Monocyte-derived macrophages from non-smoker COPD subjects exhibit defective bacterial phagocytosis

<b>Background:</b> We have previously reported that monocytes-derived macrophages (MDM) from smoker COPD (S-COPD) subjects show defective bacterial phagocytosis. However, it is not known whether the same holds true for non-smoker COPD (NS-COPD) subjects. We aimed to study the phagocytic activity of MDM from NS-COPD subjects and compare it with S-COPD and healthy (H) subjects from India. <b>Methods:</b> Monocytes were derived from peripheral venous blood from 22 H subjects, 10 S-COPD subjects and 15 NS-COPD subjects (10 biomass fuel smoke exposed and 5 from other causes). The monocytes were cultured with complete media containing granulocyte-monocyte colony stimulating factor for 16-20 days to obtain MDM. 1X10⁶ MDM/well were incubated with fluorescently-tagged, heat-killed <i>S. pneumoniae</i> (SP: 1.2X10⁹ CFU/mL) and <i>H. influenzae</i> (HI: 1.5X10⁸ CFU/mL) for 4 hours and fluorescence was measured to quantify the intracellular uptake of SP and HI. <b>Results:</b> <b>Conclusion:</b> Monocyte-derived macrophages of non-smoker COPD subjects show defective phagocytosis, which provides further evidence to suggest that there is a common susceptibility mechanism.