Pathology of the Intrahepatic Biliary Tree after Liver Transplantation
The human liver allograft is subject to a multitude of insults: ischaemia, reperfusion injury, acute and chronic rejection, infection, drug toxicity, outflow obstruction and recurrent disease. In the majority of these situations, the epithelial cells of the intra-hepatic biliary tree are affected. In some instances, the diagnosis is clear from the clinical situation: histology, however, is usually required to make or confirm the diagnosis. There are three patterns of liver allograft rejection: hyperacute, acute cellular, and chronic or ductopenic rejection. It remains unclear whether these forms of rejection represent distinct mechanisms of immune-mediated graft dysfunction or are part of a continuum. Although these terms may be misleading, they have become incorporated into the language of liver transplantation and so will be used here. Early acute rejection, also termed cellular rejection, is seen most commonly at the end of the first post-operative week, although early acute rejection may develop at any time after transplantation.