Westman M, Åberg K, Apostolovic D, et al. - As grass pollen allergy is one of the most prevalent allergies worldwide, researchers sought to determine the value of grass pollen allergen molecules for prediction of grass pollen allergy during childhood and up to adolescence. From the population-based Barn/Children Allergy Milieu Stockholm Epidemiology birth cohort, they analyzed the questionnaire data and sera obtained from the study individuals at the ages of 4, 8, and 16 years. They analyzed serum samples from 763 representative individuals, from whom sera were available at all 3 ages, for IgE reactivity to 8 Phleum pratense (Phl p) allergens (MeDALL [Mechanisms for the Development of Allergies] chip) and to timothy grass extract (ImmunoCAP). Outcomes revealed a higher prevalence of sensitization to any Phl p molecule compared with that with timothy extract at all 3 ages: at the age of 4 years, 9.7% vs 6.8%; at the age of 8 years, 28.4% vs 15.3%; and at the age of 16 years, 37.1% vs 27.1%. Natural Phl p 4 is identified to be a previously unrecognized early indicator of grass pollen allergy, in addition to Phl p 1. They suggest the added value of allergen molecules to timothy extract alone to recognize grass pollen sensitization and predict later ARg, and these may assist clinicians to improve prediction of grass pollen allergy.