It is known that young children exposed to allergens are prone to develop asthma later in life. In this issue of Immunity, de Kleer et al. (2016) identify IL-33 as a key player in the developing lung for sensitization to environmental allergens and airway hyperreactivity.
Mahlakõiv, T., & Artis, D. (2016, December 20). Allergen Exposure: When Timing Is Everything. Immunity. Cell Press. https://doi.org/10.1016/j.immuni.2016.12.007