Different expression of HLA-DR and ICAM-1 in livers from patients with biliary atresia and Bylerʹs disease

Background/Aims: Extrahepatic biliary atresia (EHBA) and chronic progressive intra-hepatic cholestasis (Bylerʹs disease) are two distinct disorders of unknown etiology in the neonate, characterized by profound cholestasis. The aim of the present study was to investigate the inflammatory reaction in liver tissue from patients with EHBA and Bylerʹs disease. Methods: The expression of HLA-DR and ICAM-1 and the number of CD4+, CD8+ and γ/δ+ T-cells were investigated with immunoperoxidase technique on cryostat sections of liver tissue from patients with EHBA (n=11), Bylerʹs disease (n=7) and (healthy controls (n=5). Results: Only mild inflammation was seen, mainly with CD4+ cells, predominantly in the portal tracts in EHBA and throughout the lobuli in Bylerʹs disease. Neither ICAM-1 nor HLA-DR was present on the bile duct cells or hepatocytes in the control patients. The bile duct cells in all EHBA patients expressed both ICAM-1 and HLA-DR. HLA-DR was expressed on the hepatocytes in five EHBA patients, but ICAM-1 was only found on the hepatocytes in two EHBA patients. In Bylerʹs disease the bile duct cells did not express ICAM-1 or HLA-DR, but the hepatocytes from all Byler patients expressed both ICAM-1 and HLA-DR. Conclusions: Although neither EHBA nor Bylerʹs disease is characterized by intense inflammatory cell infiltration, an aberrant expression of ICAM-1 and HLA-DR was found in the liver in both patients with EHBA and patients with Bylerʹs disease. The expression of HLA-DR and ICAM-1, was clearly distinct between the two disorders, indicating that it is not merely an unspecific event secondary to cholestasis.