IL1RL1 and aneurysm: Several studies have highlighted the role of IL‐33 and its receptor, ST2, in the regulation of tissue Tregs.[19, 21, 26] Our previous study found that the expression of IL‐33 and ST2 was increased in aneurysms, and IL‐33 was mainly derived from fibroblasts.[26] Here, we further explored the expression of ST2 on aorta Tregs in aneurysms and observed the roles of the IL‐33/ST2 axis on aorta Tregs by enhancing or blocking the IL‐33/ST2 signaling pathway.