[Expression and role of Tc17 cells in mice with neutrophilic asthma].

Objective: To determine the proportion of Tc17 cells in the lungs of mice with neutrophilic(NEU) asthma, and to investigate the role of Tc17 cells in the pathogenesis of NEU asthma.

Methods: Thirty-two C57/B6 mice of clean grade were randomly divided into two groups: NEU asthma and control. The mice in the NEU asthma group were sensitized by airway instillation of ovalbumin (OVA) and lipopolysaccharide (LPS), and challenged with an aerosol of OVA, while those in the control group were sensitized and challenged with normal saline. At 24 hours after the final challenge, bronchoalveolar lavage fluid (BALF) was collected, and the total number and differential counts of nucleated cells and percentage of each type were determined. The lung tissues were separated and hematoxylin-eosin staining was performed to observe the pathological changes of lungs; flow cytometry was applied to determine the percentages of Tc17 and Th17 cells in the lung tissues. Enzyme-linked immunosorbent assay was applied to determine the levels of interleukin-6 (IL-6), transforming growth factor β (TGF-β), and interleukin-17 (IL-17) in BALF.

Results: The NEU asthma group had a significantly higher total number of nucleated cells, a significantly higher percentage of eosinophils, and a significantly higher percentage of neutrophils in BALF than the control group (P<0.01). The NEU asthma group also had significantly higher percentages of Tc17 and Th17 cells than the control group (P<0.01). In the NEU asthma group, the percentage of Tc17 cells was positively correlated with that of Th17 cells (P<0.05). The NEU asthma group had significantly higher concentrations of IL-6, TGF-β, and IL-17 in BALF than the control group (P<0.05).

Conclusions: The expression of Tc17 cells in the lung tissues increases in mice with NEU asthma, and the increased number of Tc17 cells may be involved in the pathogenesis of NEU asthma. Tc17 cells may play an important role in NEU asthma through IL-17.