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To cite this article: Asarnoj A, Movérare R, Östblom E, Poorafshar M, Lilja G, Hedlin G, van Hage M, Ahlstedt S, Wickman M. IgE to peanut allergen components: relation to peanut symptoms and pollen sensitization in 8-year-olds. Allergy 2010; 65: 1189–1195. 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. [ABSTRACT FROM AUTHOR]

To cite this article: Asarnoj A, Östblom E, Ahlstedt S, Hedlin G, Lilja G, van Hage M, Wickman M. Reported symptoms to peanut between 4 and 8 years among children sensitized to peanut and birch pollen – results from the BAMSE birth cohort. Allergy 2010; 65: 213–219. Background: Specific IgE tests are sometimes difficult to interpret due to structural similarities between certain food and pollen allergens. This may be the reason why concomitant sensitization to peanut and birch pollen is frequently seen. The aim of this study was to investigate reported symptoms to peanut- and birch pollen in relation to sensitization. Methods: The data originate from 1928 children in the BAMSE birth cohort. Background factors and clinical parameters were obtained and the levels of IgE antibodies to peanut and birch pollen measured at 4 and 8 years. Results: IgE antibodies to peanut were found in 5.5% and 7.4% of the children at 4 and 8 years, respectively. The IgE antibody levels to peanut were higher in children sensitized to peanut but not birch than in children sensitized to peanut and birch among both 4- and 8-year-olds ( P = 0.093 and P = 0.003, respectively). Eight-year-olds sensitized to peanut but not birch, more often reported symptoms to peanut than children sensitized to both peanut and birch pollen (76% vs 46%, P = 0.002). The probability of reported symptoms to peanut increased significantly with increasing IgE levels to peanut, especially in 8-year-olds not sensitized to birch. Conclusions: Children sensitized to both peanut and birch pollen are less likely to report symptoms to peanut than children sensitized to peanut but not to birch pollen at 8 years. This is likely due to cross reactions between birch pollen and peanut and can explain the high sensitization rate to peanut in areas where birch trees are common. [ABSTRACT FROM AUTHOR]

Background Longitudinal data from population-based studies on the development and persistence of food hypersensitivity (FHS) during childhood are almost absent. Methods A population-based birth cohort was established, and information on various exposures and symptoms of allergic disease were obtained from questionnaires when the children were 2 months, 1, 2, 4 and 8 years of age. Complete data were available on 3104 children. Children with reported FHS and doctor's diagnosis of food allergy (RDFA) were identified and allocated into transient, intermittent, late-onset and persistent phenotypes. Food allergen-specific IgE-antibodies (abs) to a mix of six common food allergens (fx5®) were analysed at 4 and 8 years of age in 1857 children. Results The overall prevalence of reported FHS in combination with RDFA should be 3.1% at 1 year to 7.6% at 8 years of age. However, reactions to milk, egg, fish and wheat decreased, whereas an increase was seen for peanuts and tree nuts. Reported reactions to egg, peanuts or tree nuts early in life, as well as IgE-abs to food allergens at the age of 4, increased the risk of FHS at 8 years of age. Furthermore, FHS at young ages increased the risk for asthma, eczema and allergic rhinitis at 8 years of age, even when adjustments were made for children with these symptoms during the first 2 years of life. Conclusion The increasing prevalence of FHS up to the age of 8 years probably reflects an increasing prevalence of allergy to birch pollen and pollen-related reactions to foods. Reactions to egg, peanuts and tree nuts early in life increase the risk of FHS at 8 years. Furthermore, reported FHS at young ages, even though transient, seems to increase the risk for other allergic diseases at 8 years of age. [ABSTRACT FROM AUTHOR]

Background: Diagnosis of food hypersensitivity (FHS) is difficult and interpretation of food allergy tests is complicated. Objective: To investigate the probability of reported FHS in relation to levels of food-specific IgE-antibodies (AB) in a population-based setting of 4-year-old children ( n = 2336). Methods: Information on FHS was obtained from a questionnaire and specific IgE-AB to milk, egg, fish, peanut, soy and wheat were analysed. Results: Thirty-one per cent of the children with reported FHS ( n = 284) were sensitized (≥0.35 kUA/l) to at least one of the tested foods compared with 11% of children without FHS ( n = 2052). Furthermore, the probability of reported symptoms to milk, egg and fish increased with increasing levels of food-specific IgE-AB to the same food allergens. A similar trend was seen for peanut and wheat, but not for soy. Increasing levels of specific IgE-AB to milk or egg were also associated with an increasing risk of reported symptoms caused by other foods. Conclusions: Quantitative measurements of IgE-AB to milk, egg and fish are useful to evaluate IgE-associated FHS in preschool children also in a population based sample. Such measurements appear to be of limited value for soy bean and wheat, in particular as a screening method. [ABSTRACT FROM AUTHOR]