Chronic rejection of the liver allograft.

Chronic rejection remains one of the major problems in the management of liver transplant recipients. Histologic diagnosis is central to the management of this condition. It remains difficult to predict cases that will progress toward irreversible rejection, because there are no early diagnostic features. Furthermore, the determination that irreversible rejection has occurred and retransplantation is required also is difficult. There remain many unanswered questions about the cause and pathogenesis of this process. The bile duct loss and arteriopathy parallel changes seen in chronic rejection of other organs. The extent to which this process is specific to the liver or is common to the other transplanted organs and mediated by an immune attack on the vascular bed is unknown. The precise position of HLA matching or mismatching as a risk factor for subsequent chronic rejection remains to be answered but in hepatic transplantation does not seem to be a major factor. The relation between the immunologic trigger of a graft and an aggressive arteriosclerosis is a major challenge, and a greater understanding of this process should provide some new therapeutic options in preventing the disease.