CD4 and rheumatoid arthritis: The proportion of CD4+CD25+Foxp3+ Treg cells [7.14 (6.12–8.55) % vs. 5.89 (4.75–7.65) %; P < 0.05] and CD4+CD25−Foxp3+ T cells [1.11 (0.73–1.66) % vs. 0.54 (0.41 − 1.00) %; P < 0.01] was higher in the active RA group than in the inactive RA group, and no difference was observed between the inactive RA group and HCs (Fig. 1b, c).