Leukocyte adhesion molecules in rejected corneal allografts

Leukocyte adhesion molecules are believed to play a key role in the selective recruitment of different leukocyte populations to inflammatory sites. In this study, we investigated the presence and distribution of intercellular adhesion molecule-1 (ICAM-1), E-selectin (endothelial leukocyte adhesion molecule-1) and vascular cell adhesion molecule-1 (VCAM-1) in 12 rejected corneal allografts and compared the presence of these adhesion molecules with the composition of the associated inflammatory infiltrates. ICAM-1 was focally expressed on corneal epithelial cells and its expression was increased on keratocytes, corneal and vascular endothelial cells particularly at the site of dense infiltration with mononuclear leukocytes. E-selectin was present on endothelial cells of vessels in the stroma of rejected corneal allografts which were characterized by dense infiltration with T cells and macrophages. VCAM-1 was predominantly expressed on inflammatory cells of the macrophage/monocyte lineage, but only sporadically on vascular endothelial cells in the stroma of vascularized rejected corneal allografts. Our results suggest that ICAM-1, E-selectin and VCAM-1 may all be involved in the pathogenesis of corneal allograft rejection, particularly in the generation of the inflammatory infiltrates.