Sequencing analysis of hepatitis C virus mixed genotype in a hemodialysis patients.

Abstract

It has become clear that the genotypes of HCV vary with respect to pathogenicity, infectivity, response to antiviral therapy and geographic clustering. The prevalence of genotype distribution of HCV infection in Taiwan was investigated by typing with type-specific DNA primers in HCV core region. Using a design by Okamoto et al., it was found that in 280 serum samples examined, 3.3% (4/122) of the virus detected were mixed type. The implication of mixed type infection remains to be clarified: whether it is a single infection with a new variant, or infection with two HCV virions at different times or confusion with type-specific DNA primers themselves. The nucleotide sequences of the recombinant plasmid DNAs and the PCR products recovered from gel electrophoresis were analyzed by autosequencer. Gene sequences of HCV cDNAs of the two blood donors were used as control. To double check the results, we have also analyzed the DNA sequences of the cloned plasmids in the NS5 region with the primer system designed by Chayama et al. Results indicated that the hemodialysis patient was doubly infected with HCV, rather than by a HCV variant.