Innate immunity in the lung regulates the development of asthma

Summary The lung, while functioning as a gas exchange organ, encounters a large array of environmental factors, including particulate matter, toxins, reactive oxygen species, chemicals, allergens, and infectious microbes. To rapidly respond to and counteract these elements, a number of innate immune mechanisms have evolved that can lead to lung inflammation and asthma, which is the focus of this review. These innate mechanisms include a role for two incompletely understood cell types, invariant natural killer T ( iNKT ) cells and innate lymphoid cells ( ILC s), which together produce a wide range of cytokines, including interleukin‐4 ( IL ‐4), IL ‐5, IL ‐13, interferon‐γ, IL ‐17, and IL ‐22, independently of adaptive immunity and conventional antigens. The specific roles of iNKT cells and ILC s in immunity are still being defined, but both cell types appear to play important roles in the lungs, particularly in asthma. As we gain a better understanding of these innate cell types, we will acquire great insight into the mechanisms by which allergic and non‐allergic asthma phenotypes develop.