Serum inhibitory factors (SIF) are of prognostic value in acute viral hepatitis.

Serum inhibitory factors (SIF) were analysed in relation to the natural course of acute viral hepatitis in 81 patients followed over a period of 1 year. 63 patients recovered completely (group 1), and 18 had a protracted course of hepatitis (group 2) as shown by persistent transaminase activity 6 months after onset. 11 patients in group 2 still had signs of liver disease after 1 year. A gradual fall of SIF activity (in 47 patients) heralded resolving hepatitis, whereas persistence of SIF (in 8 patients) correlated with inflammatory activity and failure of hepatitis B viral antigen elimination. Absence of SIF activity was associated with either an uncomplicated or a chronic course of hepatitis in 23 and 3 patients, respectively. Repeated determination of SIF may help to predict the final outcome of hepatitis. Both excessive and failure of SIF production may result in the development of chronic liver disease.