The 'primary' antiphospholipid syndrome: antiphospholipid antibody pattern and clinical features of a series of 23 patients

Autoimmunity. 1991;9(1):69-75. doi: 10.3109/08916939108997126.


Twenty-three patients with the 'primary' antiphospholipid syndrome were studied over 2-6 years. Twenty-two (96%) had antiphospholipid antibodies detected by ELISA (87% had antibodies to thromboplastin and 70% to cardiolipin), and 18 out of the 21 tested patients (86%) had lupus anticoagulant activity by coagulative assays. Mean age of the cohort was 29.9 years and the sex ratio (female:male) 4.75:1. Eleven patients presented 18 venous and/or arterial thrombosis and 13 had 25 foetal losses (84% occurred during the second and third trimester). Other clinical features were migraine, livedo reticularis, and epilepsy. Three patients had relatives with systemic lupus erythematosus. Thrombocytopaenia was seen in 33%, antinuclear antibodies in low or moderate titre in 30%, and haemolytic anaemia in 13%. During the follow-up, two patients presented recurrent thrombosis despite anticoagulant therapy, one of them dying because of recurrent pulmonary thromboembolism. Four patients achieved successful term pregnancies after treatment with aspirin and a further patient after treatment with aspirin and low dose prednisolone. No patient developed systemic lupus erythematosus or any other definable connective tissue disease. The 'primary' antiphospholipid syndrome may exist as a distinct clinical entity and all younger patients presenting with thrombotic events, foetal losses and/or thrombocytopaenia, without any evidence of a well defined disease, should be tested for antiphospholipid antibodies in order to rule out this syndrome.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Antibodies, Anticardiolipin / blood
  • Antibodies, Antiphospholipid / blood*
  • Antiphospholipid Syndrome / complications
  • Antiphospholipid Syndrome / drug therapy
  • Antiphospholipid Syndrome / immunology*
  • Aspirin / therapeutic use
  • Enzyme-Linked Immunosorbent Assay
  • Female
  • Fetal Death / etiology
  • Fetal Death / prevention & control
  • Humans
  • Lupus Coagulation Inhibitor / blood
  • Male
  • Middle Aged
  • Pregnancy
  • Pregnancy Complications / drug therapy
  • Thromboplastin / immunology
  • Thrombosis / drug therapy
  • Thrombosis / etiology


  • Antibodies, Anticardiolipin
  • Antibodies, Antiphospholipid
  • Lupus Coagulation Inhibitor
  • Thromboplastin
  • Aspirin