title: Detection rate and antigenic specificities of antineutrophil cytoplasmic antibodies in chinese patients with clinically suspected vasculitis.
abstract: The detection rate of antineutrophil cytoplasmic antibodies (ANCA) in Chinese patients with clinically suspected small vessel vasculitis was investigated, and their antigen specificity and demographic features were analyzed. A number of sera (n = 5,604) sent to our referral laboratory for ANCA screening were tested by indirect immunofluorescence (IIF), enzyme-linked immunosorbent assays (ELISAs) for myeloperoxidase (MPO)- and proteinase 3 (PR3)-ANCA. Then the IIF-ANCA-positive sera that were negative for MPO- and PR3-ANCA were further tested by antigen-specific ELISA by using other five highly purified known ANCA antigens as solid-phase ligands. The known antigens included bactericidal/permeability-increasing protein (BPI), human leukocyte elastase (HLE), lactoferrin, cathepsin G, and azurocidins. Of the 5,604 sera, 267 (4.76%) sera were IIF-ANCA positive and 390 (7%) were antinuclear antibody (ANA) positive in the IIF assay. Of the IIF-positive samples, 213 were anti-MPO positive, 32 were anti-PR3 positive, and five cases were positive for both. Of the 48 sera positive for IIF-ANCA but negative for MPO- and PR3-ANCA, 13 sera (27%) recognized other target antigens, 7 sera recognized BPI, 5 recognized HLE, 1 recognize cathepsin G, and 1 recognized azurocidin. None of the sera recognized lactoferrin, and one serum sample recognized both BPI and HLE. The majority of ANCA-positive patients presented in summer or winter. There was no difference in gender (male/female ratio, 1:1.12) in ANCA-positive patients with a mean age of 53.1 years. The male/female ratio was 1.17:1 for patients over 60 years of age; however, it was 1:4 for patients under 20 years of age. We conclude that ANCA-related diseases are not rare in China, and the major antigens are MPO and PR3. When the IIF technique is used to detect ANCA, ANA should be carefully distinguished.
authors.affiliation: Department of Nephrology, Peking University First Hospital, Beijing 100034, People's Republic of China. mhzhao@bjmu.edu.cn
authors.forename: Gang
authors.initials: G
authors.lastname: Xin
authors.forename: Ming-Hui
authors.initials: MH
authors.lastname: Zhao
authors.forename: Hai-Yan
authors.initials: HY
authors.lastname: Wang
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000743:Anemia, Hemolytic / Q000097:blood / Q000150:complications / Q000276:immunology; D019268:Antibodies, Antineutrophil Cytoplasmic / Q000097:blood / Q000276:immunology*; D000974:Antibodies, Antinuclear / Q000097:blood; D000918:Antibody Specificity / Q000276:immunology; D023181:Antimicrobial Cationic Peptides; D001323:Autoantibodies / Q000097:blood / Q000276:immunology; D001798:Blood Proteins / Q000276:immunology; D056649:Cathepsin G; D002403:Cathepsins / Q000276:immunology; D002648:Child; D002681:China / Q000453:epidemiology; D003093:Colitis, Ulcerative / Q000097:blood / Q000150:complications / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D014890:Granulomatosis with Polyangiitis / Q000097:blood / Q000150:complications / Q000276:immunology; D006801:Humans; D007781:Lactoferrin / Q000276:immunology; D019272:Leukocyte Elastase / Q000276:immunology; D008297:Male; D008565:Membrane Proteins / Q000276:immunology; D008875:Middle Aged; D053146:Myeloblastin; D009195:Peroxidase / Q000276:immunology; D012621:Seasons; D012697:Serine Endopeptidases / Q000276:immunology; D012737:Sex Factors; D014657:Vasculitis / Q000453:epidemiology / Q000209:etiology / Q000276:immunology*
chemical_list: D019268:Antibodies, Antineutrophil Cytoplasmic; D000974:Antibodies, Antinuclear; D023181:Antimicrobial Cationic Peptides; D001323:Autoantibodies; D001798:Blood Proteins; D008565:Membrane Proteins; C021623:bactericidal permeability increasing protein; D009195:Peroxidase; D002403:Cathepsins; D007781:Lactoferrin; D012697:Serine Endopeptidases; C534094:CTSG protein, human; D056649:Cathepsin G; D019272:Leukocyte Elastase; D053146:Myeloblastin