Mast Cells and Mas-related G Protein-coupled Receptor X2: Itching for Novel Pathophysiological Insights to Clinical Relevance.

Purpose of review: Clinical interest in non-IgE activation of mast cells has been growing since the description of the human MRGPRX2 receptor. Its participation in many allergic and inflammatory conditions such as non histaminergic itch, urticaria, asthma and drug hypersensitivity has been growing. We present here an updated review of its structure, expression and biology to help understand conditions and diseases attributed to its activation and/or overpexression and the search for agonists and antagonists of clinical utility.

Recent findings: The description of patients presenting anaphylaxis when exposed to one or multiple MRGPRX2 agonists such as general anesthetics, antibiotics, opiods and other agents has provided evidence of potential heterogeneity in humans. This review provides the most recent developments into the receptor structure, tissue expression and signaling pathways including the potential enhancement of IgE-mediated mast cell activation. New insight into its agonists and antagonists is described and future developments to adress its modulations.