Serum levels of HCV RNA and core protein before and after incubation at 37degrees C for 24 h

The kinetics of HCV during interferon (IFN) therapy have recently been desc ribed and the estimated virion half-life is an average of 2.7 h, suggesting that HCV infection is highly dynamic. The aim of this study was to evaluat e serum levels of HCV-RNA and HCV core protein (HCV-AE) before and after in cubation at 37 degreesC for 24 h. We also evaluated the viral kinetics duri ng IFN treatment by determining their serum levels at 0, 24 and 48 h, and d ay 8 after the start of treatment. The decay slope was calculated as the lo garithm of the ratio of HCV-RNA levels at 0 and 24 h of incubation: log(vir us load) 24 h-1og(virus load) 0 h and the estimated half-life was also calc ulated. The decay slope was - 1.66 +/- 0.75 (- 4.12 to - 0.18) (mean +/- S. D. (range)) and the estimated virion half-life was 6.2 +/- 6.9 h (1.8-39.3) . The HCV-RNA level was rapidly decreased to 6.8 +/- 13.1% of the initial l oad after incubation independently of the serotype. In contrast, the HCV-Ag level after incubation for 24 h was 98.7 +/- 12.2% of the initial level. T he synthesized naked HCV-RNA (equivalent to 10(7) copy/ml) was not detected after 1-min incubation. These data suggested that HCV virions are very uns table and collapsed rapidly and that HCV-RNA, existing outside of virions, is immediately degraded in serum, whereas HCV-Ag remains stable. IFN treatm ent caused a rapid decrease in the levels of both HCV-RNA and HCV-Ag. The H CV-RNA decay slope was - 1.95 +/- 0.96 (range: - 3.48 to - 0.50) and was si milar to that seen in the incubation study. Our result suggested the signif icance of measuring HCV-Ag during clinical management independently of HCV- RNA, especially because of its high stability. (C) 2001 Elsevier Science Ir eland Ltd. All rights reserved.