CD4 and autoimmune disease: Finally, given that the ablation of TGFβR in CD4pos peripheral T lymphocytes, which had undergone negative selection, was reported to fail to induce autoimmunity21, we assessed whether mature CD4 SP TGFβR-KO thymocytes, which were not purged of Foxp3neg Heliospos thymocytes, can induce autoimmune disorders.