Birch pollen-related food allergy: clinical aspects and the role of allergen-specific IgE and IgG4 antibodies.
BACKGROUND
Patients with birch pollen allergy often develop allergic reactions to plant foods.


OBJECTIVE
To evaluate the prevalence, main symptoms, and triggers of birch pollen-related food allergy and the role of food-specific IgG(4) antibodies in food tolerance.


METHODS
Food-induced symptoms were evaluated in 225 individuals with birch pollen allergy by using a standardized questionnaire. IgE and IgG(4) levels specific for the major birch pollen allergen Bet v 1 and birch profilin Bet v 2 and the Bet v 1 homologs in apple (Mal d 1) and hazelnut (Cor a 1) were quantified by ImmunoCAP. Mock-treated and IgG-depleted sera from patients tolerating hazelnuts in food challenges were compared for their inhibitory activity for binding of Cor a 1-IgE complexes to B cells.


RESULTS
In total, 73% of the study population experienced food allergy, which was perennial in 86% of the affected individuals. The oral allergy syndrome was the main clinical manifestation. However, more than 58% of the patients also experienced food-induced rhinoconjunctivitis. Apples and hazelnuts were identified as the most frequent triggers. Food allergy correlated with IgE reactivity to Bet v 1 but not to Bet v 2. Mal d 1-specific and Cor a 1-specific IgG(4)/IgE ratios were significantly higher in food-tolerant individuals than individuals with food allergy. Sera from IgG(4)-positive food-tolerant patients possessed IgG-dependent IgE-inhibitory activity.


CONCLUSIONS
Birch pollen-related food allergy is highly prevalent and often perennial. High food allergen-specific IgG(4)/IgE ratios seem associated with food tolerance, potentially because specific IgG(4) blocks IgE binding to food allergens. Thus, the presence of food allergen-specific IgG(4) antibodies is no diagnostic marker for birch pollen-related food allergy.
Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria.
Marija
M
Geroldinger-Simic
Thomas
T
Zelniker
Werner
W
Aberer
Christof
C
Ebner
Cornelia
C
Egger
Antonia
A
Greiderer
Nicole
N
Prem
Jonas
J
Lidholm
Barbara K
BK
Ballmer-Weber
Stefan
S
Vieths
Barbara
B
Bohle
D000293:Adolescent; D000328:Adult; D000368:Aged; D052179:Antigens, Plant / Q000145:classification / Q000276:immunology*; D029662:Betula / Q000276:immunology*; D002648:Child; D005260:Female; D005512:Food Hypersensitivity / Q000276:immunology*; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood / Q000276:immunology*; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D011058:Pollen / Q000276:immunology*; D011795:Surveys and Questionnaires
D052179:Antigens, Plant; D007074:Immunoglobulin G; D007073:Immunoglobulin E