Abnormal lymphocyte populations in pure red cell aplasia.

Studies of blood lymphocytes from 4 patients with pure red cell aplasia were performed with lymphocyte surface markers, and with various in vitro tests for lymphocyte functions. Pathologically low B-lymphocyte values were found. In contrast, no marked deviation from normals were seen for T-lymphocytes and Fc-receptor-bearing lymphocytes thought largely to represent non-B, non-T-lymphocytes. In 3 patients normal lymphocyte transformation was found with unspecific and specific mitogens, while the DNA-synthesis induced by unspecific mitogens was subnormal in the fourth patients. The lymphocyte-mediated PHA-induced cytotoxicity against target cells in vitro was subnormal in 2 patients, while no depression was seen in antibody-dependent cytotoxicity mediated in vitro by lymphocytes (K-cells). It is concluded that considerable immunological abnormalities are associated with pure red cell aplasia, and the possible significance of this is discussed.