Cytotoxicity of spleen T lymphocytes against autologous biliary epithelial cells in patients with primary biliary cirrhosis

Abstract

The mechanism of biliary epithelial cell injury was examined by assessing spleen-derived lymphocyte cytotoxicity to autologous biliary epithelial cells in patients with primary biliary cirrhosis(PBC). Spleen-lymphocytes had cytotoxicity against autologous biliary epithelial cells in all of 3 patients with PBC but in none of 6 patients with non-PBC. The cytotoxicity was found in T cells butnot in non-T cells. CD8 positive T lymphocytes were shown to be responsible for the cytotoxicity by negative depletion and the cytotoxicity was partially suppressed by anti-MHC class I. It was suggested that T cell cytotoxicity functioned through the interaction with MHC class I antigens. The cytotoxicity was dose-dependently suppressed by anti-biliary epithelial cell antibody. Our data support the current hypothesis that the pathogenesis of PBC is due to T cell autoimmunity against biliary epithelium.