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.
Kandiah
D A
DA
Department of Immunology, Allergy and Infectious Disease, University of New South Wales, St George Hospital, Kogarah, Australia.
Krilis
S A
SA
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