Epidemiological characteristics and therapeutic strategies of hepatitis C virus genotype 6 in Guangxi area

Abstract

Objective To investigate the epidemiological characteristics and therapeutic strategies of patients infected with hepatitis C virus (HCV) genotype 6 in Guangxi area. Methods Serum samples were collected from 150 patients with serologic HCV RNA positive in Guangxi, China. Reverse transcription nested polymerase chain reaction (PCR) was employed to amplify HCV NS5B fragments and the DNA products were sequenced. The sequences obtained were compared with the sequences deposited in GenBank to construct a phylogenetic tree. Among the patients who accomplished 48-week treatment of interferon plus ribavirin and 24-week follow-up after stopping medication, 10 cases were infected with genotype 6a and 28 cases with genotype 1 HCV. The virological responses were evaluated at week 4, week 12, week 24 of treatment and week 24 after the end of the treatment. Results Among all recruited 150 cases, 21 (14.0%) cases were HCV genotype 6 including two subtypes 6a (n=20) and 6d (n=1). Genotype 6 HCV mainly affected intravenous drug users, especially with age of ≤40 years old. Phylogenetic tree showed that there was very close evolutionary distance between HCV 6 strains of Guangxi and Hongkong, China strains (Y12083, DQ 480515) and Vietnam strain (EU246930). All of 10 HCV genotype 6a patients who completed 48 weeks of antiviral therapy achieved sustained virological response (SVR). The rate of SVR was higher than that of genotype 1 patients, but without statistically different significance (10/10 vs 75.0%, P>0.05). Conclusion HCV genotype 6 in Guangxi area mainly affects young intravenous drug users with age of ≤40 years old, which has high homology with Hongkong, China and Vietnam standard strains. Patients with HCV 6 genotype infection treated with interferon plus ribavirin for 48 weeks usually achieve favorable SVR. Key words: Guangxi region; Hepacivirus; HCV genotype 6; Phylogenetic tree; Characteristics; Therapy