Erythropoietic activity and iron metabolism in autologous blood donors during recombinant human erythropoietin therapy

Abstract. The use of recombinant human erythropoietin (rhEPO) to intensify the erythropoietic response in autologous donors may reduce homologous blood requirement. We studied the effect of subcutaneous rhEPO (500 U kg^-1 body weight twice weekly during a 3 week period) on variables of erythropoiesis and iron metabolism in 62 autologous blood donors, of whom 32 received rhEPO (epo group) and 30 did not (control group). Patients donated only 2 units of blood and received oral iron in order to restrict phlebotomyinduced decrease of iron stores. Pre-phlebotomy haemoglobin concentration (14·0±0·8 g dl^-1) was completely regenerated in the epo group at surgery (13·7±1·3 g dl^-1); haemoglobin concentration in the control group fell from 13·5±1·4 g dl^-1 to 11·6±1·4 g dl^-1 after the phlebotomies and did not improve during the pre-operative phase. Total erythropoietic activity expressed as serum transferrin receptor concentration (sTfR) showed a 4-fold increase from 3·8±0·9 μ g ml^-1 to 14·9±4·8 μ g ml^-1 in the epo group. Effective erythropoietic activity measured by absolute reticulocyte count, however, declined after the fourth rhEPO injection in the epo group. Serum ferritin was lower in the epo group, but no differences in serum iron, transferrin concentration and transferrin saturation were observed between the groups. A marked increase in free erythrocyte protoporphyrin (FEP) was observed in the epo group, whereas FEP levels in the controls remained within normal ranges. Despite oral iron supplementation and the limited number of phlebotomies, the effect of rhEPO therapy in autologous donors is restricted by iron depletion.