Sputum Antineutrophil Cytoplasmic Antibodies in Serum Antineutrophil Cytoplasmic Antibody–Negative Eosinophilic Granulomatosis with Polyangiitis

We report a novel finding of ANCA reactivity in the sputa of patients with eGPA in whom disease severity is driven by respiratory complications. Investigating localized autoimmunity may lead to the discovery of novel pathomechanisms, therapeutic targets, and optimal biomarkers for diagnosing and managing eGPA.