In humans, CD8+Foxp3+ Tregs are detected in some patients with rheumatoid arthritis (RA) [22], systemic lupus erythematosus (SLE) [23], Epstein-Barr virus (EBV) infections [24], patients with prostate cancer [25] and allogeneic stem cell transplantation [26]. This evidence concerns the gene FOXP3 and rheumatoid arthritis.