A 62-year-old man with B-cell chronic lymphocytic leukemia had three separate episodes of pure red cell aplasia (PRCA). The last episode was treated with cyclosporin-A (CyA) and prednisone. After the patient was on the therapy for 2 weeks, erythropoietic recovery was observed and with continued therapy the hematocrit (Hct) became normal. The PRCA remission was associated with a fall in the blood lymphocyte count, and a reduction in the spleen and lymph node size and bone marrow lymphocyte density. At diagnosis of PRCA the blood T-cells bearing IgG Fc receptors (T gamma cells) were increased, and the marrow contained very few or no late-stage erythroid progenitors. After remission of PRCA the T gamma cell fraction decreased, and the marrow erythroid progenitor's number became normal. We speculate that therapy with CyA and prednisone inhibited the production of interleukins-1 and -2 from monocytes and T-cells, respectively, and was responsible for the reduction of the T gamma cell fraction and B-cell leukemic mass in this patient. Further, we believe that normalization of T gamma cells in association with the therapy was responsible for the PRCA remission.