The development of proliferating ductular structures in liver disease. An immunohistochemical study

Proliferation of bile ductules or ductular hepatocytes occurs in a variety of liver diseases. The origin of these ductular structures and the mechanism of their proliferation are controversial. Using cytokeratin as marker for ductular structures, liver diseases in which ductular proliferation was a consistent and prominent feature were studied. Paraffin-embedded sections of livers (five cases each) with acute or chronic obstruction of extrahepatic bile ducts, primary biliary cirrhosis (stage II), drug-induced cholestatic liver disease, liver allograft rejection, vicinity of metastatic carcinoma, and massive hepatic necrosis were studied by immunohistochemical methods using three kinds of antiserum against cytokeratin polypeptides of different molecular weights. Bile ductules in diseases involving bile ducts and ductular hepatocytes in massive hepatic necrosis were closely associated with hepatocytes at the limiting plate or with injured hepatocytes. These findings suggest that hepatocytes play an important role in the proliferation of ductular structures or may represent their origin.