Furthermore, in animal models, exogenous administration of IL-33 causes airway hyperresponsiveness (AHR) [11, 12], a canonical feature of asthma, and studies using IL-33 deficient or ST2 deficient mice indicate that IL-33 contributes to both allergic and virally-induced AHR [13, 14]. The gene discussed is IL1RL1; the disease is airway hyperresponsiveness.