Interleukin‐33 in the developing lung—Roles in asthma and infection

It has become increasingly clear that interleukin‐33 (IL‐33) plays a crucial role in initiation of type 2 immunity. The last decade of intense research has uncovered multiple mechanisms through which IL‐33 targets key effector cells of the allergic immune response. Recently, IL‐33 has been implicated in shaping the immune system of the lungs early in life, at a time which is crucial in the subsequent development of allergic asthma. In this review, we will address the current literature describing the role of IL‐33 in the healthy and diseased lung. In particular, we will focus on the evidence for IL‐33 in the development of immune responses in the lung, including the role of IL‐33–responsive immune cells that may explain susceptibility to allergic sensitization at a young age and the association between genetic variants of IL‐33 and asthma in humans. Finally, we will indicate areas for potential therapeutic modulation of the IL‐33 pathway.