Myeloid-derived suppressor cells in bronchoalveolar lavage fluid in patients with chronic obstructive pulmonary disease

Introduction Myeloid-derived suppressor cells (MDSCs) have the potent ability to suppress T-cell function, and are important in the regulation of chronic inflammation and carcinogenesis. MDSCs may influence local and systemic inflammation and carcinogenesis in COPD; however, their presence in bronchoalveolar lavage fluid (BALF) and peripheral blood (PB) or their relationship with clinical parameters in COPD has not been studied yet. Objectives The aim of the study was to assess MDSCs in BALF and PB and to analyze the relationship between MDSCs and clinical parameters in COPD. Patients and methods The study included 64 patients with stable COPD. The clinical parameters of the patients were studied, and MDSCs were assessed using monoclonal antibodies directly conjugated with fluorochromes in flow cytometry. Results The percentage of MDSCs in BALF was lower than that in PB (0.63 +/- 0.90 vs 3.94 +/- 0.38). In BALF, MDSCs (% of mononuclear cells) correlated with forced expiratory volume in 1 second (r(s) = -0.30, P = 0.0185), residual volume/total lung capacity (rs = 0.32, P = 0.0148), PaO2 (rs = -0.45, P = 0.0002), arterial oxygen saturation (SaO(2); r(s) = -0.41, P = 0.0008), and diffusion capacity of carbon dioxide (rs = -0.32, P = 0.0211). There was a significant negative correlation between MDSCs (% of all leukocytes) and arterial oxygen pressure (r(s) = -0.42, P = 0.0006) and SaO(2) (r(s) = -0.37, P = 0.0027). No correlations were found in PB. Conclusions MDSCs are present in human lung microenvironment and may be involved in local inflammation in COPD. Future studies should focus on a detailed assessment of MDSCs in local and systemic inflammation in COPD.