Abstract
Interleukin (IL)-4 and IL-13 control the phenotype of a variety of cells in health and disease. Their receptor system, signaling cascades, and functional properties have gained clarity in the past 30years. In this article, we give an overview of the production, sensing, and effects of both cytokines concluding with a discussion of the therapeutic potential of IL-4 and IL-13 inhibition or supplementation in patients.