Although some studies suggest the presence of cells co-producing IL-17 and IL-22, our findings are in keeping with studies in inflammatory diseases such as psoriasis, uveitis, atopic dermatitis, ankylosing spondylitis and RA reporting the presence of IL-22 producing cells which are distinct from IL-17 producing cells [24], [25], [26], [27]. This evidence concerns the gene IL17A and psoriasis.