Background
Although IgE antibodies to cow's milk and wheat are common in patients with EoE, titers are low and responses to diet are not dependent on having IgE antibodies.
Objective
To better define specific IgE antibody responses to foods, focusing on those foods that appear to play a role in EoE.
Methods
Adult (n=46) and pediatric (n=51) EoE patients were recruited for skin prick testing and serum measurement (whole and diluted) of IgE specific for aeroallergens, food extracts and component allergens by ImmunoCAP. Immuno Solid-phase Allergen Chip (ISAC) analysis was also used to measure IgE to 112 allergen molecules.
Results
In adults and children, there was a higher prevalence of sensitization to food extracts by ImmunoCAP compared with skin prick testing. Using ISAC to assess the specificity of IgE antibodies to 112 allergen molecules, results for food allergens were mostly negative. In contrast, ImmunoCAP assays for specific milk allergens gave positive IgE antibody results in 31/34 sera. The correlations between specific IgE antibody to Bosidi4 or Bos d 5 and milk extract were strong (R=0.89 and R=0.76 respectively; p<0.001). The evidence that IgE to foods was directed at minor components of the extracts was further supported by measurements on diluted sera.
Conclusion
The IgE responses in cow's milk sensitized EoE patients are frequently to whey proteins Bos d 4 and Bos d 5, minor components of the extract. These IgE assays may be able to identify the proteins that are relevant to EoE even though IgE is not the primary mechanism.