title: Serum DNase I activity in systemic lupus erythematosus: correlation with immunoserological markers, the disease activity and organ involvement.
abstract: BACKGROUND
  Decreased activity of serum desoxyribonuclease I (DNase I) in systemic lupus erythematosus (SLE) has been reported, but its role as a biomarker in SLE is still unelucidated.
  
  
  METHODS
  Seventy-seven SLE patients (aged 39.6 ± 13.1 years) were studied for serum DNase I activity, levels of antinuclear (ANA), anti-dsDNA [high-avidity ELISA, conventional ELISA and indirect immunofluorescence (IIF)], anti-nucleosome, anti-histone antibodies, complement components C3 and C4. SLE disease activity was evaluated by disease activity index (SLEDAI-2K). Thirty-five patients were serologically and clinically followed for 3-12 months (mean 5.6 ± 2.8). Thirty-seven healthy blood donors were the control group.
  
  
  RESULTS
  DNase I activity in SLE patients was lower than in healthy controls (p<0.01). DNase I activity was in positive correlation with SLEDAI-2K (p<0.01), levels of ANA, anti-dsDNA, anti-nucleosome and anti-histone antibodies (p<0.01) and in negative correlation with C3 concentration (p<0.05). The highest correlation was found between DNase I activity and anti-dsDNA concentrations determined by high-avidity ELISA (r=0.624), followed by IIF (r=0.541) and conventional ELISA (r=0.405). In the follow-up study, DNase I activity also correlated with SLEDAI-2K (p<0.01). SLE patients with low DNase I activity more frequently had SLE-specific cutaneous lesions (p<0.05).
  
  
  CONCLUSIONS
  Monitoring of DNase I activity simultaneously with SLEDAI-2K might be a useful tool in the follow-up of SLE. An increase of DNase I activity characterized relapse in most SLE patients, although it did not reach the levels of healthy individuals. A decrease of DNase I activity in SLE flare-ups might be a functional biomarker of a subset of patients with specific dysfunction of apoptotic chromatin degradation.
authors.affiliation: Faculty of Medicine, University of Belgrade, Belgrade, Serbia.
authors.forename: Dusan
authors.initials: D
authors.lastname: Skiljevic
authors.forename: Ivica
authors.initials: I
authors.lastname: Jeremic
authors.forename: Milos
authors.initials: M
authors.lastname: Nikolic
authors.forename: Sladjana
authors.initials: S
authors.lastname: Andrejevic
authors.forename: Mirjana
authors.initials: M
authors.lastname: Sefik-Bukilica
authors.forename: Biljana
authors.initials: B
authors.lastname: Stojimirovic
authors.forename: Branka
authors.initials: B
authors.lastname: Bonaci-Nikolic
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood / Q000378:metabolism; D001774:Blood Chemical Analysis; D003850:Deoxyribonuclease I / Q000097:blood* / Q000378:metabolism*; D004789:Enzyme Activation; D005260:Female; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000097:blood / Q000201:enzymology* / Q000276:immunology / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D055815:Young Adult
chemical_list: D015415:Biomarkers; D003850:Deoxyribonuclease I