Basophils as critical orchestrators of Th2-type immune responses

Basophils are relatively rare leukocytes that potentially play a role in both systemic anaphylaxis and, owing to their ability to migrate from the blood into various other tissues, in more localized aspects of allergic inflammation. Given their greater sensitivities to allergen provocation compared with their tissue-fixed mast cell counterparts, and by virtue of their capacity to more readily generate Th2-type cytokines, basophils have been considered to play more than a bystander role in initiating and maintaining allergic disorders. However, only very recently has clearer evidence shed light on the abilities of this cell type to orchestrate chronic allergic inflammation and promote Th2 immunity in the early induction stages of allergy. This review summarizes these recent advances in understanding the role of basophils in orchestrating and maintaining allergic responses.