title: Significance of antiprothrombin antibodies in patients with systemic lupus erythematosus: clinical evaluation of the antiprothrombin assay and the antiphosphatidylserine/prothrombin assay, and comparison with other antiphospholipid antibody assays.
abstract: Antibodies against prothrombin are detected by enzyme immunoassays (EIA) in sera of patients with antiphospholipid syndrome (APS). However, there are two methods for antiprothrombin EIA; one that uses high binding plates (aPT-A), and another that utilizes phosphatidylserine bound plates (aPS/PT). We aimed to evaluate and compare aPT-A and aPS/PT in a clinical setting. We performed EIA for anti-PT, anti-PS/PT, IgG, and IgM anticardiolipin antibodies (aCL), and IgG beta2-glycoprotein I-dependent aCL (abeta2GPI/CL) with serum samples from 139 systemic lupus erythematosus (SLE) patients (16 with history of at least one thrombotic episode) and 148 controls. We observed that: (1) although titers of anti-PT and anti-PS/PT were significantly related with each other (P < 0.0001, rho = 0.548), titer of anti-PT and anti-PS/PT differed greatly in some samples; (2) odds ratio and 95% confidence interval for each assay was 3.556 (1.221-10.355) for aPT-A, 4.591 (1.555-15.560) for aPS/PT, 4.204 (1.250-14.148) for IgG aCL, 1.809 (0.354-9.232) for IgM aCL, and 7.246 (2.391-21.966) for abeta2GPI/CL. We conclude that, while all EIA performed in this study except IgM aCL are of potential value in assessing the risk of thrombosis, aPS/PT and abeta2GPI/CL seemed to be highly valuable in clinical practice, and that autoantibodies detected by anti-PT and anti-PS/PT are not completely identical.
authors.affiliation: Division of Clinical Immunology, Major of Advanced Biomedical Applications, Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, 305-8575, Japan. atsutsum@md.tsukuba.ac.jp
authors.forename: Akito
authors.initials: A
authors.lastname: Tsutsumi
authors.forename: Taichi
authors.initials: T
authors.lastname: Hayashi
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Chino
authors.forename: Mizuko
authors.initials: M
authors.lastname: Mamura
authors.forename: Daisuke
authors.initials: D
authors.lastname: Goto
authors.forename: Isao
authors.initials: I
authors.lastname: Matsumoto
authors.forename: Satoshi
authors.initials: S
authors.lastname: Ito
authors.forename: Takayuki
authors.initials: T
authors.lastname: Sumida
mesh_terms: D017152:Antibodies, Antiphospholipid / Q000097:blood*; D016736:Antiphospholipid Syndrome / Q000097:blood*; D006801:Humans; D007124:Immunoenzyme Techniques / Q000379:methods*; D008180:Lupus Erythematosus, Systemic / Q000097:blood* / Q000150:complications / Q000276:immunology; D016017:Odds Ratio; D010718:Phosphatidylserines / Q000276:immunology; D011237:Predictive Value of Tests; D011516:Prothrombin / Q000276:immunology; D012307:Risk Factors; D018709:Statistics, Nonparametric; D013927:Thrombosis / Q000097:blood* / Q000209:etiology
chemical_list: D017152:Antibodies, Antiphospholipid; D010718:Phosphatidylserines; D011516:Prothrombin