ELSEVIER International Hepatology Communications 2 (1994) 358-362 zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA Internationul Hepatology commLlrlicationS Relationship of serum 2.5 oligoadenylate synthetase activity during interferon therapy to pretreatment levels or genotypes of serum HCV-RNA Michiari Okuda”*, Keisuke Hino”, Kouzou Kayanoa, Masafumi Kubotaa, Kazuyuki Takenakaa, Kenji Mori”, Aogu Yamashitaa, Isao Sakaida”, Fujio Murakamia, Mitsuru Yasunagaa, Kiwamu Okita”, Tomomi Konishi” zyxwvutsrqponmlkji “First Department of Internal M edicine, Yamaguchi University School zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQ of Medicine, I144 Kogushi, Ube, Yamaguchi, 755, Japan bDepartment of Internal M edicine, Shutoh General Hospital, Yamaguchi, Japan (Received 2 1 February 1994;accepted 28 April 1994) Abstract 2.5 oligoadenylate synthetase (2SAS) activity is induced during interferon (IFN) therapy of patients with chronic hepatitis C. It is assumed that the genotype and quantitative level of hepatitis C virus RNA (HCV-RNA) in serum preceding IFN therapy are closely associated with the response to IFN. However, it is not clear whether these viral factors may affect 2SAS activity during IFN therapy. We analyzed 2.5AS activity during IFN therapy in patients with different genotypes or levels of serum HCV-RNA. However, there were no statistical differenc- es in 2.5AS activity among them. In the present study, those viral factors were not associated with the induction of 2.5AS activity during IFN therapy, and it is unlikely that differences in response to IFN among patients with different genotypes or quantitative levels of HCV-RNA depend on the 2.5AS pathway. Key words: Serum 2.5AS activity; Quantitative serum HCV-RNA level; Genotype 1. Introduction Although the binding of interferon (IFN) to specific liver cell membrane receptors induces the synthesis of multiple antiviral proteins [l], 2.5 oligoadenylate synthetase (2.5AS), the well-known IFN-induced protein, is clinically relevant in establishing the mechanisms of IFN activity and its optimal dosage. Genotypes of hepatitis C virus (HCV)-RNA and quantitative HCV-RNA levels in serum are assumed to be closely *Corresponding author. 0928-4346/94/%07.00 0 1994 Elsevier Science B.V. All rights reserved SSDI 0928- 4346(94)00033- 2