Occurrence of identical hypervariable region 1 sequences of hepatitis C virus in transfusion recipients and their respective blood donors: Divergenceover time

A total of 240 stored serum specimens from 30 transfusion recipients and 12 0 blood donors from the Transfusion-Transmitted Viruses Study (TTVS) were e valuated with the objective of establishing transmission of hepatitis C vir us (HCV) by specific blood donors. Phylogenetic analysis of hypervariable r egion 1 (HVR1) and HCV genotyping were performed on the genomic region enco ding amino acids 329 to 410. Amino acid distances between HVR1 sequences we re calculated by the Kimura formula. Bootstrap analysis of HVR1 sequences p rovided support for linking recipients to specific donors. Linear regressio n analysis showed no differences between donor and recipient HVR1 sequences 7.9 weeks posttransfusion, but donor and recipient sequences diverged ther eafter (r = 0.690). The initial lag phase in the evolution of HVR1 in the i nfected recipient was attributed to the time required to mount host immunol ogic defenses against the virus. Within-recipient divergence in HVR1 was de termined from analyses of serial specimens collected within 2 weeks after t he alanine transaminase peak, at the end of the original study (1974-1979), and in the follow-up study (1987-present). HVR1 remained invariant over a period of 6.7 to 9.5 days (95% CI) during acute infection. Within-patient d ivergence in HVR1 increased over a period of 11 to 15 years (r = 0.771), re aching the degree of divergence observed between unlinked subjects. In case s in which transfusion involved more than one HCV subtype, only one of the HCV subtypes established infection in the recipient. Subtype-specific diffe rences in HVR1 were shown.