Wild‐type mice developed clear evidence of emphysema accompanied by iBALT formation from 4 months onwards (Fig 2A–C), that specifically associated with the airways further with vessels and septal tissue (Fig 2D), whereas in Ch25h−/− mice formation of iBALT and the hallmarks of emphysema failed to develop (Fig 2A–D). The gene discussed is CH25H; the disease is pulmonary emphysema.