continuous right lower limb myoclonus and mild encephalopathy. These symptoms started 2 weeks prior to evaluation. The patient had great improvement with intravenous steroids. An autoantibody panel was positive for anti-GAD. Discussion: Various clinical manifestations, including myoclonus, may relate to anti-GAD antibodies. The treatment options available include symptomatic drugs, intravenous immunoglobulin, steroids, and other immunosuppressant agents.