Diagnostics and Therapy of Antineutrophil Cytoplasmic Antibody (ANCA) Associated Vasculitides

Granulumatosis with polyangiitis (wegener's)/GPA microscopic polyangiitis (MPA) and Churg Strauss syndrome (CSS) are primary systemic vasculitides which predominantly affect small vessels, showing a high association with a positive C/PR3-ANCA in GPA and P/MPO-ANCA in MPA, so called ANCA-associated vasculitides (AAV). The diagnostic work-up relies on an interdisciplinary approach including imaging techniques and laboratory tests in order to assess disease stage and extent. The golden standard remains the histological proof of a necrotizing, pauci-immune small vessel vasculitis, in GPA additionally non-caseating granuloma is found mainly in the respiratory tract. Treatment is adapted to disease stage and extent and relies on a combination of a cytotoxic plus a tapering regimen of glucocorticosteroids. Induction of remission in “early systemic” disease without organ- and life-threatening organ manifestations and a near normal kidney function can be achieved with methotrexate. In the generalized phase with significant renal dysfunction cyclophosphamide is the mainstay of therapy, in rapidly progressive glomerulonephritis with an imminent dialysis indication plasmapheresis is performed additionally. When remission is achieved, usually after 3-6 months of induction treatment, cyclophosphamide is switched to azathioprine as maintenance of remission drug. Alternative therapies are methotrexate provided the kidney function is normal or Leflunomide in the long-term follow-up the relapse rate in ANCA-associated vasculitis is approximately 50% in 5 years, irrespective of the drug used for maintenance treatment. The relapse rate is significantly higher in GPA than in MPA and CSS.