[Source and effect of IL-22 in graft versus host disease mouse after allo-genetic bone marrow transplantation]

This study was purposed to explore the cellular source of IL-22 in graft versus host disease (GVHD) mouse following allo-genetic bone marrow transplantation. BALB/c and C57BL/6 mice were used as recipients and donors, respectively. GVHD model was established by irradiated BABL/c mice inoculated with mixed suspension of C57BL/6 bone marrow cells and splenic lymphocytes. The mice were divided into normal group (normal), total body irradiated group (TBI), bone marrow cell-transplanted group (BMT), and the combination of bone marrow cell and splenic lymphocytes-induced GVHD group (BS). The level of IL-22 in plasma was detected by ELISA. The cellular source of IL-22 and IL-22(+) subsets were detected by flow cytometry. The results showed that compared with normal mice, the level of IL-22 in plasma from BS mice was the highest (P < 0.01). All the lymphocytes of spleen, lymph nodes and peripheral blood from BS mice could produce IL-22, in which the percentage of IL-22(+)CD4(+) T cell was higher than that of IL-22(+)CD8(+) T cells. Not only Th22 cells but also Th1 and Th17 cells were the cellular source of IL-22 in GVHD mice. It is concluded that the high level of IL-22 has been found in mice with GVHD, which mainly originates from IFN-γ(-)IL-17(-)IL-22(+) Th22 cells.