Use of proteinase 3 purified by reverse phase HPLC to detect autoantibodies in systemic vasculitis.

The vasculitis autoantigen proteinase 3 was purified from neutrophil primary granules using reverse phase high performance liquid chromatography. It was shown to be free of important contaminants, was enzymatically active and was antigenic to sera containing antineutrophil cytoplasmic antibodies with a cytoplasmic pattern (C-ANCA) by indirect immunofluorescence. Development of an enzyme-linked immunosorbent assay showed that this preparation could be used to detect autoantibodies in Wegener's granulomatosis and microscopic polyangiitis. Assays based on reverse phase HPLC-purified proteinase 3 will be valuable in diagnosis and monitoring of treatment, and should increase our understanding of the autoimmune response in primary systemic vasculitis.