Even if depletion of CD4+CD25+ T cell population leads to autoimmune disease in nude mice [17], recent findings show that up to one-third of FoxP3+ cells in a naïve mouse are CD25− and will remain unaffected by anti-CD25 monoclonal antibody (mAb) administration) [18], [19], [20]. Here, FOXP3 is linked to autoimmune disease.