Effect of interferon therapy on RNA of GB virus C in the patients with chronic hepatitis who were co-infected with hepatitis C virus

Of 112 patients with chronic hepatitis C, 12 (11%) tested positive for RNA of GB virus C (GBV-C) by reverse-transcription polymerase chain reaction with primers deduced from the 5′ untranslated region. RNAs of GBV-C and hepatitis C virus (HCV) were followed in the 12 patients before and after they received 19 trials of interferon (IFN) therapy. GBV-C RNA disappeared from serum in 11 (58%) trials on eight patients. However, it stayed negative at 6 months after IFN only in two patients. One of them regained GBV-C RNA at 12 months and kept it thereafter, while an additional patient who failed to clear it at the completion of IFN turned negative at 24 months after therapy. Thus, two patients (17%) became persistently negative for GBV-C RNA. HCV RNA disappeared from serum at the completion of ten trials (53%) on eight patients, and stayed negative in three patients (25%). Two of them did not lose GBV-C RNA but kept normal transaminase levels. These results indicate that GBV-C is susceptible to IFN with a sensitivity comparable to but independent of HCV, and that GBV-C by itself would not elevate transaminases in hepatitis C patients who respond to IFN.