Elevated IL-6 Receptor Expression on CD4(+ )T Cells contributes to the increased Th17 Responses in patients with Chronic Hepatitis B

BACKGROUND: Increased numbers of Interleukin-17-producing CD4(+ )T cells (Th17) have been found in association with hepatitis B virus (HBV)-induced liver injury. However, the mechanism underlying the increase of Th17 responses in patients with HBV infection remains unclear. In this study, we investigate the possible regulatory mechanisms of increased Th17 responses in patients with chronic hepatitis B(CHB). METHODS: Th17 response and IL-6R expression on CD4(+ )T cells in peripheral blood samples were determined by flow cytometry. Cytokines TGF-β, IL-1β, IL-6 and IL-17 in plasma and/or supernatant samples were determined by ELISA and the IL-17 and IL-6R mRNA levels were quantified by quantitative real-time reverse polymerase chain reaction. RESULTS: All these data indicated that the frequency of periphery Th17 cells is significantly correlated with the percentage of CD4(+ )T cells expressing IL-6R in CHB patients. CD4(+ )T cells from patients with CHB, but not those from healthy donors, produced higher levels of IL-17 and had more IL-6R expression upon stimulation with the HBV core antigen (HBcAg) in vitro. The PMA/ionomycin and HBcAg -stimulated up-regulation of IL-17 production by CD4(+ )T cells could be reversed by a neutralizing antibody against IL-6R. CONCLUSION: we showed that enhancement of IL-6R expression on CD4(+ )T cells upon HBV infection contributes to increased Th17 response in patients with CHB.