Immunomodulatory effect of bone marrow mesenchymal stem cells on T lymphocytes in patients with decompensated liver cirrhosis

We explored the immunomodulatory effects of bone marrow mesenchymal stem cells (BMSCs) on peripheral blood T lymphocytes in patients with decompensation stage, hepatitis B-associated cirrhosis. MSCs from nine patients were analyzed by flow cytometry. Peripheral blood lymphocytes were isolated for fluorescent staining. Following stimulation by phytohemagglutinin (PHA), peripheral blood lymphocytes were co-cultured with BMSCs in serum and divided into four groups: (1) BMSC + lymphocyte + PHA contact culture group; (2) BMSC + lymphocyte + PHA non-contact culture group; (3) lymphocyte + PHA positive control group; and (4) lymphocyte-only negative control group. Lymphocyte proliferation and frequencies of CD4(+)CD25(+)CD127-Tregs and CD4(+)CD8-IL-17(+) (Th17) cells were detected. Cell proliferation in groups 1 and 2 declined compared with group 3 (P < 0.01), and was notably higher than in group 4 (P < 0.01). CD4(+)CD25(+)CD127-Tregs frequencies in groups 1 and 2 were higher than in groups 3 and 4. In an intra-group comparison before and after culture, Th17 cell frequencies in groups 1 and 2 were higher than in group 4 (P < 0.01), but lower than in group 3 (P < 0.01). The Treg/Th17 ratio in groups 1 and 2 increased (P < 0.01), but did not change significantly in groups 3 and 4 (P > 0.05). In a comparison between groups after culture, the Treg/Th17 ratio in groups 1 and 2 increased more than in groups 3 and 4 (P < 0.01). BMSCs from cirrhotic patients can inhibit the proliferation of peripheral blood T lymphocytes, upregulate the expression of CD4(+)CD25(+)CD127(-) Tregs, and improve Treg/Th17 imbalance. The mechanism by which this takes place may be associated with immunomodulatory effects induced by the secretion of soluble factors.