Occult Hepatitis B as a Cause of Cryptogenic Cirrhosis

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 PCR assay. Recently it has been shown that occult hepatitis B may be a cause of cryptogenic liver disease. The aim of this study is the investigation of occult HBV infection among patients with cryptogenic liver disease. 65 consecutive paraffin-embedded liver tissues from cases referred to RCGLD (Research Center for Gastroenterology and Liver Diseases) and THC (Tehran Hepatitis Center) during the years 2001 and 2002 for liver biopsy because of elevation of alanine aminotransferase (ALT) levels for more than six months were studied. Among these, 12 patients with cryptogenic liver disease were found. Human tissue DNA could be extracted in 7 of 12 patients. In these patients liver biopsies were reviewed and HBV-DNA and HBsAg and HBcAg were assayed in liver tissue by polymerase chain reaction (PCR) and immunohistochemistry (IHC), respectively. Histologically, chronic hepatitis, cirrhosis and nonspecific changes were reported. HBVDNA was detectable in 4 patients but IHC was negative in all. The frequency of occult HBV infection was more than 50%. Occult HBV infection is common among patients with cryptogenic liver disease. In these patients, HBV-DNA may be detected more frequently among patients with more advanced liver pathology (cirrhosis) and more aggressive clinical course (decompensated cirrhosis).