Clinical relevance of anti-PR3 capture ELISA in diagnosing Wegener's granulomatosis

Wegener's granulomatosis (WG) is one type of systemic small vessel vasculitis and antineutrophil cytoplasmic antibodies (ANCA) have become an established diagnostic tool for systemic vasculitis. The sensitivity and specificity of anti-PR3 (proteinase 3) capture enzyme-linked immunosorbent assay (ELISA) in diagnosing WG were investigated, as well as the correlation with the indirect immunofluorescence test (IIFT). Sera from 72 patients with WG, 100 disease controls, and 206 healthy blood donors were investigated for anti-PR3 and cytoplasmic ANCA (cANCA) by anti-PR3 classic ELISA, anti-PR3 capture ELISA, and IIFT. The sensitivity of anti-PR3 classic ELISA and capture ELISA in diagnosing WG was 74% and 87.5% separately. The specificity of the two ELISA was identical (100%). For the combination of IIFT with anti-PR3 capture ELISA, the sensitivity for WG patients was up to 91.6%. The sensitivity of anti-PR3 capture ELISA is superior to anti-PR3 classic ELISA, and the correlation between anti-PR3 capture ELISA and IIFT is also more superior. For suspected WG, anti-PR3 capture ELISA and IIFT should be applied in parallel.