title: Single-step autoantibody profiling in antiphospholipid syndrome using a multi-line dot assay.
abstract: BACKGROUND
  Diagnosis of antiphospholipid syndrome (APS) still remains a laboratory challenge due to the great diversity of antiphospholipid antibodies (aPL) and their significance regarding APS-diagnostic criteria.
  
  
  METHODS
  A multi-line dot assay (MLDA) employing phosphatidylserine (PS), phosphatidylinositol (PI), cardiolipin (CL), and beta2-glycoprotein I (β2 GPI) was used to detect aPL, immunoglobulin G (IgG) and immunoglobulin M (IgM) in 85 APS patients, 65 disease controls, and 79 blood donors. For comparison, anti-CL and anti-β2 GPI IgG and IgM were detected by enzyme-linked immunosorbent assay (ELISA).
  
  
  RESULTS
  The level of agreement of both methods was good for anti-CL IgG, moderate for anti-CL IgM, very good for anti-β2 GPI IgG, and moderate for anti-β2 GPI IgM (kappa = 0.641, 0.507, 0.803 and 0.506, respectively). The frequency of observed discrepancies for anti-CL IgG (1.75%), anti-CL IgM (3.93%), anti-β2 GPI IgG (1.75%), and anti-β2 GPI IgM (0.87%) was low (McNemar test, P < 0.05, not-significant, respectively). Sensitivity, specificity, positive (+LR) and negative (-LR) likelihood ratios for at least one positive aPL antibody assessed by ELISA were 58.8%, 95.8%, 14.1, and 0.4, respectively, and for at least three positive aPl IgM and/or one positive aPL IgG by MLDA were 67.1%, 96.5%, 19.3, and 0.3, respectively. The frequency of IgM to PI, PS and CL, and combination of three or more aPL IgM detected by MLDA was significantly higher in APS patients with cerebral transient ischemia (P < 0.05, respectively).
  
  
  CONCLUSIONS
  The novel MLDA is a readily available, single-step, sensitive diagnostic tool for the multiplex detection of aPL antibodies in APS and a potential alternative for single aPL antibody testing by ELISA.
authors.affiliation: Department of Rheumatology and Clinical Immunology, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Augustenburger Platz 01, 13555 Berlin, Germany. karl.egerer@charite.de
authors.forename: Karl
authors.initials: K
authors.lastname: Egerer
authors.forename: Dirk
authors.initials: D
authors.lastname: Roggenbuck
authors.forename: Thomas
authors.initials: T
authors.lastname: Büttner
authors.forename: Barbara
authors.initials: B
authors.lastname: Lehmann
authors.forename: Annushka
authors.initials: A
authors.lastname: Kohn
authors.forename: Philipp
authors.initials: P
authors.lastname: von Landenberg
authors.forename: Rico
authors.initials: R
authors.lastname: Hiemann
authors.forename: Eugen
authors.initials: E
authors.lastname: Feist
authors.forename: Gerd-Rüdiger
authors.initials: GR
authors.lastname: Burmester
authors.forename: Thomas
authors.initials: T
authors.lastname: Dörner
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D017152:Antibodies, Antiphospholipid / Q000097:blood* / Q000276:immunology; D016736:Antiphospholipid Syndrome / Q000097:blood / Q000175:diagnosis* / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D015151:Immunoblotting / Q000379:methods*; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology; D007075:Immunoglobulin M / Q000097:blood / Q000276:immunology; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D055815:Young Adult
chemical_list: D017152:Antibodies, Antiphospholipid; D007074:Immunoglobulin G; D007075:Immunoglobulin M