ICAM-1 and VCAM-1 in human renal allograft rejection

Light microscopy studies have demonstrated heightened ICAM-1 and VCAM-1 expression in renal allograft rejection in experimental animals and in humans, and administration of ICAM-1 blocking antibodies has been shown to prolong graft survival in nonhuman primates. We used a precise ultrastructural immunogold localization technique to identify the exact sites of expression of ICAM-1 and VCAM-1 in both normal human kidney and in renal allograft rejection. In the normal kidney ICAM-1 is moderately strongly expressed in glomeruli, on the endothelium and parietal epithelium and in the interstitium, on the endothelium of peritubular capillaries, arterioles and small arteries, on fibroblast-like interstitial cells and on the brush border of proximal tubules. In contrast, in normal kidney, VCAM-1 expression is restricted to the parietal epithelium and the basolateral surfaces of a few proximal tubule cells. In allograft rejection, although ICAM-1 expression appears to be increased, its pattern of distribution is similar to that seen in the normal kidney. However, VCAM-I in allograft rejection is widely expressed on the endothelium of peritubular capillaries and arterioles in association with adhesion of mononuclear leukocytes within these vessels. The tubular expression of VCAM-1, although still focal in nature, is increased on the basolateral surfaces in association with lymphocytic infiltration of tubules.(ABSTRACT TRUNCATED AT 250 WORDS)