Schuyler AJ, et al. - In children with eosinophilic esophagitis (EoE) and children from an unselected birth cohort (Project Viva), the investigation of serum food-specific IgG₄ antibodies (sIgG₄) with component diagnostics was carried out. Also, the impacts of sex, age and milk consumption on sIgG₄ levels were determined. In children having EoE, the presence of specific IgG₄ to cow’s milk (CM) proteins was common and high-titer. These subjects mostly had ≤ 4 IU/mL levels of sIgE to CM proteins. A strong association of high-titer sIgG₄ to CM proteins with EoE was found after adjusting for age and milk consumption. No clarity could be gained concerning if this response was pathogenic, the levels of sIgG₄ indicated that these antibodies are an essential feature of the local immune response that gives rise to EoE.