Background The serological test included in the classification for antiphospholipid syndrome are: IgG, IgM antibodies to cardiolipin (aCL), β2-glycoprotein (anti-β2GPI) and the lupus anticoagulant (LA). Among these antiphospholipid (aPL) antibodies, LA is considered the strongest risk factor for thromboembolic events and triple positivity of antiphospholipid antibodies (aPL)(Lupus anticoagulant /LA), aCL and antiβ2GPI) are at the highest risk for thrombosis recurrence and obstetric complications, even while on anticoagulant therapy.

Objectives To analyze the role of 4 antiphospholipid antibodies in thrombotic recurrence of patients with antiphospholipid syndrome (APS).

Methods In a cross-sectional study, we included patients with established diagnosis of APS from 1996 to 2014. The clinical files were reviewed and we obtained demographic, clinical, and treatment data. Blood samples were taken to determine titers of aPL: aCL, anti anexin 5 (anti A5), antiβ2GPI IgG and IgM by ELISA method, and LA in plasma by the coagulation method.

Results 70 APS patients were studied, 56 females and 14 males, 67 with primary APS and 3 with associated APS. The mean age was 44±12.9 years (range 18-77 years) mean disease evolution 10.8±5.8 years, thrombosis recurrence was observed in 38 patients (53.5%) and 33 patients without thrombosis recurrence (46.5%); 67 patients treated with traditional oral anticoagulants, 47 (66%) had venous thrombosis,12 (17%) had arterial thrombosis and10 (14%) had venous and arterial thrombosis. Prevalence of aPL was: 35 for IgG aCL (49.3%), 21 for IgM aCL (29.6%), 36 for IgG antiβ2GPI (50.7%), 12 for IgM antiβ2GPI (15.5%), 3 for IgG antiA5 (4.2%), 5 for IgM anti A5 (7%) and 34 for LA (46.5%), 25 patients had triple positivity for aPL (35.2%.) and 16 patients had at time of study a negative aPL profile, even though some of them had thrombosis recurrence and aPL positive in the past. Regression analysis for all aPL and thrombosis recurrence showed an OR of 7.3 CI 95%=1.19-45.1) for LA (p=0.03)

Conclusions Our study confirm that LA seems to be the most important aPL, which presence confers a major risk of thrombosis recurrence. Careful follow-up of patients with persistence of LA should be recommended to avoid thrombosis recurrence. A negative “traditional” aPL profile seems to be not an indication for stop anticoagulation.

References

1. Forastiero R. Multiple antiphospholipid antibodies positivity and antiphospholipid syndrome criteria re-evaluation. Lupus. 2014 Oct;23(12):1252-4.

2. Hernández-Molina G, Espericueta-Arriola G, Cabral AR.The role of lupus anticoagulant and triple marker positivity as risk factors for rethrombosis in patients with primary antiphospholipid syndrome. Clin Exp Rheumatol. 2013 May-Jun;31(3):382-8.

Disclosure of Interest None declared