Factors such as infections, allergens exposure, irritants and emissions cause the production of proinflammatory cytokines by neutrophils and the cytokines induce the extravasation of granules from intracytoplasmic proteins, which serve as antigens for c-ANCA antibodies: PR3- from Wegener granulomatosis (85-90%), microscopic polyangiitis (45%), Churg-Strauss syndrome (10%) and MPO from Churg-Strauss syndrome, Microscopic polyangiitis. Here, MPO is linked to microscopic polyangiitis.