CD209 and osteoarthritis: Increased CD209 expression on macrophages and DCs correlates with the degree of cartilage and bone degradation in RA patients, a correlation not found in persons with osteoarthritis or traumatic joint injuries.[10,11] Although the precise mechanisms remain unclear, single nucleotide polymorphisms (SNPs) in the promoter region of the CD209 gene are thought to modulate its expression, potentially altering immune responses and thereby increasing susceptibility to chronic inflammatory conditions, including RA, colitis, Crohn‘s disease, and Kawasaki disease.