A case of allergy to beer showing cross-reactivity between lipid transfer proteins

Background: Lipid transfer proteins (LTPs) are highly conserved proteins pr esent in a broad spectrum of fruits and vegetables that might represent a n ovel plant panallergen. Objective: To demonstrate that LTP is an important allergen in beer and tha t beer LTP cross-reacts with LTP from botanically unrelated plant-derived f oods. Methods: Serum from a patient with clinical allergy to both beer and Rosace ae was studied for IgE reactivity to LTP to several vegetable foods by PAST , ELISA, immunoblot, and inhibition studies. Results: Patient's serum showed a strong IgE reactivity to LTP purified fro m peach peel, carrot, and broccoli, and to a 10 kD protein in both apple an d peach immunoblots, whereas no reactivity to birch cross-reactive allergen s such as Bet v I, profilin, or carbohydrates was found. In inhibition stud ies, preabsorption of serum with apple, walnut, hazelnut, peanut, corn, and rice caused a fall of 97%, 20%, 66%, 91%, 94%, and 93%, respectively, of i ts reactivity to peach LTP. Beer PAST fell from 1.8 IU/mL to <0.1 IU/mL whe n a patient's serum was preabsorbed with recombinant carrot LTP. Conclusions: LTP is a relevant allergen in beer. Beer LTP may cross-react w ith LTP from several other plant-derived foods.