Abstract
Staphylococcus aureus colonizes the skin of atopic dermatitis (AD) individuals, but the impact of its enterotoxins on the chronic activation of CD4(+) T cells demands further analysis. We aimed to analyze the CD4(+) T cell anergy profile and their phenotypic and functional features through differential expression of cellular activation markers, cytokine production and response to staphylococcal enterotoxin A (SEA). A panel of 84 genes relevant to T cell anergy was assessed by PCR array in FACS-sorted CD4(+) T cells, and the most prominent genes were validated by RT-qPCR. We evaluated frequencies of circulating CD4(+) T cells secreting single or multiple (polyfunctional) cytokines (IL-17A, IL-22, TNF, IFN-γ, and MIP-1β) and expression of activation marker CD38 in response to SEA stimulation by flow cytometry. Our main findings indicated upregulation of anergy-related genes (EGR2 and IL13) promoted by SEA in AD patients, associated to a compromised polyfunctional response particularly in CD4(+)CD38(+) T cells in response to antigen stimulation. The pathogenic role of staphylococcal enterotoxins in adult AD can be explained by their ability to downmodulate the activated effector T cell response, altering gene expression profile such as EGR2 induction, and may contribute to negative regulation of polyfunctional CD4(+) T cells in these patients.