LIVER STELLATE CELLS IN CHRONIC VIRAL-HEPATITIS - THE EFFECT OF INTERFERON THERAPY

Background/Aims: Liver stellate cell proliferation and differentiation into myofibroblast-like cells is related to the development of liver fibrosis, Several cytokines, including interferons, regulate liver ste llate cell proliferation and phenotypic modulation, Recent studies ind icate that human liver stellate cells express the alpha-isotype of act in, specific to smooth muscle cell differentiation. We aimed to evalua te the expression of alpha-smooth muscle actin-positive liver stellate cells in patients with chronic viral hepatitis and to evaluate whethe r and how such expression can be modified by a-interferon treatment. M ethods: Using immunohistochemistry and a semi-quantitative scoring met hod, we evaluated alpha-smooth muscle actin expression in liver stella te cells before and after alpha-interferon therapy in a series of live r biopsies from 44 patients with chronic viral hepatitis. Results: Bef ore therapy, a large number of liver stellate cells expressing alpha-s mooth muscle actin were present throughout all acinar zones. A signifi cant reduction in alpha-smooth muscle actin expression by liver stella te cells was demonstrated in biopsies performed after suspending the i nterferon treatment. The drop in the number of alpha-smooth muscle act in-labelled cells after therapy correlated closely with the improvemen t in the histological index of activity. Conclusions: The results sugg est a specific effect of interferon on liver stellate cells, possibly related to its anti-inflammatory action.