MONOCYTES EXPRESS TISSUE FACTOR IN YOUNG-PATIENTS WITH CEREBRAL-ISCHEMIA

Activation of blood coagulation and fibrinolysis has previously been d etected in stroke patients. It is unknown, however, what factors contr ibute to the acceleration of coagulation reactions, especially in case s where no obvious predisposing factors exist. We therefore postulated and tested the hypothesis that in such patients monocytes may trigger the pathway leading to thrombosis by expressing tissue factor (TF). T F antigen was determined in 48 patients and 40 controls by flow cytome try using an indirect immunofluorescent technique. TF antigen expressi on was significantly increased on monocytes in young stroke patients i n both the acute (p < 0.01) and chronic (p < 0.05) phases of the disea se. The TF antigen also possessed functional activity, quantitated by a one-stage clotting assay. TF expression on monocytes was not associa ted with an elevation in C-reactive protein values. In both acute and chronic phases, blood coagulation activation markers, e.g. the thrombi n-antithrombin complex and F1+2 fragments, were significantly elevated . However, in the acute phase D-dimer levels were similar to those in controls and were only elevated in the chronic phase of the disease (p < 0.05). In conclusion, in cerebral ischemia TF expression on monocyt es suggests enhanced activation of blood coagulation and subsequent fi brinolysis.