Figure 5

A representative series of immunohistochemical results from normal human liver and liver tissues from patients with PBC, PSC and alcoholic liver disease showing expression of S100A4, cytokeratins and E-cadherin. Serial sections (a and b) are from a normal liver biopsy taken immediately prior to transplantation; (a) shows expression of CK-19 in IBEC forming a small intrahepatic bile duct (arrow), (b) shows that neither this duct (arrow) nor the surrounding tissue expresses S100A4. (c) A dual-labelled section from stage 3 PSC detecting CK19 (brown/black) and S100A4 (red) shows a small bile duct (arrowed) in an inflamed portal tract, which is expressing S100A4 and a low level of CK19. (d) A section from Stage 3 PBC liver shows an S100A4-expressing epithelial cell (black arrow) within a ductule together with S100A4 expression within fibroblast-like cells in the surrounding tissue (white arrow). In PSC (Stage 4), (e) shows coexpression (yellow) of CK-19 (FITC-green) and S100A4 (TRITC-red) in a medium-sized bile duct and strong S100A4 expression (red) in infiltrating cells. (f) A large bile duct in stage 4 PSC showing coexpression (yellow) of CK-19 (FITC: green) and S100A4 (TRITC: red) in the majority of biliary epithelial cells (arrows identify strongly S100A4-positive epithelial cells). Most of the inflammatory cells surrounding the duct and infiltrating the epithelium are also S100A4-positive. (g) The damaged duct in Stage 4 PSC liver is surrounded by bipolar, S100A4-expressing cells (red) identified as invasive fibroblast-like cells, possibly resulting from localised EMT. (h and i) The arrows indicate ductular epithelial cells with very low expression of CK-19 (brown/black) that strongly express S100A4 (red) and appear to be acquiring a fibroblastic morphology (PSC stages 3 and 2 respectively). From Stage 3 PBC, (j) shows a medium-sized S100A4-expressing bile duct (red) infiltrated by CD8+ T cells (black: arrows). (k) Alcoholic cirrhosis; the upper panels show sequential confocal images identifying expression of CK-7 (green) and S100A4 (red) in epithelium in a ductular reaction. The cytofluorogram, derived from the same scan, shows evidence of extensive colocalisation of S100A4 and CK-7 in ductules (yellow pixels) with a band of red pixels on the left hand side representing intensely single-labelled infiltrating cells. The triple-labelled panel includes a DAPI nuclear counterstain with CK-7 and S100A4, again from the same scan; the narrow panel shows an XZ section through an individual ductule, confirming coexpression of CK-7 and S100A4 by single cells. (l) In stage 4, PSC a medium-sized bile duct shows fragmented and cytoplasmic E-cadherin expression and S100A4 in most of the epithelial cells. (m) Typical E-cadherin expression (black) in a section of normal bile duct.