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 <1% to inhalant allergens. Maternal food sensitization was associated with infants' sensitization. [ABSTRACT FROM AUTHOR]