BackgroundA T helper cell (TH) 17-biased response has been observed in patients with allergic asthma, particularly in those with neutrophil accumulation in the lung. Therefore, we sought to test the hypothesis that neutrophils might be an important source of interleukin (IL)-17 in allergic asthma.MethodsWhole peripheral blood cells from non-asthmatic control subjects (n = 17) and patients with mild asthma (n = 7), moderate but persistent asthma (n = 4), or acute asthma (n = 6) were analyzed for IL-17A expression in CD177+ neutrophils. IL-17A expression was also analyzed in CD3+CD4+ and CD3+CD8+ lymphocyte populations. Asthmatic patients were classified as allergic to fungi, indoor allergens, or other allergens (e.g., pollen) based on a positive intradermal allergy test reaction.ResultsThe percentage of CD177+ neutrophils in whole blood of asthmatic patients was higher than in healthy controls and highest in the moderate asthma group. Furthermore, the percentage of CD177+IL-17+ neutrophils was elevated in patients with mild asthma, whereas the CD4+ IL-17+ lymphocyte population was higher in asthmatic patients and highest in those with moderate but persistent asthma. We also found that the four patients that were allergic to fungi had the highest percentage of CD177+IL17+ neutrophils and CD8+IL17+ lymphocytes.ConclusionIL17+CD177+ Neutrophils increase in allergic asthma patients especially when allergic to fungi. This cell population, through release of IL-17, might be contributing during the initial phase asthmatic disease and/or during disease progression but its role has not yet been established.

BackgroundClass-I MHC-restricted T cell-associated molecule (CRTAM) is a protein expressed by activated natural killer T (NKT) cells, natural killer (NK) cells, CD8 T cells, and certain CD4 T lymphocytes. It is also expressed in Purkinje neurons and epithelial cells. However, no studies have examined the expression of CRTAM in peripheral blood cells during homeostasis or disease. Therefore, we explored whether CRTAM expression is influenced by the presence of allergic asthma.MethodsWe collected whole peripheral blood cells from non-asthmatic control subjects (n = 17) and patients with asthma (n = 17). All patients with asthma tested positive in allergen skin prick tests. We analyzed CRTAM expression in CD4+ and CD8+ T lymphocyte populations. CRTAM expression was also analyzed in CD177+ neutrophils and IL5Rα+ eosinophils.FindingsThe percentage of CD4+CRTAM+ and CD8+CRTAM+T lymphocytes in peripheral blood was higher in allergic asthma patients compared with healthy controls. Furthermore, the percentage of CD177+CRTAM+ neutrophils in peripheral blood was also elevated in patients with allergic asthma. However, the percentage of IL5Rα+CRTAM+ eosinophils in peripheral blood was not significantly different in patients with allergic asthma compared with healthy controls.ConclusionsCRTAM expression on T cells, eosinophils, and neutrophils may be involved in bronchial inflammation in allergic asthma. Determination of CRTAM expression in peripheral blood may be useful for the diagnosis of bronchial inflammation and/or to identify recently activated immune cells.