Recipient-derived T cells participate in autoimmune-like hepatic lesions induced by graft-versus-host reaction.

Autoimmune-like hepatic lesions were induced by injection of CD4+ T cells from B10.Thy-1.1 mice into MHC class II-disparate (B10.Thy-1.1 x bm12)F1 mice. Hepatic lesions characterized by mononuclear cell accumulation in the portal area of the central vein and around interlobular bile ducts were observed in these recipients. The morphologic features of the lesions resembled primary biliary cirrhosis. The origin of T cells invading at the site of the hepatic lesions was immunohistochemically analyzed. It was shown that many recipient-derived T cells were present at the lesions and that some of them infiltrated the bile duct epithelia. Furthermore, the lesions were weakened when recipient-type T cells were depleted by thymectomy and the administration of anti-Thy-1.2 monoclonal antibody. Recipient-derived T cells were observed to take part in the formation of autoimmune hepatic lesions. These findings suggest the possibility that the tolerance of self-reactive T cells is abrogated by the graft-versus-host reaction.