title: A longitudinal study of calprotectin as an inflammatory marker in patients with reactive arthritis.
abstract: OBJECTIVE
  To examine the value of calprotectin, a major granulocyte protein with bactericide properties, as an inflammatory marker in patients with reactive arthritis.
  
  
  METHODS
  Twenty-five patients with Chlamydia-induced and 27 patients with enterobacteria-induced reactive arthritis were analysed. At the first visit and after 3, 12, 24, 52 and 104 weeks, calprotectin concentrations were measured in plasma and when possible, in synovial fluid. C-reactive protein (CRP) and the erythrocyte sedimentation rate (ESR) were analysed and clinical assessments of disease activity were performed.
  
  
  RESULTS
  Of the inflammatory markers, the plasma calprotectin concentrations were the first to normalize during recovery. Calprotectin concentrations in the plasma were highly correlated with CRP and ESR, and calprotectin was found to have high correlation coefficients with the clinical assessments of disease activity. High calprotectin concentrations were found in the synovial fluid.
  
  
  CONCLUSIONS
  The high correlations between calprotectin in plasma and clinical and laboratory markers of inflammation, as well as the rapid normalization following clinical improvement, demonstrate that calprotectin may be used as an inflammatory marker in patients with reactive arthritis.
authors.affiliation: Oslo City Department of Rheumatology, Norwegian Lutheran Hospital.
authors.forename: H B
authors.initials: HB
authors.lastname: Hammer
authors.forename: T K
authors.initials: TK
authors.lastname: Kvien
authors.forename: A
authors.initials: A
authors.lastname: Glennås
authors.forename: K
authors.initials: K
authors.lastname: Melby
mesh_terms: D000293:Adolescent; D000328:Adult; D016918:Arthritis, Reactive / Q000097:blood* / Q000503:physiopathology; D015415:Biomarkers; D001799:Blood Sedimentation; D002097:C-Reactive Protein / Q000032:analysis; D002169:Campylobacter Infections; D015816:Cell Adhesion Molecules, Neuronal / Q000097:blood* / Q000378:metabolism; D002689:Chlamydia; D004756:Enterobacteriaceae Infections; D005260:Female; D015796:HLA-B27 Antigen / Q000032:analysis; D006801:Humans; D039841:Leukocyte L1 Antigen Complex; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009994:Osmolar Concentration; D013582:Synovial Fluid / Q000378:metabolism
chemical_list: D015415:Biomarkers; D015816:Cell Adhesion Molecules, Neuronal; D015796:HLA-B27 Antigen; D039841:Leukocyte L1 Antigen Complex; D002097:C-Reactive Protein