Hepatitis C virus antibody prevalence among human immunodeficiency virus‐1‐infected individuals: Analysis with different test systems

Abstract

Sera of 383 human immunodeficiency virus (HIV)‐l‐infected individuals from Frankfurt (Main)/Germany were assayed by two hepatitis C virus (HCV) screening tests (Abbott second generation, Ortho second generation). This population showed a prevalence for reactivity with both tests of 20.8% (80/383). Examination of all reactive sera (91/383) by a supplemental assay (Chiron RIBA 2) gave for 46 sera a positive, for 33 sera an indeterminate, and for 12 sera a negative result. Further analysis focussed on these RIBA 2‐indeterminate and ‐negative samples. Analysis of the sera using an in‐house Western blot with three different Escherichia coli‐expressed HCV proteins revealed that none of the RIBA 2‐nega‐tive, but 24 of the 33 RIBA 2‐indeterminate sera, including 3 of 4 c33c (NSS)‐reactive samples, were reactive with a recombinant core protein. Twenty‐one of 22 c22‐3 (core) indeterminates stained the core antigen in the in‐house Western blot and 3 of them in addition a NS5 moiety. HCV‐polymerase chain reaction (PCR) was positive for 14 of the 24 RIBA 2 ‐indeterminate sera, but for none of the RIBA 2‐negative or Western blot nonreactive samples. Discrepant results between the two screening tests could not be explained by differences in the antigen compositions (i.e., a NS3‐NS4 moiety of 111 amino acids present in the Ortho enzyme‐linked immunosor‐bent assay (ELISA), not present in the Abbott or RIBA 2 assays).