IL22 and rheumatoid arthritis: After treatment, no significant correlation between DAS28 value and plasma cytokines or the frequencies of circulating Th subsets was detected (P ≥ 0.05); however, a positive correlation between the reduction in DAS28 score and the decrease of plasma level of IL-22 was observed in RA patients responsive to treatment (Fig. 6F; P < 0.0001, R = 0.9732).