Donor EOS were prepared from bone‐marrow cells as we recently reported.[11, 44] Due to the relatively low frequency of ILC2 (≈0.1% of total lymphocytes) and their potential surface marker alterations from in vitro expansion,[23, 24] we used freshly prepared ILC2 from mouse splenocytes after donor mice were treated with IL33 to boost ILC2 expansion in vivo.[45] Donor ILC2 (CD45.1+Lin−ICOS+CD127+KLRG1+) and EOS (CD45.1+CD11b+Siglec‐F+) from CD45.1 transgenic mice were used to confirm their homing to the AAA lesions, 7 d after surgery, by immunofluorescent staining with the CD45.1 antibody. The gene discussed is IL7R; the disease is triple-A syndrome.