Variation in expression of endothelial adhesion molecules in pretransplant and transplanted kidneys--correlation with intragraft events.

Endothelial adhesion molecules are directly involved in the localization and migration of leukocytes from the circulation into tissues at sites of inflammation. We have compared the expression of PECAM-1 (CD31), ELAM-1, ICAM-1 (CD54), and VCAM-1 in pretransplant (n = 20) and needle-core biopsies from renal transplants obtained during different clinical circumstances (n = 42). PECAM-1 was consistently expressed on all endothelium in both pretransplant and transplant biopsies. In contrast, there was variation in endothelial expression of ELAM-1 and in proximal tubular expression of ICAM-1 and VCAM-1 between pretransplant biopsies. After transplantation induced expression of endothelial ELAM-1 and VCAM-1 and tubular induction of ICAM-1 and VCAM-1 was detected. Induced adhesion molecule expression was frequently associated with focal leukocyte infiltration, and there was a significantly higher level of CD45 and CD25 positive cell infiltration in biopsies with induced adhesion molecule expression. The induction of adhesion molecule expression is evidence of endothelial activation in these transplant biopsies. Comparison of adhesion molecule expression and HLA-class II antigen expression revealed that induced tubular class II antigens may be detected in the absence of induced adhesion molecule expression.