Study on reliability of commercially available hepatitis C virus antibody tests

Abstract

The serodiagnosis of hepatitis C virus (HCV) infection was analyzed by a recombinant immunoblot assay (RIBA) with recombinant proteins encoded by the viral RNA isolated from our patients in Hamburg, Germany. The HCV RNA was amplified by PCR, and proteins encoded by the viral core and the NS3, NS4, and NS5 regions were expressed subsequently in Escherichia coli. The results obtained with our UKE RIBA were compared with the results of the Abbott HCV second-generation enzyme immunoassay (EIA). Serum samples from 270 patients, which were sent to us on the suspicion of HCV hepatitis and which were negative for hepatitis A virus and hepatitis B virus antibodies, were examined. In 227 cases (84.1%), there were identical positive (204 cases, 75.6%) or negative (23 cases, 8.5%) results in both tests. In 32 cases (11.9%), the reactive Abbott second-generation HCV EIA results could not be confirmed by the UKE RIBA and the HCV PCR. In follow-up studies conducted over 1 year, these results did not change. In three cases (1.1%), the UKE RIBA presented a positive result while the Abbott second-generation HCV EIA was negative. All three cases were positive in the HCV PCR and showed seroconversion in an HCV EIA 4 to 6 weeks later. In addition, 33 patient serum samples were examined by UKE RIBA in parallel with the Ortho RIBA 2.0. In three cases (9.1%), a positive Ortho RIBA 2.0 result could not be confirmed by the UKE RIBA and the HCV PCR. All three patients were free of complaints. The UKE RIBA showed also a smaller number of indeterminate results (3.0%) than the Ortho RIBA 2.0 (24.2%). This comparison study demonstrates that the commercially available HCV antibody tests should be further improved.

Recurrent and new hepatitis C virus infection after liver transplantation

“…In contrast, in the non-immunosuppressed population, the loss of anti-HCV is uncommon, even when RIBA-negative. 20 Interestingly, some of the four bands of reactivity detected by RIBA-2 were lost after transplantation, particularly antibody to the 5-1-1 nonstructural antigen.…”

Definition of False-Positive Reactions in Screening for Hepatitis C Virus Antibodies

“…Therefore, results obtained by EIA need to be confirmed by additional testing. However, the commercially available assay RIBA 2.0 (Chiron Corporation) does not fulfill the criteria defining a confirmation assay since it consists of recombinant proteins identical to those in the EIA (1,5,9). HCV PCR cannot be used for confirmation of positive EIA results, since a negative PCR result does not exclude the possibility of HCV infection with low-level viremia (below the limit of detection).…”

Non‐Structural Protein 3 of Hepatitis C Virus Inhibits Phosphorylation Mediated by cAMP‐Dependent Protein Kinase

“…It also interacts, in a ligand-independent way, with the corresponding receptor [8-101. The RNA genome of HCV encodes a polyprotein with 3010 [ll, 121 or 3011 [13] amino acids. The polyprotein is cleaved into a core protein, two envelope proteins and four non-structural proteins, named NS2-5 in analogy to the related flaviviruses [14], by cellular proteases and a virally encoded serine protease, which is localized in the NH,-terminal region of NS3 [15, 161. Although individual HCV proteins have not been isolated, it is possible to detect them in infected cells by means of immunofluorescence [17,181 and to synthesize recombinant proteins that can be identified with anti-HCV Ig [19]. Thus, the existence of the HCV proteins mentioned above is now accepted, although the exact boundaries of the proteins are still hypothetical.…”