title: The association between anti-plasminogen antibodies and disease activity in ANCA-associated vasculitis.
abstract: OBJECTIVE
  Previous studies have shown that in patients with ANCA-associated vasculitis (AAV), anti-plasminogen antibodies were associated with reduced renal function and the presence of fibrinoid necrosis and cellular crescents in renal histology. The purpose of the current study was to investigate whether anti-plasminogen antibodies are associated with the systemic disease activity of AAV.
  
  
  METHODS
  One hundred and four Chinese patients with AAV were recruited. Anti-plasminogen antibodies were detected in sequential serum samples at initial onset and remission of the disease. Associations of anti-plasminogen antibodies with clinicopathological parameters were analysed.
  
  
  RESULTS
  The prevalence of anti-plasminogen antibodies was significantly higher in AAV patients than in healthy controls (19/104 vs 0/50, χ(2) = 8.8, P = 0.003). The prevalence of anti-plasminogen antibodies was significantly higher in the active stage of AAV than in remission (19/104 vs 1/48, χ(2) = 7.5, P = 0.013). The level of anti-plasminogen antibodies (expressed as a percentage of the positive controls) correlated with the ESR (r = 0.207, P = 0.042), serum creatinine (r = 0.302, P = 0.002), d-dimer (r = 0.273, P = 0.009) and the percentage of glomeruli with crescents in renal specimens (r = 0.393, P = 0.004). The level of Birmingham vasculitis activity scores and the prevalence of arthralgia and gastrointestinal involvement in patients with anti-plasminogen antibodies were significantly higher than in patients without anti-plasminogen antibodies [22.5 (s.d. 5.63) vs. 19.4 (s.d. 4.66), P = 0.015; 63.2% vs. 25.8%, P = 0.002; 57.9% vs. 21.1%, P = 0.001, respectively].
  
  
  CONCLUSIONS
  Circulating anti-plasminogen antibodies were associated with systemic disease activity and renal disease activity of AAV.
authors.affiliation: Renal Division, Department of Medicine, Peking University First Hospital, Beijing 100034, China. leimeng@public3.bta.net.cn.
authors.forename: Jian
authors.initials: J
authors.lastname: Hao
authors.forename: Chen
authors.initials: C
authors.lastname: Wang
authors.forename: Shen-Ju
authors.initials: SJ
authors.lastname: Gou
authors.forename: Ming-Hui
authors.initials: MH
authors.lastname: Zhao
authors.forename: Min
authors.initials: M
authors.lastname: Chen
mesh_terms: D000368:Aged; D056648:Anti-Neutrophil Cytoplasmic Antibody-Associated Vasculitis / Q000175:diagnosis* / Q000276:immunology*; D000888:Antibodies, Anti-Idiotypic / Q000097:blood*; D018771:Arthralgia / Q000453:epidemiology; D016022:Case-Control Studies; D002681:China; D005260:Female; D005767:Gastrointestinal Diseases / Q000453:epidemiology; D006801:Humans; D053208:Kaplan-Meier Estimate; D007668:Kidney / Q000473:pathology / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D010958:Plasminogen / Q000276:immunology*; D015995:Prevalence; D012720:Severity of Illness Index
chemical_list: D000888:Antibodies, Anti-Idiotypic; D010958:Plasminogen
keywords: ANCA; antibodies; plasminogen; vasculitis