Assessment of G-CSF stimulated BM hematopoietic stem cells in normal donors

Background The clinical use of G-CSF has recently been expanded to include mobilization of stein cells for both autologous and allogeneic transplantation. Most of the published studies have focused on stein cells released into the peripheral blood (PB) after G-CSF treatment. However little is known about the effects of G-CSF on BM. This study evaluated the concurrent effects of short-term G-CSF on both BM and PB stein and progenitor cells in normal individuals. Methods Volunteers received 5 or 70 mug/kg of G-CSF for 5 consecutive days (Days 1-5). On Days 0, 3, 6, 9 and 15, BM and PB samples were obtained. Flow cytometry and functional assay were performed to analyze stem cells, subpopulations, adhesion molecules, colony-forming units and LTCIC. Results The total nucleated cells and absolute numbers of CD34(+)/mL showed a similar response pattern in both BM and PB, with a peak around Day 6 that returned to baseline levels by Day 15. However, there was a reciprocal change in the percentage of CD34(+) cells between BM and PB compartments. The expressions of adhesion molecule showed an up- and down-regulation of alpha4 and alpha5 integrin subunits, respectively, also correlated with the CD34(+) mobilization patterns. Discussions The functional characterization of integrins, and further clinical examination of G-CSF-stimulated BM is warranted. G-CSF-stimulated BM may be considered as an alternative source of stem cells in transplantation.