Anti-beta2-glycoprotein I and anti-prothrombin antibodies in patients with the 'antiphospholipid' syndrome: immunological specificity and clotting profiles.
Lupus anticoagulant (LA) antibodies have been shown to be directed to protein-phospholipid complexes. In this study, we report on LA antibodies from patients with the 'antiphospholipid' syndrome (APS), that are directed to prothrombin and beta2-glycoprotein I, but not to the complexes of these plasma proteins to anionic phospholipids. The anti-prothrombin antibodies studied had different reactivities in two clotting assays: the dilute Russell's viper venom time (dRVVT) and the dilute kaolin clotting time (dKCT). Anti-prothrombin and anti-beta2-glycoprotein I (anti-beta2GPI) antibodies, affinity-purified from one patient with APS were not cross-reactive and had different effects in the dRVVT and dKCT clotting tests. Polyclonal anti-prothrombin antibodies, affinity-purified on a prothrombin column, from two patients with prothrombin reactivity in their plasma, have affinity constants to prothrombin of 104 and 192 nM. The patient with affinity-purified antibodies to prothrombin and beta2GPI, had affinity constants to prothrombin and beta2GPI, respectively, of 192 nM and 3030 nM, respectively. LA antibodies are a heterogeneous population of antibodies that have different immunological specificities and clotting test reactivities in different patients.
Department of Immunology, Allergy and Infectious Disease, University of New South Wales, St George Hospital, Kogarah, Australia.
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Kandiah
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Krilis
D000328:Adult; D016736:Antiphospholipid Syndrome / Q000097:blood / Q000276:immunology*; D001780:Blood Coagulation Tests; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006023:Glycoproteins / Q000276:immunology*; D006801:Humans; D016682:Lupus Coagulation Inhibitor / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D011516:Prothrombin / Q000276:immunology*; D053482:beta 2-Glycoprotein I
D006023:Glycoproteins; D016682:Lupus Coagulation Inhibitor; D053482:beta 2-Glycoprotein I; D011516:Prothrombin