Lymphocyte-mediated enhancement of hepatic fibrosis in chronic active hepatitis.

The effect of the supernatant from a culture of liver specific protein-stimulated lymphocytes on collagen production by cultured fibroblasts was examined. The supernatant from the culture of unstimulated lymphocytes was used as a control. Both supernatants were added to the culture medium of L929 fibroblast monolayer. After incubation for 72 hours, 1 microCi of tritium-labelled proline was added to the culture medium of the monolayer. The radioactivity of tritium labelled hydroxyproline incorporated into collagen was measured. The results demonstrated that the supernatant from the culture of stimulated lymphocytes enhanced collagen production in 5 of 6 cases of chronic active hepatitis and in 2 of 14 cases of chronic inactive hepatitis. These findings suggest that cellular immune regulation may play an important role in the development of hepatic fibrosis in chronic active hepatitis.