IL2 and atherosclerosis: Interleukin-2 (IL-2) plays a key role in Treg cell development, expansion, survival and suppressive function.17 18 Deficiency of either IL-2 or IL-2 receptor in mice greatly compromises Treg development and promotes autoimmune responses.19 Supplementation of IL-2 substantially increases Treg cell levels and significantly limits plaque development and inflammation in mice prone to atherosclerosis.20 21 Treg cells show a much lower threshold response to IL-2 receptor signalling compared with effector T cells.