Nociceptor analog, MRGPRX2, mediates pseudo-allergic response to pharmacological compounds

Classical allergic response is mediated via IgE. However, some allergic responses to small peptides, pharmacological or chemical compounds are independent of IgE. 

New study in journal Nature suggests that mechanism for this so called pseudo-allergic response is driven by mast cells expressing nociceptor analog, MRGPRX2 (Mrgprb2 in mouse).

The authors showed that mast cells from mice deficient for Mrgprb2 expression failed to respond to classical mast cell activator (secretagogue), compound 48/80, while retaining IgE mediated responsiveness.

Additional experiments confirmed that Mrgprb2 mediated injection site reactions (ISR) and mast cell histamine release in response to drugs such as Icatibant (bradykinin-receptor antagonist), tubocurarine (skeletal muscle relaxant) and ciprofloxacin (fluoroquinolone antibiotic).

Knowledge of chemical motifs (THIQ) responsible for Mrgprb2 activation will help to prevent and treat pseudo-allergic reactions to life-saving medical drugs.

David Usharauli