INVITRO TESTS FOR DISTINGUISHING POSSIBLE IMMUNE-MEDIATED APLASTIC-ANEMIA FROM TRANSFUSION-INDUCED SENSITIZATION

Abstract

To determine whether or not transfusion-induced sensitization is responsible for the in vitro inhibition by patient lymphocytes of HLA-identical erythroid burst-forming units (BFU-E), 42 patients with aplastic anemia [AA] were studied. Lymphocytes from 12 of 34 transfused patients apparently inhibited normal colony growth. Lymphocytes from none of the 8 untransfused patients demonstrated inhibition. Co-culture studies apparently would not be useful for identifying immune-mediated AA in transfused patients. To identify possible immune-related AA, BFU-E from patient blood before and after T[thymus-derived] cell depletion were assayed. In all 32 patients studied, BFU-E failed to grow from peripheral blood cells before T cell depletion, but in 8 cases, normal-appearing BFU-E grew after T cells were removed. Growth of patient BFU-E colonies was inhibited in 6 cases when patient T cells were added back to the culture, indicating that in these 6 patients, an autoimmune mechanism may have been present.