Lay summary
We recently discovered that the healthy skin of humans and mice harbours a population of innate lymphoid cells that constitutively produce the cytokine IL-13. IL-13 is normally produced during allergic immune responses, and its steady-state production by innate lymphoid cells in healthy skin renders the skin especially prone to allergy development. In this application we will investigate how altering the niche of IL-13-producing innate lymphoid cells, by replacing these cells with other IL-13-negative immune cell populations, or affecting their ability to produce IL-13 in skin, may influence generation of allergic immune responses. To establish clinical relevance, we will examine the proportions of IL-13-positive and IL-13-negative lymphocyte populations in the skin of healthy donors and patients affected by allergic and non-allergic skin inflammatory diseases, and their impact on dendritic cells. These studies will establish how environment and immune history may affect allergy incidence by regulating innate immune populations in skin.