Persistent central memory phenotype of circulating Fel d 1 peptide/DRB1∗0101 tetramer-binding CD4+ T cells

BackgroundAlthough substantial evidence suggests that T cells are important in the pathogenesis of atopic dermatitis (AD), little is known of the differentiation status of CD4+ T cells specific for common environmental allergens.ObjectiveTo determine the frequency, differentiation phenotype, and function of circulating allergen-specific CD4+ T cells in adult individuals with severe persistent AD and controls.MethodsUsing tetrameric complexes of an HLA DRB1∗0101 restricted epitope from Fel d 1, the major IgE-reactive component of cat dander, we studied ex vivo and cultured T-cell frequency and phenotype in individuals with AD and healthy controls. Cytokine secretion was measured by ex vivo and cultured IFN-γ, IL-4, and IL-10 enzyme linked immuno-spot analysis.ResultsEx vivo Fel d 1–specific DRB1∗0101-restricted CD4+ T cells express high levels of CCR7, CD62L, CD27, and CD28 and proportionately low levels of tissue-specific homing receptors and TH1 and TH2 cytokine production, placing the cells largely within the central memory subgroup.ConclusionCirculating Fel d 1-specific DRB1∗0101-restricted CD4+ T cells maintain central memory capacity, consistent with a potential to contribute to persisting clinical atopic disease.Clinical implicationsPersisting central memory characteristics of allergen-specific CD4+ T cells in individuals with AD may contribute to chronic disease.