For example, quinolone containing tetrahydroisoquinoline (THIQ) motif (ciprofloxacin, vancomycin, morphine, rocuronium and others) bind to mast-cell specific Mas-related G protein-coupled receptor (MRGPRX2) and may cause severe allergy-type symptoms without involving IgE (183). This evidence concerns the gene IGHE and Allergy.