Kinetics and Significance of Serum Hepatitis C Virus Core Antigen in Patients with Acute Hepatitis C

Abstract

An immunoassay detecting hepatitis C virus core antigen was evaluated for its ability to predict clinical outcome in a series of patients with acute hepatitis C. In subjects who cleared the virus, core antigen was no longer detectable within 16 weeks of onset, whereas considerable fluctuations were noted among patients progressing to chronic hepatitis, one of whom showed consistently negative values despite the intermittent presence of viral RNA

Monitoring Response to Antiviral Therapy for Patients with Chronic Hepatitis C Virus Infection by a Core-Antigen Assay

“…Collectively, these findings confirm that HCV core antigen is a reliable surrogate marker of HCV replication only for HCV RNA titers above approximately 10,000 IU/ml, determined by a signal amplification technique, as shown in several previous studies (2,4,8)-although we did occasionally, but not reproducibly, detect core-antigen levels above cutoff in some samples for HCV RNA values around 5,000 IU/ml. It is important to emphasize that the HCV core antigen-to-RNA ratio may differ among patients, suggesting variations in the amount of core protein per RNA molecule in different sera, in agreement with the presence of excess core protein not associated with viral genomes and vice versa (2).…”

“…A standardized enzyme immunoassay for quantitative detection of circulating HCV core protein, originally developed for blood bank screening purposes, has been recently released. The assay is highly specific, even though it is less sensitive than molecular assays (2,4). The finding of a strong correlation with HCV RNA levels suggests that serum core antigen may represent an excellent surrogate marker of HCV replication (2).…”

“…Spontaneous resolution of persistent infection is anecdotical (3), and the current standard of care involves a long-term combination treatment with various formulations of alpha interferon and ribavirin (4). Therapeutic responses to antiviral drugs are currently monitored by qualitative or quantitative HCV RNA determination and-in most studies-early decline or disappearance of HCV RNA was found to be predictive of sustained virological response (9,10).…”

Subversion of effector CD8+ T cell differentiation in acute hepatitis C virus infection: the role of the virus

“…Therefore, a possible explanation, which we are attempting to verify in further studies, is that HCVcore affects only HCV-specific CTL priming in vivo, because the latter occurs in the hepatic environment, which should be a constant source of elevated HCVcore levels, as well as in our in vitro system. By contrast, CTL priming occurring in different anatomical districts might be randomly affected only in the case that a high peak of circulating HCVcore that generally is not maintained at constantly elevated levels [47], is present during the priming in that district. Studies are in progress in order to explore the interplay between HCVcore and CTL responses against unrelated hepatotropic viruses in HCV-coinfected individuals.…”

Benefit of Hepatitis C Virus Core Antigen Assay in Prediction of Therapeutic Response to Interferon and Ribavirin Combination Therapy

“…Methods for detecting viral antigens (Ag) were developed by applying a monoclonal antibody to the HCV core Ag (19,33,35); however, the assays have been insufficient for clinical application because of their low sensitivity and the requirement for complicated specimen pretreatment. An accurate and specific new HCV core Ag detection assay system (total HCV core Ag assay) (2) has recently been developed and is commercially available in European countries (trak-C assay) (7,20,24,25,31); it has a lower detection level limit of 1.5 pg/ml, which is equivalent to 20 KIU/ml. More recently, Lumipulse Ortho HCV Ag (Lumipulse-Ag), with a lower detection level limit of 50 fmol/liter (equivalent to 1.0 pg/ml), was developed in Japan (1,34).…”