We previously reported that the percentages of circulating Th22, IL-22+Th1, and IL-22+Th17 cells, and serum IL-22 levels were significantly higher in RA patients than in healthy individuals15, suggesting that the major IL-22-producting CD4+Th cells may act through the overproduction of IL-22 to stimulate the pathogenesis of RA. The gene discussed is CD4; the disease is rheumatoid arthritis.