Expertise of French laboratories in detection, genotyping, and quantification of hepatitis C virus RNA in serum.

Before initiating new large-scale therapeutic trials for hepatitis C virus (HCV)-infected patients, the French Health Authorities for HCV research decided to organize an evaluation of the expertise of laboratories that could be engaged to undertake molecular biology assays in such trials; 21 experienced laboratories participated in this national evaluation of laboratory expertise, which was performed in two successive rounds. The first round evaluated the laboratories for their abilities to detect HCV RNA in serum, determine genotypes, and quantify HCV RNA loads. The results observed by qualitative assays for HCV RNA detection were 100% sensitivity and 100% specificity for all laboratories. The genotyping results were 100% concordant for 9 laboratories and greater than 90% for 10 laboratories. By contrast, large coefficients of variation were observed for quantitative determination of HCV RNA loads, leading to a second round with standardized quantitative assays only. The dispersion of the results was larger by the AMPLICOR HCV Monitor assay than by the branched-DNA assay (mean coefficients of variation, 57.4 and 16.9%, respectively). In the majority of cases, discrepancies between the results of the two tests were found for samples with high viral loads. These results indicate the usefulness of validating, by controlling for expertise, both the reliabilities of laboratories involved in multicenter work and the standardized assays chosen for use in the evaluation of the biological impacts of new therapies.

Complete or partial seroreversion in immunocompetent individuals after self-limited HCV infection: consequences for transfusion.

BACKGROUND: The disappearance of anti-HCV antibodies over time, after a self-limited infection, also referenced seroreversion, has been observed. The frequency of this phenomenon remains controversial, especially in immunocompetent subjects. However, it has important implications in the context of transfusion inquiries, in particular in case of a blood donor suspected to have transmitted HCV through a past blood donation. STUDY DESIGN AND METHODS: Our findings are presented of a longitudinal study, including 16 patients from a cohort of 78 immunocompetent, multitransfused individuals who were positive for anti-HCV (EIA and confirmatory assay [RIBA]) and followed over a long period of time without having received any antiviral therapy. The aim was to establish whether a past and self-resolved HCV infection could evolve toward a negative serology. RESULTS: The 16 patients were classified in three groups: 1) 12 patients who remained anti-HCV positive with no evolution in their RIBA pattern after a mean follow-up of 7.6 years; 2) one patient who presented a complete seroreversion 6 years after enrollment; and 3) three patients with a partial seroreversion over a mean follow-up of 16 years. CONCLUSION: HCV infection is not always characterized by a persistent antibody response, even in immunocompetent individuals. This should be taken into consideration when transfusion inquiries are conducted.