ATG + tacrolimus + methotrexate

ATG + tacrolimus + methotrexate is a combination immunosuppressive regimen used primarily for the prevention of graft-versus-host disease (GVHD) in patients undergoing allogeneic hematopoietic stem cell transplantation (HSCT). - **Antithymocyte globulin (ATG)** is a polyclonal antibody preparation that targets human T lymphocytes, leading to their depletion and broad immunosuppression. - **Tacrolimus** is a calcineurin inhibitor that suppresses T-cell activation by inhibiting interleukin-2 transcription, thereby reducing immune responses. - **Methotrexate** is an antimetabolite and folate antagonist that inhibits DNA synthesis and has cytotoxic effects on rapidly dividing cells, including activated T cells involved in GVHD. This triple-drug regimen aims to reduce the incidence and severity of both acute and chronic GVHD by targeting multiple pathways in the immune response. The combination is particularly considered for patients at higher risk of GVHD or when using unrelated or mismatched donors[3][6].