title: The neutrophil protein S100A12 is associated with a comprehensive ultrasonographic synovitis score in a longitudinal study of patients with rheumatoid arthritis treated with adalimumab.
abstract: BACKGROUND
  The calcium-binding protein S100A12 correlates with measures of disease activity in patients with rheumatoid arthritis (RA). The protein reflects neutrophil activation and the present objective was to explore in a pilot study the associations between S100A12 and other inflammatory markers, clinical assessments as well as degree of synovitis detected by a comprehensive ultrasonography (US) examination in RA patients during biologic treatment.
  
  
  METHODS
  Twenty patients with RA were examined clinically and by use of US as well as laboratory markers S100A12, calprotectin, C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) before starting adalimumab, with follow-up after 1, 3, 6 and 12 months. Ultrasonographic B-mode (BM) and power Doppler (PD) assessments of 78 joints, 36 tendons/tendon groups and 2 bursas were performed, and sum US scores calculated. Wilcoxon signed rank test assessed treatment response and Spearman rank correlation test was used to calculate correlations.
  
  
  RESULTS
  The concentrations of S100A12 decreased after 3 months (p < 0.01) and significant correlations were found between S100A12 and the other laboratory markers during follow-up (0.50-0.62, p < 0.05). Of the clinical assessments, S100A12 had highest correlations with the assessor's global VAS (0.46-0.85, p < 0.05). Compared with CRP and ESR, S100A12 showed higher correlations with the sum US scores (both BM and PD), with median (range) correlation coefficients of 0.55 (0.35-0.78 (NS-p < 0.001)) for sum BM scores and 0.45 (0.27-0.75 (NS-p < 0.001)) for sum PD scores.
  
  
  CONCLUSIONS
  The S100A12 protein was significantly associated with other inflammatory markers, clinical assessments as well as sum US scores, indicating that S100A12 is a potential marker of inflammation in RA patients.
authors.affiliation: Broegelmann Research Laboratory, Department of Clinical Science, University of Bergen, Postboks 7804, N-5020 Bergen, Norway. Hilde.Nordal@k2.uib.no.
authors.forename: Hilde Haugedal
authors.initials: HH
authors.lastname: Nordal
authors.forename: Johan G
authors.initials: JG
authors.lastname: Brun
authors.forename: Anne-Kristine
authors.initials: AK
authors.lastname: Halse
authors.forename: Roland
authors.initials: R
authors.lastname: Jonsson
authors.forename: Magne K
authors.initials: MK
authors.lastname: Fagerhol
authors.forename: Hilde Berner
authors.initials: HB
authors.lastname: Hammer
mesh_terms: D000068879:Adalimumab; D000328:Adult; D000368:Aged; D061067:Antibodies, Monoclonal, Humanized / Q000627:therapeutic use*; D018501:Antirheumatic Agents / Q000627:therapeutic use; D001172:Arthritis, Rheumatoid / Q000097:blood* / Q000000981:diagnostic imaging*; D015415:Biomarkers / Q000097:blood; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009504:Neutrophils; D010865:Pilot Projects; D009418:S100 Proteins / Q000097:blood*; D000067616:S100A12 Protein; D013585:Synovitis / Q000097:blood* / Q000000981:diagnostic imaging*; D016896:Treatment Outcome; D014463:Ultrasonography; D055815:Young Adult
chemical_list: D061067:Antibodies, Monoclonal, Humanized; D018501:Antirheumatic Agents; D015415:Biomarkers; D009418:S100 Proteins; D000067616:S100A12 Protein; C090441:S100A12 protein, human; D000068879:Adalimumab