Treatment of severe aplastic anemia.

A total of 100 patients with severe aplastic anemia were treated and evaluated in a prospective study at our hospital between January 1976 and October 1983: 28 patients had an HLA-identical sibling donor and were treated with bone marrow transplantation, and 72 patients without an HLA-identical sibling donor were given antilymphocyte globulin followed by oral low-dose androgen therapy. At 1 1/2-9 years after treatment, 13 patients (46%) survive in the transplant group and 45 patients (75%) survive in the second group. All except one in the second group have self-sustaining hematopoiesis without need for transfusions. There is one major difference between the two therapies. Marrow transplantation restores bone marrow function completely and no late hematologic complications have been seen in this group. The majority of patients treated with antilymphocyte globulin in contrast have residual abnormalities of hematopoiesis: macrocytosis, mild granulocytopenia, and mild thrombopenia. Relapse (11 of 72 patients) and clonal hematologic disorders, such as paroxysmal nocturnal hemoglobinuria (four patients) and leukemia (one patient) can occur years after complete bone marrow reconstitution with antilymphocyte globulin. These late disorders are of concern. Despite this, we conclude that antilymphocyte globulin treatment is an effective therapy with low early mortality and morbidity and a high chance for a long, sustained remission. Results are better or at least equivalent to bone marrow transplantation and patients with donors should be given the option of transplant or antilymphocyte globulin.