The Effect of Recombinant Human Erythropoietin on Circulating Hematopoietic Progenitor Cells in Anemic Premature Infants

In vitro and animal studies suggest that high concentrations of recombinant human erythropoietin (rHuEPO) might divert multipotent progenitors into erythroid maturation at the expense of granulocyte production. We determined whether changes of number and lineage commitment of peripheral blood progenitor cells occur in premature infants during therapy with rHuEPO. Thirty preterm infants were randomly assigned either to receive 300 IU of eopoetin alpha s.c. per kilogram body weight three times a week for four weeks or to a control group. At study entry and after two weeks of treatment the numbers of circulating BFU‐E, granulocyte‐macrophage colony‐forming units (CFU‐GM) and granulocyte‐erythrocyte‐macrophage‐megakaryocyte CFU (CFU‐GEMM) were analyzed by semisolid culture technique, CD34+ cells and early myeloid CD34+CD45RA− progenitors by flow cytometry. As compared with the control group, rHuEPO treatment did not exert any significant modulatory effect on numbers of CFU‐GM, nor was there a significant change in numbers of BFU‐E, CFU‐GEMM, total‐CFU, percentage of CD34+ or CD34+CD45RA− cells. Mean neutrophil count was not significantly reduced at any period during the study. Compared with the control group, the infants receiving rHuEPO had higher hematocrit values (p = 0.003) and absolute reticulocyte counts (p < 0.001). The median cumulative volume of blood transfused per kilogram per day was 0.86 ml (first quartile 0.5 ml; third quartile 1.1 ml) in the control group and 0 ml (first quartile 0 ml; third quartile 0.47 ml) in the rHuEPO group (p = 0.038). We conclude using a relatively high dose of rHuEPO in premature infants, no significant in vivo effect on circulating peripheral blood progenitor or neutrophil count could be detected.