Publication Date:
2008-11-16
Description:
BACKGROUND: Antiphospholipid antibodies (APA) that persist ≥12 weeks in adults with acute thrombosis are predictive of thrombus recurrence. The significance of APA in children with thrombosis is unclear. This study was developed to examine the relationship of a persistently positive lupus anticoagulant (≥ 12 weeks), assessed by the dilute Russell Viper Venom Time (dRVVT), to adverse thrombus outcomes including progression or recurrence. In addition, the relationship of a persistently positive dRVVT to the prevalence and titer of several other APA in children with thrombosis were examined. METHODS: Data from a consented prospective inceptional cohort study of pediatric thrombosis and thrombophilia (COMIRB 05–0339) were extracted for this analytic project. Eligibility included age ≤ 21 years at presentation, objectively confirmed thrombus, dRVVT within 4 weeks of presentation and repeated ≥ 12 weeks later. Patients with a persistently positive dRVVT (ratio of Screen/Confirm ≥1.2) were classified as having antiphospholipid syndrome (APS positive), and those with a negative dRVVT were classified as APS negative. Twelve or more weeks from presentation, patient plasmas were tested in ELISA assays for the presence and titer of IgM and IgG antibodies directed against protein C (PC), protein S (PS), prothrombin (II), β-2-Glycoprotein I (B2GPI), and cardiolipin (ACA). A euglobulin clot lysis assay (ELT) and hexagonal (II) phase phospholipid assay (STACLOT LA, Diagnostica Stago, Inc.) were also performed. RESULTS: The cohort included 122 cases with thrombosis. Of these, 35 failed eligibility due to transient dRVVT positivity or lack of blood sampling within the specified time period. Of the remaining 87 patients, 43 were APS positive and 44 were APS negative. APS positivity was associated with longer duration of therapy (p
Print ISSN:
0006-4971
Electronic ISSN:
1528-0020
Topics:
Biology
,
Medicine