P121 Differential responses of M1 and M2 monocyte-derived macrophage phenotypes in COPD

IntroductionInflammation in chronic obstructive pulmonary disease (COPD) is associated with increased numbers of highly activated macrophages with a reduced phagocytic capacity. Macrophages may exist as M1 “classically activated” or M2 “alternatively activated” with different phagocytic and inflammatory mediator profiles, suggesting in COPD a more persistent, M1 macrophage predominates. It is unknown whether circulating monocytes in COPD patients predetermine whether M1 macrophages will be preferentially activated, thus driving an inflammatory phenotype.ObjectivesThis study investigated differences between monocyte-derived macrophages (MDM) from non-smokers, smokers and COPD patients driven towards M1and M2 phenotypes.MethodsMonocytes were isolated from whole blood and cultured with GM-CSF (2 ng/ml) or M-CSF (100 ng/ml) for 12d to generate M1 and M2 MDM respectively. Cells were stimulated with LPS (0.01–100 ng/ml) for 24 h and TNFα, CXCL8 and IL-10 measured by ELISA. Phagocytosis was measured fluorimetrically following exposure to fluorescent beads, H influenzae or S pneumoniae for 4 h.ResultsThere were no differences in baseline release of any of the cytokines measured between subject groups. Cells released cytokines in response to LPS in a concentration-dependent manner. M1MDM derived from non-smokers and COPD patients released greater concentrations of LPS-stimulated (10 ng/ml) TNFα compared to M2 MDM. (Non-smokers: 7.4±2.3 vs 1.5±0.2 ng/ml, n=4; p