IFNA2 and chronic hepatitis B virus infection: Injected interferons (standard interferon-α and pegylated interferon-α) are approved to treat chronic hepatitis B in many countries, and have been confirmed to be effective in preventing the disease progression of chronic hepatitis B. Acute exacerbation of chronic hepatitis B is not uncommon during interferon-α(IFN-α) therapy because that IFN-αexerts a variety of immuno-modulatory effects [2].