In systemic lupus erythematosus, antiphospholipid antibodies increase the risk of which complication?

• A. Infectious endocarditis
• B. Thrombosis
• C. Renal failure
• D. Pulmonary hypertension

Answer: (B)

Antiphospholipid antibodies in systemic lupus erythematosus create a hypercoagulable state that makes clots more likely to form in both veins and arteries. These antibodies (lupus anticoagulant, anticardiolipin, and anti–β2 glycoprotein I) bind phospholipid-binding proteins, activating platelets and the endothelium and disrupting natural anticoagulant pathways. The result is an increased risk of thrombosis, such as deep vein thrombosis, pulmonary embolism, stroke, and other arterial or venous clots. While they can prolong clotting tests in the lab, they promote clotting in the body. This is why thrombosis is the prominent complication associated with antiphospholipid antibodies in lupus.