Studies on pure red cell aplasia. X. Association with acute leukemia and significance of bone marrow karyotype abnormalities

Thirty-one patients with chronic primary pure red cell aplasia (PRCA) had blood and marrow cell karyotypes performed prior to immunosuppressive treatment. Only one patient had an abnormal marrow cell karyotype, which revealed a clone of hyperdiploid cells with 47 chromosomes (47, XY, + G). His blood cell karyotype was normal. This patient had no erythroid response to prednisone and cyclophosphamide, or splenectomy, and after 3 yr he developed acute myelomonocytic leukemia with the emergence of a new clone of hyperdiploid cells with multiple ring chromosomes (46,XY/47,XY, + G/49,XY,–G,+4r) in the blood and marrow. These studies indicate that chronic primary PRCA probably has a much lower incidence of abnormal karyotypes and acute leukemia than other refractory anemias (myelodysplastic syndromes), but that an abnormal marrow karyotype may portend a leukemia. The role of cytotoxic immunosuppressive drugs in the treatment of PRCA patients with an abnormal karyotype remains unknown.