Egg-specific IgE and basophil activation but not egg-specific T cells correlate with phenotypes of clinical egg allergy

Publication date: Available online 5 March 2018
Source:Journal of Allergy and Clinical Immunology
Author(s): M. Cecilia Berin, Alexander Grishin, Madhan Masilamani, Donald Y. Leung, Scott H. Sicherer, Stacie M. Jones, A. Wesley Burks, Alice K. Henning, Peter Dawson, Joanna Grabowska, Charuta Agashe, Wendy F. Davidson, Robert A. Wood, Hugh A. Sampson
BackgroundEgg allergy is phenotypically heterogeneous. A subset of egg allergic individuals can tolerate egg in an extensively heated form. Inclusion of baked-egg (BE) into their diet accelerates resolution of egg allergy. Conversely, BE reactivity is associated with persistent disease. The immune basis of this clinical heterogeneity is unknown.ObjectivesTo study egg-specific antibody, basophil, and T cell responses in children with reactivity or tolerance to BE.MethodsAll participants underwent double-blind placebo-controlled challenges to BE, and those who tolerated BE were challenged to unheated egg white protein to confirm clinical egg reactivity. Laboratory studies included serum antibodies, basophil activation tests, and CD154-based detection of egg responsive T cells by flow cytometry.ResultsOf the 129 children studied, BE reactive participants had significantly higher levels of egg, ovalbumin, and ovomucoid-specific IgE, lower ratios of egg-specific IgG4/IgE, and increased basophil activation in response to egg. Among all participants, CD154-based profiling revealed egg-responsive T cells producing IL-4 and IL-13, but little IL-10 or IFN-γ, as well as presence of egg-responsive Foxp3+CD25+CD127low Tregs. Egg-responsive T cells expressed CCR4, CCR6, and CXCR5, indicating capacity for homing to skin, mucosa, and B cell follicles. However, neither the frequency nor phenotype of egg-responsive T cells were different in those with tolerance or reactivity to BE.ConclusionsEgg-specific antibody and basophil responses, but not T cell responses, are higher in those with reactivity versus tolerance to BE. The egg-specific antibody and T cell responses were highly heterogeneous in this cohort. The clinical implications of this immune heterogeneity will need to be studied longitudinally.

Teaser

In a study of 129 children challenged to baked and unheated forms of egg, significantly lower egg-specific IgE and basophil activation, but no differences in egg-specific Th2 cells or Tregs, were associated with tolerance to BE.


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