IgE to peanut allergen components: relation to peanut symptoms and pollen sensitization in 8-year-olds.
BACKGROUND
Allergen-specific IgE testing is often performed with crude peanut extract, but the results may be difficult to interpret because of cross-reactions between peanut and other plant allergens. The aim was to investigate IgE reactivity to peanut allergen components in children from a birch-rich region in relation to pollen sensitization and peanut symptoms.


METHODS
From a birth cohort, clinical parameters were obtained through questionnaires and IgE antibody levels to peanut and birch pollen were measured. Different peanut/birch sensitization phenotypes were defined among 200 selected children. IgE reactivity to peanut and pollen allergen components was analysed using microarray technique.


RESULTS
Peanut symptoms were reported in 87% of the children with IgE reactivity to any of the peanut allergens Ara h 1, 2 or 3 but not to Ara h 8 (n = 46) vs 17% of children with IgE reactivity to Ara h 8 but not to Ara h 1, 2 or 3 (n = 23), P < 0.001. Furthermore, symptoms were more severe in children with Ara h 1, 2 or 3 reactivity. Children with IgE reactivity both to Ara h 2 and to Ara h 1 or 3 more often reported peanut symptoms than children with IgE only to Ara h 2 (97%vs 70%, P = 0.016), particularly respiratory symptoms (50%vs 9%, P = 0.002).


CONCLUSIONS
IgE analysis to peanut allergen components may be used to distinguish between peanut-sensitized individuals at risk of severe symptoms and those likely to have milder or no symptoms to peanut if sensitized to pollen allergens and their peanut homologue allergens.
National Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden. anna.asarnoj@ki.se
A
A
Asarnoj
R
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Movérare
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E
Ostblom
M
M
Poorafshar
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Lilja
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Hedlin
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M
van Hage
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Ahlstedt
M
M
Wickman
D055516:2S Albumins, Plant / Q000276:immunology*; D052179:Antigens, Plant / Q000276:immunology*; D010367:Arachis / Q000276:immunology; D029662:Betula / Q000276:immunology; D002648:Child; D015331:Cohort Studies; D003429:Cross Reactions; D005260:Female; D006023:Glycoproteins / Q000276:immunology*; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood*; D008297:Male; D021183:Peanut Hypersensitivity / Q000150:complications / Q000453:epidemiology / Q000209:etiology / Q000276:immunology / Q000503:physiopathology*; D011058:Pollen / Q000276:immunology*; D006255:Rhinitis, Allergic, Seasonal / Q000150:complications / Q000453:epidemiology / Q000276:immunology / Q000503:physiopathology
D055516:2S Albumins, Plant; D052179:Antigens, Plant; C500890:Ara h 2 allergen, Arachis hypogaea; D006023:Glycoproteins; D007073:Immunoglobulin E