Published online Nov 14, 2015. doi: 10.3748/wjg.v21.i42.11931
Peer-review started: April 18, 2015
First decision: June 2, 2015
Revised: June 28, 2015
Accepted: September 14, 2015
Article in press: September 14, 2015
Published online: November 14, 2015
The development of sensitive assays to detect small amounts of hepatitis B virus (HBV) DNA has favored the identification of occult hepatitis B infection (OBI), a virological condition characterized by a low level of HBV replication with detectable levels of HBV DNA in liver tissue but an absence of detectable surface antigen of HBV (HBsAg) in serum. The gold standard to diagnose OBI is the detection of HBV DNA in the hepatocytes by highly sensitive and specific techniques, a diagnostic procedure requiring liver tissue to be tested and the use of non-standardized non-commercially available techniques. Consequently, in everyday clinical practice, the detection of anti-hepatitis B core antibody (anti-HBc) in serum of HBsAg-negative subjects is used as a surrogate marker to identify patients with OBI. In patients with chronic hepatitis C (CHC), OBI has been identified in nearly one-third of these cases. Considerable data suggest that OBI favors the increase of liver damage and the development of hepatocellular carcinoma (HCC) in patients with CHC. The data from other studies, however, indicate no influence of OBI on the natural history of CHC, particularly regarding the risk of developing HCC.
Core tip: Occult hepatitis B infection (OBI) is a virological condition characterized by a low level of hepatitis B virus (HBV) replication with HBV DNA detectable in liver tissue in the absence of detectable surface antigen of HBV in serum. Some studies indicate that OBI may favor the increase of liver fibrosis and the development of hepatocellular carcinoma in patients with chronic hepatitis C, whereas other investigations refute this. Here, we review all the available data on this topic and discuss the possible influence of OBI on the natural course of chronic hepatitis C.