Evaluation of quantitative assay for antibody to hepatitis C virus core in patients treated with interferon.

We titrated antibody to hepatitis C virus (anti-HCV) core of serum samples from 57 patients with chronic HCV infection, in an attempt to clarify the relationship between the level of HCV RNA and the outcome of interferon treatment. The patients studied were positive for both anti-HCV, by second-generation assay, and HCV RNA, by polymerase chain reaction, and had been treated with interferon for six months. Of the 57 patients, HCV RNA was eliminated in 16 by the time of discontinuation of interferon treatment (CR); in 19 this elimination was transient (PR) and for 22 elimination was nil (NR). The low HCV RNA level was accompanied by high titers of anti-HCV core while high HCV RNA levels were accompanied by low titers of anti-HCV core, with an inverse correlation (r = -0.322, P < 0.05). The mean titer of anti-HCV core before interferon treatment was 324 units in CR, 205 in PR, and 168 in NR, with a correlation ratio of 0.382 (P < 0.05). A decreased titer (more than 50%) was found in 68% of the CR. At the time of six-month follow-up, the anti-HCV core titers of CR had decreased by more than 50%, compared to pretreatment titers, while in PR and NR, there was an increase to above the pretreatment titers, without increases in HCV RNA levels or worsening of the hepatitis. In conclusion, quantitative assay for anti-HCV core is useful to assess the status of HCV replication.