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.
Asarnoj
A
A
National Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden. anna.asarnoj@ki.se
Movérare
R
R
Ostblom
E
E
Poorafshar
M
M
Lilja
G
G
Hedlin
G
G
van Hage
M
M
Ahlstedt
S
S
Wickman
M
M
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