Abstract
BACKGROUND/AIM: Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis, though rare, is the most common form of autoimmune encephalitis, predominantly affecting young individuals, particularly females. Standard treatments include corticosteroids, intravenous immunoglobulins (IVIG), and plasmapheresis, with rituximab recommended for those unresponsive to first-line therapies. However, reliable biomarkers for clinical assessment remain elusive. This study investigated the efficacy of adjunctive hydrogen therapy in a patient with anti-NMDAR encephalitis. CASE REPORT: This case report describes a 14-year-old boy with anti-NMDAR encephalitis who exhibited poor response to initial treatment, but showed significant improvement with rituximab and adjunctive hydrogen therapy. Immunophenotyping revealed correlations between treatment outcomes and shifts in B cell subsets, PD-1+ cytotoxic T cells, and regulatory T cell subtypes. CONCLUSION: This case underscores the importance of integration traditional clinical assessments with advanced diagnostics such as flow cytometry-based immunophenotyping, and suggests a potential role for hydrogen therapy in modulating immune response in this complex autoimmune condition.