GENOTYPES OF HEPATITIS-C VIRUS IN TAIWAN AND THE PROGRESSION OF LIVER-DISEASE

The existence of four genotypes of hepatitis C virus (HCV) - types la, Ib, 2a, and 2b - has been suggested based on variations in nucleotide sequences of the core region. The aim of this study was to investigat e the prevalence of HCV ge notypes in chronic type C liver disease in Taiwan and correlate distinct genotypes to severity of liver disease. The genotypes of 175 patients with chronic type C liver disease were d etermined by a polymerase chain reaction with type-specific primers. T he prevalence of each genotype in Taiwan was as follows: type la, n=1 (0.6%); Ib, n=125(71.4%); 2a, n=21 (12%); 2b, n=6 (3.4%); mixed types, n=18 (10.3%); and unclassified, n=4 (2.3%). The demographic and clini cal features were comparable between patients with different genotypes , except that the mean peak serum transaminase levels of patients with double viruses and type Ib HCV infections were significantly higher t han were those of patients with type 2a virus. Moreover, type Ib HCV w as more prevalent in patients with liver cirrhosis alone or with hepat ocellular carcinoma. In conclusion, type Ib virus is the predominant g enotype in chronic hepatitis C in Taiwan, and type Ib virus and mixed infection may trigger more severe liver disease.