Utility of a novel HCV-NS4 antigen detection immunoassay for monitoring treatment of HCV-infected individuals with pegylated interferon α-2a

Hepatitis C virus (HCV) infection continues to be an emerging global health concern. With the advent of additional treatment protocols, a simple and reliable assay for changes in HCV load may permit more frequent patient assessment and tailoring of the therapeutic regimen. Recently, we have developed a highly sensitive and specific enzyme immunoassay (EIA) for the detection of an HCV-Nonstructural 4 (NS4) antigen in serum. Here, we evaluated the efficacy of the developed assay in monitoring the virologic responses to pegylated interferon alpha-2a. Thirty-six (HCV genotype IV) out of 150 initially screened chronic HCV patients met the entry criteria and randomly (in a 1:2 ratio) assigned to receive monotherapy with peginterferon alpha-2a (Pegasys) or combined therapy of peginterferon alpha-2a plus ribavirin; respectively. No significant differences (P > 0.05) were shown between the virologic responses defined by standard PCR-based HCV RNA testing and those defined by EIA-based HCV-NS4 antigen detection either at the end of treatment (week 24) or at the end of follow-up (week 48). Sustained virologic responses defined by the HCV-NS4 antigen in combined therapy patients were significantly higher (P < 0.05) than those in monotherapy patients. In conclusion, the HCV-NS4 antigen as an alternative direct marker of HCV infection may be suitable for use in monitoring HCV-infected patients. (C) 2003 Elsevier B.V. All rights reserved.