Correlation of interferon treatment response with GBV-C/HGV genomic RNA and anti-envelope 2 protein antibody.

The clinical significance of GB virus C/hepatitis G virus (GBV-C/HGV) co-infection was studied retrospectively in 100 consecutive patients with hepatitis C virus (HCV) infection. All 100 patients had been treated with interferon-alpha (IFN-alpha). Co-infection with GBV-C/HGV and HCV was detected in 10 of the 100 patients (10%) and anti-envelope 2 region (anti-E2) antibody was detected in 25 patients. None of the patients with GBV-C/HGV RNA had anti-E2 antibody. Co-infected patients were younger (P < .005) and their serum transaminase levels were lower than HCV-only infected patients (P< .01). In 7 of the 10 co-infected patients, HCV RNA was eradicated from serum after IFN-alpha treatment and normal alanine transaminase (ALT) levels continued in 6 of these 7 patients. In one patient who was negative for HCV RNA but positive for GBV-C/HGV RNA, the ALT level relapsed transiently. The rate of clearance of HCV and normalization of the ALT level was significantly higher in co-infected patients than in HCV-only infected patients (P < .05). GBV-C/HGV RNA disappeared from 6 of the 10 co-infected patients (60%) upon cessation of IFN-alpha treatment. However, continuous clearance of GBV-C/HGV was observed in only two patients and anti-E2 antibody could not be detected in the serum of these patients. These results indicate that co-infected patients tend to be younger and more sensitive to IFN-alpha treatment. However, long-term clearance of GBV-C/HGV after IFN-alpha treatment may be difficult. Moreover, anti-E2 antibody may act to neutralize GBV-C/ HGV.