Lack of crossreaction with Bet v 1 in patients sensitized to Dau c 1, a carrot allergen

Characterization of the T-cell response to Dau c 1, the Bet v 1-homolog in carrot

“…Here, we applied the same approach to study Dau c 1‐specific T cells and provide strong evidence that the major carrot allergen may induce T‐cell responses independently from Bet v 1. These findings complement previous findings on Bet v 1‐independent IgE responses to Dau c 1 in carrot‐allergic individuals 9, 12, 13.…”

“…The nonsensitizing proteins Api g 1 and Mal d 1 lack major T‐cell epitopes, whereas the major sensitizer Bet v 1 contains the region Bet v 1 142–156 recognized by 63% of birch pollen‐allergic patients. Dau c 1 confirms these findings as it contains an immunodominant T‐cell‐activating region and induces IgE responses independently from Bet v 1 9, 12, 13. Beyond that, a high proportion of Dau c 1 remained intact for 48 h of incubation with endolysosomal proteases (Fig.…”

“…Thus, in addition to cross‐reactivity with the major birch pollen allergen, Dau c 1 itself may show sensitizing activity. This evidence is supported by the demonstration of Bet v 1‐independent IgE responses to Dau c 1 in patients 1, 9, 12, 13 and by immunological properties of Dau c 1 that are characteristic for sensitizing allergens, namely high stability to endolysosomal proteolysis and the existence of major T‐cell‐activating regions. We conclude that Dau c 1 has a special status among Bet v 1‐related food allergens.…”

“…In contrast to Dau c 1, IgE binding to Api g 1 is completely abolished by Bet v 1 10, 11. Additional evidence for a Bet v 1‐independent Dau c 1‐specific IgE response has been provided by the detection of significant Dau c 1‐specific IgE levels in 4 adult patients with strong immediate systemic reactions to raw carrot who displayed no Bet v 1‐specific IgE antibodies 12. The same applied to two patients with carrot‐induced asthma 13.…”

Birch Pollen-Related Food Allergy: An Excellent Disease Model to Understand the Relevance of Immunological Cross-Reactivity for Allergy

“…From the clinical point of view, the majority of patients develop food-induced allergic symptoms after the onset of respiratory allergy (Geroldinger-Simic et al, 2011). Furthermore, a high number of birch pollen-allergic patients shows IgE-reactivity to Bet v 1-related food allergens without developing clinical reactions to the respective foods whereas only very few food-allergic individuals display IgE-reactivity to Bet v 1-homologous food allergens in the absence of Bet v 1-specific IgE antibodies (Flinterman et al, 2006, Moneo et al, 1999. Finally, patients suffering from allergic reactions to stone-fruits and hazelnuts in birch-free areas are not sensitized to Bet v 1-homologous food allergens but to other plant food allergens, e.g.…”