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Regulatory T Cell Immunophenotype Is Influenced By Food Allergy Status
Monday, March 7, 2016
South Exhibit Hall H (Convention Center)
Ashley L Devonshire, MD, MPH, Kristin A Erickson, Benjamin T Prince, MD, Dalia Fuleihan, Christine Szychlinski, Anne Marie Singh
Rationale: The development and maintenance of regulatory T cell (Treg) populations may be important in the pathogenesis of food allergy.  We hypothesize that children with food allergy have decreased number or function of Treg cells.  These differences may be influenced by age and the presence of concomitant atopic dermatitis. 

Methods:  Peripheral blood mononuclear cells (PBMC) of 136 children (50 without atopic disease and 86 with food allergy) were stained and analyzed by flow cytometry for surface (CD25, CD127) and intracellular (Foxp3) markers of Treg cells.  Cells were further phenotyped to assess homing (CCR6), memory (CD45RO) and TCR Vb expression.  ANOVA, simple and multivariable linear regression were performed to assess differences in cell populations while controlling for possible confounders.

Results:  We found no difference in the bulk Treg cell population (CD25+CD127loFoxP3+/CD4+) in food allergic versus non-atopic children (p=0.944).  In unadjusted analysis, food allergic children had increased CD45RO+/CD25+CD127loFoxP3+ cells (p=0.045) and CD45RO+/CD25+CD127loCCR6+ cells (p=0.053) compared to non-atopic children.  In adjusted analysis, food allergic children had more CD45RO+/CD25+CD127lo (p<0.001), CD45RO+/ CD25+CD127loCCR6+ (p=0.001) and CD45RO+/ CD25+CD127loFoxP3+ (p<0.001) cells compared to non-atopic children.  Additionally, in adjusted analysis, food allergic children had a trend of increased Vb(3,5)+/ CD25+CD127loFoxP3+ cells.  

Conclusions:  Food allergic children have increased memory Treg cells and gut-homing memory Treg cells compared to non-atopic children.  Food allergic children also have increased staphylococcus-responsive Treg cells compared to non-atopic children.  These findings suggest phenotypic differences in Treg cell subsets that may be important in the pathogenesis of food allergy.  Naïve Treg cells may be important to maintain oral tolerance.