Using a range of assays on PB samples from patients with chronic RA and healthy controls, CD3+CD4+CD25+CD127low Treg cells from the CD45RO+ or CD45RA+ T cell compartments were analyzed for phenotype, cytokine expression (ex vivo and after in vitro stimulation), suppression of Teff cell proliferation and cytokine production, suppression of monocyte‐derived cytokine/chemokine production, and gene expression profiles. This evidence concerns the gene CD4 and rheumatoid arthritis.