Can the Pattern of Early Sensitization to Allergen Molecules Drive a New Approach for Prevention of Allergy?

https://doi.org/10.1016/j.ebiom.2017.11.016 2352-3964/© 2017 The Author(s). Published by Elsevier B Identifying the causative agent is a major aim of diagnostic work-up any allergic symptom of rhinitis, asthma or eczema by questionnaires. for allergy. However, a positive result from skin tests or in vitro specific IgE measurement indicates sensitization but not necessarily clinical allergy. In fact, it is quite common to see a patient with positive tests to pollens with no respiratory symptoms during the specific flowering seasons of such pollens. Using as example the most recent study, 53.5% of 501 unselected subjects aged 12–21 years fromAustria showed IgE reactivity to at least one allergen, with the highest rate for grass pollen, dust mites, birch pollen and cat, but only 21.9% had a diagnosed allergy (Stemeseder et al., 2017). Among the different hypotheses on the immunological mechanisms underlying asymptomatic sensitization, some issues, as reviewed by Bodtger in 2004, were apparent to characterize asymptomatic sensitization (Bodtger, 2004). They included the lack of a late-phase reaction and of eosinophil stimulation and migration in response to allergen challenge, and low levels of interleukin (IL)-5, that is themajor cytokine responsible for activation, proliferation and survival of eosinophils. A role for allergen avoidance was suggested to be successful in reducing development of allergy (Bodtger, 2004). Actually, in a study assessing during 5 years the longitudinal sensitization to 6 aeroallergens in 828 children aged 6–11 years living in the semiarid US southwest, new allergen sensitizations were detected in 30.2%. Also remittance from positive to negative tests was observed, mostly concerning seasonal allergens (Stern et al., 2004). In recent years, the introduction of molecular diagnostics, by which specific IgE (sIgE) to single allergen molecules are measured, was a significant advance not only for diagnosis of allergy but also for investigating epidemiologic and natural history aspects (Matricardi et al., 2016). In the present issue of the Journal, Wickman et al. report the results of a study on IgE reactivity to 132 allergen molecules in a population based birth cohort of children from Sweden and in birth cohort of children from U.K. (Wickman et al., n.d.) The Swedish cohort included a random sample of 786 children (from the original number of 4089). At the age of 4, 8 and 16 years IgE reactivity was analyzed, along with the collection of