ANCA (ANTI NEUTROPHIL CYTOPLASMIC ANTIBODIES) (P- ANCA + C-ANCA) WITH TITRE
Anti-neutrophil cytoplasmic antibodies (ANCAs) are a group of autoantibodies, mainly of the IgG type, against antigens in the cytoplasm of neutrophils (the most common type of white blood cell) and monocytes.
They are detected as a blood test in a number of autoimmune disorders, but are particularly associated with systemic vasculitis, so called ANCA-associated vasculitides (AAV).
The c-ANCA antigen is specifically proteinase 3 (PR3). p-ANCA antigens include myeloperoxidase (MPO) and bacterial permeability increasing factor Bactericidal/permeability-increasing protein (BPI). Other antigens exist for c-ANCA (atypical), however many are as yet unknown.
Classical p-ANCA occurs with antibodies directed to MPO. p-ANCA without nuclear extension occurs with antibodies to BPI, cathepsin G, elastase, lactoferrin and lysozyme.