Molecular analysis of HCV type 1 to 5 envelope gene: application to investigations of posttransfusion transmission of HCV

BACKGROUND: Until 1990, HCV infection was common in transfused patients, re sulting in more than 200,000 cases of posttransfusion hepatitis C in France alone. A molecular method that permits the investigation of posttransfusio n hepatitis C infections is presented. STUDY DESIGN AND METHODS: Viral sequences in the envelope region of HCV wer e obtained for 12 pairs of blood recipients and their respective blood dono rs. The HCV strains studied belonged to types 1 (subtypes la and Ib), 2, 3, 4, and 5. Genetic distances and mutation rates were determined, and sequen ces were submitted to phylogenetic analysis along with sequences retrieved from nucleotide databases. RESULTS: Pairwise distances in the donor-recipient pairs were found to be l ess than 0.05 mutation per site, which corresponds to a mutation rate rangi ng from 0.6 x 10(-3) to 2.1 x 10(-3) per site per year. Sequences obtained from the 12 donor-recipient pairs clustered in 12 monophyletic nests. CONCLUSION: The genetic analysis of the envelope region of HCV can be used for the forensic evaluation of virus transmission. It permits the refutatio n of a link between blood transfusion and HCV transmission, rather than pro of of the existence of such a link.