[Primary antiphospholipid syndrome evolving into systemic lupus erythematosus: a report of 3 new cases and a review of the literature].

The antiphospholipid syndrome (APS) is characterized by the presence of venous and arterial thrombosis, fetal losses, and thrombocytopenia, associated with the presence of antiphospholipid antibodies (aPL). This syndrome may be "primary" or associated with other diseases, particularly systemic lupus erythematosus (SLE). There is considerable debate on the interrelations between primary APS and SLE as well as on the value of the American College of Rheumatology (ACR) criteria to distinguish between both entities. Several authors have suggested that some patients with primary APS may ultimately develop SLE. Likewise, some authors have proposed exclusion criteria for primary APS. The presence of any of these criteria in a patient with the initial diagnosis of APS might indicate progression of SLE. Three new cases are here reported in whom the diagnosis evolved into SLE some years after the initial diagnosis of primary APS was made. Similar cases previously reported in the literature are reviewed.