We have systemically examined three potential markers, Helios, CD226 and TIGIT, that are possibly related to Treg identification, and found that Helios expression on CD4<sup>+</sup>Foxp3<sup>+</sup>cells was decreased and negatively correlated with the disease activity of RA patients, while CD226 and TIGIT both showed elevated expression levels in CD4<sup>+</sup>Foxp3<sup>+</sup>cells in RA patients and they were not associated with disease activity of RA patients.