F2 and systemic lupus erythematosus: Lupus anticoagulants are a heterogenic group of immunoglobulins that specifically aim at epitopes of negatively charged protein binding phospholipids of the cellular membrane, prothrombin, and beta2-glycoprotein I, which in vitro prolongs the coagulation tests dependent on phospholipids when there is competition with coagulation factors for phospholipids [22].