antithymocyte globulin + cyclosporine

Antithymocyte globulin (ATG) + cyclosporine is an immunosuppressive combination therapy primarily used for treating severe aplastic anemia. This combination works through complementary mechanisms to suppress T-cell mediated immune destruction of bone marrow. ATG is a polyclonal immunoglobulin G fraction purified from sera of rabbits or horses previously immunized with human lymphocytes, which causes immediate immune cell depletion, particularly T lymphocytes, through multiple mechanisms including antibody-dependent cell cytotoxicity, complement-dependent cell cytotoxicity, opsonization, and activation-induced cell death. Cyclosporine prevents T-lymphocytes from becoming active, blocking their function and stopping them from attacking stem cells in the bone marrow. When used together, these medications allow bone marrow stem cells to grow back and start making blood cells again in patients with aplastic anemia.