Antiphospholipid antibodies disappearance in primary antiphospholipid syndrome: Thrombosis recurrence

Objective: To evaluate the clinical outcome after aPL (antiphospholipid antibodies) disappearance in primary APS patients.

Methods: From a cohort of 70 patients with primary APS, we selected patients with positive aPL determinations at onset and ≥2 subsequent negative aPL determinations during the last 5years. To corroborate the immunologic profile, we determined IgG/IgM aCL antibodies, IgG/IgM antiβ2GPl, anti-annexin A5 antibodies and lupus anticoagulant (LA). All patients continued treatment with oral anticoagulants. Clinical data and aPL determinations at onset/after disappearance were obtained.

Statistical analysis: descriptive statistics and Kaplan-Meier analysis.

Results: We found 24 patients with persistently negative aPL, including the last immunologic profile, 17 females, 7 males, mean age 51.7, disease evolution 16.3years, mean of 4 aPL previous positive determinations. aCL was positive at onset in 87.5%, 29% had double aPL positivity at onset (aCL/LA). Deep venous thrombosis (DVT) and ischemic stroke in 33% and pulmonary embolism in 12.5% were the most frequent manifestations at onset. INR range: 2-3. Time with aPL positive 109.4±80.7months. After 60months of follow-up since aPL disappearance, 45.8% of patients presented thrombosis recurrence, DVT in 9 patients, ischemic stroke in 1, pulmonary artery hypertension in 1. Other non-thrombotic APS manifestations were chronic ulcers in lower extremities and severe thrombocytopenia.

Conclusions: This study suggest, that in primary APS, persistent negative aPL profile is not an indication to interrupt oral anticoagulant therapy. However, there is a subset of patients that remained asymptomatic. Other studies are necessary in order to elucidate this controversy.