Serum sIgG4, but not sIgA, is involved in induced and natural tolerance to egg allergens

Methods Patients. We recruited children aged 5 to 16 years with previous history of IgE-mediated egg allergy, skin prick test ≥3mm and sIgE >0.35 to ovalbumin (OVA) or ovomucoid (OVM). Egg allergy or tolerance at inclusion was assessed through a double-blind placebo-controlled egg challenge. Allergic children were divided in 2 groups: G1 underwent OIT with raw egg white, whereas G2 continued avoiding egg. Tolerant children constituted group G3. Additionally, 2 groups of atopic (nut-allergic, G4) and non atopic children (G5) were included. Serum sIgE, sIgG4 and sIgA to OVA and OVM were determined at baseline (T0) in all groups, and repeated 9 months after in G1 and G2. A second DBPCFC was performed in G2 in T1. Comparisons among groups were performed through non parametrical tests using SPSS 19.0. 2-tailed p<0.05 was considered significant.