Staphylococcus aureus enterotoxins modulate IL-22-secreting cells in adults with atopic dermatitis.

Atopic dermatitis (AD) is a chronic inflammatory immune-mediated skin disease characterized by skin colonization by Staphylococcus aureus. Interleukin (IL)-22, in cooperation with IL-17, triggers antimicrobial peptide elaboration and enhances certain immunological responses. In AD, IL-22 is related to epidermal hyperplasia, keratinocyte apoptosis, and inhibition of antimicrobial peptide (AMP) production. We aimed to evaluate the impact of staphylococcal enterotoxins on the Tc22/Th22 induction in the peripheral blood of AD patients and on CD4 ^+/ CD8 ⁺ T cells expressing IL-22 in AD skin. Our study showed inhibition of the staphylococcal enterotoxins A and B (SEA and SEB) response by Th22 (CD4 ⁺ IL-22 ⁺ IL-17A ^- IFN-γ ^- ) cells in AD patients. In contrast, Tc22 (CD8 ⁺ IL-22 ⁺ IL-17A ^- IFN-γ ^- ) cells were less susceptible to the inhibitory effects of staphylococcal enterotoxins and exhibited an enhanced response to the bacterial stimuli. In AD skin, we detected increased IL-22 transcript expression and T lymphocytes expressing IL-22. Together, our results provide two major findings in response to staphylococcal enterotoxins in adults with AD: dysfunctional CD4 ⁺ IL-22 secreting T cells and increased Tc22 cells. Our hypothesis reinforces the relevance of CD8 T cells modulated by staphylococcal enterotoxins as a potential source of IL-22 in adults with AD, which is relevant for the maintenance of immunological imbalance.