Phenotypic characterization of mononuclear infiltrate present in liver of biliary atresia

Aetiology of biliary atresia: what is actually known?

Biliary atresia (BA) is a rare disease of unknown etiology and unpredictable outcome, even when there has been timely diagnosis and exemplary surgery. It has been the commonest indication for liver transplantation during childhood for the past 20 years. Hence much clinical and basic research has been directed at elucidating the origin and pathology of BA. This review summarizes the current clinical variations of BA in humans, its occasional appearance in animals and its various manifestations in the laboratory as an experimental model.

Biliary atresia

BA is a rare disease of unclear etiology; nevertheless, its impact in the field of pediatric hepatology is significant. It is the most common surgically correctable cause of neonatal cholestasis and is the most common pediatric disease referred for liver transplantation. Little progress has been made with regard to improving outcome or understanding its pathogenesis in the past decade. Fortunately, however, a national, government-sponsored collaborative endeavor has begun that will hopefully make a significant impact upon the progress of designing new treatments for BA and develop a better understanding of its pathogenesis.

Biliary atresia and cytomegalovirus infection: a DNA study

The cause of extrahepatic biliary atresia (EHBA) is undetermined in most instances, but an infectious agent is widely suspected. Cytomegalovirus (CMV) infection has been associated with intrahepatic bile duct destruction and paucity, raising the question of its role in EHBA. We identified 12 children in the past 5 years with biliary atresia and examined the bile duct biopsy. These showed acute/chronic inflammation and epithelial degeneration. CMV inclusions were not identified. We used in situ hybridization and the polymerase chain reaction (PCR) for CMV-DNA on formalin-fixed, paraffin-embedded tissue. All samples showed the presence of amplifiable DNA using beta-globin primers. No biopsy tissue showed CMV DNA using specific probes and primers. The absence of demonstrable CMV DNA by in situ hybridization and PCR in EHBA biopsies implies that it is unlikely that this virus has any major role in the pathogenesis of this condition.

Differential expression of the major histocompatibility antigens and ICAM-1 on bile duct epithelial cells in biliary atresia

Aberrant expression on biliary epithelial cells of the major histocompatibility complex (MHC) antigens in association with adhesion molecule intercellular adhesion molecule-1 (ICAM-1) may be crucial to the immunopathogenesis of biliary atresia. The patterns of MHC class I and II expression in relation to ICAM-1 expression as well as the associated lymphocyte subpopulations were studied in frozen section liver biopsies from six infants with biliary atresia. Intense ICAM-1 expression was found on all ductal epithelial cells in association with MHC I. No ductal epithelial cells demonstrated MHC II expression. Lymphocyte populations within the portal tracts all expressed LFA-1 and were predominantly CD4 positive (> 70%). CD8 positive cells accounted for less than 30%. The expression of ICAM-1 appears to be important in the pathogenesis of biliary atresia but is not linked to the expression of MHC II determinants. This result suggests that different regulatory mechanisms govern the expression of these important immunological receptors on biliary epithelial cells.