[Autoantibodies associated with vasculitis]

A variety of autoantibodies have been associated with vasculitis, including that to neutrophils or to endothelial cells. Anti-neutrophil cytoplasmic antibodies (ANCA) have been described as sensitive and specific markers for active Wegener's granulomatosis (WG). ANCA in WG produces a characteristic cytoplasmic staining pattern (cANCA) and are directed against proteinase 3 (PR3-ANCA). PR3-ANCA occur in more than 90% of patients with extended WG, in 75% of patients with limited WG without renal involvement and in some 40% to 50% of patients with vasculitic overlap syndrome such as microscopic polyarteritis. Change in levels of cANCA precede disease activity and may be used as guidelines for treatment. Antibodies producing a perinuclear staining of ethanol-fixed neutrophils (pANCA) occur in a wide range of disease. They are directed against different cytoplasmic constituents of neutrophils. Among these, antibodies to myeloperoxidase (MPO-ANCA) are found in patients with idiopathic crescentic glomerulonephritis, the Churg-Strauss syndrome, polyarteritis nodosa and vasculitic overlap syndromes. Anti-endothelial cell antibodies (AECA) have been described in various autoimmune (systemic lupus erythematosus, scleroderma, rheumatoid arthritis) and vasculitic disorders (WG, polyarteritis nodosa, Kawasaki syndrome). They have been implicated in the pathogenesis of vascular injury common to these disorders.