The photograph shows an interlobular artery with marked luminal reduction due to inflammatory cells infiltrating the intima.
Inflammatory cells are also present in the interstitium.
Two glomeruli are present in the upper field and appear somewhat ischemic. The etiology of organ transplant rejection is complex, basically immunological. Transplanted kidney is recognized as foreign by the patient's immune system. Grossly, the kidney may vary from unremarkable to necrotic, depending on the extent and stage. The most characteristic changes involve the arterial vasculature.