IFNA1 and hepatitis B virus infection: The clinical relevance of these findings was validated by gene expression profiling of patient biopsies taken after a single dose of pegylated (PEG)-IFN-α [23] and more recently in patients with hepatitis B. The latter study compared BER gene expression and antiviral effects in patient blood and liver biopsy samples taken before and after PEG-IFN-α therapy.