BINDING OF AUTOIMMUNE CARDIOLIPIN-REACTIVE ANTIBODIES TO HEPARIN - A MECHANISM OF THROMBOSIS

Autoimmune CL-rA need a plasma protein, beta 2GPI, to bind anionic PL. While beta 2GPI could be the true antigen, beta 2GPI binding to solid phase heparin did not determine its recognition by CL-rA when using p atient plasmas. We tested plasmas from four patients with antiphosphol ipid syndrome in this study and no CL-rA binding to heparin sepharose was obtained. On the contrary, when CL-rA were first purified from the plasmas by means of a CL-octyl sepharose column, the purified materia l bound to the heparin sepharose column. Thus, after recognizing beta 2GPI, CL-rA bind heparin. 'In vivo' CL-rA binding to heparin like-subs tances could inhibit the antithrombotic properties of endothelial cell s.