Abstract
INTRODUCTION: Sepsis, a life-threatening dysregulated immune response to infection, has a high global mortality rate. Tregs play dual roles in sepsis pathogenesis, with their expansion linked to immunosuppression. This study explores Treg dynamics and the novel role of CD82 in sepsis. METHODS: Peripheral blood from sepsis patients was analyzed using scRNA-seq. Machine learning (SVM, LASSO, random forest) integrated scRNA-seq data with three GEO datasets (n=380) to identify biomarkers. CD82 expression in Tregs was validated via flow cytometry and RT-qPCR in CLP mouse model. Anti-CD25 antibody depleted Tregs in mice. RESULTS: The scRNA-seq revealed neutrophil expansion and T/NK cell reduction in sepsis. Tregs were enriched and exhibited CD82 upregulation. A seven-gene diagnostic signature (CD82, CD52, EVI2B, IL32, RCAN3, AQP3, NAP1L1) achieved high accuracy (AUCs up to 99.9%). Treg-depleted CLP mice showed reduced CD82 expression, elevated IL-6 and neutrophils, and worsened inflammation, implicating CD82 in immune modulation. DISCUSSION: CD82 may mediate Treg hyperactivation during sepsis, balancing the immune response and suppression. The gene signature shows diagnostic potential, but CD82's mechanistic role needs further investigation. Therapeutic targeting of CD82 could improve sepsis management.