[Antibodies against hepatitis C virus. Experience with a second generation test]

Area of Science:

• Virology
• Immunology
• Diagnostic Assays

Background:

• Hepatitis C virus (HCV) infection diagnosis relies on serological assays.
• Early enzyme-linked immunosorbent assays (ELISA) for anti-HCV antibodies, like those using the c100-3 antigen, showed limitations.
• Second-generation assays are needed to improve diagnostic accuracy and identify specific viral components recognized by antibodies.

Purpose of the Study:

• To evaluate the performance of the second-generation Recombinant Immunoblot Assay II (RIBA II) for detecting antibodies against Hepatitis C virus (HCV).
• To assess the reactivity of RIBA II against individual antigenic components, including new structural antigens (c33c, c22-3), compared to the original ELISA c100-3.
• To determine the diagnostic utility of RIBA II in confirming HCV infection in patients with various liver conditions.

Main Methods:

• Applied RIBA II to 30 serum samples previously found repeatedly reactive to ELISA anti-HCV c100-3.
• Included samples from hemodialysis patients, chronic hepatitis patients, and cirrhosis patients.
• Analyzed antibody reactivity against four HCV antigenic components: c100, 5-1-1, c33c, and c22-3.

Main Results:

• RIBA II showed a 77% (23/30) reactive rate, 13% (4/30) indeterminate, and 10% (3/30) non-reactive results.
• Significant variation in antigen-specific antibody responses was observed.
• The c22-3 antigen, a structural component, exhibited the highest reactivity and intensity, indicating superior sensitivity.

Conclusions:

• RIBA II is a valuable tool for confirming HCV infection in ELISA-reactive sera.
• The inclusion of new antigens, particularly the structural c22-3, enhances the sensitivity and diagnostic capability of second-generation HCV antibody assays.
• RIBA II results correlated well with ELISA, with non-reactive RIBA samples showing low ELISA optical density, underscoring assay concordance.