Figure 1. As can be seen from the above photomicrograph, a minority of the portal spaces are involved and the inflammation is mild overall. In the Rejection Activity Index(RAI), this would receive a score of "1" or mild portal inflammation. However, on closer examination(inset, top right), lymphocytic injury to the ductal epithelium is evident. It is accompanied by reactive changes in the biliary epithelium, such as increased nuclear:cytoplasmic ratio and the appearance of nucleoli.