Virological and serological characterization of asymptomatic blood donors positive for anti-hepatitis C virus antibody

To study the virological and serological characteristics of asymptomatic hepatitis C virus (HCV) carriers, 165 blood donors positive for antibody against HCV proteins by the second generation assay, were analyzed for their clinical backgrounds, serological reactivity against antigens derived from HCV by recombinant immunoblot assay, and the amount and genotype of HCV by the polymerase chain reaction. Compared with blood donors having abnormal levels of alanine aminotransferase (ALT), sera from the donors with normal levels of ALT reacted less frequently against NS4 antigens (anti-5-1-1: 34.4% vs. 54.5%, P = 0.0609; anti-c100-3: 34.4% vs. 56.1%, P < 0.05). Also the positivity for antibodies against these antigens were more frequent in sera from donors with genotype 1b HCV-RNA than other genotypes (anti-5-1-1: 61.0% vs. 23.5%, P < 0.01; anti-c 100-3: 61.0% vs. 26.5%, P < 0.01). The prevalence of each genotype in blood donors with normal ALT levels was different from that in patients with advanced liver disease (P < 0.05), genotype 1b being less and genotype 2a being more frequent. The number of HCV-RNA copies/0.5 ml in donors with normal ALT was 10(7.9 +/- 1.0) (n = 27) and that in patients with chronic liver disease was 10(7.4 +/- 0.8) (n = 116), the difference being statistically significant (P < 0.05). In conclusion, the results of this study suggest that asymptomatic blood donors carrying HCV have the serological and virological characteristics different from the patients with advanced liver disease.