ANCA Associated Vasculitis (Anti-Neutrophil Cytoplasmic Antibody) - Causes, Pathophysiology, Types

Small Vessel Vasculitis Vasculitis is inflammation of the blood vessels resulting in damaged vessels leading to potential complication such as tissue ischaemia from lumen narrowing or from thromboembolic events from platelet consumption during vessel repair. Primary vasculitides are classified into the size of the blood vessels affected; large vessel, medium vessel and small vessel vasculitis. The small vessel vasculitis can be further divided into ANCA associated vasculitis (AAVs) and immune complex-mediated vasculitis. ANCA-associated vasculitis is so called because in the person's blood there is presence of ANCA which is abbreviated to antineutrophil cytoplasmic antibody. AAVs usually tends to affect small and medium-sized arteries. There are three main types of ANCA - Microscopic polyangiitis - Granulomatosis with polyangiitis - Eosinophilic granulomatosis with polyangiitis The pathophysiology of AAV involve presence of ANCA and also granulomatosis. ANCA target certain proteins in the cytoplasmic granules of neutrophils and monocytes. The neutrophil for example contains enzymes myeloperoxidase and proteinase 3 in granules. What it thought to happen is that during inflammation cytokines such as TNFa and IL1 stimulates the translocation of proteinase 3 and myeloperoxidase to the cell membrane allowing these enzymes to be exposed.

Video by: Armando Hasudungan