Anti-erythropoietin antibodies usually cross-react with all kinds of recombinant erythropoietins; therefore erythropoiesis-stimulating agent (ESA)-induced pure red-cell aplasia (PRCA) is not rescued by different ESAs. diagnosis. Interestingly anti-erythropoietin antibodies were still detectable although their concentration was too low for titration. In conclusion darbepoetin-α can improve ESA-induced PRCA when the anti-erythropoietin antibody titer declines and its neutralizing capacity is lost. Keywords: Red-Cell Aplasia Pure; Kidney Failure Chronic; Erythropoietin Recombinant; Darbepoetin-alfa INTRODUCTION Pure red-cell aplasia (PRCA) is a disorder of erythropoiesis that leads to sudden-onset progressive and severe anemia. Since 1998 there have been cases of recombinant human erythropoietin (rEPO) antibody-associated PRCA in patients with chronic kidney disease who receive subcutaneous treatment with rEPOs. In general patients developing erythropoiesis-stimulating agent (ESA)-induced PRCA should not be treated with another ESA because anti-EPO antibodies will certainly cross-react with the ESA and can induce systemic adverse reactions (1 2 However some case reports have described patients with ESA-induced PRCA who recovered responsiveness to the same or different ESA after immunosuppressive therapy. A rechallenge with the same or another ESA has been proposed after patients become free off the antibodies following immunosuppressive therapy or renal transplantation (3 4 Herein we report a case of ESA-induced PRCA in a 36-yr-old woman with chronic kidney disease caused by immunoglobulin A nephropathy (5) whose condition improved after reintroduction of darbepoetin-α when the Rabbit Polyclonal to SLK. anti-EPO antibody titer declined without further immunosuppression. CASE REPORT A 36-yr-old female patient was admitted for severe anemia in July 2002. She had been diagnosed with chronic kidney disease CP-547632 caused by immunoglobulin A (IgA) nephropathy. In October 2000 she began to receive rEPO therapy with Epokine (CJ Corp Seoul Korea) an EPO-α product at a dose of 4 0 IU/week on subcutaneous (SC) route for anemia. Her hemoglobin (Hb) level was maintained at 10-12 g/dL before hemodialysis. In January 2002 she was started on hemodialysis and her Hb level was maintained at 8-10 g/dL under EPO-α treatment at a dose of 3 0 0 IU/week. Eleven months after the start of hemodialysis her Hb level dropped to 5.3 g/dL although she was treated with rEPO-α CP-547632 at a dose of 12 0 IU/week. Even with the cumulative ESA dose of 224 0 IU over 26 months her anemia did not improve. Therefore she was transfused with two units of packed red blood cells every three weeks to maintain her Hb level despite the ESA treatment (12 0 0 IU/week). Meanwhile she received three types of rEPO-α products (Epokine Espogen [LG Life Sciences Seoul Korea] and Eporon [Dong-A Pharmaceutical Co. Ltd. Seoul Korea]) and one rEPO-β (Recormon [Roche Basel Switzerland]) product transiently but her anemia did not improve at all. Initial laboratory test values on admission were as follows: leukocyte count 4 610 cells/μL; Hb 5.4 g/dL; platelet count 113 0 cells/μL; reticulocytes 0.27%; total iron binding capacity 220 μg/dL (39.38 μM/L); ferritin 1 760 μg/L; iron 201 μg/dL (35.98 μM/L); parathyroid hormone 23 ng/L; blood urea nitrogen 83 mg/dL (29.63 mM/L); creatinine 12.3 mg/dL (1 CP-547632 87.32 μM/L); C-reactive protein 0.75 mg/dL. Serologic tests for hepatitis viruses cytomegalovirus Epstein-Barr virus human immunodeficiency virus and parvovirus B19 were all negative. Thoracic computed tomographic scans or abdominal sonography showed no evidence of an abnormal mass such as thymoma or lymphoma. Bone marrow examination showed CP-547632 reduced cellularity (0-20%) and severe erythroid hypoplasia whereas thrombopoiesis was in the low normal range and granulopoiesis was normal findings consistent with PRCA (Fig. 1). Fig. 1 Bone marrow biopsy findings. (A) Bone marrow section The cellularity is 0-20% which is hypocellular for age. Trilineage hematopoiesis is markedly decreased and the decrease of erythropoiesis is remarkable. Plasma cells lymphocytes and eosinophils are … In June 2003 anti-EPO antibodies were screened by competition enzyme-linked immunoassay (ELISA). The result of ELISA showed 1. 9 times higher antibody titer in patients serum compared with in control serum and ESA treatment was discontinued. The PRCA did not respond to oxymetholone treatment from June 2003 to July 2003. Although we.