CD40LG and antiphospholipid syndrome: Antiphospholipid syndrome (APS) is an autoimmune disease characterized by specific antiphospholipid antibodies (APLAs)—anti-cardiolipin IgM and IgG, anti-beta2glycoprotein IgM and IgG, and lupus anticoagulant—which cause a hypercoagulable state, leading to venous and arterial thromboses.