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Background: Grass pollen allergy is one of the most common allergies worldwide., Objective: The aim of this study was to evaluate the usefulness of grass pollen allergen molecules for prediction of grass pollen allergy during childhood and up to adolescence., Method: Questionnaire data and sera obtained from the study subjects at the ages of 4, 8, and 16 years from the population-based Barn/Children Allergy Milieu Stockholm Epidemiology birth cohort were used. Sera from 763 representative subjects with serum samples available at all 3 ages were analyzed for IgE reactivity to 8 Phleum pratense (Phl p) allergens (MeDALL [Mechanisms for the Development of Allergies] chip) and to timothy grass extract (ImmunoCAP). Allergic rhinitis to grass pollen (ARg) was defined as upper airway symptoms during grass pollen exposure., Results: The prevalence of sensitization to any Phl p molecule was higher compared with that to timothy extract at all 3 ages: at the age of 4 years, 9.7% versus 6.8%; at the age of 8 years, 28.4% versus 15.3%; and at the age of 16 years, 37.1% versus 27.1%. General estimating equations analyses revealed that among children sensitized at the age of 4 years, the overall odds ratio (OR) of later ARg (up to 16 years) was increased only for IgE reactivity to Phl p 1 (OR = 4.9) and natural Phl p 4 (OR = 6.9). The likelihood of later symptoms increased with the number of allergen molecules; at the age of 4 years, 2 or more molecules predicted ARg to 78% and 3 or more molecules predicted ARg to 95%. A positive test result for timothy extract predicted ARg to 70%., Conclusions: Natural Phl p 4 is a hitherto unrecognized early indicator of grass pollen allergy, in addition to Phl p 1. To identify grass pollen sensitization and predict later ARg, allergen molecules are of added value to timothy extract alone and may help clinicians improve prediction of grass pollen allergy., (Copyright © 2020 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.)

Background: Children with multimorbid asthma and rhinitis show IgE polysensitization to several allergen sources. This association remains poorly studied in adolescents and adults using defined allergen molecules. We investigated IgE sensitization patterns towards a broad panel of aeroallergen components in adults and adolescents with a focus on individuals with asthma and rhinitis multimorbidity., Methods: IgE reactivity to 64 micro-arrayed aeroallergen molecules was determined with the MeDALL-chip in samples from the French EGEA study (n = 840, age = 40.7 ± 17.1) and the Swedish population-based birth cohort BAMSE (n = 786, age = 16 ± 0.26). The age- and sex-adjusted associations between the number of IgE-reactive allergen molecules (≥0.3 ISU) and the asthma-rhinitis phenotypes were assessed using a negative binomial model., Results: Groups representing 4 phenotypes were identified: no asthma-no rhinitis (A-R-; 30% in EGEA and 54% in BAMSE), asthma alone (A+R-; 11% and 8%), rhinitis alone (A-R+; 15% and 24%) and asthma-rhinitis (A+R+; 44% and 14%). The numbers of IgE-reactive aeroallergen molecules significantly differed between phenotypes (median in A-R-, A+R-, A-R+ and A+R+: 0, 1, 2 and 7 in EGEA and 0, 0, 3 and 5 in BAMSE). As compared to A-R- subjects, the adjusted ratio of the mean number of IgE-reactive molecules was higher in A+R+ than in A+R- or A-R+ (10.0, 5.4 and 5.0 in EGEA and 7.2, 0.7 and 4.8 in BAMSE)., Conclusion: The A+R+ phenotype combined the sensitization pattern of both the A-R+ and A+R- phenotypes. This multimorbid polysensitized phenotype seems to be generalizable to various ages and allergenic environments and may be associated with specific mechanisms., (© 2018 EAACI and John Wiley and Sons A/S. Published by John Wiley and Sons Ltd.)

Background: In Africa, peanuts are frequently consumed, but severe allergic reactions are rare. We investigated immunological patterns of clinical tolerance to peanut in peanut-sensitized but asymptomatic patients from central Africa compared to peanut-allergic and peanut-sensitized but asymptomatic patients from Sweden., Methods: Sera from allergic patients (n = 54) from Zimbabwe sensitized to peanut but without allergic symptoms to peanut, and sera from peanut-allergic (n = 25) and peanut-sensitized but asymptomatic (n = 25) patients from Sweden were analyzed toward peanut allergen components (Ara h 1-3, 6, 8-9) and other allergen molecules from important allergen sources using microarray. IgE to Ara h 2 peptide epitopes was analyzed, and allergenic activity was assessed by basophil activation assay., Results: Forty-six percent of the African and all peanut-allergic Swedish patients showed IgE toward one of the highly allergenic peanut allergens (Ara h 1-3, 6, 9). However, 48% of the African patients had IgE to cross-reactive carbohydrate determinants (CCDs) with low allergenic activity and 60% of the Swedish asymptomatic patients had IgE against the PR protein Ara h 8. IgG and IgG4 specificities and levels could not discriminate between the African asymptomatic and Swedish peanut-allergic patients. Asymptomatic patients almost lacked IgE to Ara h 2 peptides, which were recognized by peanut-allergic patients. Peanut IgE from peanut asymptomatic patients showed poor allergenic activity compared with IgE from peanut-allergic patients., Conclusions: Natural clinical tolerance to peanut in the African patients can be caused by IgE to low allergenic peanut components and by poor allergenic activity of peanut-specific IgE., (© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Component-resolved diagnosis might improve the prediction of future allergy in young children., Objective: We sought to investigate the association between IgE reactivity to the pathogenesis-related class 10 (PR-10) protein family and allergic rhinitis to birch pollen (ARbp) from early childhood up to age 16 years., Method: Questionnaire data and sera obtained at 4, 8, and 16 years of age from the Barn/Children Allergi/Allergy Milieu Stockholm Epidemiologic (BAMSE) study birth cohort were used. Sera from 764 children were analyzed for IgE reactivity to 9 PR-10 allergen proteins at the 3 time points by using an allergen chip based on ISAC technology. ARbp was defined as upper airway symptoms during birch pollen exposure., Results: IgE reactivity to Bet v 1 was found in 12%, 17%, and 25% of children at 4, 8, and 16 years of age. IgE reactivity of PR-10 proteins showed a hierarchic intrarelationship: Bet v 1 > Mal d 1 > Cor a 1.04 > Ara h 8 > Pru p 1 > Aln g 1 > Api g 1 > Act d 8 > Gly m 4. There was an increased risk of incidence and persistence of ARbp up to age 16 years with increasing levels of Bet v 1-specific IgE or increasing numbers of IgE-reactive PR-10 proteins at 4 years. Children with severe ARbp at age 16 years had higher levels of Bet v 1-specific IgE at age 4 years compared with children with mild symptoms., Conclusion: ARbp at age 16 years can be predicted by analysis of IgE reactivity to PR-10 proteins in early childhood., (Copyright © 2014 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.)