NUCLEOTIDE AND AMINO-ACID DIVERSITIES OF E2 NS1 HYPERVARIABLE REGION-1 AND RESPONSE TO INTERFERON THERAPY IN PATIENTS WITH CHRONIC HEPATITIS-C VIRUS-INFECTION/

To clarify the relationship between nucleotide and amino acid diversit ies of the E2/NS1 hypervariable region 1 (HVR1) of hepatitis C virus ( HCV) and response to subsequent interferon-c! (IFN) therapy, pretreatm ent serum samples were studied from 13 Japanese patients, who were inf ected with HCV genotype Ib, had similar histological profiles and seru m HCV RNA levels (1-10 million eq ml(-1)), and were subsequently treat ed with the same IFN treatment protocol. Nucleotide sequence of HVR1 w as determined by dideoxynucleotide chain termination in eight clones d erived from each serum sample. Nucleotide and amino acid diversities w ere calculated from the mean of the genetic distances among these eigh t clones by six-parameter method. Of the 13 patients, four showed a co mplete and sustained response, three were complete responders followed by early relapse, and six were non-responders to IFN therapy. No sign ificant differences in clinical or virological parameters among the th ree groups were found. There was no significant difference in.the dive rsity of HVR1 among the three groups, indicating that when host and vi ral factors were controlled, nucleotide and amino acid diversities in HCV HVR1 might not correlate well with response to IFN. (C) 1998 Elsev ier Science Ireland Ltd. All rights reserved.