Anti-thymocyte globulin treatment for aplastic anemia.

20 patients with severe aplastic anemia were treated with anti-thymocyte globulin (ATG), 6 of them in combination with haplo-identical bone marrow. 7 patients (35%) showed a good clinical response within 6 months; they were off transfusions and had greater than or equal to 0.8 x 10(9)/l neutrophils. ATG had the greatest effect on red-cell production and the least on platelet production. The hematological recovery with ATG could not be predicted from the bone-marrow histology, CFU-c growth, or clinical data. However, patients with strong HLA antibodies seemed to respond more often. The actuarial survival was 55% at 5 years. Under intensive supportive care, even 7 out of 12 non-responders were alive after 1 year. ATG appears to be a useful form of therapy for patients with severe aplastic anemia who are not candidates for bone-marrow transplantation.