New insights into clinical spectrum of antineutrophil cytoplasmic autoantibody associated disease

PURPOSE OF REVIEW: Antineutrophil cytoplasmic autoantibody (ANCA) vasculitis is a systemic autoimmune disease characterized by small-vessel inflammation caused by pathogenic autoantibodies directed against myeloperoxidase or proteinase 3. The clinical spectrum of ANCA vasculitis has expanded in recent years. This review summarizes emerging phenotypes and novel disease associations that have increased our understanding of ANCA disease and may be relevant for classification and treatment. RECENT FINDINGS: ANCA disease exhibits marked clinical heterogeneity in terms of organ involvement and disease severity. Recent studies have further increased phenotypic diversity of ANCA vasculitis by describing less common manifestations, such as involvement of large vessels and interstitial lung disease, characterizing features associated with elderly and ANCA-negative patients, and exploring new cluster associations defined by clinical and serologic features. Novel entities, such as immune checkpoint inhibitor-induced vasculitis and vasculitis associated with monogenic and autoinflammatory conditions, have also been increasingly recognized. SUMMARY: Recognition of less frequent manifestations within major clinicopathological variants of ANCA vasculitis and the identification of new disease associations underscore the diversity of pathogenic mechanisms (e.g., immune, genetic, and environmental) involved in ANCA-associated disease. Future disease phenotyping refinement will likely improve precision medicine and patient care.