title: Immunohistochemical evidence for hepatic progenitor cells in liver diseases.
abstract: OBJECTIVE
  Proliferative bile ductular reactions occur in a variety of liver diseases in humans. It is a matter of debate whether such reactions result from progenitor cell proliferation with biliary and hepatocytic differentiation, versus biliary metaplasia of damaged hepatocytes. We investigated bile ductular reactions in liver diseases, paying particular attention to the presence of cells with intermediate (hepatocytic/biliary) features (oval-like cells).
  
  
  METHODS
  Five specimens each were selected of submassive hepatic necrosis and cirrhosis due to hepatitis B, hepatitis C, autoimmune hepatitis, alcohol injury, primary biliary cirrhosis and primary sclerosing cholangitis. Immunohistochemical stains were performed for biliary markers (cytokeratins [CKs] 7 and 19), as well as hepatocytic markers (HepParl and alpha-fetoprotein[AFP]) in sequential sections. The degree of staining of each cell type (biliary, hepatocytic, intermediate) was graded semiquantitatively.
  
  
  RESULTS
  Hepatocytes always stained diffusely for HepParl, occasionally for CK7, and rarely for CK19. Biliary cells were always diffusely positive for CK7 and CK19, and rarely for HepParl. Intermediate cells were identified in all cases and showed widespread staining for both HepParl and CK7, and less commonly for CK19. AFP was not expressed in any cell type. The morphologic and immunohistochemical features of bile ductular reactions were similar in the different diseases.
  
  
  CONCLUSIONS
  Proliferating hepatic parenchymal cells with intermediate (hepatocytic/biliary) morphologic features and combined immunophenotype can be identified in a variety of acute and chronic liver diseases. The similarity of bile ductular reactions among chronic hepatitic, alcoholic and biliary diseases suggests that they result from proliferation of oval-like progenitor cells.
authors.affiliation: Department of Pathology, New York University Medical Center, New York, NY 10016, USA.
authors.forename: Jianyou
authors.initials: J
authors.lastname: Tan
authors.forename: Prodromos
authors.initials: P
authors.lastname: Hytiroglou
authors.forename: Rosemary
authors.initials: R
authors.lastname: Wieczorek
authors.forename: Young NyuN
authors.initials: YN
authors.lastname: Park
authors.forename: Swan N
authors.initials: SN
authors.lastname: Thung
authors.forename: Byron
authors.initials: B
authors.lastname: Arias
authors.forename: Neil D
authors.initials: ND
authors.lastname: Theise
mesh_terms: D000911:Antibodies, Monoclonal; D001653:Bile Ducts, Intrahepatic / Q000378:metabolism / Q000473:pathology*; D015415:Biomarkers / Q000032:analysis; D022781:Hepatocytes / Q000276:immunology / Q000473:pathology*; D006801:Humans; D007124:Immunoenzyme Techniques; D007633:Keratins / Q000378:metabolism; D008107:Liver Diseases / Q000378:metabolism / Q000473:pathology*; D013234:Stem Cells / Q000378:metabolism / Q000473:pathology*; D000509:alpha-Fetoproteins / Q000378:metabolism
chemical_list: D000911:Antibodies, Monoclonal; D015415:Biomarkers; D000509:alpha-Fetoproteins; D007633:Keratins