Antiphospholipid antibodies, antiphospholipid syndrome and infections

Since the association between antiphospholipid antibodies (aPL) and syphilis was first described, many other viral, bacterial and parasitic infections have been shown to induce antiphospholipid antibodies, notably anticardiolipin antibodies (aCL). A review of the literature shows that while aCL occur frequently in viral infections, particularly in HIV (49.75%), HBV (24%) and HCV (20%), it is very rarely associated with anti-β2 glycoprotein I antibodies (anti-β2GPI) and is not correlated with thrombosis risk or hematological manifestations of the antiphospholipid syndrome (APS). Concerning bacterial infections, aCL is often present in leprosy (42.7%), where it is frequently associated with the presence of anti-β2GPI (44.8%), and in syphilis infections (8 to 67%), though without correlation with thrombotic events. Though few individual patients with unequivocal infection-induced aPL satisfy criteria for APS, the lack of statistical association with thrombotic events strongly argues against the identification of a true APS subset in this context. However, physicians should keep in mind the fact that an infection, generally bacterial, in patients with confirmed APS, may lead to catastrophic antiphospholipid syndrome with a possible fatal outcome.