title: Four Anti-dsDNA Antibody Assays in Relation to Systemic Lupus Erythematosus Disease Specificity and Activity.
abstract: OBJECTIVE
  Analysis of antibodies against dsDNA is an important diagnostic tool for systemic lupus erythematosus (SLE), and changes in anti-dsDNA antibody levels are also used to assess disease activity. Herein, 4 assays were compared with regard to SLE specificity, sensitivity, and association with disease activity variables.
  
  
  METHODS
  Cross-sectional sera from 178 patients with SLE, of which 11 were followed consecutively, from a regional Swedish SLE register were analyzed for immunoglobulin G (IgG) anti-dsDNA by bead-based multiplex assay (FIDIS; Theradig), fluoroenzyme-immunoassay (EliA; Phadia/Thermo Fisher Scientific), Crithidia luciliae immunofluorescence test (CLIFT; ImmunoConcepts), and line blot (EUROLINE; Euroimmun). All patients with SLE fulfilled the 1982 American College of Rheumatology and/or the 2012 Systemic Lupus International Collaborating Clinics (SLICC-12) classification criteria. Healthy individuals (n = 100), patients with rheumatoid arthritis (n = 95), and patients with primary Sjögren syndrome (n = 54) served as controls.
  
  
  RESULTS
  CLIFT had the highest SLE specificity (98%) whereas EliA had the highest sensitivity (35%). When cutoff levels for FIDIS, EliA, and EUROLINE were adjusted according to SLICC-12 (i.e., double the reference limit when using ELISA), the specificity and sensitivity of FIDIS was comparable to CLIFT. FIDIS and CLIFT also showed the highest concordance (84%). FIDIS performed best regarding association with disease activity in cross-sectional and consecutive samples. Fisher's exact test revealed striking differences between methods regarding associations with certain disease phenotypes.
  
  
  CONCLUSIONS
  CLIFT remains a good choice for diagnostic purposes, but FIDIS performs equally well when the cutoff is adjusted according to SLICC-12. Based on results from cross-sectional and consecutive analyses, FIDIS can also be recommended to monitor disease activity.
authors: From the Department of Clinical and Experimental Medicine, Linköping University, Linköping, and the Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.H. Enocsson, Postdoctoral, PhD; C. Sjöwall, MD, PhD, Associate Professor; L. Wirestam, MSc, PhD-student; C. Dahle, MD, PhD, Associate Professor; A. Kastbom, MD, PhD; J. Wetterö, PhD, Associate Professor; T. Skogh, MD, PhD, Professor, Department of Clinical and Experimental Medicine, Linköping University; J. Rönnelid, MD, PhD, Professor, Department of Immunology, Genetics and Pathology, Uppsala University. helena.enocsson@liu.se.
authors: Helena
authors: H
authors: Enocsson
authors: From the Department of Clinical and Experimental Medicine, Linköping University, Linköping, and the Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.H. Enocsson, Postdoctoral, PhD; C. Sjöwall, MD, PhD, Associate Professor; L. Wirestam, MSc, PhD-student; C. Dahle, MD, PhD, Associate Professor; A. Kastbom, MD, PhD; J. Wetterö, PhD, Associate Professor; T. Skogh, MD, PhD, Professor, Department of Clinical and Experimental Medicine, Linköping University; J. Rönnelid, MD, PhD, Professor, Department of Immunology, Genetics and Pathology, Uppsala University.
authors: Christopher
authors: C
authors: Sjöwall
authors: From the Department of Clinical and Experimental Medicine, Linköping University, Linköping, and the Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.H. Enocsson, Postdoctoral, PhD; C. Sjöwall, MD, PhD, Associate Professor; L. Wirestam, MSc, PhD-student; C. Dahle, MD, PhD, Associate Professor; A. Kastbom, MD, PhD; J. Wetterö, PhD, Associate Professor; T. Skogh, MD, PhD, Professor, Department of Clinical and Experimental Medicine, Linköping University; J. Rönnelid, MD, PhD, Professor, Department of Immunology, Genetics and Pathology, Uppsala University.
authors: Lina
authors: L
authors: Wirestam
authors: From the Department of Clinical and Experimental Medicine, Linköping University, Linköping, and the Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.H. Enocsson, Postdoctoral, PhD; C. Sjöwall, MD, PhD, Associate Professor; L. Wirestam, MSc, PhD-student; C. Dahle, MD, PhD, Associate Professor; A. Kastbom, MD, PhD; J. Wetterö, PhD, Associate Professor; T. Skogh, MD, PhD, Professor, Department of Clinical and Experimental Medicine, Linköping University; J. Rönnelid, MD, PhD, Professor, Department of Immunology, Genetics and Pathology, Uppsala University.
authors: Charlotte
authors: C
authors: Dahle
authors: From the Department of Clinical and Experimental Medicine, Linköping University, Linköping, and the Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.H. Enocsson, Postdoctoral, PhD; C. Sjöwall, MD, PhD, Associate Professor; L. Wirestam, MSc, PhD-student; C. Dahle, MD, PhD, Associate Professor; A. Kastbom, MD, PhD; J. Wetterö, PhD, Associate Professor; T. Skogh, MD, PhD, Professor, Department of Clinical and Experimental Medicine, Linköping University; J. Rönnelid, MD, PhD, Professor, Department of Immunology, Genetics and Pathology, Uppsala University.
authors: Alf
authors: A
authors: Kastbom
authors: From the Department of Clinical and Experimental Medicine, Linköping University, Linköping, and the Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.H. Enocsson, Postdoctoral, PhD; C. Sjöwall, MD, PhD, Associate Professor; L. Wirestam, MSc, PhD-student; C. Dahle, MD, PhD, Associate Professor; A. Kastbom, MD, PhD; J. Wetterö, PhD, Associate Professor; T. Skogh, MD, PhD, Professor, Department of Clinical and Experimental Medicine, Linköping University; J. Rönnelid, MD, PhD, Professor, Department of Immunology, Genetics and Pathology, Uppsala University.
authors: Johan
authors: J
authors: Rönnelid
authors: From the Department of Clinical and Experimental Medicine, Linköping University, Linköping, and the Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.H. Enocsson, Postdoctoral, PhD; C. Sjöwall, MD, PhD, Associate Professor; L. Wirestam, MSc, PhD-student; C. Dahle, MD, PhD, Associate Professor; A. Kastbom, MD, PhD; J. Wetterö, PhD, Associate Professor; T. Skogh, MD, PhD, Professor, Department of Clinical and Experimental Medicine, Linköping University; J. Rönnelid, MD, PhD, Professor, Department of Immunology, Genetics and Pathology, Uppsala University.
authors: Jonas
authors: J
authors: Wetterö
authors: From the Department of Clinical and Experimental Medicine, Linköping University, Linköping, and the Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.H. Enocsson, Postdoctoral, PhD; C. Sjöwall, MD, PhD, Associate Professor; L. Wirestam, MSc, PhD-student; C. Dahle, MD, PhD, Associate Professor; A. Kastbom, MD, PhD; J. Wetterö, PhD, Associate Professor; T. Skogh, MD, PhD, Professor, Department of Clinical and Experimental Medicine, Linköping University; J. Rönnelid, MD, PhD, Professor, Department of Immunology, Genetics and Pathology, Uppsala University.
authors: Thomas
authors: T
authors: Skogh
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D004247:DNA / Q000276:immunology*; D005260:Female; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D008180:Lupus Erythematosus, Systemic / Q000175:diagnosis* / Q000276:immunology; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D055815:Young Adult
chemical_list: D004247:DNA
keywords: AUTOANTIBODIES; DOUBLE-STRANDED DNA; IMMUNOASSAY; INFLAMMATION; RHEUMATIC DISEASE; SYSTEMIC LUPUS ERYTHEMATOSUS