ACLY and antiphospholipid syndrome: Antiphospholipid syndrome (APS) is an acquired autoimmune disorder characterized by the presence of antiphospholipid antibodies (aPLA) such as IgG/IgM anticardiolipin (aCL), anti-β2-glycoprotein I antibodies (aβ2GPI), or lupus anticoagulant (LA).