Different IgE Reactivity Profiles in Birch Pollen-Sensitive Patients from Six European Populations Revealed by Recombinant Allergens: An Imprint of Local Sensitization

Abstract

Background: Sensitivity to birch pollen allergens is a common feature among European patients with seasonal pollen allergy. In this in vitro study, we examined the specific serum IgE binding profiles to individual birch pollen allergens in birch-sensitive patients from six European populations. Methods: The study included 242 patients from Finland, Sweden, Austria, France, Switzerland and Italy. All suffered from seasonal rhinoconjunctivitis and/or asthma. Their sera were analyzed for specific IgE reactivity to individual birch pollen allergens (recombinant Bet v 1, Bet v 2 and Bet v 4) and natural birch pollen extract using Pharmacia CAP System™ and immunoblotting. Results: Almost all Finnish, Swedish and Austrian sera contained IgE specific for Bet v 1 (≧98%). Bet v 1-specific IgE antibodies were found in 90% of the French sera, and in 65 and 62% of the sera from Switzerland and Italy, respectively. Few Finnish (2%) and Swedish (12%) patients had IgE to Bet v 2, while Bet v 2 reactivity was more common in the other populations (20–43%). Reactivity to Bet v 4 was rare in all populations (5–11%) except for the Italian patients, in whom 3 of 11 sera were positive (27%). The immunoblot results supported the specific IgE profiles obtained with Pharmacia CAP System showing a broader IgE reactivity profile in patients from central and southern Europe as compared to northern Europe. Conclusion: Component-resolved allergy diagnosis with recombinant allergens reveals that the IgE reactivity profiles to individual birch pollen allergens vary between European populations. This observation may be explained by sensitization to different allergen sources and will have an impact on allergen-specific prevention and therapy strategies.

Allergic Rhinitis and its Impact on Asthma (ARIA) 2008*

“…Recombinant allergens have been used for the in vitro diagnosis of grass (1206,1207,1213,1246,1247), birch and Fagaleae (1248)(1249)(1250)(1251)(1252)(1253), Oleaceae (1199,1254), pollens or mites (1255)(1256)(1257). A single recombinant allergen or a combination of a few major recombinant allergens can substitute the crude extract for in vitro diagnostic purposes (1258,1259).…”

Profiles of Birch Sensitization (Bet v 1, Bet v 2, and Bet v 4) and Oral Allergy Syndrome Across Italy

“…An intriguing gradient of sensitization across Europe has been reported: Bet v 1 is predominant in northern Europe, whereas Bet v 2 and Bet v 4 are more relevant in southern Europe [19][20][21][22]. Therefore, this study aimed to evaluate the profile of sensitization to birch allergen molecules in a large sample of allergic patients in Italy by taking into consideration the geographic area and the presence of associated OAS.…”

Pollen Allergenicity is Highly Dependent on the Plant Genetic Background: The “Variety”/“Cultivar” Issues

“…1994;Tinghino et al 2002). Bet v 4, a 9 kDa Ca-binding protein (Engel et al 1997;Twardosz et al 1997;Ferreira et al 1999;Grote et al 2002), Bet v 5, a 35 kDa isoflavone reductase-related protein (Vieths et al 1998;Karamloo et al 1999;Stewart and McWilliam, 2001), Bet v 6, a 30-35 kDa protein, PCBER (Phenylcoumaran benzylic ether reductase) (Karamloo et al 2001), Bet v 7, a 18 kDa protein, characterized as a cyclophilin (Cadot et al 2000) and Bet v 11 (Moverare et al 2002).…”