Immune responses to liver membrane antigens in patients with cystic fibrosis and liver disease.

Biliary obstruction by viscid mucus, although important, may not be the only factor for the development of liver disease in some patients with cystic fibrosis. In the present study the relationship between immune responses to liver antigens and the presence of liver damage was investigated using the leucocyte migration test and lymphocyte cytotoxicity to isolated rabbit hepatocytes. Inhibition of leucocyte migration by purified liver-specific lipoprotein, derived from hepatocyte plasma membrane, was found in 9 of 11 children with liver disease, but in only 5 of 14 with cystic fibrosis and no overt liver disease (P < 0.025). Lymphocyte toxicity to isolated rabbit hepatocytes was significantly increased in 10 of 13 children with liver disease, but in only 6 of 29 children without liver disease (P < 0.001). Experiments using lymphocyte subpopulations showed that the cytotoxicity was mediated by a non-T-cell population and could be blocked with liver-specific lipoprotein in 7 out of 10 cases, suggesting that the reaction in these patients was specifically directed against liver-specific lipoprotein. The study suggests that sensitisation against liver membrane antigens, whether arising primarily or secondarily in some way to other hepatic lesions, may contribute to the progression of liver damage in cystic fibrosis.