Long-term survival after marrow transplantation for paroxysmal nocturnal hemoglobinuria with aplastic anemia.

Four patients with paroxysmal nocturnal hemoglobinuria and severe marrow aplasia were given marrow grafts either from allogeneic human-leukocyte-antigen-identical siblings (three patients) or from a syngeneic donor (one patient). The patients with allogeneic grafts were conditioned with regimens that included cyclophosphamide and had sustained and complete marrow engraftment; subsequent tests were negative for paroxysmal nocturnal hemoglobinuria. One patient developed chronic graft-versus-host disease that resolved over 4 years. The patient receiving a syngeneic graft received marrow infusion without preceding immunosuppression. He had prompt engraftment, and hematologic variables returned to normal. A Ham's test done at 3 years was negative, but a complement lysis sensitivity test done 10 years after grafting was positive; the patient, however, remains asymptomatic. All four patients are alive and well 4, 9, 10, and 12 years after transplantation. Paroxysmal nocturnal hemoglobinuria apparently can be treated successfully by allogeneic or syngeneic marrow transplantation without subsequent maintenance therapy.