The significance of hepatitis G virus infection in patients with non-A to C hepatic diseases.

The clinical significance of hepatitis G virus (HGV) infection was studied in 35 patients with various liver diseases of unknown etiology. Diseases included 5 cases of acute hepatitis, 23 cases of chronic liver diseases, and 7 cases of hepatocellular carcinoma. None of the patients showed evidence of hepatitis A, B, or C virus infection. HGV RNA was detected by reverse transcription polymerase chain reaction (RT-PCR) within 5' untranslated region (5'UTR), nonstructure (NS) 3 region, and NS5 region. RT-PCR within 5'UTR and NS5 detected HGV RNA in 9 of 35 patients, while that within NS3 detected HGV RNA in only 2 patients. This result suggests that RT-PCR within 5'UTR and NS5 as a primer is more sensitive than NS3 in Japanese patients. HGV RNA was detected in 3 of 5 cases of acute hepatitis, 3 of 23 cases of chronic liver diseases, and 1 of 7 cases of hepatocellular carcinoma. The HGV positive rate was high in patients with acute hepatitis suggesting that HGV might cause acute liver injury. In patients with chronic liver injury, the elevation of serum ALT levels was mild for about 2 years, but persistent HGV infection existed. The studied patients had no causative agent except for HGV. Therefore, HGV was thought to be an important etiological agent for liver injury.