ANTIHEPARIN ACTIVITY OF SOME HUMAN BLOOD PROTEIN FRACTIONS AND THEIR POSSIBLE RELATIONSHIP TO THROMBOSIS.

In view of the possible relationship to thrombosis the ;anti-heparin' activity of blood protein fractions was studied. Serum and plasma were separated by continuous paper curtain electrophoresis and two different groups of fractions with anti-heparin activity found. One group was associated with the fast gamma globulins and the other with the alpha globulins. The fast gamma activity appeared to be identical with the contact activation product (activated factors XI and XII). The alpha globulin activity is different from any of the known serum clotting factors. This activity may be due to a previously unrecognized clotting factor or may be a coagulant property of certain blood proteins which act by binding heparin. The clinical implications of these findings are discussed. It is suggested that the fast gamma globulin anti-heparin fraction may be identical with Wessler's serum thrombotic accelerator and the alpha globulin activity is a separate entity.