This article reviews recent changes in our understanding of the basic
aspects of the Antiphospholipid syndrome (APS) with special emphasis o
n interactions with phospholipid binding proteins. We survey the histo
ry of the development of tests for the APS, and discuss current method
s of detection of antiphospholipid antibodies, clinical events associa
ted with APS, and new concepts regarding the immunological specificity
of the antibodies.