Supplementary Material for: Low-Dose Oral Immunotherapy Using Low-Egg-Allergen Cookies for Severe Egg-Allergic Children Reduces Allergy Severity and Affects Allergen-Specific Antibodies in Serum

<p><b><i>Background:</i></b> We evaluated the safety and efficacy of low-egg-allergen cookies (LAC) as low-dose oral immunotherapy (OIT) in children with severe egg allergy. We also examined the relationship between mild desensitization by low-dose OIT and serum biomarkers of allergy. <b><i>Methods:</i></b> We enrolled 13 children with egg allergy who could not receive OIT with hard-boiled egg white (EW). For 11 participants, OIT was carried out using LAC for 3-4 months. Open food challenges with hard-boiled EW and blood samplings were performed before and after OIT. Participants were divided into 2 groups: high effect (H-E) and no/low effect (N/L-E). Serum levels of total IgE and egg yolk-, EW-, and ovomucoid (OM)-specific IgE, ovalbumin (OVA)- and OM-specific IgG<sub>4</sub>, IgA<sub>1</sub>, and IgA<sub>2</sub>, and the percentage of CD 203c<sup>+</sup> were measured. <b><i>Results:</i></b> Allergic severity was reduced in 7 patients, who were assigned to the H-E group. Moreover, no study participants were taken off the intake of LAC during OIT. In the H-E group, OVA-specific IgA<sub>2</sub> levels after OIT were significantly higher than before OIT. The ratios of OM-specific IgG<sub>4</sub>/OM-specific IgE and OM-specific IgA<sub>2</sub>/OM-specific IgE in the H-E group after OIT were significantly higher than before OIT. <b><i>Conclusion:</i></b> Our findings suggest that low-dose OIT using LAC is an effective and safe treatment for patients with severe egg allergy.</p>