MCAM and rheumatoid arthritis: CD146 has been reported to be involved in many inflammatory diseases, including MS,18,19,46 atherosclerosis,20 rheumatoid arthritis,47,48 Crohn’s disease,49 and vasculitis.50 Many studies, including ours, have shown that CD146 is expressed on both endothelial cells and proinflammatory leukocytes under various inflammatory conditions.18,19 As a marker of angiogenesis, CD146 actively participates in the activation, cytoskeletal remodeling, and migration of endothelial cells.