| A rare inflammatory necrotizing systemic vasculitis that affects predominantly small vessels (i.e. small arteries, arterioles, capillaries, venules) in multiple organs, including the kidney, the lungs, the skin and the peripheral nerves. This disease is an antineutrophil cytoplasmic autoantibodies (ANCA)-associated autoimmune disease with little or no immune complex deposition. Evidence indicates that ANCA can activate neutrophils and monocytes and cause them to attack vessel walls. |