Influence of polymorphonuclear leukocytes on the plasma clot formation as evaluated by thromboelastometry (ROTEM)

It has been emphasized that polymorphonuclear leukocytes (PMN) participate in the regulation of coagulation. However, the mechanisms of action are not clear. Besides a procoagulant activity, anticoagulant or fibrinolytic properties are attributed to these cells. To explore their global effect, we have studied their involvement in the clot formation with thromboelastometry, which gives global view over the clotting process, in particular on the structure of the clot and on the kinetic of its formation.

PMN were isolated from healthy blood donors and resuspended into autologous platelet-free plasma. The ROTEM device was used. Coagulation was triggered only by adding calcium chloride. Thromboelastometric profiles of PMN-rich plasma (PMN-RP) were compared with autologous platelet-rich (PRP) and platelet-poor plasma (PPP). The inhibition of both tissue factor and intrinsic pathways was also studied.

The procoagulant activity of resting PMN was demonstrated as the initiation of fibrin formation with PMN-RP was significantly faster compared with both PRP and PPP. The kinetic of plasma clotting was remarkably improved with PMN-RP compared with PPP. However, the clot with PMN-RP had the same poor viscoelastical properties as PPP. Thromboelastometry gives a new point of view in the involvement of PMN in coagulation, in the absence of any PMN pre-activation. Their impact was centred on the kinetic and the facilitation of the clot formation.