Antineutrophilic Cytoplasmic Antibodies in Systemic Vasculitis: The author replies

Abstract

I appreciate the letter from MacIsaac and associates. Antineutrophilic cytoplasmic antibodies (ANCA) in small-vessel vasculitis (microscopic polyarteritis) were not mentioned in my article on systemic necrotizing vasculitis because I was unsure of their role in that syndrome. As mentioned in the letter, these antibodies have been described in microscopic polyarteritis. A series with sufficient numbers of patients diagnosed as having microscopic polyarteritis, however, has not been analyzed for ANCA to determine the diagnostic efficiency of this finding, whereas these antibodies have been shown to be present in more than 90% of patients with Wegener's granulomatosis, and in this disorder ANCA have been shown to be useful in determining the activity of the disease. Another problem in determining the role and significance of ANCA in microscopic polyarteritis is the fact that at least two different staining patterns may be present, an indication of antibodies to different antigens in that test system. The antibodies found in Wegener's granulomatosis demonstrate a cytoplasmic staining pattern, and these antibodies appear to be directed toward serine protease antigens distinct from elastase and cathepsin.1Goldschmeding R van der Schoot CE ten Bokkel Huinink D Hack CE van den Ende ME Kallenberg CGM von dem Borne AEGK Wegener's granulomatosis autoantibodies identify a novel diisopropylfluorophosphate-binding protein in the lysosomes of normal human neutrophils.J Clin Invest. 1989; 84: 1577-1587Crossref PubMed Scopus (383) Google Scholar These same antibodies have been recognized, as mentioned, in some cases of small-vessel vasculitis and in some patients with rapidly progressive glomerulonephritis.2Nölle B Specks U Lüdemann J Rohrbach MS DeRemee RA Gross WL Anticytoplasmic autoantibodies: their immunodiagnostic value in Wegener granulomatosis.Ann Intern Med. 1989; 111: 28-40Crossref PubMed Scopus (680) Google Scholar, 3Specks U Wheatley CL McDonald TJ Rohrbach MS DeRemee RA Anticytoplasmic autoantibodies in the diagnosis and follow-up of Wegener's granulomatosis.Mayo Clin Proc. 1989; 64: 28-36Abstract Full Text Full Text PDF PubMed Scopus (246) Google Scholar Antineutrophilic cytoplasmic antigens have been described in various types of vasculitis and connective tissue diseases. In the non-Wegener's group, the pattern demonstrated on immunofluorescent microscopy is a perinuclear staining pattern on the neutrophil preparation.4Falk RJ Jennette JC Anti-neutrophil cytoplasmic autoantibodies with specificity for myeloperoxidase in patients with systemic vasculitis and idiopathic necrotizing and crescentic glomerulonephritis.N Engl J Med. 1988; 318: 1651-1657Crossref PubMed Scopus (1257) Google Scholar In this situation, the antibodies appear to be directed in part toward myeloperoxidase. This difference in staining patterns and antibody specificity was recognized by the 2nd International Workshop on Antineutrophil Cytoplasmic Antibodies, which was held in May 1989. C-ANCA is used to designate the cytoplasmic staining antineutrophilic cytoplasmic antibodies as seen in Wegener's granulomatosis, and P-ANCA (perinuclear staining antineutrophilic cytoplasmic antibodies) is the designation for that pattern seen in other types of vasculitis and connective tissue diseases. Consequently, when similar testing techniques and interpretations have been used in the assessment of sufficient numbers of patients with various types of vasculitis, then we may be able to answer the question of the role of specific types of ANCA in small-vessel systemic vasculitis. Antineutrophilic Cytoplasmic Antibodies in Systemic VasculitisMayo Clinic ProceedingsVol. 65Issue 1PreviewWe read with interest the article entitled “Update on Systemic Necrotizing Vasculitis,” written by Dr. D. L. Conn and published in the May 1989 issue of the Proceedings (pages 535 to 543). The review did not mention the role of antineutrophilic cytoplasmic antibodies (ANCA) in the diagnosis, management, and monitoring of patients with a systemic vasculitis of small vessels. Full-Text PDF