Significance of autoantibodies to purified proteinase 3 in systemic vasculitis.

Proteinase 3 was purified from human neutrophils and used in ELISA to examine sera from 150 patients with systemic vasculitis. It was found to be the major target of autoantibodies in Wegener's granulomatosis, and anti-proteinase 3 antibodies were also found in some patients with microscopic polyarteritis. Anti-proteinase 3 antibodies were associated with a chronic relapsing course.