[PCR-based HCV genotyping with type-specific primers derived from core gene and IFN responsiveness]

Based on the sequence similarity of HCV isolates for which the entire nucleotide sequence is determined, at least five genotypes of HCV (I, II, III, IV and V) have been reported which differ from each other in more than 21% of approximately 9.4 kilobases. HCV genomes are classifiable into the five defined genotypes by PCR amplification with type-specific primers derived from core gene. Genotype of HCV appears to an important factor in determining the response to IFN in patients with chronic hepatitis C. It would be worthwhile to genotype HCV in pretreatment sera, for correlation with therapeutic efficacy of IFN for chronic hepatitis C, in districts where HCV variants with unclassifiable genotypes are prevailing and therapeutic trials are planned.