NFATC2IP and airway hyperresponsiveness: Next, we investigated the impact of IL-33 on airway hyperresponsiveness and found that NIP45−/− mice intranasally treated with rIL-33 displayed a significant increase in the Penh value in response to methacholine compared to OVA alone, reaching Penh values comparable to the wild type asthmatic mice without exogenous rIL-33 (Fig. 6b).