CD40LG and autoimmune polyendocrinopathy: Thrombotic antiphospholipid syndrome (APS) is an acquired autoimmune thrombophilia characterized by venous, arterial, and/or microvascular thrombosis in conjunction with persistent antiphospholipid antibodies (aPL): lupus anticoagulant (LA), immunoglobulin (Ig)G and/or IgM anticardiolipin antibodies (aCL), and IgG and/or IgM anti-beta 2 glycoprotein I (aβ2GP1) antibodies.