title: Assessment of Deoxyribonuclease Activity in Serum Samples of Patients With Systemic Lupus Erythematosus: Fluorescence-Based Method Versus ELISA.
abstract: BACKGROUND
  We report the improvement of previously described method for determining deoxyribonuclease (DNase) activity in serum samples that uses a fluorescently labeled DNA fragment as a substrate METHODS: Activity of serum DNase was analyzed in 31 patients with systemic lupus erythematosus (SLE) and 13 healthy individuals by fluoresence-based method and ELISA test RESULTS: We found a mean decrease in DNase activity between cases and controls of 12.46% measured by the fluoresence-based method and of 12.21% measured by ELISA method. High level of positive correlation between two methods for DNase activity was observed: P < 0.001 and Pearson correlation coefficient 0.740. Decreased DNase activity was found in 25 of 31 SLE patients (81%) by fluoresence-based method and in 24 of 31 SLE patients (77%) by ELISA test. We also observed the significant positive correlation between titer of anti-dsDNA antibodies and DNase activity measured by both methods (P < 0.05).
  
  
  CONCLUSIONS
  The key improvement is the use of internal control in the fluorescence-based method, which diminishes the influence of technical errors on the obtained results and increases reliability of the assay. This improved fluorescence-based method, with additional validation, may provide an alternative to more expensive and time-consuming conventional methods, such as ELISA.
authors.affiliation: Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia.
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Vancevska
authors.affiliation: Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia. aleksni@imgge.bg.ac.rs.
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Nikolic
authors.affiliation: Clinic of Allergy and Clinical Immunology, Clinical Centre of Serbia, Faculty of Medicine, University of Belgrade, Belgrade, Serbia.
authors.forename: Branka
authors.initials: B
authors.lastname: Bonaci-Nikolic
authors.affiliation: Clinic of Dermatovenereology, Clinical Centre of Serbia, Faculty of Medicine, University of Belgrade, Belgrade, Serbia.
authors.forename: Dusan
authors.initials: D
authors.lastname: Skiljevic
authors.affiliation: Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia.
authors.forename: Dragica
authors.initials: D
authors.lastname: Radojkovic
mesh_terms: D000293:Adolescent; D000328:Adult; D004247:DNA / Q000276:immunology; D003851:Deoxyribonucleases / Q000097:blood*; D004338:Drug Combinations; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D005260:Female; D005341:Fibrinolysin; D005456:Fluorescent Dyes / Q000378:metabolism; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000097:blood*; D008297:Male; D008875:Middle Aged; D055815:Young Adult
chemical_list: D004338:Drug Combinations; D005456:Fluorescent Dyes; C021490:deoxyribonuclease, plasmin drug combination; D004247:DNA; D003851:Deoxyribonucleases; D005341:Fibrinolysin
keywords: ELISA; deoxyribonuclease activity; fluorescence; systemic lupus erythematosus