Combined with previous studies showing intact suppressive function of Treg cells derived from the inflamed joint 1, 2, 3, 4, 5, 6, 7, 25, 26, 27, these findings imply that persistent disease activity in chronic RA cannot simply be attributed to defective CD4+CD25+CD127low Treg cell function in the circulation. This evidence concerns the gene CD4 and rheumatoid arthritis.