Definitive and potentially curative therapy with haematopoietic stem cell transplantation However, only a minority (30 %) of patients have a suitable donor. Immunosuppressive therapy with horse or rabbit antithymocyte globulin plus cyclosporine is the most commonly used alternative treatment in about two thirds of cases. Response is associated with a favorable long-term outlook. 30 -40% of patients are refractory to immunosuppressive therapy and remain pancytopenic after therapy. Even patients that respond to immunosuppressive therapies with an improvement in their life-threatening neutropenia sometimes have persistent thrombocytopenia .