Importantly, by using both naïve or IgE-sensitised mast cells, especially those derived from humans, provides the best opportunity to detect the degranulating inducing properties of the four peptides in vitro, because both types of cells may be present in vivo, as opposed to mast cell lines (e.g., laboratory of allergic disease 2 cells; LAD2 cells) and genetically engineered cells (e.g., Chinese hamster ovary cells; CHO cells) overexpressing MRGPRX2. This evidence concerns the gene IGHE and allergic disease.