Serum samples from 226 patients covering a wide spectrum of
liver disease were tested for
antibodies to hepatitis C virus (HCV) using both first and second generation
enzyme linked
immunosorbent assays. Selected sera were also tested by
peptide immunoassays, by the four-
antigen recombinant immunoblot assay (RIBA II), and for viral genome by the polymerase chain reaction. Antibody to c100-3 was detected in 61% of patients with chronic non-A, non-B (NANB)
hepatitis and/or 46.5% with presumed NANB-related
cirrhosis by the first generation test. These figures increased to 77% and 58% when
antibodies to recombinant structural and non-structural HCV
antigens were sought by the second generation assay. Supplemental testing against
peptide Sp75 and Sp65/sp67 confirmed that reactivity of sera by second generation assays was due to
antibodies to the additional structural and non-structural
antigens. Samples negative by the first generation assay were not confirmed by the supplemental assay using
peptides Sp75 and Sp65/Sp67. HCV
RNA was detected in 60% of the anti-HCV positive sera tested, most of which were also RIBA II positive. Our findings confirm that the introduction of the structural and non-structural
antigens, especially the putative
nucleocapsid protein, improves sensitivity of detection of
antibodies to HCV, and facilitates diagnosis in patients with "
cryptogenic" chronic hepatitis.