Antineutrophil Cytoplasmic Antibody-Associated Vasculitis: Toward an Individualized Approach

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), characterized by the presence of autoantibodies to neutrophil cytoplasmic antigens, proteinase 3 (PR3), and myeloperoxidase (MPO), typically involves small blood vessels of the respiratory tract and kidneys. It includes distinct clinical syndromes: microscopic polyangiitis (MPA), granulomatosis with polyangiitis (GPA), and eosinophilic GPA. GPA is commonly associated with PR3-ANCA, while MPA is associated with MPO-ANCA. AAVs have a complex pathogenesis, influenced by genetics and environmental factors. There is evidence for a loss of tolerance to neutrophil proteins, which leads to ANCA-mediated neutrophil activation and injury, with effector T cells and activation of the alternative pathway of the complement also involved. Advances in immunosuppressive treatment have drastically reduced mortality of AAV in the past decades, opting for a more individualized approach. Careful assessment of ANCA specificity, disease activity, organ damage, and quality of life allows for a tailored immunosuppressive therapy. Contemporary AAV treatment is characterized by regimens that minimize the cumulative exposure to glucocorticoids and cyclophosphamide, and novel approaches including complement blockage and immunosuppressant combinations might be the standard of care in the future. In this review, we examine the pathogenesis, clinical approach, and evidence-based treatment options for the management of AAV patients.