A case of aplastic anemia with a 17 years' history which responded to antilymphocyte globulin treatment was reported. The patient was a 54-year-old male who had been followed up under diagnosis of aplastic anemia with prednisolone, oxymetholone, and subsequant mepitiostane treatment until 1986, when he became severely anemic. In January 1987, although he showed rather atypical findings for aplastic anemia such as reticulocytosis and erythroblastosis in the peripheral blood, he received antilymphocyte globulin (Merieux) and responded well to this treatment. Neither colony formation of T-depleted bone marrow cells nor detection of 20.3 (monoclonal antibody)-positive cells in the peripheral blood by fluorocytometry could be an indicator predictive of response to ALG therapy. It may be suggested that antilymphocyte globulin therapy would be recommended for the treatment of even atypical aplastic anemia.
