In marked contrast, serum IL-10 and IL17A was selectively increased in patients with RA with ACPA (Fig. 5c, e), and/or with an increased DAS28 (Fig. 5 d,f), and there was no significant association between the levels of these cytokines and ACPA positivity or the DAS28 in the SF. Here, IL17A is linked to rheumatoid arthritis.