CCL20 and rheumatoid arthritis: The importance of CCR6 was further highlighted by GWAS studies, which have described a polymorphism of CCR6 in patients with RA.22, 23, 24, 25, 26 Moreover, an involvement of CCR6 in RA is further substantiated by the finding of elevated CCL20 levels in the joints of RA patients as compared to patients with osteoarthritis.11