Background The contribution of different T cell subsets to the overall measured cytokine response to food allergens is largely unexplored.
Method The patterns of cytokine production of peripheral blood-derived T cells after allergen stimulation were studied in 22 children with multiple food allergies and in 20 non-allergic children as controls, using flow cytometry.
Results Proportions of T cells of food-sensitized children spontaneously secreting IFN-γ and IL-10 (without antigen stimulation) were lower than non-atopic children and adult controls (P0.001). The proportions of IL-4-producing cells in vitro were significantly increased (P0.04) and IFN-γ-producing cells were significantly reduced (P0.05) in sensitized children after incubation with and without dendritic cell presentation of peanut extract, β-lactoglobulin and ovalbumin. The reverse pattern was found in non-sensitized children and adult controls. IL-4 secretion in allergic children to sensitizing allergens was mainly restricted to the CD4+ CD45 RO+ population while in non-atopic controls both CD4+ and CD8+ CD45 RO+ cells produced mostly IFN-γ. Food-specific IgE values did not correspond with cytokine responses but IL-4 production and IFN-γ reduction relative to normal children were closely associated with total IgE levels.
Conclusion Food-allergic children's IL-4 cytokine response to their relevant allergens is predominantly from a memory population of CD4+ CD45 RO+ cells, whereas IL-4 and IFN-γ secretion of non-allergic controls was predominantly from mixed CD4+ and CD8+ CD45 RO+ populations.