Fractalkine and in‰ammatory diseases

The migration of leukocytes into in‰amed peripheral tissues and lymphoid organs involves a cascade of molecular events ˆnely regulated by cell adhesion molecules and chemokines. Fractalkine/CX3CL1 is a membrane-bound chemokine that functions not only as a chemoattractant but also as an adhesion molecule, and is expressed on endothelial cells activated by proin‰ammatory cytokines. The fractalkine receptor, CX3CR1, is expressed on cytotoxic eŠector lymphocytes including NK cells and cytotoxic eŠector T cells (TCE), mature monocytes/macrophages, and mucosal dendritic cells, all of which play important roles in elimination of pathogens and cancer cells. Recently, accumulating evidence in both clinical studies and animal disease models has shown that fractalkine is also involved in the pathogenesis of various chronic in‰ammatory diseases, such as rheumatoid arthritis and atherosclerosis. This article reviews the unique functions of fractalkine and its pathophysiological roles in various clinical conditions.