Parasitic helminths and allergens induce a type 2 immune response leading to profound changes in tissue physiology, including hyperplasia of mucus-secreting goblet cells and smooth muscle hypercontractility. This response, known as ‘weep and sweep’, requires interleukin (IL)-13 production by tissue-resident group 2 innate lymphoid cells (ILC2s) and recruited type 2 helper T cells (TH2 cells). Experiments in mice and humans have demonstrated requirements for...