IGHE and allergic disease: One possibility to overcome the limitations of natural allergen extracts for HDM‐specific immunotherapy is therefore to develop molecular vaccines which are based on recombinant allergens, allergen derivatives or allergen‐derived peptides.16 Several new forms of allergy vaccines have been successfully evaluated in clinical trials which are based on defined molecular components.17, 18 The construction of these vaccines depends heavily on the definition of the clinically relevant allergens of a given allergen source and the knowledge of IgE and T‐cell epitopes of the key allergens.