Serum 2'-5'oligoadenylate synthetase as a monitoring marker of anti-viral effect during interferon therapy for chronic type B hepatitis.

We evaluated the usefulness of serum 2'-5'oligoadenylate synthetase (2-5AS) activity assay in monitoring the anti-viral activity of chronic type B hepatitis patients during IFN therapy. The serum 2-5AS activity was rapidly increased during the above therapy and was maintained at a medium-to-high level throughout the therapy period, although the capacity for increase reflected differences among individuals. The kinetics of serum 2-5AS activity during the therapy was almost consistent with that of the PBMCs 2-5AS activity. 2-5AS activity had an inverse correlation with DNA-P; i.e. DNA-P often disappeared from serum after interferon treatment in patients with a marked response in serum 2-5AS activity. The enhancement of serum 2-5AS activity during IFN therapy seemed to correlate with an increase in anti-viral activity. The results suggest that the serum 2-5AS activity assay is a useful probe for monitoring the anti-viral activity of chronic type B hepatitis patients during interferon therapy.

Early loss of serum hepatitis C virus RNA can predict a sustained response to interferon therapy in patients with chronic hepatitis C.

OBJECTIVES: We evaluated whether the loss of serum hepatitis C virus (HCV) RNA early in interferon (IFN) therapy would indicate a subsequent response to IFN therapy. METHODS: One hundred fourteen patients with chronic hepatitis C were treated with IFN-alpha for 24 weeks. All patients were positive for anti-HCV antibodies and serum HCV RNA. Serum HCV RNA was measured by highly sensitive and specific RT-PCR (modified Amplicor HCV). RESULTS: Of 114 patients who were treated with IFN-alpha for 24 weeks, 22 of 29 patients (75.9%) who lost HCV RNA at the first week of treatment, 5 of 14 patients (35.7%) who lost HCV RNA at the second week, and 2 of 16 patients (12.5%) who lost HCV RNA at fourth week were judged as sustained responder (SR). The SR rate was significantly higher in patients who lost HCV RNA at the first week of therapy (p < 0.05). On the contrary, none of 55 patients who retained HCV RNA during the first 4 weeks of IFN therapy were judged as SR. Concerning the patients who lost HCV RNA at the first week of therapy, there were no significant differences in the SR rate in either HCV genotype (1b, 2a, and 2b). CONCLUSIONS: Our study confirms that the early response to IFN (loss of HCV RNA at the end of the first week of IFN therapy) can be a predictor of the subsequent sustained response to IFN therapy. Additionally, positivity of HCV RNA at the fourth week of IFN therapy can be a predictor of the subsequent nonsustained response to IFN therapy.