Pegylated interferon α-2a(Peg-IFN-α)and Nucleoside analog(ue) drugs can inhibit viral replication , but Peg-IFN-α also play an important role in immune regulation. In hepatitis B infection, CD8+T cells are the main effector cells in adaptive immune response.Peg-IFN-α recommended as the first-line treatment has a higher chance to achieve HBeAg seroconversion and even HBsAg disappearance than nucleoside analog(ue) drugs, which may be related to the functional activation of CD8+T cells in the case of hepatitis and the function enhancement of CD8+T cells during Peg-IFN-α therapy. This study was aimed at investigating the changes of CD8+T cells frequency and function, and the expression of costimulatory molecules during Peg-IFN-αand nucleoside analog(ue) therapy.Meanwhile, the investigators want to explore whether the decline of HBsAg and HBeAg resulted in recovery of CD8+T cells function, or recovery of CD8+T cells function led to the decrease of HBsAg and HBeAg. Several studies demonstrated that HBsAg and HBeAg could damage CD8+T cells function, and the loss of HBsAg and HBeAg led to recovery of CD8+T cells function.