[Antineutrophil cytoplasmic antibodies as marker and follow-up parameter of vasculitis and glomerulonephritis].

Antineutrophil cytoplasmatic antibodies (ANCA) represent a heterogeneous group of autoantibodies targeting cytoplasmatic proteins in neutrophils and monocytes. They can be subdivided into c-ANCA which react with proteinase 3 (PR3) and p-ANCA which recognize myeloperoxidase (MPO). PR3 and MPO are found in the azurophilic granules of neutrophils. Activated neutrophils express these proteins on the cell surface; therefore, they can interact with ANCA. This interaction induces neutrophil degranulation with release of lytic enzymes and free oxygen-radicals. The vasculitic process is thus initiated. The c-ANCA can be detected mainly in Wegener's granulomatosis, and the titers can be used to monitor disease activity. The p-ANCA are mainly found in pauci-immune, rapidly progressive glomerulonephritides (RPGN). Recently, a host of additional inflammatory diseases have been associated with ANCA, for example ulcerative colitis and Crohn's disease. The pathogenic role of ANCA in these inflammatory bowel diseases is largely unknown.