Treatment of hemolytic disease of the newborn caused by anti-Kell antibody with recombinant erythropoietin

Recent data suggest that antibody-mediated suppression of erythroid progenitors may contribute to the anti-Kell-induced alloimmune hemolytic disease of the newborn (HDN). A 32-week-old girl who was positive for Kell was born to a mother who was negative for Kell but known to have anti-Kell antibodies. After birth, the baby had HDN and hyperbilirubinemia develop (peak bilirubin 21 mg/dL at day 9 of life), which was treated with phototherapy. Although the hyperbilirubinemia resolved, she became progressively anemic (hematocrit 22%) with an inappropriately Low reticulocyte response (1.1%) and erythropoietin (EPO) level (20 mU/mL). To avoid the need for a blood transfusion, she was treated with recombinant erythropoietin (rEPO) and oral iron supplements. One week after starting EPO, the reticulocyte count increased to 9.1%. Erythropoietin therapy was continued for a total of 9 weeks, with resolution of her anemia at the end of therapy (hematocrit 35%). Thus, we were able to successfully treat the anemia with rEPO with avoidance of blood transfusion. This patient demonstrates that the antibody-mediated erythroid suppression in Kell alloimmune anemia can be overcome by rEPO. Recombinant erythropoietin should therefore be considered in the management of infants with severe or hypoproliferative anti-Kell-associated anemia.