Leukocyte adhesion molecules in diseased corneas

To help define the possible role of leukocyte adhesion molecules in the pathogenesis of corneal inflammation, we investigated the presence and distribution of intercellular adhesion molecule-1 (ICAM-1), E-selectin (endothelial leukocyte adhesion molecule-1 [ELAM-1]), and vascular cell adhesion molecule-1 (VCAM-1) in various corneal diseases. Monoclonal antibodies (mAbs) to ICAM-1, E-selectin, and VCAM-1 were used for immunohistochemical staining of frozen sections of 55 human corneas with various inflammatory and degenerative diseases. In addition, we used a panel of mAbs to characterize the composition and density of the inflammatory infiltrates in the diseased corneas. ICAM-1 was focally expressed on epithelial cells in corneas with chronic allograft rejection, herpetic stromal keratitis, zoster keratitis, chemical burns, atopic keratitis, fungal keratitis, and bacterial keratitis. Furthermore, the expression of ICAM-1 was focally increased on keratocytes, corneal endothelial cells, and vascular endothelial cells (particularly at the site of lymphoid infiltration) in these corneas. E-selectin was present on vascular endothelial cells of limbal vessels in corneas with bacterial keratitis and also on endothelial cells of vessels in the stroma of several corneas with chronic inflammatory diseases. VCAM-1 was focally expressed on endothelial cells of vessels in the stroma of some corneas with chronic allograft rejection, herpetic stromal keratitis, chemical burns, and atopic keratitis. Interestingly, VCAM-1 was also found on inflammatory cells of the macrophage-monocyte lineage in inflamed corneas. Our results demonstrate that ICAM-1, E-selectin, and VCAM-1 are expressed in diseased corneas, often in areas of inflammation.