title: Clinical usefulness of anti-RNA polymerase III antibody measurement by enzyme-linked immunosorbent assay.
abstract: OBJECTIVE
  To evaluate the clinical usefulness of measuring anti-RNA polymerase (RNAP) III antibody with a commercially available ELISA in Japanese patients with SSc.
  
  
  METHODS
  This multicentre study involved 354 patients with SSc, 245 with non-SSc CTDs and 102 healthy controls. ELISAs were used to detect anti-RNAP III antibody, anti-topo I antibody and ACA. The presence of anti-RNAP III antibody in selected serum samples was confirmed by immunoprecipitation (IP) assay.
  
  
  RESULTS
  By ELISA, anti-RNAP III antibody was detected in 38 (10.7%) patients with SSc, 3 (1.2%) with non-SSc CTD and no healthy controls. The clinical specificity for SSc was excellent (98.8%), although a small number of false positives occurred. The sensitivity of the anti-topo I and ACA ELISAs for SSc was 59.9%, which increased to 68.2% without a reduction in specificity when the anti-RNAP III measurement was added. Clinical features associated with positivity for the anti-RNAP III antibody include dcSSc, a high total skin score and a trend towards high prevalence of renal crisis, consistent with previous studies that used an IP assay. Furthermore, on clinical severity scales, SSc patients with anti-RNAP III antibody scored highest for skin and renal involvement among patients subgrouped by the presence of individual SSc-related antibodies.
  
  
  CONCLUSIONS
  The measurement of anti-RNAP III antibody by ELISA is useful in routine clinical practice, because it helps diagnose SSc and identify a disease subset with severe skin and renal involvement.
authors.affiliation: Department of Internal Medicine, Division of Rheumatology, Keio University School of Medicine, Tokyo 160-8582, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Satoh
authors.forename: Osamu
authors.initials: O
authors.lastname: Ishikawa
authors.forename: Hironobu
authors.initials: H
authors.lastname: Ihn
authors.forename: Hirahito
authors.initials: H
authors.lastname: Endo
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Kawaguchi
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Sasaki
authors.forename: Daisuke
authors.initials: D
authors.lastname: Goto
authors.forename: Kazuo
authors.initials: K
authors.lastname: Takahashi
authors.forename: Hiroki
authors.initials: H
authors.lastname: Takahashi
authors.forename: Yoshikata
authors.initials: Y
authors.lastname: Misaki
authors.forename: Tsuneyo
authors.initials: T
authors.lastname: Mimori
authors.forename: Yoshinao
authors.initials: Y
authors.lastname: Muro
authors.forename: Norihito
authors.initials: N
authors.lastname: Yazawa
authors.forename: Shinichi
authors.initials: S
authors.lastname: Sato
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Takehara
authors.forename: Masataka
authors.initials: M
authors.lastname: Kuwana
mesh_terms: D000328:Adult; D000368:Aged; D000974:Antibodies, Antinuclear / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D003240:Connective Tissue Diseases / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D006801:Humans; D047468:Immunoprecipitation; D008297:Male; D008875:Middle Aged; D012320:RNA Polymerase III / Q000276:immunology*; D012595:Scleroderma, Systemic / Q000175:diagnosis* / Q000276:immunology; D012720:Severity of Illness Index
chemical_list: D000974:Antibodies, Antinuclear; D015415:Biomarkers; D012320:RNA Polymerase III