IGHE and food allergy: Certain cat allergen molecules such as Fel d 5 and Fel d 6, both of which may contain the carbohydrate galactose-α-1,3-galactose (i.e., α-Gal), and Fel d 2, cat albumin, may show immunoglobulin E (IgE) cross-reactivity with allergens involved in food allergies [10,11,12].