Objective    To investigate the cellular immune state and pathological mechanism of HBV chronic infection by analyzing the cytokines produced by peripheral blood mononuclear cells (PBMCs) of asymptomatic HBV carriers.     Methods    PBMCs were prepared from diagnosed chronic asymptomatic HBV individuals and cultured in the presence of different antigens and antibodies. The levels of IFN-γ

IL-12

TNF-α

TGF-β and IL-10 in the culture supernatants were respectively detected by ELISA.     Results    The levels of IFN-γ

IL-12 were significantly lower than in the counterparts from healthy controls; meanwhile

those of TGF-β and IL-10 were elevated markedly. Neutralization of TGF-β and IL-10 simultaneously restore the IFN-γ production from PBMCs of HBV carriers

and exogenous IL-12 in low dose combined with specific HBV antigens promoted IFN-γ production.     Conclusion    Reduction of IL-12 from PBMCs may be the fundamental reason of viral persistence in HBV chronic carriers

combined IL-12 and specific HBV antigen promoted the celluar immunity of PBMCs from HBV carriers.