The coagulation properties of human erythrocytes.

A thromboplastic factor has been demonstrated in human red cells by Shinowara (1951), Ottaviani, Dettori, and Manai (1954), Quick, Georgatsos, and Hussey (1954), Leupold (1955), Bounameaux (1957a), and Georgatsos, Hussey, and Quick (1955), and named the "erythrocyte clotting factor" (E.C.F.). Its activity is similar though not identical with that of platelet factor 3. Thromboplastic activity is not produced by whole erythrocytes, but only after lysis by freezing or dilution with distilled water. Lysed erythrocytes increase the prothrombin consumption of plateletpoor or platelet-rich plasma and restore to normal the prolonged recalcification time and the impaired prothrombin consumption of a thrombocytopenic plasma (Georgatsos et al., 1955). The E.C.F. activity depends on the presence of thromboplastinogen (Izarn, Hussey, and Quick, 1955). The increase of prothrombin consumption of a platelet-free haemophilic plasma, to which thromboplastinogen is added, is higher when platelets are replaced by lysed erythrocytes, when there is a linear relationship between this increase and the amount of thromboplastinogen. The prothrombin consumption test in the presence of lysed erythrocytes, as suggested by Izarn et al. (1955), should therefore be very sensitive in detecting small quantities of thromboplastinogen or antihaemophilic globulin (A.H.G.) and it should be useful in differentiating between mild and severe A.H.G. deficiencies. It was also shown by Leupold (1955), Georgatsos et al. (1955), and Bounameaux (1957a) that lysed red cells can be substituted for platelets in the thromboplastin generation test of Biggs and Douglas (1953). This paper records an investigation into the coagulation properties of lysed erythrocytes. The possible interference of lysed erythrocytes in the various stages of the clotting process has been investigated and a study made as to whether other activities might be detected in red cells comparable with those already found in platelets by Deutsch, Johnson, and Seegers (1955). A preliminary report on the antiheparin activity of lysed erythrocytes has been published (Serafini and Centurelli, 1957).