IL17A and rheumatoid arthritis: Similar to previous observations, we found that YY1 mRNA expression was upregulated in purified CD4+ cells of patients with RA compared with HD (Figure 1F), and correlation analysis revealed there was still a positive correlation between YY1 and IL-17A (Figure 1G) yet no significant correlation between YY1 and IL-22 (Figure 1H) in purified CD4+ cells from patients with RA.