Objective: To investigate the regulatory roles of cytokines expressed on peripheral blood T cells in chronic hepatitis B virus (HBV) infection.
Methods: Sixty patients with chronic HBV infection were categorized into immune tolerance phase (IT), immune clearance phase (IC), and inactive carrier phase (IA) groups. Twenty healthy individuals were enrolled as healthy controls. Another 21 HBeAg-positive chronic hepatitis (CHB) patients were administrated with entecavir (0.5 mg/d) for 6 months. Serum alanine transaminase (ALT) levels were tested by automatic biochemistry analyzer, and HBV DNA loads were tested by PCR, and cytokines expressed on T cells were examined by flow cytometry.
Results: There were negative correlations between IFN-γ levels expressed by peripheral blood CD4(+)T cells and CD8(+)T cells and serum HBV DNA loads in patients with chronic HBV infection, and there were negative correlations between the ratio of IFN-γ/IL-4 in peripheral blood CD4(+)T cells and CD8(+)T cells and serum HBV DNA loads. In addition, the expression levels of IFN-γ were gradually elevated and the expression levels of IL-4 were gradually lowered from IT to IA. In IT, the level of IFN-γ expressed by T cells in patients was lower than that in healthy controls and the level of IL-4 was higher than that in healthy controls. In IA, the levels of IFN-γ and IL-4 were recovered to the normal. Anti-virus therapy reduced serum HBV DNA load and ALT levels in patients, which was accompanied with the increase of IFN-γ level and IFN-γ/IL-4 ratio in CD8(+)T cells.
Conclusion: During chronic HBV infection, IFN-γ and IL-4 expressed by peripheral blood T cells play dual immunoregulatory roles, which are correlated with the efficacy of entecavir.