title: A longitudinal study of calprotectin in patients with polymyalgia rheumatica or temporal arteritis: relation to disease activity.
abstract: OBJECTIVE
  Calprotectin is a granulocyte and monocyte cytosolic protein that is released during activation of these cells. The plasma level of calprotectin is raised in various inflammatory conditions and correlates with disease activity in a wide range of rheumatic diseases. We wanted to investigate whether calprotectin may be useful as a measure of disease activity in polymyalgia rheumatica (PMR) and temporal arteritis (TA).
  
  
  METHODS
  Forty-seven patients with PMR and/or TA were followed up to 3 years in a prospective longitudinal design. Plasma calprotectin was correlated with acute phase parameters, erythrocyte sedimentation rate (ESR), and peroral steroid usage before start of treatment and at four subsequent time intervals.
  
  
  RESULTS
  Thirty-three patients had PMR, 10 had TA, and four had both diagnoses. Calprotectin was highly correlated with the acute phase parameters and ESR during the study period. Calprotectin was significantly decreased after start of treatment with oral prednisolone, and correlated with the daily dosage of prednisolone (r = 0.36, p < 0.01).
  
  
  CONCLUSIONS
  Calprotectin plasma levels were significantly associated with acute phase parameters, ESR, and prednisolone usage in PMR and TA, indicating that calprotectin may be a good measure of disease activity in these conditions.
authors.affiliation: Department of Rheumatology, Haukeland University Hospital, Bergen, Norway. johan.brun@helse-bergen.no
authors.forename: J G
authors.initials: JG
authors.lastname: Brun
authors.forename: T M
authors.initials: TM
authors.lastname: Madland
authors.forename: J T
authors.initials: JT
authors.lastname: Gran
authors.forename: G
authors.initials: G
authors.lastname: Myklebust
mesh_terms: D000210:Acute-Phase Reaction / Q000097:blood; D000368:Aged; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use; D015415:Biomarkers / Q000097:blood*; D001799:Blood Sedimentation; D005260:Female; D013700:Giant Cell Arteritis / Q000097:blood* / Q000175:diagnosis; D006801:Humans; D039841:Leukocyte L1 Antigen Complex / Q000097:blood*; D008297:Male; D011111:Polymyalgia Rheumatica / Q000097:blood* / Q000175:diagnosis / Q000188:drug therapy; D011239:Prednisolone / Q000627:therapeutic use; D011446:Prospective Studies
chemical_list: D000893:Anti-Inflammatory Agents; D015415:Biomarkers; D039841:Leukocyte L1 Antigen Complex; D011239:Prednisolone