VARIATION OF HEPATITIS-C VIRUS HYPERVARIABLE REGION-1 IN IMMUNOCOMPROMISED PATIENTS

The viral variability of 5 hepatitis C virus (HCV)-infected immunocomp romised patients was analyzed and compared with that in isolates from immunocompetent subjects. The patients were followed longitudinally wi th regard to changes in hypervariable region 1 (HVR1) of HCV using a d irect DNA sequencing approach. For the immunocompromised patients, vir al nucleotide sequence variability was markedly lower than in immunoco mpetent HCV-positive patients, For 1 agammaglobulinemic patient and 1 AIDS patient, no variation in the major amino acid sequence of HCV HVR 1 could be observed, while another agammaglobulinemic patient exhibite d transient variations and amino acid substitutions despite the lack o f functioning humoral immune response, The study supports the general hypothesis of humoral immune selection as the main force of sequence v ariation in the HVR1 region but suggests that other selection mechanis ms may contribute to modulation of the composition of the viral popula tion.