Hepatitis G virus infection in chronic hepatitis C: frequency, features and response to interferon therapy.

BACKGROUND/AIMS: The pathogenic relevance of the hepatitis G virus (HGV) and its sensitivity to interferon are currently under investigation. This study aimed to investigate the prevalence of HGV infection in patients with chronic hepatitis C and to elucidate if HGV co-infection modifies the clinical course and the response to interferon therapy in this disease. METHODS: HGV-RNA was investigated by reverse transcription-polymerase chain reaction in serum from 143 consecutive patients who received interferon alpha-2b (3 MU t.i.w.) for 24 weeks. Baseline features and response to therapy in HGV-infected and non-infected patients were compared. To assess the antiviral effect of interferon, serial quantitative measurement of HCV-RNA and HGV-RNA in serum was performed in patients co-infected with HCV and HGV. RESULTS: Eight patients (5.6%) presented HGV-RNA sequences in serum. No significant differences were found between HGV-infected and non-infected patients in relation to age, sex, source of infection, liver function tests, liver histology and HCV genotype, nor in the biochemical response to interferon, which was sustained in 12% and 15%, transient in 37% and 30% and absent in 50% and 55% of HGV-infected and non-infected patients, respectively. HGV-RNA became negative in all treated patients, but sustained viral inhibition was observed only in those with low viral load. CONCLUSIONS: The prevalence of HGV infection in HCV-infected patients is relatively low in our geographical area. HGV co-infection does not appear to modify the clinical presentation nor the response to interferon in chronic hepatitis C. HGV is sensitive to interferon, particularly if pre-treatment viral load is low.