[An ELISA for the detection of anti-neutrophil cytoplasmic antibodies using the cytoplasmic alpha-fraction--clinical use for the diagnosis of Wegener granulomatosis and for monitoring its activity].

Anti-neutrophil cytoplasmic antibodies (ANCA) have been reported to be a disease-specific marker for Wegener's granulomatosis (WG). In the present study we developed an enzyme-linked immunosorbent assay (ELISA) for detecting and quantifying ANCA. The cytoplasmic alpha-fraction of neutrophils obtained from healthy human donors was used as an antigen. The alpha-fraction was purified from supernatants of homogenized neutrophils by sucrose gradient centrifugation. Peroxidase conjugated rabbit anti-human IgG was used as a secondary antibody. Diluted sera from 13 patients with WG, 15 with Sjögren syndrome, 1 with polymorphic reticulosis, 3 with relapsing polychondritis, 4 with other collagen diseases, 4 with sinusitis and 18 healthy donors were examined. It was concluded that this ELISA was sufficiently specific and sensitive for WG, and the ELISA units correlated individually with the ANCA titers as determined by an indirect immunofluorescence technique. This ELISA provides precise ANCA quantitation and will be useful for the diagnosis of WG and for monitoring its activity.