A Genetic Disposition for Autoimmune Encephalitis: Searching for Human Leukocyte Antigen (HLA) Complex Subtypes

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.

Pediatric anti-NMDA-receptor autoimmune encephalitis in siblings: Developmental, Electrophysiologic, and Genetic Implications

BACKGROUND

Anti-NMDAR encephalitis is a leading cause of autoimmune encephalitis in children. Untreated disease can lead to long-term neurological disability.

CASE REPORT

We present siblings with pediatric-onset anti-NMDAR encephalitis. One was treated early, while the other's diagnosis and treatment were delayed by several years. Developmental, electrophysiologic, and genetic implications are discussed.

CONCLUSION

Anti-NMDAR encephalitis is a severely debilitating disease that often requires prompt initiation and early escalation in treatment. Delayed treatment may lead to irreversible neurological sequalae. Further studies exploring associations between timing and tier of treatment initiation and longitudinal outcomes are needed.

Rapidly progressive cognitive decline associated with teprotumumab in thyroid eye disease

Teprotumumab (Tepezza), an insulin-like growth factor type 1 receptor antagonist, was approved for treatment of thyroid eye disease in 2020. Teprotumumab is administered intravenously every 3 weeks for a total of eight doses. Common side effects include nausea, diarrhoea, muscle spasms, hearing impairment, dysgeusia, headaches, dry skin, infusion reactions and hyperglycaemia. We report here a 76-year-old man with Graves-related thyroid eye disease who developed a rapidly progressive cognitive decline after receiving four out of eight doses of teprotumumab (cumulative dose 4620 mg). He was admitted for workup and teprotumumab infusions were discontinued. Intravenous glucocorticoids and immunoglobulin were given which showed no improvement in clinical symptoms. He subsequently underwent plasmapheresis with resolution of his symptoms, suggesting a teprotumumab-induced encephalopathy. Further studies involving larger populations and longer durations are needed.