Abstract
Background Patients positive for all three types of antiphospholipid antibodies (aPLs; triple positivity) have been identified for having a high risk for thrombotic events. However, the clinical significance of isolated lupus anticoagulant (LAC) positivity is debated.
Objectives To investigate the clinical relevance of isolated LAC.
Methods A total of 456 patients were enrolled in this study; 66 antiphospholipid syndrome patients and 390 control patients. The control group consisted of autoimmune patients ( n =91), patients with thrombosis but without aPLs ( n =127), and normal controls ( n =172). LAC, anticardiolipin (anti-CL), and anti-beta 2 glycoprotein I (anti-beta 2GPI) immunoglobulin G (IgG) and immunoglobulin M (IgM) were determined according to the International Society on Thrombosis and Haemostasis (ISTH) guidelines. Anti-CL and anti-beta 2GPI were measured by four different solid-phase platforms to overcome variability between test systems. The noncriteria IgA anti-CL and anti-beta 2GPI, antidomain I of beta 2GPI IgG, and antiphosphatidylserine/prothrombin antibodies (anti-PS/PT) IgG and IgM were detected according to the ISTH guidelines for solid-phase assays.
Results In total, 70 patients were positive for LAC, of which 44 were negative for both anti-beta 2GPI and anti-CL antibodies. We found that isolated LAC proved to be strongly associated with vascular thrombosis (odds ratio [OR]: 7.3; 95% confidence interval [CI]: 3.3-16.1), even better than triple-positive samples (OR: 4.3; 95% CI: 1.6-12.2). The titers of the anti-PS/PT IgG and IgM were significantly higher in triple-positivity samples compared with samples with isolated LAC positivity. The majority of single LAC positives were anti-PS/PT-negative. We observed that LAC positivity was weaker in isolated LAC-positive patients compared with LAC activity in triple-positive patients.
Conclusion Isolated LAC was highly associated with thrombosis. The presence of anti-PS/PT antibodies could not explain LAC positivity in isolated LAC. Isolated LAC showed a weaker LAC activity compared with triple-positive patients.
Original language | English |
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Pages (from-to) | 1220-1227 |
Number of pages | 8 |
Journal | Thrombosis and Haemostasis |
Volume | 121 |
Issue number | 09 |
DOIs | |
Publication status | Published - Sept 2021 |
Keywords
- antiphospholipid antibodies
- β
- 2 glycoprotein I
- lupus anticoagulant
- prothrombin
- thrombosis