Lupus anticoagulant (LA1 / LA2) in the blood plasma

Lupus anticoagulant (LA) is an autoantibody (IgG) against phospholipids, and the cause of antiphospholipid syndrome (APS).

The antibodies got their name because they were first detected in patients with systemic lupus erythematosus. Phospholipids are important structural components of the cell wall, especially in blood vessels. The exact cause of LA is unknown, but its presence is due to a failure in the immune system, which often occurs after various infections. LA becomes the cause of antiphospholipid syndrome, the main manifestations of which consist in the occurrence of a high risk of thrombosis. Lupus coagulant inhibits phospholipase A2 and protein S, thereby reducing the production of prostacyclin (an inhibitor of platelet aggregation) by endothelial cells, which creates conditions for thrombosis. LA is a likely factor in thrombosis of unclear genesis.

As a consequence, the syndrome does not have special clinical manifestations, it can be suspected in cases of pregnancy failure (due to placental vascular thrombosis), hemodynamic disorders in the form of strokes or thrombosis, in the presence of autoimmune diseases.

APS is characterized by a paradoxical prolongation of the APPT and a tendency to thrombosis, while other indicators of the coagulogram have no abnormalities.

When prescribing the test it is necessary to cancel heparin 2 days prior, and oral anticoagulants 2 weeks prior the test, as a false positive result is possible (“Guide to Laboratory Methods of Diagnosis” Dr. M.Sc., Prof. A.A. Kishkun, 2007)".