Infection with hepatitis C virus. New generation of assays should improve screening

The relationship of histology to genotype in chronic HCV infection

The histological description of chronic hepatitis is undergoing considerable change at present. It has become important to define chronic hepatitis aetiologically and then define levels of necro-inflammatory change (grade) and fibrosis (stage). The aim of this study was to compare the ability of different histological scoring systems to detect differences in the pathological changes associated with infection with the different HCV genotypes that are known to have different natural histories. The histological appearances of liver biopsies from 29 HCV infected patients were compared by the Knodell histological activity index (HAI), modified histological activity index and the Scheuer histological scoring system. HCV genotyping was performed for each patient by sequence analysis of the 5' non-coding region. The histological appearances from HCV 1 infected patients showed a tendency towards more active necro-inflammatory changes when compared with those from HCV 2 or 3 infected patients. The levels of fibrosis were similar for all genotypes. The modified HAI and Scheuer scoring systems detected differences, not revealed by the Knodell system, in the types of inflammatory pathology produced by the different genotypes of HCV. In particular these scoring systems noted significant differences in the component scores of inflammation, in addition to the total inflammatory scores. In conclusion, the recently introduced scoring systems were able to detect differences in liver pathology produced by infection of similar duration with different viral genotypes. As genotype is considered an important determinant of disease progression and response to anti-viral therapy, it is likely that those scoring systems correlating with genotype will yield more useful histological information than those that do not.