title: Endothelium-derived haemostatic factors and the antiphospholipid syndrome.
abstract: The cause of thrombosis in the antiphospholipid syndrome (APS) is unknown. There have been reports of abnormalities in the antigenic levels or activity of endothelium-derived haemostatic factors, such as tissue-type plasminogen activator (t-PA) and plasminogen activator inhibitor type 1 (PAI-1); however the data from these studies are conflicting. We studied plasma from nine patients with APS; seven of them had a history of thrombosis, and three had systemic lupus erythematosus (SLE). We also studied nine matched control patients who had SLE without APS, and 14 healthy individuals. We measured t-PA, von Willebrand factor (vWF), anticardiolipin antibody (ACA) and anti-endothelial cell antibody (AECA) levels by enzyme-linked immunoassay (ELISA), PAI-1 activity by a parabolic-rate chromogenic assay, and lupus anticoagulant (LA) activity by a standard mixing test. For t-PA and PAI-1, measurements were made on morning and evening plasma samples. The two groups of patients did not differ significantly with respect to age, sex, plasma lipids or anti-inflammatory drugs. Most APS patients (7/9) but none of the controls were taking warfarin. Between the APS and the control patients no significant differences were detected in t-PA, PAI-1, vWF or AECA levels. When APS patients were considered alone, vWF levels correlated positively with IgG ACA levels (r = 0.81, P < 0.01) and negatively with platelet count (r = -0.68, P < 0.05). There was no correlation between levels of ACA or LA activity and t-PA, PAI-1 or AECA. Compared with healthy volunteers, the diurnal variation of t-PA and PAI-1 was blunted in the two patient groups.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Rheumatology Unit, RPMS, London.
authors.forename: C G
authors.initials: CG
authors.lastname: Mackworth-Young
authors.forename: F
authors.initials: F
authors.lastname: Andreotti
authors.forename: I
authors.initials: I
authors.lastname: Harmer
authors.forename: S
authors.initials: S
authors.lastname: Loizou
authors.forename: B E
authors.initials: BE
authors.lastname: Pottinger
authors.forename: J D
authors.initials: JD
authors.lastname: Pearson
authors.forename: G J
authors.initials: GJ
authors.lastname: Davies
authors.forename: A
authors.initials: A
authors.lastname: Maseri
authors.forename: M J
authors.initials: MJ
authors.lastname: Walport
mesh_terms: D000328:Adult; D017152:Antibodies, Antiphospholipid / Q000097:blood*; D016736:Antiphospholipid Syndrome / Q000097:blood* / Q000276:immunology; D001323:Autoantibodies / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010507:Periodicity; D017395:Plasminogen Activator Inhibitor 1 / Q000097:blood*; D013223:Statistics as Topic; D010959:Tissue Plasminogen Activator / Q000097:blood*; D014841:von Willebrand Factor / Q000032:analysis*
chemical_list: D017152:Antibodies, Antiphospholipid; D001323:Autoantibodies; D015415:Biomarkers; D017395:Plasminogen Activator Inhibitor 1; C087589:anti-endothelial cell antibody; D014841:von Willebrand Factor; D010959:Tissue Plasminogen Activator