Fifty years of antineutrophil cytoplasmic antibodies (ANCA) testing: do we need to revise the international consensus statement on testing and reporting on ANCA?

During the first international workshop on antineutrophil cytoplasmic antibodies (ANCA), Copenhagen 25 and 26 January 1988, ANCA, as detected by the indirect immunofluorescence (IIF) technique, was extensively discussed. Cytoplasmic fluorescence pattern was found in patients with vasculitis. In contrast, perinuclear fluorescence pattern was found in vasculitis but also in many other inflammatory disorders. At the workshop, it was stated that IIF should be combined with an antigen-specific technique and capture and direct enzyme-linked immunosorbent assay techniques were discussed. In 1999/2003, an international consensus statement on testing and reporting on ANCA was published. For vasculitis, IIF was advocated as a screening assay, followed by an antigen-specific assay. In other non-vasculitic inflammatory diseases, only IIF on ethanol-fixed granulocytes was advocated. Recently, it was demonstrated that antigen-specific tests could be used as screening tests. Furthermore, it became clear that antigen-specific tests, in which antigens are directly coated to the solid phase, demonstrate highly variable sensitivities and specificities, whereas when capture or anchor technologies are used, more reproducible results are obtained. Based on these studies, we propose that the international consensus statement on ANCA should be revised.