Abstract

Objective: Occult hepatitis B virus (HBV) infection is characterized by presence of HBV infection with undetectable hepatitis B surface antigen (HBsAg). Diagnosis of occult HBV infection requires sensitive HBV-DNA polymerase chain reaction (PCR) assay. Occult hepatitis B is a new entity and the prevalence of it and its clinical importance has not been investigated yet in Iran. The aim of this study is to investigate the prevalence and clinical importance of occult hepatitis B among chronic liver disease patients in Iran. Methods: We studied 35 consecutive paraffin-embedded liver tissues cases referred to Research Center for Gastroenterology and Liver Diseases, Tehran, Iran during the year 2001 to 2002 for liver biopsy due to its elevation of alanine aminotransferase (ALT) levels for more than 6 months. Liver biopsies were reviewed and HBV-DNA and HBsAg and Hepatitis B core antigen were assayed in liver tissue by PCR and immunohistochemistry (IHC). Results: Our patients with chronic liver disease (CLD) included hepatitis C (77.1), cryptogenic liver disease (20), and autoimmune hepatitis (2.9). Histologically, chronic hepatitis, cirrhosis and non-specific changes were reported. Hepatitis B virus-DNA was detectable in 8 (22) patients; however, IHC was negative in all. Conclusion: Occult hepatitis B is relatively frequent among patients with CLD in Iran. It maybe associated with more advanced liver pathology (cirrhosis) and more aggressive clinical course (decompensated cirrhosis). Occult HBV infection causes strong suppression of viral gene expression.