Cigarette smoke (CS) has strong links with the dominance of M2 phenotype in COPD, reveals a recent study by a team of scientists from the Department of Respiratory Medicine, Wuxi People’s Hospital Affiliated to Nanjing Medical University, China. The researchers underlined the importance of their findings by pointing out that macrophage polarisation plays an important role in the pathogenesis of COPD emphysema. The researchers wrote that they measured macrophage polarisation and the levels of matrix metalloproteinases (MMPs) in the lung tissues of COPD patients and cigarette smoke (CS)-exposed mice to find an increased M2 macrophages. The MMP9 and MMP12 levels were observed in COPD patients, CS-exposed mice and THP-M cells co-cultured with CS extract (CSE)-treated human bronchial epithelial (HBE) cells.