Accordingly, MPO‐ANCA‐positive interstitial pneumonia may include not only microscopic polyangiitis and unclassified AAV [11] but also MPO‐ANCA‐positive interstitial pneumonia without systemic vasculitis manifestations, as well as pulmonary‐limited AAV preceding the onset of AAV. The gene discussed is MPO; the disease is necrotizing vasculitis.