ANCA-associated vasculitis and interstitial lung disease: challenges and open questions.

Interstitial lung disease (ILD) is increasingly recognized as a common manifestation in anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), particularly in patients with microscopic polyangiitis and myeloperoxidase (MPO)-ANCA. Its pathogenesis mainly involves MPO-ANCA production, oxidative stress, the formation of neutrophil extracellular traps, and genetic predisposition. The occurrence of ILD has major impacts on patients' quality of life and mortality risk. Usual interstitial pneumonia is reported as the most common CT pattern, and it is specifically associated with a poor prognosis. Treatment should be individualized, including immunosuppression, and antifibrotic therapy for progressive fibrosis, though the optimal management approach presently remains uncertain.