Decrease in circulating Th17 cells correlates with increased levels of CCL17, IgE and eosinophils in atopic dermatitis

BackgroundClinical significance of circulating CD4+ T cell subsets, including T-helper (Th)1, Th2, Th17 and regulatory T (Treg) cells, in patients with atopic dermatitis (AD) remains unclear. No previous studies have simultaneously evaluated the four T cell subset profiles in AD.ObjectiveThe aim of the present study was to explore whether the percentage of these four subsets of CD4+ T cells correlate to the severity parameters of AD patients.MethodsIntracellular expression of interferon (IFN)-γ, interleukin (IL)-4, IL-17 and forkhead box P3 (Foxp3) in CD4+ T cells was evaluated in peripheral blood mononuclear cells from normal controls and patient with AD as well as with chronic eczema using a flow cytometer. Serum CCL17 levels were measured as an objective severity parameter of AD together with percentage of eosinophils and serum IgE levels.ResultsIn AD patients, the number of Th1 (IFN-γ+) and Th17 (IL-17+) subsets was significantly decreased, but that of Th2 (IL-4+) and Treg (Foxp3+) subsets was similar to that of normal controls. The T cell subset profiles of patients with chronic eczema were not different with those of normal controls. The frequency of Th17cells, particularly that of the IFN-γnegaIL-17+ subset, showed a significant negative correlation with CCL17, IgE and eosinophil levels in AD patients. This was, however, not the case in Th1, Th2 and Treg cells.ConclusionDecreased circulating Th17 cells might contribute to activity of AD.