Bronchoalveolar lavage T cell cytokine profiles and their association with lung function in children withMycoplasma pneumoniae-associated bronchiolitis obliterans

Background Mycoplasma pneumoniae(M. pneumoniae) infection may progress to bronchiolitis obliterans (BO), with an underlying chronic inflammatory process. The aim of this study was to investigate the cytokine profiles in pulmonary T-lymphocytes and their associations with lung function in patients with BO followingM. pneumoniaeinfection. Methods Bronchoalveolar lavage (BAL) samples were obtained from 10 controls and 18 children withM. pneumoniae-associated BO. We analyzed the BAL T cells for interferon (IFN)-gamma, interleukin (IL)-4, IL-9, IL-17, CD25, and Foxp3 by intercellular flow cytometry. The associations with T-cell subpopulations and lung function parameters were determined. Results In BAL fluid, significantly increased proportions of T-helper 1 (Th1), Th17, and Tc1 cells were found inM. pneumoniae-associated BO patients when compared with controls. The percentages of Th17 cells showed correlations with forced expiratory volume in 1 second % predicted value (r = -0585;P < .05) and forced expiratory flow at 25% to 75% (FEF25%-75%) % predicted value (r = -.618;P < .01). Higher proportions of Tc1 (r = -.488;P < .05) and Tc17 (r = -.542;P < .05) were significantly correlated with a reduced FEF25%-75%% predicted value inM. pneumoniae-associated BO patients. Conclusions Our comprehensive cytokines analysis of BAL T cells revealed correlations of IL-17-producing and IFN-gamma-producing T cells with lung function, suggesting that increased T-cell subpopulations may play a role inM. pneumoniae-associated BO progression.