To examine food allergen specific T cell responses in food anaphylaxis and EGIDs, cohorts with peanut anaphylaxis (PA), allergic eosinophilic gastroenteritis (AEG), or healthy non-atopic control (NA) subjects were recruited. Effector/memory T cell cytokine responses were measured using intracellular cytokine staining and polychromatic flow cytometry. IL-4, IL-5, IFN-gamma and TNF responses were measured in both the CD4 and CD8 T cell subsets. Antigens that were studied included peanut, Ara h1, soy, shrimp, and staphylococcal enterotoxin B (SEB). ? ? Food allergen specific T cell responses were found exclusively within the CD4 T cell compartment and were clearly demonstrable in both food allergic cohorts. Constitutive cytokine production was low for all groups. In particular, AEG subjects did not demonstrate constitutive IL-5 expression. Similar frequencies of peanut specific IL-4+ T cells were found in both the PA and AEG subject groups, but not in the NA group. In contrast to IL-4, the frequency of food allergen specific IL-5+ T cells was significantly higher in the AEG group relative to both the PA and NA subjects. Furthermore, AEG subjects demonstrated greater IL-4 and IL-5 responses to non-peanut food allergens than either the PA or NA subject groups. In contrast to the above, a group of 3 subjects with non-allergic EG did not have food allergen specific Th2 responses. In agreement with the antigen specific data, CD4 T cell responses to SEB demonstrated that AEG was associated with a significantly greater frequency of IL-5+ cells relative to the other subject groups. ? ? These findings demonstrate a significant correlation between AEG disease status and the presence of IL-5 expressing food allergen specific T cells across multiple food allergens. Given that IL-5 is a major eosinophil active cytokine, it is likely that this association is of immunopathological significance and suggests that IL-5 producing food allergen specific T cells drive the eosinophilic inflammation found in EGIDs. Additionally, these findings suggest that although the expression of IL-4 and IL-5 are linked, each is controlled in a different manner, which may have important consequences for the immunopathogenesis of allergic diseases.? ? Current work is aimed at continued development of high fidelity polychromatic flow cytometry assays to simultaneously examine multiple Th2 cytokines (IL-4, -5, -9, -13) in an allergen specific manner. This technical capacity will facilitate future interventional clinical studies designed to examine immunomodulation of allergic Th2 responses in peanut anaphylaxis and EGIDs.
| Foster, Barbara; Prussin, Calman; Liu, Fei et al. (2007) Detection of intracellular cytokines by flow cytometry. Curr Protoc Immunol Chapter 6:Unit 6.24 |
