Unrelated bone marrow transplantation in two severe aplastic anemia patients preconditioned with a regimen of cyclophosphamide, antithymocyte globulin, and total body irradiation]

We report our experiences with HLA-matched unrelated bonemarrow transplantation combining a preconditioning regimen of cyclophosphamide, antithymocyte globulin (ATG), and total body irradiation for two patients with severe aplastic anemia (SAA) who had already undergone repeated blood transfusions. Short-term methotrexate and cyclosporine were administered for graft-versus-host disease (GVHD) prophylaxis. Both patients achieved rapid engraftment within 3 weeks, furthermore, neither acute nor chronic GVHD developed. Our conditioning regimen appeared to be well-suited for unrelated bone marrow transplantation in heavily transfused SAA patients. However, both patients experienced bouts of fever about 20-30 and 40-50 days after transplantation, and it was difficult to differentiate whether they were affected by acute GVHD, cytomegalovirus (CMV) infections, or serum sickness. Because weakly positive CMV antigenemia was detected, both patients were given ganciclovir. Although their fever did not respond initially, it gradually subsided following the combined administration of prednisolone. These outcomes suggest it is essential that attention be devoted to the potential for serum sickness and the high risk of herpes virus infections, particularly by CMV, following the use of intensive preconditioning regimens that include ATG.