| Atopic dermatitis (AD) is a common inflammatory skin disease. Autoimmunity has been suggested to play a role in the pathogenesis of AD. The recently described TH17 cells are reported to be involved in the pathogenesis of some autoimmune diseases. We examined the expression of the TH17-associated cytokines in AD patients and explored the presence of this T cell subset particularly in chronic lesions. AD patients (acute and chronic) were recruited together with a comparable group of normal subjects. Skin biopsy specimens were taken from each. The expression of IL-17A, IL-17F, and IL-22 were studied using immunocytochemistry. Identification of IL-17A/F-producing T lymphocytes was confirmed by immunofluorescence. Using laser capture microdissection (LCM), we isolated mononuclear inflammatory cells and investigated the expression of TH17-associated cytokines mRNA by quantitative real time PCR. We detected significantly higher numbers of IL-17A, and IL-17F immunoreactive cells in AD (especially in chronic) cases compared to controls. We successfully isolated mononuclear inflammatory cells from skin of chronic AD lesions by LCM and have demonstrated the expression of IL-17A and IL-17F mRNA, similarly. Our data suggest that TH17-associated cytokines are highly expressed in chronic AD lesions. These cytokines might be implicated in the pathogenesis of AD, especially chronic lesions. |
