Allergen-specific IgG antibodies are often associated with tolerance, but specific IgG antibodies (sIgG) to causally relevant foods have recently been reported in adult eosinophilic esophagitis (EoE). Prevalence and levels of food-sIgG are not well established in the general pediatric population.
We sought to investigate serum food-sIgG with component diagnostics in children with EoE and children from an unselected birth cohort and to explore the effects of sex, age and milk consumption on sIgG4 levels METHODS: Sera from 71 cases of pediatric EoE and 210 early-adolescent children from an unselected birth cohort (Project Viva) were assayed for sIgG and specific IgE (sIgE) to major cow's milk (CM) proteins (α-lactalbumin, β-lactoglobulin, caseins) and to wheat, soy, egg, and peanut proteins.
In the EoE cohort high-titer sIgG (≥ 10 μg/mL) to CM proteins were more common than in control sera, and achieved odds ratios (OR) for EoE ranging from 5.5 - 8.4. Levels of sIgE to CM proteins were mostly ≤ 4 IU/mL in EoE, such that mean sIgG:sIgE ratios were often ≥10,000. When adjusted for age and milk consumption, high-titer sIgG to CM proteins were strongly associated with EoE, with an OR > 20 to all three CM proteins in boys.
Specific IgG to CM proteins are common and high-titer in children with EoE.While it is not clear that this response is pathogenic, the levels of sIgG imply that these antibodies are an important feature of the local immune response that gives rise to EoE.