Lupus anticoagulant (LA) is considered a risk factor for thromboembolism (TE) and adverse pregnancy outcomes (APOs). However, quite a few patients diagnosed with LA positivity do not suffer these adverse events. Further testing of anticardiolipin (aCL), anti-beta2-glycoprotein I (anti-β2GPI) or anti-domain 1 of β2GPI (anti-D1) may help to assess the occurrence risk of TE and APOs. Therefore, we aimed to study how to stratify LA-positive patients. In our study, 167 LA-positive patients were consecutively enrolled from January 2015 to December 2016. Serum aCL and anti-β2GPI (IgG, IgM and IgA) and anti-D1 IgG were simultaneously measured. Among these patients, 114 (68.3%) were followed for an average of 36.5 months for TE and APOs. The outcomes showed that 105 patients experienced TE and/or APOs, and 62 patients were LA carriers. Anti-D1 had good consistency with triple positivity (LA+, aCL+, anti-β2GPI+) (kappa = 0.742). Elevated anti-D1 was related to increased risks for TE [odds ratio (OR) 29.87, 95% confidence interval (CI) 8.05–110.74] and APOs (OR 8.73, 95% CI 3.41–22.31). Area under curve showed that the diagnostic power of anti-D1 for TE and APOs was 0.856 (95% CI 0.743–0.970) and 0.682 (95% CI 0.599–0.765), respectively. Survival analysis revealed that patients with high anti-D1 titres had a high cumulative incidence of APOs (hazard ratio 4.66, 95% CI 1.46–14.87). In conclusion, anti-D1, based on good consistency with triple positivity in LA-positive patients, has a stronger association with TE and APOs and, to some degree, could predict pregnancy outcomes. Therefore, anti-D1 may aid risk stratification in LA-positive patients.
Lupus anticoagulant Thromboembolism Adverse pregnancy outcomes Anti-domain 1 of beta2-glycoprotein I Antiphospholipid antibodies
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This work was supported by Natural Science Foundation of China (Grant No. 81601824) and the interdisciplinary medicine Seed Fund of Peking University (Grant No. BMU2017MX013).
HG designed the research, interpreted data, performed statistical analysis and wrote the manuscript; YZ designed the research, interpreted data, AL and CW collected samples; SY and YZ analysed samples; JZ reviewed the manuscript; and RQ designed the research, identified sample characteristics and reviewed the manuscript.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
All procedures performed in studies were got approval from the Ethics Committee of Peking University Third Hospital according to the 1964 Helsinki Declaration and its latter amendments or comparable ethical standards.
Informed consent was signed from all participants included in the study.
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