Serum hepatitis C virus core protein level during interferon-α therapy in patients with chronic hepatitis C: relationship between biochemical and virologic responses

Abstract

Although interferon-α (IFN) has been shown to provide effective therapy in patients with chronic hepatitis C, the relationship between virologic and biochemical responses to IFN therapy is not well understood. To quantitate viremia levels of hepatitis C virus (HCV)—with a simple and stable method compared with quantitation methods of HCV RNA— a fluorescent enzyme immunoassay (FEIA) has been developed to quantify core protein level. To investigate the biochemical and virologic responses to IFN therapy, serum HCV core protein levels were serially quantitated by FEIA before, during and after IFN therapy in 35 Japanese patients with chronic hepatitis C. The biochemical response to IFN therapy was defined by the serum alanine aminotransferase (ALT) level, as complete and sustained response (SR, n = 14), complete response during IFN followed by relapse after IFN (Rel, n = 7), complete response but followed by relapse of ALT during IFN (BT, n = 6) and no response (NR, n = 8). In the same way, the virologic response to IFN was defined by the serum HCV core protein level as vSR ( n = 14), vRel ( n = 10), vBT ( n = 7) and vNR ( n = 4). All the SR patients showed vSR. Of seven Rel patients, six showed vRel and one showed vNR. All six BT patients also showed vBT. In contrast, of eight NR patients, four (50%) showed vRel and one (12.5%) showed vBT, while three (37.5%) were vNR. Among the four biochemical response groups, there was no difference of age, gender, history of transfusion and the ratio of HCV genotype (1:2), however there was a significant difference in the pretreatment HCV viremia levels between the SR patients and other patients ( P < 0.01). There was no significant difference in clinical and virologic characteristics among the Rel, BT and NR patients. This data indicates that (1) the low pretreatment HCV core protein level was a predicting factor of SR and (2) there were heterogeneous virologic responders in the NR patients.