Asthma and lower airway diseaseToward improved prediction of risk for atopy and asthma among preschoolers: A prospective cohort study
Section snippets
Patients and sample collection
Subjects in this study were part of an ongoing prospective birth cohort (n = 198), as previously described.3, 9 All subjects were enrolled antenatally and classified as having an atopic family history based on a standard questionnaire3 and a positive doctor's diagnosis of asthma, hay fever, or atopic dermatitis for 1 or both parents. Blood was collected at birth and at 0.5, 1, 2, 3, 4, and 5 years, and children were assessed by one of the authors for the presence of atopic disease. PBMCs and
Postnatal development of IgE responses in atopic and nonatopic children
Fig 1 shows the age-related increase in the frequency of sensitization to inhalant allergens in the study cohort. Forty-six percent of the cohort were sensitized to 1 or more aeroallergens by age 5 years, and 26% were sensitized to food allergens (overall population figures for this age range are 40% and 22%, respectively). The dominant inhalant allergen affecting this population is HDM, and the frequency of sensitization increased progressively over the observation period, reaching 37% at
Discussion
The available evidence indicates that resistance to sensitization to ubiquitous environmental allergens is an active process involving the development of various forms of immunologic tolerance. In the gastrointestinal tract this involves generation of “oral tolerance” to dietary allergens, and in the respiratory tract the corresponding process by which responsiveness to aeroallergens is controlled is known as “inhalation tolerance.”13 Data from a number of cohort studies have established that
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Supported by the National Health and Medical Research Council of Australia. Reagents for antibody assays were provided by Phadia AB.
Disclosure of potential conflict of interest: The authors have declared that they have no conflict of interest.