The lupus anticoagulant and the anticardiolipin antibody were characterized as acquired antibodies. Clinical and serologic criteria for the classification of APS have been proposed on the basis of a study of 667 SLE patients:
Classification of antiphospholipid syndrome
- Vascular thrombosis (one or more clinical episodes of arterial, venous or small vessel thrombosis).
- Pregnancy morbidity (one or more unexplained deaths of a morphologically normal foetus at or beyond the 10th week of gestation/one or more premature births at or before the 34th week of gestation/three or more unexplained consecutive spontaneous abortions before the 10th week of gestation).
- Anticardiolipin antibodies (IgG and/or IgM)
- Lupus anticoagulant
Definite antiphospholipid antibody syndrome is considered to be present if at least one of the clinical criteria and one of the laboratory criteria are met.
Multiple faces of antiphospholipid syndrome
(Asherson RA, Cervera R (2003) Autoim Rev 2: 140-151)
Single vessel involvement or multiple vascular occlusions may give rise to a wide variety of presentations.
Deep vein thrombosis, sometimes accompanied by pulmonary embolism, is the most frequently reported manifestation in this syndrome (about 39%).
Cerebrovascular accidents – stroke (20%) or transient ischaemic attacks (11%) – are the most common arterial thrombotic manifestations.
Early foetal loss (35%), late foetal loss (17%), premature birth (11%), and pre-eclampsia (10%) are the most frequent foetal and obstetric manifestations.
Several other clinical features are relatively common in these patients, i.e. thrombocytopaenia (30%), livedo reticularis (24%), heart valve lesions (12%), haemolytic anaemia (10%), epilepsy (7%), myocardial infarction (6%), leg ulcers (6%) and amaurosis fugax (5%).
However, a large variety of clinical manifestations has been described occasionally in patients with APS, with prevalences lower than 5%. Virtually any organ, system or tissue of the body can be affected.
APS can be manifested in such diverse conditions as chorea, intracardiac thrombus, ARDS, Addison's disease, Budd-Chiari syndrome, AVN of bone or HELLP syndrome, to name just a few.