Efficacy of interferon therapy to GBV-C/HGV in patients with GBV-C/HGV and HCV coinfection

Abstract GB virus C (GBV-C) and hepatitis G virus (HGV) seemed to be the cause of hepatic injury in a setting of both acute and chronic infection. Some patients with hepatitis C virus (HCV) infection were coinfected with GBV-C/HGV. In the present study, we examined the effect of interferon on the GBV-C/HGV in chronic hepatitis C patients who were coinfected with GBV-C/HGV, in order to clarify the clinical significance of GBV-C/HGV infection. For GBV-C/HGV-RNA detection, the reverse transcription-nested polymerase chain reaction (RT-PCR) with primers from the 5′ untranslated subgenomic region was used. For GBV-C/HGV-RNA quantitative analysis, competitive RT-PCR was employed. Polymerase chain reaction products were directly sequenced. During IFN therapy, serum GBV-C/HGV-RNA became negative in nine patients (90%). However, a breakthrough of GBV-C/HGV was seen in two patients (20%), a virological relapse was seen after the cessation of IFN therapy in four patients (40%), and only three patients (30%) were sustained as negative. The changes in serum alanine aminotransferase levels after the cessation of IFN therapy correlated well with the changes in HCV-RNA. However, the correlation with GBV-C/HGV-RNA was poor. These results suggest that [1] GBV-C/HGV is sensitive to IFN therapy; and [2] In chronic hepatitis C patients coinfected with GBV-C/HGV and HCV, HCV appears to be involved with hepatocellular injury. It is less likely that GBV-C/HGV is directly involved in the initiation and progression of hepatic injury.