Extract and molecular-based early infant sensitization and associated factors—A PreventADALL study

Background More knowledge about sensitization patterns in early infancy, including impact of molecular allergology, is needed to help predict future allergy development more accurately. Objective We aimed to determine the prevalence and patterns of allergic sensitization at 3 months of age, and explore possible associated factors. Methods From the Scandinavian antenatally recruited PreventADALL mother–child cohort, we included 1110 3-month infants with available serum. Sensitization was defined as s-IgE of ≥0.1 kUA/L by Phadiatop Infant® (ThermoFisher Scientific) including birch, cat, grass, dog, milk, egg, peanut and wheat. Further ImmunoCAP analyses to ovomucoid, casein, Ara h 1-3, omega-5-gliadin were performed in food extract s-IgE-positive children. Maternal sensitization was defined as s-IgE ≥ 0.35 kUA/L to Phadiatop® (inhalant allergen mix) and/or Fx5 (food allergen mix) at 18-week pregnancy. Results Overall 79 (7.3%) infants had specific sensitization, many with low s-IgE-levels (IQR 0.16–0.81 kUA/L), with 78 being sensitized to food extract allergens; 41 to egg, 27 to milk, 10 to peanut, and 25 to wheat. A total of 62/78 were further analysed, 18 (29%) had s-IgE to ovomucoid, casein, Ara h 1-3 and/or omega-5-gliadin. Eight infants (0.7%) were sensitized to inhalant allergens. Maternal sensitization to food allergens was associated with infant sensitization, odds ratio 3.64 (95% CI 1.53–8.68). Conclusion Already at 3 months of age, 7% were sensitized to food, mostly without detectable s-IgE to food allergen molecules, and