The LCN2‐containing N1 progenitor neutrophil signature, which was enriched in the OAC4 group, also contains the alarmins (S100A8, S100A9, S100A12) that drive mucus hypersecretion, alveolar destruction and lung function decline in COPD.26, 27. Here, S100A9 is linked to chronic obstructive pulmonary disease.