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.