Additionally, hepatitis B e antigen (HBeAg) can be used as a marker for clinical detection of chronic hepatitis B. However, due to its high amino acid sequence homology with the hepatitis B core antigen (HBcAg), most of the existing anti-HBe antibodies cross-react with HBcAg, which greatly interferes with the accurate detection of HBeAg. Here, HBE1 is linked to chronic hepatitis B virus infection.