Current Status of Treg Therapy in Transplantation and Autoimmune Disease.

Regulatory T cells (Tregs) represent a critical subset of T lymphocytes essential for maintaining immune homeostasis. Through diverse molecular mechanisms, Tregs exert potent immunosuppressive effects that preserve self-tolerance and mitigate aberrant immune activation. Dysregulation in Treg frequency or function is closely associated with the development of various immune-mediated disorders. This has prompted extensive preclinical investigations and clinical trials evaluating the therapeutic potential of Tregs in conditions such as graft-versus-host disease, solid organ transplantation, and autoimmune diseases, which have yielded promising outcomes. This review provides a comprehensive overview of current preclinical and clinical applications of Treg-based therapies, including adoptive Treg transfer, low-dose IL-2, and CAR-Treg therapy, and discusses their effectiveness in modulating immune responses across diverse pathological contexts.