title: Coexistence of anti-β2-glycoprotein I domain I and anti-phosphatidylserine/prothrombin antibodies suggests strong thrombotic risk.
abstract: BACKGROUND
  Highly specific assays for measuring antiphospholipid antibodies (aPLs) are required for accurate assessment of thrombotic risk. aPLs against β2-glycoprotein I domain I (anti-β2GPIdI) and against prothrombin complexed with phosphatidylserine (anti-PS/PT) have been recently identified as being associated with a hypercoagulable state. This study evaluated the synergism between anti-β2GPIdI and anti-PS/PT for predicting thrombotic events.
  
  
  METHODS
  A total of 180 patients with clinical suspicion of hypercoagulability were evaluated. The plasma levels of lupus anticoagulant (LA) and antibodies against anticardiolipin (anti-CL) (IgG and IgM), β2GPI (IgG and IgM), PS/PT (IgG and IgM), and β2GPI dI (IgG) were measured.
  
  
  RESULTS
  IgG anti-β2GPIdI and LA were highly associated with thrombosis. Mean values and positivity rates of IgG anti-β2GPI dI and IgG anti-PS/PT were significantly higher in the triple-positive group (LA+, IgG anti-CL+, IgG anti-β2GPI+) than in the other groups. Interestingly, the thrombotic risk [odds ratio (OR) 24.400, 95% confidence interval (CI) 1.976-63.273, p<0.001] of the newly defined triple positive group (LA+, IgG anti-CL+, IgG anti-β2GPIdI+; OR 11.182, 95% CI 1.976-63.273, p=0.006) was more than twice that of the triple-positive group (LA+, IgG anti-CL+, IgG anti-β2GPI+). Double positivity for IgG anti-PS/PT and IgG anti-β2GPI also indicated significant thrombotic risk (OR 7.467, 95% CI 2.350-23.729, p=0.001). Furthermore, the thrombotic risk associated with double positivity for IgG anti-PS/PT and IgG anti-β2GPIdI was markedly elevated (OR 33.654, 95% CI 6.322-179.141, p<0.001).
  
  
  CONCLUSIONS
  Our data suggest that simultaneous measurement of IgG anti-β2GPIdI and IgG anti-PS/PT may improve clinical decision-making for aPL-positive patients.
authors.affiliation: Department of Laboratory Medicine, Seoul National University College of Medicine, Seoul, Republic of.
authors.forename: Jee-Soo
authors.initials: JS
authors.lastname: Lee
authors.affiliation: Department of Laboratory Medicine, Seoul National University College of Medicine, Seoul, Republic of.
authors.forename: JaYoon
authors.initials: J
authors.lastname: Gu
authors.affiliation: Department of Laboratory Medicine, Seoul National University College of Medicine, Seoul, Republic of.
authors.forename: Hee Sue
authors.initials: HS
authors.lastname: Park
authors.affiliation: Department of Laboratory Medicine, Seoul National University College of Medicine, Seoul, Republic of.
authors.forename: Hyun Ju
authors.initials: HJ
authors.lastname: Yoo
authors.affiliation: Department of Laboratory Medicine, Seoul National University College of Medicine, Seoul, Republic of.
authors.forename: Hyun Kyung
authors.initials: HK
authors.lastname: Kim
mesh_terms: D000328:Adult; D017152:Antibodies, Antiphospholipid / Q000097:blood* / Q000276:immunology*; D005260:Female; D006801:Humans; D008297:Male; D010718:Phosphatidylserines / Q000276:immunology*; D011379:Prognosis; D011516:Prothrombin / Q000276:immunology*; D012306:Risk; D013927:Thrombosis / Q000097:blood* / Q000175:diagnosis / Q000276:immunology; D053482:beta 2-Glycoprotein I / Q000276:immunology*
chemical_list: D017152:Antibodies, Antiphospholipid; D010718:Phosphatidylserines; D053482:beta 2-Glycoprotein I; D011516:Prothrombin
keywords: antibodies; antiphospholipid; phosphatidylserines; prothrombin; thrombosis; β2-glycoprotein I