New Approaches in TransplantationLiver transplantationVariation of CD4+CD25+Foxp3+ Regulatory T Cells and Th17 Cells in the Peripheral Blood of Human Liver Allograft Patients With Long-term Survival

•Liver allograft recipients were stable after operation wtih FK506 IS.•The operation of T-lymphocyte subpopulation have relationship with long-term survival.•Treg percentages in CD4+ T cells were significantly reduced in postoperative patients.•Ratio of Th17/CD4+ T cells slightly increased and then remained almost unchanged.

BackgroundMonitoring of peripheral blood (PB) lymphocyte subpopulation counts may be useful to underlie immune status after liver transplantation (LT). We aimed at exploring the variation of regulatory cells and Th17 in the PB of liver allograft patients with long-term survival.MethodsForty-two patients who took FK506 drugs were divided into 3 groups: patients who survived for 6 months to 3 years were in the Tac1 group (n = 15), those who survived for 3-10 years were in the Tac2 group (n = 15), and those who survived for >10 years were in the Tac3 group (n = 12). Healthy individuals were recruited in the control group (n = 20). Liver function was tested. Peripheral blood mononuclear cells (PBMCs) were separated. T-cell subpopulations were analyzed using flow cytometry.ResultsNo difference in liver function indicators was observed compared with all the groups. Treg percentages in CD4+ T cells were significantly down-regulated in Tac1, Tac2, and Tac3 versus the control group; Tregs/CD4+ T ratio in Tac2 and Tac3 were even lower versus that in the Tac1 group. Th17 percentages in CD4+ T cells showed no difference compared with Tac3 and control, compared with Tac1, Tac2, and Tac3 groups. Liver allograft patients with long-term survival had normal liver function same as healthy individuals. With survival time increasing, the ratio of Tregs/CD4+ T cells was significantly reduced and the ratio of Th17/CD4+ T cells was kept almost unchanged in the stable postoperational patients under FK506 immunosuppression.ConclusionsOur work enriched our understanding of Tregs in the solid organ transplantation field.