Basophils and type 2 immunity

Mechanisms involved in the development of in-vivo type 2 immunity are poorly defined. Basophils are potent IL-4-producing cells and may contribute to the process of polarizing immune responses.

Although basophils represent fewer than 0.5% of blood leukocytes, their frequency dramatically increases under certain circumstances, particularly Th2-related responses including parasitic infection and allergic inflammation. Recent studies proposed the hypothesis that basophils could contribute to the development of type 2 immunity by providing initial IL-4 important in T cell polarization and by recruiting other effector cells such as eosinophils or neutrophils. Multiple stimuli of IgE-dependent and IgE-independent pathways that lead to release of cytokines and mediators from activated basophils have been identified. In addition, progenitors that differentiate into mature basophils have recently been identified.

The current review revisits basophils with the goal of providing insights into understanding unappreciated roles of basophils in vivo.