Activation of the coagulation system and leukocytes kinetics in plasma exchange.

The activation of the coagulation system--commonly occurring in other extracorporeal circulation--is still debated, in plasma exchange (PE), data being conflicting due to the different types of replacement fluid used in 25 patients treated by PE using a discontinuous plasma separator (14 with freshly-frozen plasma, 8 with half plasma half 5% albumin, 3 with only 5% albumin). The occurrence of leukocytes stress is proved by their marked increase at the end of the procedure while the platelet fall is superimposable to the HTC fall. A coagulation-fibrinolytic activation seems to be demonstrated by plasma increase in endoplatelet constituents, fibrinogen and antithrombin III consumption, and shortening in fibrinolytic tests, but caution must be made in interpreting these results because the donor's plasma units show high levels of platelet endogranular constituents and a wide variable range of coagulation-related proteins, which can interfere with an appropriate evaluation of the results.