Interleukin-33 and its receptor: multifaceted roles and emerging therapeutic potential.

Interleukin-33 (IL-33) is an alarmin and cytokine that has potent biological effects in various tissues. It acts on a broad array of immune cell populations and is involved in many processes associated with health and disease. This Review discusses the biology of IL-33 and its receptor, ST2, and the functional relevance of IL-33-ST2 signalling. It focuses particularly on the differential regulation of IL-33 sensitivity in distinct cell types in diverse tissue settings. Furthermore, we describe the effects of IL-33 in various diseases, including viral infections, cancer, graft-versus-host disease, colitis, autoimmunity, chronic obstructive pulmonary disease, asthma and allergy. We also consider the roles of IL-33 in physiological reactions such as fat tissue biology and tissue regeneration. The Review aims to provide a comprehensive understanding of IL-33 signalling, including its potential as a target for developing new treatments, and to suggest future research directions.