Pure red cell aplasia is a rare occurrence in patients with chronic lymphocytic leukemia (CLL). This report is based on two casesCLL patients with documented pure red cell aplasia who responded remarkably to anti-CD20 or rituximab(Drug information on rituximab) (Rituxan).
Case 1 involves a 79-year-old man with B-cell CLL (trisomy 12) who presented with severe anemia with a hemoglobin below 8 g/dL in April 2000. His white blood cell (WBC) count was 25,000/µL, with normal lactate dehydrogenase (LDH), negative Coombs, very low reticulocyte count (0.1%), and absent red blood cell precursors in his bone marrow. He also had negative parvovirus B19 titers and a high erythropoietin(Drug information on erythropoietin) level.
Despite therapy with cyclosporine (Neoral, Sandimmune) and prednisone(Drug information on prednisone), the patient had no response and remained transfusion dependent for 6 months. Intravenous immunoglobulin was also tried at 1 g/kg for 2 days, to no avail. Rituximab was then started at 375 mg/m²/wk for 8 weeks, beginning October 2000. He became transfusion independent after the fourth treatment and his reticulocyte count rose to 4% with normalization of hemoglobin (13 g/dL) and WBC count (4,900/µL). Repeat bone marrow biopsy confirmed resolution of his pure red cell aplasia. As of January 2002, the patient remains in complete remission of his CLL and pure red cell aplasia.
Case 2 is a 47-year-old woman who had had B-cell CLL for the last 7 years. She was started on therapy with fludarabine (Fludara) in February 2000, based on rapid rise of her WBC count (160,000/µL) with normal hemoglobin at the time. After five cycles of therapy, her hemoglobin dropped to less than 8 g/dL and she became transfusion dependent. Her reticulocyte count was near 0%, with normal LDH and negative Coombs.
The patient was started on erythropoietin injections with still no response. After six cycles of fludarabine therapy, her WBC count was 12,000/µL with 10,000 lymphocytes, and she was still blood transfusion dependent. Rituximab was started in August 2000 at the same dose as the patient in case 1 above. Gradually, her hemoglobin normalized over 4 to 6 weeks, and she became transfusion independent. Her reticulocyte count rose to 10%, WBC count was 4,300/µL (40% lymphocytes), and hemoglobin was 13.5 g/dL. As of February 2002, she is still in remission.
CONCLUSION: To our knowledge, this is the first report of pure red cell aplasia in patients with CLL responding to rituximab therapy. We believe it deserves further investigation.