HLA genotyping and clinical characteristics of early-onset and late-onset anti-LGI1 encephalitis: a single-center cohort study in China.

Objectives: To investigate the human leukocyte antigen (HLA) associations and clinical characteristics of anti-Leucine-rich glioma-inactivated 1 (LGI1) encephalitis in a Chinese cohort, focusing on potential differences between early-onset and late-onset patients. Methods: Eighty patients diagnosed with anti-LGI1 encephalitis at Peking Union Medical College Hospital between the years 2016 and 2024 were included. Patients were stratified into early-onset (<50 years, n=22) and late-onset (≥50 years, n=58) groups for clinical features analysis. High-resolution NGS HLA genotyping was performed and compared with 984 healthy controls. Logistic and linear regressions were used to analyze disease susceptibility, age of onset associations, and prognostic factors. Results: Compared with the late-onset group, the early-onset group more frequently presented with generalized tonic-clonic seizures (GTCS) as the initial symptom (45.5% Conclusions: This study suggests that early-onset and late-onset anti-LGI1 encephalitis may possess differential immunogenetic and clinical profiles. In addition to the broad susceptibility conferred by DRB1*07:01, the presence of A*02:01 is significantly associated with an earlier onset age. These findings provide insights into the role of HLA genotyping in accounting for the observed differences between early-onset and late-onset patients.