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Clinical manifestations of antiphospholipid syndrome (APS) with and without antiphospholipid antibodies (the so-called ‘seronegative APS’)
  1. Jose Luis Rodriguez-Garcia1,
  2. Maria Laura Bertolaccini1,
  3. Maria Jose Cuadrado1,2,
  4. Giovanni Sanna1,2,
  5. Oier Ateka-Barrutia1,
  6. Munther A Khamashta1
  1. 1Lupus Research Unit, The Rayne Institute, King's College London School of Medicine, St Thomas' Hospital, London, UK
  2. 2Louise Coote Lupus Unit, Guy's and St Thomas' NHS Foundation Trust, St Thomas' Hospital, London, UK
  1. Correspondence to Munther Khamashta, Lupus Research Unit, The Rayne Institute, King's College London School of Medicine, 4th Floor Lambeth Wing, St Thomas' Hospital, London SE1 7EH, UK; munther.khamashta{at}


Objectives Although the medical literature currently provides a growing number of isolated case reports of patients with clinically well-defined antiphospholipid syndrome (APS) and persistently negative antiphospholipid antibodies (aPL), there are no studies including a series of patients addressing the clinical features of this condition.

Methods The authors assessed clinical manifestations of APS in 154 patients: 87 patients with seropositive APS and 67 patients with thrombosis and/or pregnancy morbidity persistently negative for aPL and presenting with at least two additional non-criteria manifestations of APS (the so-called ‘seronegative APS’, SN-APS). Patients were interviewed at the time of recruitment, and a retrospective file review was carried out.

Results There were no significant differences in the frequency of thrombotic events or obstetric morbidity in patients with SN-APS versus patients with seropositive APS: deep vein thrombosis (31.4% vs 31.0%), pulmonary embolism (23.8% vs 28.7%), stroke (14.9% vs 17.2%), transient ischaemic attack (11.9% vs 10.3%), early spontaneous abortions (67.1% vs 52.1%), stillbirths (62.5% vs 59.4%), prematurity (28.1% vs 21.7%) or pre-eclampsia (28.1% vs 23.1%).

Conclusions Classic and SN-APS patients show similar clinical profiles. The results suggest that clinical management in patients with APS should not be based only on the presence of conventional aPL.

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  • Funding Supported by a grant from the Instituto de Salud Carlos III, Spain (BA09/90006). Maria Laura Bertolaccini is funded by the Louise Gergel Fellowship.

  • Competing interest None.

  • Patient consent Obtained.

  • Ethics approval Obtained.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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