Reply to correspondence of Elst et al.

We thank Elst and colleagues for their commentary on our recently published article in this journal, which facilitates greater discussion on the topic. We agree that, although strongly suggested by pre-clinical studies, direct evidence for MRGPRX2 involvement in clinically-manifested, drug-induced anaphylaxis is currently wanting. The study of Navines-Fererr, that is sometimes used to suggest a direct role for MRGPRX2 in anaphylaxis to some neuromuscular blocking agents (NMBAs), is complex to interpret and careful, discriminatory characterisation between IgE and MRGPRX2 pathways in a clinical setting is challenging. The recent studies of Ebo et al, and the use of the basophil-activation test in clinical stratification, are thus a welcome addition to the literature.