Expression of neural cell adhesion molecule in human liver development andin congenital and acquired liver diseases

In the liver, neural cell adhesion molecule (NCAM) is a marker of immature cells committed to the biliary lineage and is expressed by reactive bile du ctules in human liver diseases. We investigated the possible role of NCAM i n the development of intrahepatic bile ducts and aimed at determining wheth er immature biliary cells can contribute to the repair of damaged bile duct s in chronic liver diseases. Therefore, we performed immunohistochemistry f or NCAM and bile duct cell markers cytokeratin 7 and cytokeratin 19 on froz en sections of 85 liver specimens taken from 14 fetuses, 10 donor livers, 1 8 patients with congenital liver diseases characterized by ductal plate mal formations (DPMs), and 43 cirrhotic explant livers. Duplicated ductal plate s and incorporating, bile ducts during development showed a patchy immunore activity for NCAM, while DPMs were continuously positive for NCAM. Bile duc ts showing complete or patchy immunoreactivity for NCA M were found in cirr hotic livers, with higher frequency in biliary than in posthepatitic cirrho sis. Our results suggest that NCAM may have a function in the development o f the intrahepatic bile ducts and that NCAM-positive immature biliary cells can contribute to the repair of damaged bile ducts in chronic liver diseas es.