CANCA

Anti-neutrophil cytoplasmic antibodies (ANCA) are autoantibodies that cause systemic vascular inflammation by binding to target antigens of neutrophils. These autoantibodies can be found in serum from patients with systemic small-vessel vasculitis, and they are considered a biomarker for ANCA-associated vasculitis (AAV). There are two main kinds of ANCA. Each targets a specific protein inside white blood cells: cANCA, which targets a protein called PR3 (proteinase 3), and pANCA, which targets a protein called MPO (myeloperoxidase). An antigen-specific ANCA assay measures both cANCA (or PR3-ANCA) and pANCA (or MPO–ANCA) and is used to diagnose and monitor the treatment of the type of ANCA-associated small-vessel vasculitis such as granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), eosinophilic granulomatosis with polyangiitis (EGPA) or polyarteritis nodosa (PAN).