title: Changes in proteinase 3 anti-neutrophil cytoplasm autoantibody levels in early systemic granulomatosis with polyangiitis (Wegener's) may reflect treatment rather than disease activity.
abstract: OBJECTIVE
  To investigate the nature of the relationship between proteinase 3 anti-neutrophil cytoplasm autoantibody (PR3-ANCA) and relapse in patients with early systemic granulomatosis with polyangiitis (Wegener's) (GPA).
  
  
  METHODS
  Clinical data from 16 relapsing and 12 non-relapsing patients with early systemic GPA from a randomised clinical trial were correlated to monthly PR3-ANCA values over 18 months. Each sample was examined using 9 different enzyme-linked immunosorbent assays (ELISAs) to ensure reliability of ANCA results. PR3-ANCA peaks were identified by the highest sum of logarithmic transformation values from all assays in samples after remission.
  
  
  RESULTS
  A PR3-ANCA peak was identified in all relapsing and non-relapsing patients and coincided with relapse in all 14 evaluable relapsing patients. The monthly increment before the peak, however, was similar in relapsing and non-relapsing patients in all assays. Increments from remission to peak were higher in relapsing patients in 2/9 assays. PR3-ANCA values at entry and peak PR3-ANCA values were higher in relapsing patients in 3/9 and 2/9 assays, respectively. However, large overlaps of PR3-ANCA values prevented a distinction between relapsing and non-relapsing patients. The median time to reach peak values was 14 months in relapsing and 12 months in non-relapsing patients with scheduled termination of treatment at 12 months.
  
  
  CONCLUSIONS
  The predictive value for relapses of PR3-ANCA determinations confirm and extend previous reports. Although all relapses were related to PR3-ANCA increases, reduction or withdrawal of immunosuppression without relapse was also related to increases and may explain the lack of predictive value of sequential PR3-ANCA determinations.
authors: Department of Biochemistry and Immunology, Statens Seruminstitut, Copenhagen, Denmark. NIR@ssi.dk
authors: N
authors: N
authors: Rasmussen
authors: A
authors: A
authors: Salmela
authors: A
authors: A
authors: Ekstrand
authors: K
authors: K
authors: de Groot
authors: G
authors: G
authors: Gregorini
authors: J W
authors: JW
authors: Cohen Tervaert
authors: W L
authors: WL
authors: Gross
authors: A
authors: A
authors: Wiik
authors: D R W
authors: DR
authors: Jayne
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D019268:Antibodies, Antineutrophil Cytoplasmic / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D014890:Granulomatosis with Polyangiitis / Q000097:blood / Q000175:diagnosis* / Q000188:drug therapy* / Q000276:immunology; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D053146:Myeloblastin / Q000276:immunology*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012008:Recurrence; D012074:Remission Induction; D012720:Severity of Illness Index; D013997:Time Factors; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D019268:Antibodies, Antineutrophil Cytoplasmic; D015415:Biomarkers; D007166:Immunosuppressive Agents; D053146:Myeloblastin