Additionally, while the importance of IL-33 in allergic disease has thus far been attributed to its effect on priming type 2 immunity, our findings establish a mechanistic link between IL-33 and neutrophilic inflammation during allergic inflammation: rather than a direct effect on neutrophils, our data support that mast cell–derived IL-33 functions by inducing a basophil intermediary to secrete neutrophil-attracting chemokines. Here, IL33 is linked to allergic disease.