Our results demonstrate that ADAM15 is expressed in lining cells, endothelial cells of blood vessels and macrophage-like cells in the sublining layer of RA synovium with a direct correlation with vascular density in the synovium, and that the expression of ADAM15 is up-regulated by the action of VEGF165 via VEGFR-2. This evidence concerns the gene KDR and rheumatoid arthritis.