title: Revised classification criteria for antiphospholipid syndrome and the thrombotic risk in patients with autoimmune diseases.
abstract: BACKGROUND
  The classification criteria for antiphospholipid syndrome (APS) were updated in 2006.
  
  
  OBJECTIVE
  The aim of the study was to analyze associations between clinical complications and laboratory test abnormalities typical for APS in a group of patients with autoimmune diseases, based on the recently updated criteria.
  
  
  METHODS
  Three hundred and thirty-six patients were enrolled into the study, with the majority (n = 235) suffering from systemic lupus erythematosus. Laboratory determinations included: lupus anticoagulant (LA), anticardiolipin (aCL) and anti-beta(2)-glycoprotein I (anti-beta(2)GPI) antibodies (ABs) [of both immunoglobulin G (IgG) and IgM class].
  
  
  RESULTS
  A significant association was found between laboratory and clinical features of APS; odds ratios (ORs) for thrombosis associated with the presence of LA, aCL, and anti-beta(2)GPI Abs were 4.04 [95% CI: 2.44-6.68], 3.71 (95% CI 2.32-5.92) and 2.57 (95% CI 1.60-4.1), respectively. Detailed analysis showed marked differences between the risk of clinical complications associated with the presence of an antibody in the IgG class (OR 4.15, 95% CI 2.42-7.12, and OR 4.77, 95% CI 2.37-9.61 for aCL and anti-beta(2)GPI, respectively) and in the IgM class (OR 2.2, 95% CI 1.31-3.70, and OR 1.9, 95% CI 1.15-3.14 for aCL and anti-beta(2)GPI, respectively). The postulated inclusion of anti-beta(2)GPI antibody positivity into the previous laboratory criteria changed only slightly the number of patients diagnosed with APS (from 112 to 117).
  
  
  CONCLUSIONS
  The updated APS classification criteria clearly represent a step forward. However, our results argue against the use of overall positivity for aCL or anti-beta(2)GPI, and favor a clear distinction between the IgG and IgM classes of antiphospholipid ABs. Patients with both LA and anti-beta(2)GPI IgG or LA and aCL IgG positivity may represent the subgroups at the highest risk of thrombotic complications.
authors.affiliation: Department of Medicine, Jagiellonian University School of Medicine, Kraków, Poland.
authors.forename: J
authors.initials: J
authors.lastname: Swadźba
authors.forename: T
authors.initials: T
authors.lastname: Iwaniec
authors.forename: A
authors.initials: A
authors.lastname: Szczeklik
authors.forename: J
authors.initials: J
authors.lastname: Musiał
mesh_terms: D000328:Adult; D000368:Aged; D016736:Antiphospholipid Syndrome / Q000145:classification* / Q000150:complications; D001327:Autoimmune Diseases / Q000150:complications*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D013927:Thrombosis / Q000209:etiology*