title: [Prevalence and significance of immunoglobulin G-anti-cyclic citrullinated peptide antibodies in primary Sjogren's syndrome patients].
abstract: OBJECTIVE
  To investigate the prevalence and significance of IgG-anti-cyclic citrullinated peptides (CCP) antibody in PSS patients.
  
  
  METHODS
  A total of 120 patients diagnosed with PSS were investigated in the first affiliated hospital of Baotou Medical College from March 2006 to December 2009. IgG-anti-CCP antibody was assayed by enzyme-linked immunosorbent assay (ELISA), also anti-Sjogren's syndrome type A (SSA) and Sjogren's syndrome type B (SSB) antibody were assayed by immunoblotting. Erythrocyte sedimentation rate (ESR) was assayed by westergren in serum, and C reactive protein (CRP), IgA, IgM, IgG and IgM-RF were detected by immune turbidimetric. At the same time, clinical symptoms and involvement of important organs were observed. Following up the patients above 3 years, the primary Sjogren's syndrome (PSS) patients who had progressed to rheumatoid arthritis (RA) were evaluated.
  
  
  RESULTS
  The positive rate of anti-CCP antibody in the PSS patients was 19.17%; After 3 years, more patients who were positive for anti-CCP antibody had progressed to RA (χ² = 5.015,P=0.022) than the patients in negative group; The patients in anti-CCP antibody positive group were more prone to joint involvement (χ² = 8.058,P<0.05), more swollen joints (U=152.00, P<0.05) and longer morning stiffness (U=100.00, P<0.05) than the patients with negative anti-CCP antibody, but the involvement of vital organs in the two groups had no significant difference (χ² = 0.208,0.099,0.000 and 0.122, P>0.05); The positive rate of anti-SSA and SSB antibody in anti-CCP antibody positive group and negative group had no significant difference (χ² = 0.008 and 0.56, P>0.05); Multiple linear regression showed that the level of anti-CCP antibody was positively correlated with IgM-RF levels in the PSS patients (B=0.61, 95% CI=0.36-0.86, P<0.05), but had no significant correlation with ESR, CRP, IgA, IgM and IgG levels (P>0.05).There were no significant differences in the level of ESR, CRP, IgA, IgM and IgG between anti-CCP antibody positive group and negative group (P>0.05), but the level of IgM-RF in anti-CCP antibody positive group was significantly higher than that in the negative group (U=623.50, P<0.05).
  
  
  CONCLUSIONS
  Positive rate of IgG-anti-CCP antibody in PSS is 19.17%, also it is associated with joint involvement and more prone to progressing to RA.
authors.affiliation: Department of Rheumatology and Immunology, the First Affiliated Hospital of BaoTou Medical College, Inner Mongolia Baotou 014010, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Liu
authors.forename: Yong-fu
authors.initials: YF
authors.lastname: Wang
authors.forename: Kai-li
authors.initials: KL
authors.lastname: Wang
authors.forename: Feng-feng
authors.initials: FF
authors.lastname: Lv
mesh_terms: D001172:Arthritis, Rheumatoid / Q000473:pathology; D001323:Autoantibodies / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D010456:Peptides, Cyclic / Q000276:immunology*; D015995:Prevalence; D012859:Sjogren's Syndrome / Q000276:immunology* / Q000473:pathology
chemical_list: D001323:Autoantibodies; D015415:Biomarkers; D010456:Peptides, Cyclic; C487763:cyclic citrullinated peptide; D002097:C-Reactive Protein