Expression of cytokeratin 19 during human liver organogenesis.

Immunohistochemistry with monoclonal anti-cytokeratin antibodies has revealed the presence of cytokeratin 19 in embryonic and early fetal hepatocytes. With the differentiation of bile ducts at about the 10th week, cytokeratin 19 disappears from liver cells but remains in bile duct cells. This marks an important step in the organogenesis of the liver.