IL22 and rheumatoid arthritis: Therefore, all these data suggest the involvement of Th22 cells in the pathogenesis of RA, a point that is supported by the potential proinflammatory effect of IL-22 as well as the pathogenic role of these lymphocytes in other chronic inflammatory conditions, including psoriasis, multiple sclerosis, or autoimmune thyroid disease [12, 27, 29, 36].