IgE-independent drug-induced anaphylaxis, MRGPRX2, basophils and mast cells: connecting the dots.

Anaphylaxis is a potentially life-threatening generalized reaction in which degranulation of basophils and mast cells (MC) is critical. Anaphylaxis can result from allergen that cross-links specific IgE bound to the membrane of the effector cells. This cross-linking of IgE initiates downstream signalling with release of vasoactive mediators (e.g. histamine), along with preformed proteases and cytokines, and de novo synthesis and secretion of lipid mediators and additional cytokines. However, evidence has accumulated that anaphylaxis can also occur in response to IgEindependent stimuli, including occupation of the Mas-related G protein-coupled receptor MRGPRX2. Although quintessence of these studies appears to indicate off-target occupancy of the MRGPRX2 receptor to constitute a novel non-immune endotype of MC-driven drug anaphylaxis, prudence is called upon interpretation of the findings as data in patients are lacking. We will take advantage of our experience in studying mechanisms governing basophil and mast cell activation/degranulation to unveil the processes after MRGPRX2-related anaphylaxis to drugs. Flow-assisted quadruple analysis of activation markers, inhibition receptors, signalling molecules and mediator release by individual human cells will capture data that are inaccessible in animal models or by traditional techniques requiring homogeneous cell populations and of which results only represent an average of all stimulated cells.

Keywords:MAST CELLS, BASOPHILS

Disciplines:Immunology