title: Decreases in serum levels of S100A8/9 (calprotectin) correlate with improvements in total swollen joint count in patients with recent-onset rheumatoid arthritis.
abstract: BACKGROUND
  The aim of this study was to examine the serum levels of S100 proteins and to evaluate their role in patients with recent-onset rheumatoid arthritis (RA).
  
  
  METHODS
  Serum levels of S100A8/9 and S100A12 were analysed in 43 patients with recent-onset RA, both before and three months after the initiation of conventional treatment, as well as in 32 healthy individuals. Disease activity was assessed based on serum levels of C-reactive protein (CRP), the Disease Activity Score for 28 joints (DAS28) and the total number of swollen joints count for 66 joints (SJC).
  
  
  RESULTS
  The levels of serum S100A8/9 and S100A12 were significantly higher in patients with recent-onset RA compared to the levels in healthy individuals (P < 0.0001) and normalised after three months of treatment. Using age- and sex-adjusted analysis, S100A8/9 levels were correlated with CRP (r = 0.439, P < 0.01), DAS28 (r = 0.501, P = 0.002) and SJC (r = 0.443, P = 0.007), while S100A12 was less significantly correlated with these parameters. Higher levels of S100A8/9 at baseline predicted improvement in the levels of CRP and SJC over time. Moreover, decreases in serum S100A8/9 were associated with decreased serum levels of CRP (r = 0.459, P = 0.005) and improvements in SJC (r = 0.459, P = 0.005). In multiple linear regression analyses, decreases in S100A8/9 but not CRP were significant predictors for improvements in SJC (P = 0.001).
  
  
  CONCLUSIONS
  This study is the first to show normalisation of elevated S100 proteins in patients with recent-onset RA after the initiation of conventional treatment. Therefore, S100A8/9 might potentially be a predictive marker for improvement in the total number of swollen joints in patients in the early phase of RA.
authors.affiliation: Institute of Rheumatology, First Medical Faculty, Charles University, Na Slupi 4, 128 50 Prague 2, Czech Republic.
authors.forename: Lucie
authors.initials: L
authors.lastname: Andrés Cerezo
authors.forename: Heřman
authors.initials: H
authors.lastname: Mann
authors.forename: Ondřej
authors.initials: O
authors.lastname: Pecha
authors.forename: Lenka
authors.initials: L
authors.lastname: Pleštilová
authors.forename: Karel
authors.initials: K
authors.lastname: Pavelka
authors.forename: Jiří
authors.initials: J
authors.lastname: Vencovský
authors.forename: Ladislav
authors.initials: L
authors.lastname: Senolt
mesh_terms: D018501:Antirheumatic Agents / Q000627:therapeutic use; D001172:Arthritis, Rheumatoid / Q000097:blood* / Q000188:drug therapy / Q000473:pathology*; D015415:Biomarkers / Q000097:blood*; D040501:Calgranulin A / Q000097:blood*; D040502:Calgranulin B / Q000097:blood*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007596:Joints / Q000473:pathology; D008297:Male; D008875:Middle Aged
chemical_list: D018501:Antirheumatic Agents; D015415:Biomarkers; D040501:Calgranulin A; D040502:Calgranulin B