title: Clinical significance and correlations between anti-β2 glycoprotein I IgA assays in antiphospholipid syndrome and/or systemic lupus erythematosus.
abstract: BACKGROUND
  The objective of this investigation was to examine the clinical significance of IgA anti-β2 glycoprotein I (anti-β2GPI) antibodies and the inter-assay relationships between kits for their determination.
  
  
  METHODS
  Serum samples from 269 patients with clinical diagnoses of systemic lupus erythematosus (SLE) and/or antiphospholipid syndrome (APS), individuals positive for antiphospholipid antibodies (aPL) with or without APS or SLE, and 182 controls were tested for anti-β2GPI IgA antibodies using kits from four manufacturers.
  
  
  RESULTS
  The positivity rates for the different IgA anti-β2GPI antibody kits varied in the disease groups; 7.8-14.7% (SLE only), 12.0-15.7% (SLE and APS/aPL), 14.7-58.8% (APS only), and 17.4-52.2% (aPL only). Kappa agreements between any 2 kits within disease groups were also variable and ranged from 0.25-1.00 (SLE), 0.18-1.00 (SLE and APS/aPL), 0.22-0.94 (APS only), and 0.32-0.91 (aPL only). Univariate analyses also showed variable relative risks for specific APS clinical manifestations with the different kits evaluated. Overall, diagnostic and predictive values for IgA anti-β2GPI antibodies are kit-dependent; therefore results are not interchangeable. While all 4 kits seem able to predict venous thrombosis tolerably well, there was a variable performance in predicting pregnancy related morbidity.
  
  
  CONCLUSIONS
  Efforts to standardize these assays are highly needed prior to their formal adoption in routine clinical evaluation.
authors.affiliation: Department of Pathology, University of Utah, Salt Lake City, USA; ARUP Laboratories, Institute of Clinical and Experimental Pathology, Salt Lake City, USA. Electronic address: anne.tebo@hsc.utah.edu.
authors.forename: Anne E
authors.initials: AE
authors.lastname: Tebo
authors.affiliation: Rheumatology/Internal Medicine, University of Texas Medical Branch, Galveston, USA.
authors.forename: Rohan
authors.initials: R
authors.lastname: Willis
authors.affiliation: ARUP Laboratories, Institute of Clinical and Experimental Pathology, Salt Lake City, USA.
authors.forename: Troy D
authors.initials: TD
authors.lastname: Jaskowski
authors.affiliation: Hospital for Special Surgery, New York, USA.
authors.forename: Marta
authors.initials: M
authors.lastname: Guerra
authors.affiliation: Rheumatology/Internal Medicine, University of Texas Medical Branch, Galveston, USA.
authors.forename: Silvia S
authors.initials: SS
authors.lastname: Pierangeli
authors.affiliation: Hospital for Special Surgery, New York, USA.
authors.forename: Jane
authors.initials: J
authors.lastname: Salmon
authors.affiliation: John Hopkins University School of Medicine, Baltimore, USA.
authors.forename: Michelle
authors.initials: M
authors.lastname: Petri
authors.affiliation: Maternal Fetal Medicine, University of Utah and Intermountain Healthcare, Salt Lake City, USA.
authors.forename: D Ware
authors.initials: DW
authors.lastname: Branch
mesh_terms: D000328:Adult; D017152:Antibodies, Antiphospholipid / Q000097:blood; D016736:Antiphospholipid Syndrome / Q000175:diagnosis*; D001323:Autoantibodies / Q000097:blood; D005260:Female; D006801:Humans; D007070:Immunoglobulin A / Q000276:immunology; D008180:Lupus Erythematosus, Systemic / Q000175:diagnosis*; D008297:Male; D011247:Pregnancy; D011249:Pregnancy Complications, Cardiovascular / Q000175:diagnosis; D011933:Reagent Kits, Diagnostic / Q000592:standards*; D020246:Venous Thrombosis / Q000175:diagnosis; D053482:beta 2-Glycoprotein I / Q000276:immunology*
chemical_list: D017152:Antibodies, Antiphospholipid; D001323:Autoantibodies; D007070:Immunoglobulin A; D011933:Reagent Kits, Diagnostic; D053482:beta 2-Glycoprotein I
keywords: Anti-β(2) glycoprotein I antibodies; Antiphospholipid syndrome; Diagnosis; Performance characteristics