The critical role of allergen-specific IgE, IgG4 and IgA antibodies in the tolerance of IgE-mediated food sensitisation in primary school children

Primary objective. There are about 6% of children who are either intolerant to or lose their ability to tolerate food allergens, resulting in the development of food hypersensitivity. The hypothesis that increase in food allergen-specific IgE antibody level is associated with the decrease in the levels of food allergen-specific IgG4 and IgA antibodies was used as a biomarker of food tolerance. Methods & Procedures. The Modified International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire (added gastrointestinal allergy questions) and Phadiatop infant test were used to screen one hundred 6-8-year-old allergic school children. Food allergen-specific IgE, IgG and IgA antibodies were measured by using the Phadia ImmunoCAP system radioabsorbent test (RAST). Immunoglobin E antibodies to common aeroallergens, were also detected by enzyme-linked immunosorbent assay. Main outcome. The level of analysed food specific-IgE antibody was obviously higher in the study population. Sensitivity to dust mites among the children was nearly 90%, and that to cockroach was 47%. Egg white-, cow's milk-, alpha-lactoalbumin-, beta-lactoglobulin- and casein-specific IgG4/IgE and IgA/IgE ratios were lower in the atopic school children but not in the tropomysin-, mango- and kiwi-sensitive participants. Conclusion. The level of cow's milk-and egg white-specific IgE antibody still remained high along with a decrease in the specific IgG4/IgE and IgA/IgE ratios in our study population. Therefore, allergen-specific IgG4 and IgA antibodies are important biomarkers of tolerance establishment, and failure to establish tolerance to food allergens may be related to the regulation of the inhalant allergens encountered in late childhood stages.