Figure 3. Subendothelial infiltration of the portal and/or central veins, also known as endotheliitis, is a useful feature for establishing the diagnosis of acute rejection, although it is not always present. As shown in this figure, lymphocytes are located between the hypertrophied venous endothelium and the underlying connective tissue matrix. In the Banff schema, the venous inflammation shown here would receive a score of "1", if similar changes were present in more than an occasional, but not a majority of veins. Mild bile duct injury is also evident(arrow).