Abstract
AbstractAbstract 4870 Background and objectives:Human leukocyte antigen –G (HLA–G) is a nonclassic HLA class I molecule and has the immunosuppressive activity. We investigate the effects of Granulocyte colony-stimulating factor (G-CSF) on the expression and secretion level of HLA-G in peripheral blood and bone marrow cells, and attempt to explain the mechanism of the low incidence of graft-versus-host disease (GVHD) in G-CSF-primed bone marrow (G-BM) or peripheral blood stem cells (G-PBSC) transplantation. Methods:Bone marrow and peripheral blood cells of 10 donors were collected pre-mobilization and at day 5 after G-CSF mobilization. Flow cytometry was used to detect the expression of membrane-bound HLA-G (mHLA-G) of CD3+CD4+ T lymphocytes, CD3+CD8+ T lymphocytes, CD19+ B lymphocytes, CD56+ NK cell, CD14+ monocytes and CD33+ granulocytes. The levels of soluble HLA-G (sHLA-G) and cytokine were determined by enzyme-linked immunosorbent assay (ELISA). Bone marrow cells and peripheral blood cells of pre-mobilization were incubated for 24h, which are divided into 5 groups: (a) blank group, (b) with G-CSF, (c) with G-CSF and blocking antibody of IL-10, (d) with G-CSF and blocking antibody of IFN-γ, (e) with G-CSF, blocking antibody of IL-10 and blocking antibody of IFN-γ. Results:The levels of mHLA-G of CD3+CD4+ lymphocytes, CD3+CD8+ lymphocytes and the levels of sHLA-G at day 5 after G-CSF mobilization groups were significantly higher than the pre-mobilization groups both in bone marrow and peripheral blood cells, especially in CD3+CD8+ lymphocytes. The levels of mHLA-G of CD19+ B lymphocytes, CD56+ NK cells, CD14+ monocytes and CD33+ granulocytes had no significant difference in the two groups. The levels of IL-10 or IFN-γ in plasma of bone marrow or peripheral blood at day 5 after G-CSF mobilization groups were much higher than the pre-mobilization groups. The levels of mHLA-G of CD3+CD4+ lymphocytes, CD3+CD8+ lymphocytes and the levels of sHLA-G in bone marrow cells or peripheral blood cells incubating with G-CSF for 24h were significantly higher than the groups without incubating with G-CSF. And the blocking antibody of IL-10 or the blocking antibody of IFN-γ could not reduce the expression levels of mHLA-G and sHLA-G in vitro. Conclusion:G-CSF can act on cells directly to increase the expression levels of HLA-G in CD3+CD4+ T lymphocytes and CD3+CD8+ T lymphocytes. It might be assciated with the low incidence of GVHD in G-BM transplantation or G-PBSC transplantation.Supported by National Natural Science Foundation of China (30971300), Science and Technology Planning Project of Guangdong Province of China (2009A030200007) and China Postdoctoral Science Foundation (200902332, 20080440776). Disclosures:No relevant conflicts of interest to declare.
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