Thymosin Alpha 1 and IgM Levels in Sepsis

This prospective, single-arm study will evaluate whether thymosin alpha 1 treatment affects serum immunoglobulin M (IgM) levels in adults with sepsis. Participants will receive standard care plus thymosin alpha 1 1.6 mg by subcutaneous injection every 12 hours for 5 days. Blood samples will be collected before treatment and on days 1, 3, 5, and 7 to measure IgM and plasma microvesicles. The study aims to clarify whether thymosin alpha 1 may support early immune responses in sepsis.

Inclusion Criteria: 1. Adults aged 18 to 85 years. 2. Admitted to the Department of Critical Care Medicine, Zhongda Hospital Southeast University, with sepsis diagnosed according to the Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3.0): confirmed or highly suspected infection with an acute increase in Sequential Organ Failure Assessment (SOFA) score of at least 2 points from baseline. 3. Written informed consent provided by the participant or legally authorized representative. Exclusion Criteria: 1. Previous solid organ or bone marrow transplantation. 2. Active connective tissue disease (for example, rheumatoid disease or systemic lupus erythematosus) or glomerulonephritis. 3. Pregnancy or lactation. 4. Current malignancy. 5. Treatment within the past 30 days with immunosuppressive drugs (for example, tripterygium wilfordii, mycophenolate mofetil, cyclophosphamide, or tacrolimus) or continuous treatment with more than 10 mg/day prednisolone or an equivalent dose of another corticosteroid. 6. Use of thymosin drugs within the past 30 days or participation in another clinical study of a drug or device affecting immunity (for example, Xuebijing, ulinastatin, or continuous renal replacement therapy). 7. History of allergy or intolerance to thymalfasin. 8. Expected survival of less than 72 hours or a decision to receive restricted life-support treatment (comfort care only). 9. Current or previous B-cell lymphoma, multiple myeloma, or leukemia.