Pathophysiology Exam 1: Immunodeficiency and Autoimmune Disease Practice Exam

Antiphospholipid syndrome involves autoantibodies directed against phospholipid-binding proteins, especially anticardiolipin and anti-β2 glycoprotein I, which give the lupus anticoagulant activity. These antibodies target protein-cofactor complexes on phospholipid surfaces, interfering with normal coagulation in vitro while promoting a hypercoagulable state in vivo. That means patients can experience thrombosis and pregnancy-related complications even though some clotting tests appear prolonged when run in the lab.

The other targets don’t fit APS. DNA-binding proteins are associated with different autoimmune disorders (such as anti-dsDNA in lupus). Muscle-specific kinase is related to myasthenia gravis, and antibodies against RNA polymerase II appear in other connective tissue diseases.