Progress in the Study of Combined Immunosuppression in Patients with Cryptogenic Hepatitis B

Occult hepatitis B virus infection (OBI), as a special form of HBV infection, refers to HBsAg-negative body, but can be detected in liver tissues and/or serum with a low load of HBV DNA, often less than 200 IU/mL, and is still pathogenic and infectious. OBI does not lead to obvious damage to the liver in general, but when it is necessary to receive immunosuppressive treatment for coexisting diseases, reactivation of hepatitis B virus may occur, with the risk of developing into viral hepatitis, cirrhosis and liver cancer. In general, OBI does not cause significant liver damage, but when immunosuppressive therapy is required due to other diseases, reactivation of hepatitis B virus may occur, and there is a risk of developing viral hepatitis, cirrhosis and hepatocellular carcinoma. In this paper, we review the definition of OBI, its clinical characteristics, and the related research progress when receiving immunosuppressive therapy under different circumstances.