Hyporegenerative anemia associated with Rh hemolytic disease: treatment failure of recombinant erythropoietin.

A postnatal hyporegenerative anemia may complicate Rh hemolytic disease. Intramedullary hemolysis, bone marrow suppression, and erythropoietin deficiency have been implicated etiologically. Treatment with recombinant erythropoietin (r-EPO) has yielded encouraging preliminary results. The authors describe an infant with Rh isoimmunization who developed severe hyporegenerative anemia unresponsive to a 5-week course of r-EPO. Two additional doses at 12 weeks resulted in brisk reticulocytosis, coinciding with a 16-fold decline in the anti-Rh(D) antibody titer. Thus, treatment with r-EPO may be ineffective when anti-Rh(D) antibody titers are high. The authors also show that erythropoietin deficiency in hyporegenerative anemia is not as frequent and severe as originally thought.