The levels of
2'-5' oligoadenylate synthetase activity (2-5AS) were measured in the lymphocytes and sera of 32 patients with acute viral
hepatitis and 20 patients with
HBeAg positive chronic type B
hepatitis, and the relationship between the effectiveness of
interferon (IFN)
therapy and 2-5AS reactivity was then studied. The lymphocyte 2-5AS (L.2-5AS) and the serum 2-5AS (S.2-5AS) levels in patients with any type of acute viral
hepatitis at the acute stage were significantly higher than in the healthy subjects. The 2-5AS level in cases of acute type A viral
hepatitis was significantly higher than in type B and type non A non B
hepatitis. However, no significant difference in the 2-5AS levels between type B
hepatitis and type non A non B
hepatitis was observed. After recovery, the L.2-5AS and S.2-5AS levels decreased in patients with any type of acute viral
hepatitis. No significant difference between the L.2-5AS level in healthy subjects and patients with chronic type B
hepatitis was observed. The S.2-5AS level was significantly higher in patients with chronic type B
hepatitis than in healthy subjects. During IFN administration, the L.2-5AS and S.2-5AS levels increased, with the maximum level and maximum rate of increase obtained on the 3rd day with respect to the L.2-5AS, and after one week with respect to the S.2-5AS. Of the 20 patients with chronic type B
hepatitis with positive HBe
antigen, 11 showed normalization of
DNA-P, 4 disappearance of HBe
antigen and 2 seroconversion of HBe
antigen. In cases with a higher maximum rate of increase of the L.2-5AS, the effect of IFN
therapy was observed to be greater.