Dicker AJ, et al. - In cystic fibrosis and bronchiectasis, genetic mannose binding lectin (MBL) deficiency is associated with increased exacerbations and earlier mortality. Herein, researchers investigated if MBL deficiency impacted on clinical outcomes or microbiota composition in chronic obstructive pulmonary disease (COPD). Among COPD patients, a lower risk of exacerbations and a more diverse lung microbiota were observed in patients with MBL deficient genotype. In this study, a genetic association with the lung microbiota in COPD was identified for the first time.