title: Anti-dsDNA, anti-nucleosome and anti-C1q antibodies as disease activity markers in patients with systemic lupus erythematosus.
abstract: BACKGROUND
  In spite of the growing number of reports on the study of anti-nucleosome and anti-C1q antibodies, there are still controversies on their significance as disease activity markers in patients with systemic lupus erythematosus (SLE) and their use in everyday clinical practice.
  
  
  OBJECTIVE
  Our aim was to assess the presence of anti-dsDNA, anti-nucleosome and anti-C1q antibodies in SLE patients, as well as to establish their sensitivity, specificity, positive and negative predictive value, and their correlation with SLE and lupus nephritis clinical activity.
  
  
  METHODS
  The study enrolled 85 patients aged 45.3 +/- 9.7 years on the average, with SLE of average duration 10.37 +/- 7.99 years, hospitalized at the Institute,,Niska Banja" during 2011, and 30 healthy individuals as controls. Disease activity was assessed using Systemic Lupus Erythematosus Disease Activity Index (SLEDAI). In all examinees the levels of anti-dsDNA, anti-nucleosome and anti-C1q antibodies were measured using the ELISA method with Alegria Test Strips Orgentec (Germany).
  
  
  RESULTS
  Patients with active lupus nephritis had a higher presence of anti-C1q antibodies and higher co-positivity of anti-dsDNA, anti-nucleosome, and anti-C1q antibodies compared to those with inactive lupus nephritis (77.77% vs. 21.74%; p < 0.01). SLE patients with SLEDAI > or = 11 had a higher presence of antinucleosome (93.75% vs. 64.15%; p < 0.01) and anti-C1q antibodies (46.87% vs. 22.64%; p<0.05), as well as a higher mean level of anti-nucleosome antibodies (107.79 +/- 83.46 U/ml vs. 57.81 +/- 63.15 U/ml; p < 0.05), compared to those with SLEDAI of 0-10. There was a positive correlation between the SLEDAI and the level of anti-dsDNA (r=0.290; p<0.01), anti-nucleosome (r = 0.443; p < 0.001), and anti-C1q antibodies (r = 0.382; p < 0.001). Only anti-C1q antibodies demonstrated correlation with proteinuria (r = 0.445; p < 0.001).
  
  
  CONCLUSIONS
  Anti-nucleosome and anti-C1q antibodies demonstrated association with SLE and lupus nephritis activity, suggesting their potential usefulness in making predictions about lupus nephritis and assessment of disease activity.
authors.forename: Valentina
authors.initials: V
authors.lastname: Zivković
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Stanković
authors.forename: Tatjana
authors.initials: T
authors.lastname: Cvetković
authors.forename: Branka
authors.initials: B
authors.lastname: Mitić
authors.forename: Svetislav
authors.initials: S
authors.lastname: Kostić
authors.forename: Jovan
authors.initials: J
authors.lastname: Nedović
authors.forename: Bojana
authors.initials: B
authors.lastname: Stamenković
mesh_terms: D000328:Adult; D001323:Autoantibodies / Q000097:blood; D015415:Biomarkers / Q000097:blood; D015922:Complement C1q / Q000276:immunology*; D004247:DNA / Q000276:immunology; D005260:Female; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000175:diagnosis / Q000276:immunology*; D008181:Lupus Nephritis / Q000175:diagnosis / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D009707:Nucleosomes / Q000276:immunology*; D012680:Sensitivity and Specificity
chemical_list: D001323:Autoantibodies; D015415:Biomarkers; D009707:Nucleosomes; D015922:Complement C1q; D004247:DNA