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Clinical and Developmental Immunology
Volume 2013, Article ID 724592, 8 pages
Research Article

Detection of Antiphosphatidylserine/Prothrombin Antibodies and Their Potential Diagnostic Value

1Immunology Laboratory, Department of Rheumatology, University Medical Centre, 1000 Ljubljana, Slovenia
2Faculty of Mathematics, Natural Science and Information Technology, University of Primorska, 6000 Koper, Slovenia
3Faculty of Pharmacy, University of Ljubljana, 1000 Ljubljana, Slovenia

Received 30 April 2013; Accepted 15 July 2013

Academic Editor: Guixiu Shi

Copyright © 2013 Polona Žigon et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Antiprothrombin antibodies, measured with phosphatidylserine/prothrombin complex (aPS/PT) ELISA, have been reported to be associated with antiphospholipid syndrome (APS). They are currently being evaluated as a potential classification criterion for this autoimmune disease, characterized by thromboses and obstetric complications. Given the present lack of clinically useful tests for the accurate diagnosis of APS, we aimed to evaluate in-house and commercial assays for determination of aPS/PT as a potential serological marker for APS. We screened 156 patients with systemic autoimmune diseases for antibodies against PS/PT, β2-glycoprotein I, cardiolipin and for lupus anticoagulant activity. We demonstrated a high degree of concordance between the concentrations of aPS/PT measured with the in-house and commercial assays. Both assays performed comparably relating to the clinical manifestations of APS, such as arterial and venous thromboses and obstetric complications. IgG aPS/PT represented the strongest independent risk factor for the presence of obstetric complications, among all tested aPL. Both IgG and IgM aPS/PT were associated with venous thrombosis, but not with arterial thrombosis. Most importantly, the association between the presence of IgG/IgM aPS/PT and lupus anticoagulant activity was highly significant. Taken together, aPS/PT antibodies detected with the in-house or commercial ELISA represent a promising serological marker for APS and its subsets.