ERYTHROPOIETIC ACTIVITY AND IRON-METABOLISM IN AUTOLOGOUS BLOOD-DONORS DURING RECOMBINANT-HUMAN-ERYTHROPOIETIN THERAPY

The use of recombinant human erythropoietin (rhEPO) to intensify the e rythropoietic response in autologous donors may reduce homologous bloo d requirement. We studied the effect of subcutaneous rhEPO (500 U kg(- 1) body weight twice weekly during a 3 week period) on variables of er ythropoiesis and iron metabolism in 62 autologous blood donors, of who m 32 received rhEPO (epo group) and 30 did not (control group). Patien ts donated only 2 units of blood and received oral iron in order to re strict phlebotomy-induced decrease of iron stores. Pre-phlebotomy haem oglobin concentration (14.0 +/- 0.8 g dl(-1)) was completely regenerat ed in the epo group at surgery (13.7 +/- 1.3 g dl(-1)); haemoglobin co ncentration 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 se rum transferrin receptor concentration (sTfR) showed a 4-fold increase from 3.8 +/- 0.9 mu g ml(-1) to 14.9 +/- 4.8 mu g ml(-1) in the epo g roup. Effective erythropoietic activity measured by absolute reticuloc yte count, however, declined after the fourth rhEPO injection in the e po group. Serum ferritin was lower in the epo group, but no difference s in serum iron, transferrin concentration and transferrin saturation were observed between the groups. A marked increase in free erythrocyt e protoporphyrin (FEP) was observed in the epo group, whereas FEP leve ls in the controls remained within normal ranges. Despite oral iron su pplementation and the limited number of phlebotomies, the effect of rh EPO therapy in autologous donors is restricted by iron depletion.