From the bench to the clinic: basophils and type 2 epithelial cytokines of thymic stromal lymphopoietin and IL-33.

Type 2 epithelial cytokines, including thymic stromal lymphopoietin and IL-33, play central roles in modulation of type 2 immune cells, such as basophils. Basophils are a small subset of granulocytes within the leukocyte population that predominantly exist in the blood. They have non-redundant roles in allergic inflammation in peripheral tissues such as the lung, skin and gut, where they increase and accumulate at inflammatory lesions and exclusively produce large amounts of IL-4, a type 2 cytokine. These inflammatory reactions are known to be, to some extent, phenocopies of infectious diseases of ticks and helminths. Recently, biologics related to both type 2 epithelial cytokines and basophils have been approved by the US Food and Drug Administration for treatment of allergic diseases. We summarised the roles of Type 2 epithelial cytokines and basophils in basic science to translational medicine, including recent findings.