Role of serum hepatitis B core-related antigen in chronic hepatitis B infection

Hepatitis B core-related antigen (HBcrag) is a novel serum marker consisting of hepatitis B core antigen, hepatitis e antigen (HBeag) and a 22 kDa precore protein without c-terminal arginine rich domain. all these core-related proteins can be simultaneously detected in serum and quantified by chemiluminescence enzyme immunoassay. Current available data indicate that HBcrAg serum levels vary according to the different phases of chronic hepatitis B (cHB) infection showing a strong correlation with both serum HBV DNa and intrahepatic HBV covalently closed circular DNa (cccDNa). in addition, HBcrag levels seem able to identify cHB patients likely to respond to interferon-based therapy and those treated with nucleos(t)ide analogues that have higher possibility of successful treatment cessation. Finally, recent data pointed out an association between HBcrAg levels and hepatocellular carcinoma (HCC) development and recurrence. In this review we report and discuss novel findings and clinical applications of HBcrag determination in patients with chronic hepatitis B virus infection.