Detection of 2',5' oligoadenylate synthetase activity in acute viral hepatitis with special reference to histologic features in the acute stage.

We measured the sequential changes in 2',5' oligoadenylate synthetase activity in 21 patients with acute viral hepatitis (5 with type A, 6 with type B, and 10 with type non-A, non-B hepatitis) by radioimmunoassay. Liver biopsies were performed during the acute phase in all patients. Among patients with acute hepatitis A and B, the 2',5' oligoadenylate synthetase levels were transiently elevated at the time of the peak alanine aminotransferase level in the patients in whom a liver biopsy showed acute hepatitis or non-specific reactive hepatitis. Of 10 patients with acute non-A, non-B hepatitis, 4 showed a similar 2',5' oligoadenylate synthetase activity pattern and liver histology to those observed in acute hepatitis A and B. In the remaining 6, the 2',5' oligoadenylate synthetase levels remained elevated for 3.5 to 6 months while the alanine aminotransferase was elevated. Liver biopsy in these patients showed chronic hepatitis. Persistent detection of raised 2',5' oligoadenylate synthetase activity levels during the acute stage of non-A, non-B hepatitis may thus be an indicator of progression of the disease.