The production of IFN-γ was higher in CD4+CD25−Foxp3+ T cells than in CD4+CD25+Foxp3+ Treg cells and CD4+CD25+Foxp3− effector T cells in both the RA group [10.34 (5.96–16.54) % vs. 3.72 (2.73–5.73) % vs. 6.83 (3.44–12.66) %; p < 0.05] and HCs [9.87 (4.61–11.20) % vs. 2.96 (1.57–4.28) % vs. 3.62 (3.54–4.32) %; p < 0.05]. In the HC group, the production of IL-17A [3.20 (1.85–5.51) % vs. 14.98 (8.58–19.07) %; p < 0.05] in CD4+CD25−Foxp3+ T cells was significantly lower than that in CD4+CD25+Foxp3 effector T cells. This evidence concerns the gene CD4 and rheumatoid arthritis.