title: Serum levels of calreticulin in correlation with disease activity in patients with rheumatoid arthritis.
abstract: OBJECTIVE
  The aim of our study was to investigate the contribution of serum calreticulin (CRT) in the assessment of disease activity in rheumatoid arthritis (RA).
  
  
  METHODS
  Serum CRT levels were measured by ELISA in 70 patients with established RA, 30 systemic lupus erythematosus (SLE), 25 other autoimmune diseases, 20 osteoarthritis (OA), and 35 of healthy controls (HC). Correlations of CRT serum levels with disease activity [Disease Activity Score for 28 joints (DAS28)], erythrocyte sedimentation rate(ESR) and C-reactive protein (CRP) were assessed. Serum CRT levels were also detected in RA patients whose RF, anti-CCP and anti- MCV antibodies were positive and negative.
  
  
  RESULTS
  Serum CRT levels in RA patients (4.817 ± 2.425 ng/ml) was significantly higher (P <0.05) compared with those in the serum of OA (3.574 ± 0.942 ng/ml), SLE (4.013 ± 1.536 ng/ml), other autoimmune diseases (3.882 ± 0.837 ng/ml) and HC (3.726 ± 0.627 ng/ml). Significant positive correlation of CRT with DAS28, ESR and CRP was found in RA patients. Furthermore, RA patients whose anti-CCP and anti-MCV antibodies were positive had higher levels of CRT (P < 0.01).
  
  
  CONCLUSIONS
  Serum CRT levels were increased in patients with RA compared with those controls. Moreover, a significant correlation was observed between serum CRT levels and disease activity in RA. It might be used as a potential biomarker for clinical diagnosis and provide additional information regarding disease activity along with the traditional indices such as ESR and CRP.
authors.affiliation: School of Laboratory Medicine, Tianjin Medical University, 1 Guangdong Road, Tianjin 300203, China.
authors.forename: Min
authors.initials: M
authors.lastname: Ni
authors.forename: Wei
authors.initials: W
authors.lastname: Wei
authors.forename: Yichao
authors.initials: Y
authors.lastname: Wang
authors.forename: Na
authors.initials: N
authors.lastname: Zhang
authors.forename: Hongmei
authors.initials: H
authors.lastname: Ding
authors.forename: Chen
authors.initials: C
authors.lastname: Shen
authors.forename: Fang
authors.initials: F
authors.lastname: Zheng
mesh_terms: D000906:Antibodies / Q000276:immunology; D001172:Arthritis, Rheumatoid / Q000097:blood* / Q000276:immunology; D015415:Biomarkers / Q000097:blood; D001799:Blood Sedimentation; D002097:C-Reactive Protein / Q000276:immunology / Q000378:metabolism; D037282:Calreticulin / Q000097:blood* / Q000276:immunology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged
chemical_list: D000906:Antibodies; D015415:Biomarkers; D037282:Calreticulin; D002097:C-Reactive Protein