%0 Journal Article
%T Effect of anti-IgE therapy on food allergen specific T cell responses in eosinophil associated gastrointestinal disorders
%A Barbara Foster
%A Shabnam Foroughi
%A Yuzhi Yin
%A Calman Prussin
%J Clinical and Molecular Allergy
%D 2011
%I BioMed Central
%R 10.1186/1476-7961-9-7
%X To test this hypothesis, food allergen specific T cell responses were examined during a 16-week clinical trial of omalizumab in nine subjects with eosinophilic gastroenteritis and food sensitization. Allergen specific T cell responses were measured using carboxyfluorescein succinimidyl ester dye dilution coupled with intracellular cytokine staining and polychromatic flow cytometry. Four independent indices of allergen specific T cell response (proliferation, Ag dose response, precursor frequency, and the ratio of Th2:Th1 cytokine expression) were determined.Eight of the 9 subjects had measurable food allergen specific responses, with a median proliferation index of 112-fold. Allergen specific T cell proliferation was limited to CD4 T cells, whereas CD8 T cell did not proliferate. Food allergen specific responses were Th2 skewed relative to tetanus specific responses in the same subjects. In contradistinction to the original hypothesis, anti-IgE treatment did not diminish any of the four measured indices of allergen specific T cell response.In sum, using multiple indices of T cell function, this study failed to demonstrate that anti-IgE therapy broadly or potently inhibits allergen specific T cell responses. As such, these data do not support a major role for IgE facilitated Ag presentation augmenting allergen specific T cell responses in vivo.ClinicalTrials.gov identifier NCT00084097Fc¦ÅRI, the high affinity IgE receptor, is expressed by mast cells and basophils, and upon cross-linking by allergen activates these cells, leading to immediate hypersensitivity[1]. Fc¦ÅRI is also expressed by dendritic cells (DCs) and monocytes and in this capacity Fc¦ÅRI may have additional functions beyond immediate hypersensitivity. Fc¦ÅRI expression by APCs can facilitate the IgE mediated uptake of allergen, ultimately resulting in enhanced antigen presentation and increased T cell activation in vitro[2]. In a similar manner, CD23, the low affinity IgE receptor expressed by B cell can a
%U http://www.clinicalmolecularallergy.com/content/9/1/7