Package "ANCA screening"
ANCA associated vasculitis (AAV) belong to the autoimmune diseases group affecting mainly small- caliber vessels (capillaries, venules, arterioles and small arteries), rarely affecting medium-caliber vessels.
AAV is characterized by the production of anti-neutrophil cytoplasmic autoantibodies (ANCAs) known as anti-proteinase 3 antibodies (anti-PR3) or anti-myeloperoxidase antibodies (anti-MPO). In AAV, these antibodies activate neutrophils and the complement system, leading to inflammation and damage to the vascular walls.
ANCA-vasculitis group involves:
- Microscopic polyangiitis (MPA)
- Granulomatosis with polyangiitis (GPA)
- Eosinophilic granulomatosis with polyangiitis (EGPA)
All these diseases show signs of small vessel damage and, in addition, affect various target organs, most commonly the respiratory tract and kidneys.
In ANCA vasculitis active stage, anti-myeloperoxidase and/or anti-proteinase-3 antibodies are detected in almost all patients with MPA and GPA, and are found in at least 40% of patients with EGPA.
AAV clinical picture ranges from mild (not life-threatening) to severe, often with potentially life-threatening multi-organ damage. Determination of antibody concentrations to Anti-PR3 and Anti-MPO, included in the ANCA screening package, may be crucial in diagnosis and provides additional information on the differential diagnosis and course of AAV.