Scientific Study

BACKGROUND: Food allergy to hazelnut occurs both with and without concomitant pollen allergy. OBJECTIVE: We sought to evaluate a panel of hazelnut allergens for diagnosis of hazelnut allergy in Spain; Switzerland; and Denmark. METHODS: Fifty-two patients with a positive double-blind; placebo-controlled food challenge result with hazelnuts; 5 patients with a history of anaphylaxis; 62 patients with pollen allergy but hazelnut tolerance; and 63 nonatopic control subjects were included. Serum IgE levels to hazelnut extract; recombinant hazelnut allergens (rCor a 1.04; rCor a 2; rCor a 8; rCor a 11); and native allergens (nCor a 9; nCor a Bd8K; nCor a Bd11K) were analyzed by means of ImmunoCAP. RESULTS: Among patients with hazelnut allergy; 91% (Switzerland/Spain; 100%; Denmark; 75%) had IgE to hazelnut extract; 75% to rCor a 1.04; 42% to rCor a 2; 28% to rCor a 8; and 2% to rCor a 11. The highest rate of sensitization to Cor a 1.04 was found in the northern regions (Switzerland/Denmark; 100%; Spain; 18%); whereas IgE to the lipid transfer protein rCor a 8 prevailed in Spain (Spain; 71%; Switzerland; 15%; Denmark; 5%). IgE to profilin rCor a 2 was equally distributed (40% to 45%). Among control subjects with pollen allergy; 61% had IgE to hazelnut extract; 69% to rCor a 1.04; 34% to rCor a 2; 10% to rCor a 8; and 6% to rCor a 11. CONCLUSION: Component-resolved in vitro analyses revealed substantial differences in IgE profiles of hazelnut allergic and hazelnut tolerant patients across Europe.