Anaphylactic versus Mild Reactions to Hazelnut and Apple in a Birch-Endemic Area: Different Sensitization Profiles?

Background: Hazelnut and apple are common causes of food allergy in Europe. In northern Europe, symptoms are usually mild and associated with cross-reactivity to the birch pollen allergen, Bet v 1. In the Mediterranean area, symp-toms are more frequently severe and associated with sensi-tization to lipid transfer protein (LTP). This study compared patients with anaphylactic versus mild reactions to hazelnut and apple in The Netherlands, a birch-endemic area, with respect to sensitization to Bet v 1 -homologues (i.e. PR10-pro-teins) and LTP. Methods: Twenty-one patients fulfilling the criteria for anaphylaxis and 21 with only mild symptoms (oral allergy) to hazelnut and/or apple were recruited. Specific immunoglobulin Eto birch pollen, apple, hazelnutand PR10-proteins (rBet v 1, rPru p 1, rMal d 1 and rCor a 1) and recom-binant LTP (rPru p 3 and rCor a 8) was measured by Immuno-CAP. Results: Both mild and anaphylactic apple-allergic pa-tients were sensitized to PRIO-proteins, whereas only 1/7 of the mild and none of the anaphylactic apple-allergic pa-tients was sensitized to LTP. In contrast, anaphylactic hazelnut-allergic patients displayed no such clear sensitization pattern: some were sensitized to both PRIO-proteins and ha-zelnut LTP (1/9), and others to only LTP (2/9) or to only PRIO-proteins (4/9) or to neither PR10-proteins nor LTP (2/9). Con-clusion: This study shows that in a birch-endemic area, the sensitization profile to PRIO-proteins and LTP in anaphylac-tic patients may differ between different plant foods. In this patient group, anaphylaxis to hazelnut can be LTP-associat-ed, whereas anaphylaxis to apple is not. [ABSTRACT FROM AUTHOR]