ABSTRACT
This chapter analyzes how Anti-phospholipid antibodies (aPL) might perturb the biological activities of anionic phospholipids in a manner that could decrease the natural anticoagulant capacity of the protein C pathway. aPL are heterogeneous immunoglobulins of G, M, or A class with specificity directed towards anionic phospholipids, mainly cardiolipin (diphosphatidylglycerol) or phosphatidylserine, and phosphatidylinositol or phosphatidylglycerol to a lesser extent. They can be detected in the plasma or serum of a variety of subjects presenting various minor or major diseases. Since the latter category was first detected in patients with systemic lupus erythematosus they were termed lupus anticoagulants3-4 but, lupus-like anticoagulants (LLA) would now appear preferable. The striking clinical paradox with patients with LLA is their increased susceptibility to arterial or venous thromboembolic disorders whereas, on the basis of the laboratory clotting tests one would have expected them to suffer from hemorrhagic episodes.
