Response to cyclosporin in pure red blood cell aplasia. A 54-year-old man has had acquired pure red blood cell aplasia associated with B-cell chronic lymphocytic leukemia since 1994. At diagnosis, the Direct Antiglobulin Test was negative. In May 1996, while receiving prednisolone (70 mg/d), his reticulocyte count was 7.1 × 109/L (reference range, 20 to 80 × 109/L); his hemoglobin level varied from 5.6 to 6.2 g/dL before red blood cell transfusions that he required every 1 to 2 weeks; his platelet count was 133 × 109/L; his leukocytes were 22.7 × 109/L, with a lymphocytosis of 15.9 × 109/L; and he had a normal granulocyte count of 5.6 × 109/L. The bone marrow showed severe erythroid hypoplasia, a reduced number of megakaryocytes, a normal proportion of granulocyte precursors, and marked lymphocytic infiltration (A). Two weeks after starting cyclosporin A at 250 mg twice daily, the drug concentration in whole blood was 155 μg/L and his reticulocyte count had increased to 145 × 109/L. By 4 weeks, the hemoglobin level had increased to 11.4 g/dL without red blood cell transfusion and the prednisolone decreased to 5 mg/d. Repeat marrow biopsy 3 weeks after initiating cyclosporin therapy showed an increased number of erythroid precursor cells (arrows in B). (Courtesy of I.E. Okpala, MRCPath, FWACP, Bronglais General Hospital, Aberystwyth, UK.)
