[Effects of rhG-CSF mobilization on Th17 cells in donors' peripheral blood and bone marrow grafts]

The study was aimed to explore the effects of recombination human granulocyte colony-stimulating factor (rhG-CSF) on Th17 cells in donors' peripheral blood (GPB) and bone marrow grafts (GBM). 25 healthy donors were injected subcutaneously with rhG-CSF 5 µg/(kg·d) for 5 consecutive days. GBM and GPB were harvested after injection on day 4 and 5 respectively. Some of these donors' steady-state bone marrow (SSBM) and steady-state peripheral blood (SSPB) were harvested before rhG-CSF injection. The changes of IL-17 secreted by T cells in donor BM and PB before and after mobilization were detected by flow cytometry. The results showed that the ability to secrete IL-17 from CD4(+) T cells and CD8(+) T cells in GBM was significantly lower than those in SSBM (GBM vs SSBM Th17/CD4(+) T, 0.74% ± 0.27% vs 1.78% ± 1.19%, p < 0.05; Tc17/CD8(+)T, 0.19% ± 0.16% vs 0.36% ± 0.37%, p < 0.05), changes in peripheral blood and bone marrow were same (GPB vs SSPB Th17/CD4(+) T, 1.82% ± 0.91% vs 3.26% ± 1.89%, p < 0.01; Tc17/CD8(+) T, 0.21% ± 0.17% vs 0.44% ± 0.28%, p < 0.01). The ratios of Th17/CD4(+) T and Tc17/CD8(+) T in GPB were higher than in GBM (p < 0.05, p < 0.01). It is concluded that rhG-CSF in vivo can inhibit the generation of Th17 cells both in bone marrow and peripheral blood grafts, and it may be partial reason for GPB/GBM mixed transplantation without increasing the GVHD incidence.