Deserters on the Atopic March: Risk Factors, Immune Profile and Clinical Outcomes of Food Sensitized-Tolerant Infants

Abstract

To investigate the phenotypic features of infants who demonstrate immunoglobulin E sensitization to foods that they clinically tolerate. Such understanding may help elucidate strategies in the prevention of food allergies.A birth cohort of 1074 from southeastern Australia was composed of subjects <32 weeks’ gestation at time of enrollment and the mother planning to give birth at a local hospital. Participants were characterized as nonsensitized, sensitized-tolerant (ST), or food allergic (FA) on the basis of skin-prick testing and food challenge at 12 month of age.Environmental exposures were recorded throughout the study period of the cohort. Cord blood regulatory T-cell populations were measured at birth. Subsequent childhood allergic disease was assessed by parent report, clinical examination, and repeat skin-prick testing.Covariants were assessed among nonsensitized (n = 698), ST (n = 27), and FA (n = 61) groups and revealed that the ST group was more similar to the nonsensitized group than to the FA group in the following measures: family history of eczema (nonsensitized: 44.6%; ST: 44.6%; FA: 65.6%), pet ownership at 12 months (nonsensitized: 71.5%; ST: 81.5%; FA: 45.8%), eczema during the first 12 months (nonsensitized: 19%; ST: 32%; FA: 64%), and aeroallergen sensitivity at the age of 4 years (nonsensitized: 19.1%; ST 28.6%; FA 44.4%). At birth, a higher proportion of activated regulatory T cells was associated with the ST group.Infants who are sensitized but tolerant have similar pattern of exposures, immunity, and outcomes to nonsensitized infants. An elevated proportion of activated regulatory T cells at birth was specific to the ST infants and may be relevant to the clinical suppression of disease.Genetic and environmental factors are well known to play a role in the development of allergies. With this study, the authors compare prebirth cohorts to determine more specific factors that may put infants at higher risk for developing food allergies. A robust method of skin-prick testing plus an oral food challenge was used to confirm food allergies. The differences in proportion of cord blood naïve versus activated regulatory T cells in cohort groups provides insight into a mechanism for the prevention of food allergies.