The most important method to slow down and stop the liver disease progression in patients with chronic hepatitis B is antiviral therapy, by which to achieve maintaining viral response during treatment or obtain sustained viral response after treatment. The aim of the therapy with interferon is make patients obtain immune control to HBV, in clinical practice, it was expressed as HBeAg seroconversion, HBsAg loss and sustained viral response in HBeAg positive patients. However, those targets can't be get in most patients by 48 weeks of interferon treatment, and some patients need extended treatment to enhance the rate of HBeAg seroconversion and HBsAg loss. In this cohort study, the efficacies of extended therapy of interferon in HBeAg positive chronic hepatitis B patients will be evaluated.

In this cohort study, the HBeAg positive chronic hepatitis B patients would be treated with peginterferon alpha 2a(PEG-IFN a-2a) for 96 week and followed 24 weeks after treatment. Serum HBV DNA load, HBsAg/anti-HBs level, HBeAg/anti-HBe will be tested at enrollment and every 3 months during treatment and follow period. Parameters of liver and kidney function, and liver ultrasound examination will be tested with intervals 1-3 months. The rates of HBeAg seroconversion, HBsAg loss, and sustained viral response will be evaluated after treatment and follow up.

Inclusion Criteria:

• HBeAg positive chronic hepatitis B patients

Exclusion Criteria:

• Active consumption of alcohol and/or drugs
• Co-infection with human immunodeficiency virus, hepatitis C virus, or hepatitis D virus
• History of autoimmune hepatitis
• Psychiatric disease
• Evidence of neoplastic diseases of the liver

the population in this cohort study was composed of HBeAg positive chronic hepatitis B patients defined as HBsAg positive, HBeAg positive, and detectable HBV DNA load with ALT level ≥41 U/L for more than 6 months.