title: Antibodies to prothrombin imply a risk of myocardial infarction in middle-aged men.
abstract: Antiphospholipid antibodies in patients with "antiphospholipid syndrome" may be directed at least in part against plasma phospholipid-binding proteins, such as beta 2-glycoprotein I or prothrombin, which are involved in the control of thrombosis and haemostasis. IgG-class antibodies against prothrombin and beta 2-glycoprotein I were measured by enzyme-linked immunoassay in initially healthy middle-aged dyslipidaemic men (non-high-density lipoprotein > 5.2 mml/l). Serum samples had been drawn at entry to a 5-year coronary primary-prevention trial with gemfibrozil from 106 subjects who experienced either a non-fatal myocardial infarction or cardiac death during the follow-up and from 106 subjects without coronary episodes, matched for treatment group (gemfibrozil/placebo) and geographical area. The antiprothrombin antibody level, as expressed in optical density units, was significantly higher in patients than in controls (0.26 +/- 0.17 versus 0.22 +/- 0.09; p < 0.02). A high level of antiprothrombin antibodies (highest tertile of distribution) predicted a 2.5-fold increase in the risk (95% confidence interval 1.2-5.3) of myocardial infarction or cardiac death. The distribution of IgG-class antibodies against beta 2-glycoprotein I did not differ significantly between cases and controls. The joint effect of antiprothrombin antibodies and other factors associated with hypercoagulative state: triglyceride level, lipoprotein(a) and smoking, was multiplicative for the risk. Antiprothrombin antibodies are a new immunological predictor of myocardial infarction and the effect of these antibodies may be mediated by hypercoagulative mechanisms.
authors.affiliation: Department of Immunobiology, National Public Health Institute, Helsinki, Finland.
authors.forename: O
authors.initials: O
authors.lastname: Vaarala
authors.forename: M
authors.initials: M
authors.lastname: Puurunen
authors.forename: M
authors.initials: M
authors.lastname: Mänttäri
authors.forename: V
authors.initials: V
authors.lastname: Manninen
authors.forename: K
authors.initials: K
authors.lastname: Aho
authors.forename: T
authors.initials: T
authors.lastname: Palosuo
mesh_terms: D001053:Apolipoproteins / Q000276:immunology*; D016022:Case-Control Studies; D006023:Glycoproteins / Q000276:immunology*; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood*; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000276:immunology*; D011516:Prothrombin / Q000276:immunology*; D012307:Risk Factors; D053482:beta 2-Glycoprotein I
chemical_list: D001053:Apolipoproteins; D006023:Glycoproteins; D007074:Immunoglobulin G; D053482:beta 2-Glycoprotein I; D011516:Prothrombin