Clinical utility of a hepatitis C virus core antigen assay in management of chronic hepatitis C

Abstract

Background : Hepatitis C virus (HCV) core antigen (cAg) is known to be correlating with HCV RNA, and may be used an alternative marker for assessing the levels of viremia in chronic hepatitis C (CHC) patients. In this study, we assessed the utility of HCVcAg assay in predicting treatment response to pegylated interferon (PEG-IFN) and ribavirin (RBV) therapy in CHC patients.Methods : Eighty-five patients with CHC, receiving a regimen of PEG-IFN and RBV therapy were retrospectively investigated. Pretreatment samples from enrolled patients were used to evaluate HCVcAg and HCV RNA assays (genotype1:57;genotype2:28).Results : Sustained virological response (SVR) was achieved in 49 (57.6%) patients (43.9% in genotype 1, and 85.7% in genotype 2). There was a good correlation between HCVcAg and HCV RNA concentrations (68/85 samples positive for both markers; r=0.713). Pretreatment levels of HCV RNA were not significantly different (p=0.088) and HCVcAg were significantly lower in SVR patients comparing of non-SVR patients (p=0.018). The area under the receiver operating characteristic (AUROC) to predict SVR was 0.609 for HCV RNA and 0.645 for HCVcAg and AUROC was not significantly different between HCVcAg and HCV RNA (p=0.53). The cutoff level of HCV RNA was 800,000 IU/mL (sensitivity, 42.9%; specificity, 86.1%; positive predictive value (PPV), 80.8%; negative predictive value (NPV), 52.5%; diagnostic accuracy (DA), 61.2%). The cutoff level of HCVcAg was 300 fmol/L (sensitivity, 44.9%; specificity, 86.1%; PPV, 81.5%; NPV, 53.4%;DA, 62.4). Combining HCV RNA < 800,000 IU/mL and HCVcAg 300 < fmol/L, the prediction of SVR by a single point evaluation achieved 31.3% sensitivity, 97.3% specificity, 93.8% PPV, 52.2% NPV, and 60.0% DA. Conclusions : Baseline quantification of HCVcAg is useful to predict treatment response, and considering the ease of use and low cost of this assay, it may be an important tool for evaluating therapeutic decisions in patients with CHC.