GM-CSF-based mobilization effect in normal healthy donors for allogeneic peripheral blood stem cell transplantation

It is important to optimize methods to mobilize hematopoietic stem cells into peripheral blood (PB) for successful allogeneic peripheral blood stem cell (PBSC) transplantation. Our primary intent was to investigate the role of GM-CSF for mobilization in normal healthy donors and to compare its efficacy in mobilizing stem cells alone, in concurrent combination and in sequential combination with G-CSF in this study. We analyzed the results of the PBSC harvest through large volume leukapheresis from 48 normal healthy donors mobilized by three different regimens including GM-CSF. Donors were assigned sequentially to one of the following regimens for mobilization: GM-CSF 10 microg/kg/day alone (group 1, n = 9); concurrent combination (group 2, n = 20) of G-CSF 5 microg/kg/day and GM-CSF 5 microg/kg/day; sequential combination (group 3, n = 19) of GM-CSF alone 10 microg/kg/day for 3 days followed by G-CSF alone 10 microg/kg/day for 2-3 days. The harvested CD34(+) cell count (P < 0.05) was statistically higher in group 3 than in group 1 or 2. Pre-collection WBC count in donors (P < 0.05), harvested MNC (P < 0.05) and CD3(+) cell count (P < 0.05) of group 2 or 3 were significantly higher than those of group 1. Recipients who received stem cells mobilized with combination regimens showed an earlier recovery of WBC and platelets count than those with GM-CSF alone. The incidence of acute graft-versus-host disease was not statistically different among three recipient groups. GM-CSF-based mobilization was well tolerated in normal healthy donors. The sequential combination regimen appears to be an excellent mobilization strategy and might be preferred as the optimal method in some clinical situations that need a higher number of stem cells.