ADMINISTRATION OF RHUEPO AND G-CSF IN DONOR/RECIPIENT PAIRS TO COLLECT PERIPHERAL BLOOD PROGENITOR CELLS (PBPC) AND RED BLOOD CELL UNITS FOR USE IN THE RECIPIENT AFTER ALLOGENEIC PBPC TRANSPLANTATION Running head: Allogeneic RBC units and PBPC collection with rHuEpo

Background and objectives: Reducing exposure of transplant recipients to homologous blood may be of interest. This may be achieved by procuring donor-derived RBC units, collecting more PBPC with a combination of G-CSF + rHuEpo and by administering rHuEpo posttransplant. Design and methods: Eight ABO-compatible donors were treated with rHuEpo and IV iron to collect 12 RBC units for use in their recipient. PBPC were collected after mobilization with rHuEpo and G-CSF in the same donors. The recipients received G-CSF and rHuEpo posttransplant. A control group of 10 donor/recipient pairs received G-CSF alone for PBPC mobilization and posttransplant. Results: Eighty-six out of 91 planned RBC units were collected in the donors without significant Hct decrease because of a 4-fold increase in RBC production despite functional iron deficiency. After 2 leukaphereses, the cumulative yields of NC and CFU-GM were lower in the study group while those of BFU-E, CFU-Mix and CD34+ cells were similar. However, erythroid recovery was significantly accelerated in the study group. Interpretation and conclusions: (1) Collection of 12 units RBC within 6 weeks is feasible with rHuEpo and IV iron; (2) this strategy allows a dramatic reduction in recipient exposure to homologous blood; (3) rHuEpo has no synergistic effect with G-CSF for mobilization of PBPC in normal donors and may even be deleterious; and (4) rHuEpo in the recipient may enhance erythroid engraftment.