Expression of cell adhesion molecules in inflammatory myopathies.

We examined the expression of cell adhesion molecules in 25 cases of inflammatory myopathies. Inflammatory myopathies showed upregulation of adhesion molecules. ICAM-1 was strongly expressed on endothelial cells as well as on fibroblasts and infiltrating leukocytes while the expression of VCAM-1, similar in its distribution, was much weaker. A few muscle fibers in polymyositis revealed sarcolemmal labeling for ICAM-1. ELAM-1 showed only weak expression on vessels. The inflammatory cellular infiltrates contained varying amounts of cells bearing the VCAM-1 ligand VLA-4 and the ELAM-1 ligand SLeX as well as large amounts of cells expressing LFA-1 alpha and beta, ligands of ICAM-1.