Elevated Th17 cells accompanied by decreased regulatory T cells and cytokine environment in infants with biliary atresia

Abstract

The aim of this study was to investigate the role of Th17 and T reg cells in biliary atresia (BA) and to assess the liver cytokine environment in BA patients. The percentages of Th17 and T reg cells in peripheral blood mononuclear cells (PBMCs) of BA patients and healthy controls (HC) were evaluated. The serum concentrations of IL-17a and IL-23 as well as Foxp3, IL-17a, ROR-γt, IL-6, IL-1β and TGF-β1 m-RNA and protein expressions in liver tissues and the number of Foxp3, IL-17a, ROR-γt, CD4 expressing cells which infiltrated the hepatic tissues were determined. The Th17/T reg cell ratio (P < 0.001) and blood concentrations of IL-17a and IL-23 (P < 0.05) were increased in the BA as compared to the HC group. Expressions of Foxp3, ROR-γt, IL-17a, IL-1β, IL-6 as well as TGF-β1 mRNA and proteins were significantly increased in BA as compared to HC livers (P < 0.01, P < 0.05). High levels of IL-17a/ROR-γt-positive and moderate levels of Foxp3-positive cells infiltrated damaged BA bile ducts and the ratio of FoxP3+ T to CD4+ T cells was significantly lower in BA than in HC samples (P < 0.01). Cytokine-induced imbalance between Th17 and T reg cells in BA livers may be involved in bile duct damage.