Antibody-mediated pure red cell aplasia after treatment with darbepoetin-alpha postrenal transplantation

Abstract

Pure red cell aplasia (PRCA) is a rare normochromic, normocytic anemia with a near-to-complete absence of erythroblasts in the bone marrow. Erythropoiesis-stimulating agents have been used widely to improve anemia in patients with chronic kidney disease. We present a case of a 38-year-old woman who was detected to have anemia (hemoglobin: 10 g/dl) and renal dysfunction (creatinine: 3 mg/dl) on a routine health check in December 2016. Her kidney biopsy showed chronic interstitial nephritis. She received intravenous (IV) iron and was started on darbepoetin-alpha. Her hemoglobin after 3 months of treatment was 12 mg/dl. She underwent preemptive one haplomatch renal transplantation on June 2017. She was discharged with serum creatinine of 0.9 mg/dl and hemoglobin of 8 g/dl. She was not on any Erthropoietin stimulating agents (ESA) at discharge. In the 4th week after transplant, her hemoglobin dropped to 7 g/dl, and she was restarted on darbepoetin-alpha 40 μg subcutaneously once a week. In the 6th week posttransplant, her hemoglobin dropped to 6 g/dl. Her peripheral smear showed normocytic normochromic anemia with no evidence of hemolysis. Transferrin saturation was 81%, serum ferritin levels were 1812 ng/ml, and reticulocyte count was 0.1%. Bone marrow biopsy showed suppression of erythroid precursors with myeloid-to-erythroid ratio of 8:1, adequate iron stores, and normal white blood cell and platelet precursors with no dysplastic cells. Paroxysmal Nocturnal hemoglobinuria (PNH) workup; antinuclear antibody; and screening for hepatitis B, hepatitis C, HIV, CMV, and human parvovirus B19 were negative. Anti-erythropoietin (EPO) antibody by enzyme-linked immunosorbent assay was positive. She was diagnosed to have PRCA secondary to anti-EPO antibodies. She was managed with pulse doses of methylprednisolone, adequate dose of tacrolimus, IV immunoglobulin of 125 g (2 g/kg) over 5 days, and two packed red cell transfusions. Darbepoetin-alpha was stopped. At present, her hemoglobin is 12.5 g/dl with serum creatinine of 1 mg/dl on triple immunosuppression with no requirement of ESA.