FLOATING DENSITY OF HEPATITIS-C VIRUS-PARTICLES AND RESPONSE TO INTERFERON TREATMENT

Hepatitis C virus (HCV) particles can be classified into two major fra ctions according to their floating density in serum. However, the geno mic heterogeneity of each fraction and the relationship between this v iral characteristic and interferon (IFN) response in patients with chr onic hepatitis are nor known, in this study, floating density and sing le strand conformation polymorphism (SSCP) of the hypervariable region 1 (HVR1) of HCV were examined in 16 patients with chronic hepatitis p rior to IFN treatment. The ratio of HCV RNA titers in the top (T) and bottom (B) fractions, or T:B ratio, was 10:1 in 4 patients, 1:1 in 7, and 1:10 in 5. Three of the 4 patients with a 10:1 ratio showed a sust ained response to IFN, while none of the 5 patients with a 1:10 ratio demonstrated a sustained response (P < 0.05). All 4 patients with a 10 :1 ratio had 1 or 2 SSCP hands, and 4 of the 5 patients with a 1:10 ra tio had 4 or 5 bands (P < 0.01). Furthermore, the number of SSCP bands in the top fraction from 6 sustained responders (1.8 +/- 0.3) was sig nificantly smaller than from 10 non sustained responders (4.1 +/- 0.8) (P < 0.05). Thus, patients with a high T:B ratio and low heterogeneit y in HVR1 demonstrated sustained responses to IFN, while those with lo w T:B ratios and high heterogeneity did not. (C) 1998 Wiley-Liss, Inc.