Anti-neutrophil cytoplasmic antibody-associated vasculitis

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a group of rare autoimmune disorders characterized by inflammation and destruction of small blood vessels, associated with the presence of circulating autoantibodies directed against proteins in neutrophil cytoplasm. AAV encompasses three main conditions: granulomatosis with polyangiitis (GPA, formerly Wegener's granulomatosis), microscopic polyangiitis (MPA), and eosinophilic granulomatosis with polyangiitis (EGPA, formerly Churg-Strauss syndrome). These conditions can affect multiple organ systems, most commonly the kidneys (glomerulonephritis), lungs (pulmonary hemorrhage, nodules, or infiltrates), upper respiratory tract (sinusitis, nasal crusting, saddle nose deformity), skin (purpura, ulcers), peripheral nerves (mononeuritis multiplex), and eyes. The two main types of ANCA detected are proteinase 3-ANCA (PR3-ANCA, also called c-ANCA) and myeloperoxidase-ANCA (MPO-ANCA, also called p-ANCA). Key symptoms vary depending on the specific subtype but commonly include fatigue, fever, weight loss, joint pain, kidney dysfunction (hematuria, proteinuria, rapidly progressive renal failure), respiratory symptoms (cough, hemoptysis, dyspnea), and skin lesions. Untreated AAV can be life-threatening, particularly when the kidneys or lungs are severely involved. Rapidly progressive glomerulonephritis is a medical emergency that can lead to end-stage renal disease if not promptly treated. Treatment of AAV typically involves two phases: induction of remission and maintenance therapy. Induction therapy generally includes high-dose glucocorticoids combined with either cyclophosphamide or rituximab (an anti-CD20 monoclonal antibody). Plasma exchange may be considered in severe cases with life-threatening organ involvement. Maintenance therapy commonly involves rituximab, azathioprine, or methotrexate to prevent relapse. More recently, avacopan (a complement C5a receptor inhibitor) has been approved as an adjunctive treatment. Despite advances in therapy, relapses are common, and long-term monitoring is essential. Prognosis has improved significantly with modern immunosuppressive regimens, though treatment-related side effects and chronic organ damage remain important concerns.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

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