IL17A and chronic obstructive pulmonary disease: Neutrophils have long been recognised to be a hallmark feature in stable COPD present in 60–80% of patients4,5 and are further increased during exacerbations2,6 Despite this, attempts to target neutrophilic inflammation (e.g., CXCR2 antagonists, IL-17 monoclonal antibodies) have largely failed to show efficacy in clinical trials25–27.