ANCA associated pulmonary fibrosis: vasculitis or not vasculitis

The intersection of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) and interstitial lung disease (ILD) represents a complex and increasingly recognized clinical challenge. This review aims to summarize current understanding, highlight diagnostic and therapeutic approaches, and identify key gaps in the literature regarding ANCA-associated ILD.

ANCA positivity-particularly MPO-ANCA- is increasingly identified in patients with fibrotic ILD, even in the absence of systemic vasculitis. This overlap raises questions about disease classification and management, especially as radiologic patterns such as usual interstitial pneumonia (UIP) appear to predict prognosis. Immunosuppressive therapy remains the mainstay of treatment, though its role varies depending on the presence of systemic features and lung fibrosis. Emerging biomarkers, and the potential role of antifibrotic agents offer promising avenues for improved monitoring and therapy.

ANCA-ILD represents a heterogeneous and underexplored disease spectrum that challenges existing classification systems. A multidisciplinary approach is critical, and prospective studies are urgently needed to redefine diagnostic criteria and guide treatment strategies in order to improve clinical outcomes.