RESUMO
BACKGROUND: To determine the relationship between diversity of hepatitis C virus quasispecies and viremia, activity of liver disease and response to interferon therapy. METHODS: HCV quasispecies heterogeneity in 68 patients with chronic hepatitis C were detected by single stranded conformational polymorphism (SSCP) analysis of the HCV E2 hypervaribale region 1 (HVR1); of these, 48 were subsequently treated with interferon-alpha for 6 months. RESULTS: HVR1 was amplified in 61 patients. The average number of SSCP bands was 6.2+/-2.4. Quasispecies heterogeneity significantly correlated with serum HCV RNA levels (P<0.01), but not with serum ALT, AST levels and histological activity index (P>0.05). Of the patients who received interferon therapy, 43 were HVR1 positive. Patients who gained sustained response (n=11) had lower pre-treatement quasispecies heterogeneity (3.3+/-1.2) compared to those who had complete end-of-treatment response (ETR) with relapse (6.3+/-2.2, n=12, P<0.5) or no response (8.0+/-3.3, n=20, P<0.01). At the end of treatment, HVR1 could still be detected in 16 patients. The number of quasispecies heterogeneity in these patients decreased to 3.4+/-1.2, which was significantly lower than that in the patients who didn't receive interferon therapy (6.8+/-2.5, P<0.01). Of these 16 patients, 10 had change in quasispecies patterns. CONCLUSIONS: Increased quasispecies heterogeneity can cause high HCV viremia, but it is not related to severity of liver disease. Quasispecies heterogeneity is another marker to predict the response to interferon-alpha in patients with chronic hepatitis C.
