Besides, systemic markers of inflammation such as C-reactive protein (CRP), MMP-7, IL-15, plasminogen activator inhibitor (PAI)-1, and soluble vascular adhesion protein (sVAP)-1 are upregulated in OA as compared to controls, although to a lesser extent than that observed in RA [18, 23]. This evidence concerns the gene IL15 and rheumatoid arthritis.