Granulomatosis with polyangiitis in childhood.

Granulomatosis with polyangiitis (GPA) is a rare yet frequently organ- or life-threatening systemic vasculitis affecting small- to medium-sized arteries in multiple organs. It characteristically leads to alveolar hemorrhage and destructive, pauci-immune glomerulonephritis. GPA is also characterized by granulomas in the upper and lower respiratory tract causing erosive sinusitis and nodular or even cavitating lesions in the respiratory tract. Antineutrophil cytoplasmic antibodies, a hallmark of GPA, are likely integral to the pathogenesis and recently have become a therapeutic target. International collaborations in childhood vasculitis have led to the development and validation of childhood vasculitis classification criteria,advanced our understanding of the clinical phenotype at presentation of GPA, and improved our ability to capture disease activity and determine treatment choices. Treatment efficacy and safety data continue to be largely derived from adult GPA studies. This review focuses on the recent publications on epidemiology, pathogenesis, and treatment in childhood GPA and relevant publications from the adult GPA literature.