Abstract

In severe acquired aplastic anemia, hematopoietic failure is the result of immune-mediated destruction of bone marrow stem and progenitor cells. Immunosuppressive therapy with antithymocyte globulin (ATG) plus cyclosporine is an effective alternative to stem-cell transplantation and improves blood counts and survival. Although horse ATG is the standard therapy, rabbit ATG is more potent in depleting peripheral-blood lymphocytes and is preferred in other clinical circumstances.