Objective: To investigate the effect of granulocyte colony stimulating factor (G-CSF) on myeloid-derived suppressor cells (MDSCs) in the bone marrow and peripheral blood, and explore the relationship between MDSC and graft-versus-host disease (GVHD).
Methods: Bone marrow, peripheral blood and peripheral blood stem cells were obtained from 12 healthy hemopoietic stem cell donors before and on day 5 after G-CSF mobilization. Flow cytometry was employed to examine the number of MDSC, and the relationship between MDSC number and the incidence of GVHD was analyzed.
Results: In normal physiological conditions, MDSC could be detected in the peripheral blood and bone marrow with a cell percentages of (1.35±0.35)% and (2.44±1.11)%, respectively, showing a significantly higher cell percentage in the bone marrow (P=0.015). On the 5th day after G-CSF mobilization, the percentage of MDSCs increased to (4.01±1.82)% in the peripheral blood and to (4.38±2.19)% in the bone marrow, showing no significant difference between them (P=0.083). The mobilization caused a significant increase in the number of MDSCs in the peripheral blood (P=0.047) but not in the bone marrow (P=0.761). The number of MDSCs in the collected samples showed a significant inverse correlation to the incidence of GVHD (P=0.048).
Conclusions: MDSCs are present in the peripheral blood and bone marrow of healthy donors, with a greater number in the bone marrow. G-CSF can mobilize the MDSCs from the bone marrow to the peripheral blood to increase number of MDSCs in the peripheral blood, which may contribute to a lowered incidence of GVHD in hematopoietic stem cell transplantation (HSCT).