IL-33 and Thymic Stromal Lymphopoietin in mast cell functions

Thymic Stromal Lymphopoietin (TSLP) and Interleukin 33 (IL-33) are two cytokines released by cells that are in proximity to our environment, e.g., keratinocytes of the skin and epithelial cells of the airways. Pathogens, allergens, chemicals and other agents induce the release of TSLP and IL-33, which are recognized by mast cells. TSLP and IL-33 affect several mast cell functions, including growth, survival and mediator release. These molecules do not directly induce exocytosis, but cause release of de novo synthesized lipid mediators and cytokines. TSLP and IL-33 are also implicated in inflammatory diseases where mast cells are known to be an important part of the pathogenesis, e.g., asthma and atopic dermatitis. In this chapter we describe and discuss the implications of TSLP and IL-33 on mast cell functions in health and disease.