Two different types of flares were recognized during PEG-IFN therapy of HBeAg-positive chronic hepatitis B. Host-induced flares, characterized by an ALT flare followed by a subsequent decrease in HBV DNA, were associated with response to treatment and may result in decline and clearance of HBV DNA, HBeAg, and HBsAg. This evidence concerns the gene GPT and chronic hepatitis B virus infection.