Procogulant Activities of Leukocytes
In the haemostasis field, it is well accepted that platelets are the only blood cells that play a specific role in the normal coagulation process. The procoagulant activity (PCA) of leukocytes, however, has been described well over hundred years ago (Addison 1842). Recent studies have now shown that monocytes, macrophages and lymphocytes are implicated in the clotting process, in health and many disease states. Most of the studies have been focused on monocytes and macrophages; the major procoagulant component being tissue factor (Niemetz 1972, Prydz 1978) which triggers the extrinsic pathway of coagulation by its interaction with F.VII. The production of other clotting factors such as F.IX, X, VII, and V; and direct activators of F.X and prothrombin by monocytes and macrophages have also been reported (Tsao et al 1984; Lindahl et al 1982; Osterud et al 1980; Hogg et al 1983; Shands 1983). The procoagulant activity of monocytes and macrophages may be modulated by products secreted by lymphocytes (Edwards et al; Schwartz et al 1981; Levy et al 1980), however, there is no concrete evidence of lymphocytes themselves exhibiting procoagulant activity.
KeywordsLymphoma Myeloma Thrombin Prothrombin Phorbol
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