Expression of intercellular adhesion molecule-1 and lymphocyte function-associated antigen-1 protein and messenger RNA in primary biliary cirrhosis.

OBJECTIVE: This study examined the role of intercellular adhesion molecule-1 (ICAM-1) and lymphocyte function-associated antigen-1 (LFA-1) in the autoimmune process of bile duct destruction in the early stages of primary biliary cirrhosis (PBC).
MATERIALS AND METHODS: Ten PBC liver samples and five control samples were studied. Immunohistochemical studies of ICAM-1 and LFA-1, and Western blot of ICAM-1 were performed. Immunoelectron microscopy was conducted using immunoglobulin-gold and silver staining. Human ICAM-land LFA-1 peptide nucleic acid probes were used for in situ hybridization.
RESULTS: In PBC liver samples, immunohistochemistry showed aberrant ICAM-1 expression on bile duct epithelial plasma membrane and also luminal sites of endothelial plasma membrane of terminal portal venules. Western blot confirmed ICAM-1 protein expression. LFA-1-positive lymphocytes were associated with epithelial cells of septal and interlobular bile ducts. Immunoelectron microscopy localized ICAM-1 on the luminal and basal surfaces as well as on lymphocytes around damaged bile duct epithelial cells, and LFA-1 on lymphocytes around damaged bile ducts. Messenger RNA expression of ICAM-1 was demonstrated in bile ducts, and LFA-1 in lymphocytes around bile ducts.
CONCLUSION: De novo expression of ICAM-1 and LFA-1 at protein and mRNA levels in PBC may imply an inductive role of ICAM-1 through binding with its ligand LFA-1 in the extravasation of activated lymphocytes and lymphocyte-mediated bile duct destruction.