Platelet-leukocyte interaction and platelet activation in acute stroke with and without preceding infection.

OBJECTIVE Acute coronary syndromes and ischemic cerebral stroke share similarities regarding elevated platelet activation. In coronary syndromes, the importance of inflammation with platelet-leukocyte interaction has been demonstrated. Recent infection is an established risk factor for ischemic stroke; the role of platelet-leukocyte interaction in these patients had not been investigated. METHODS AND RESULTS Using a flow cytometric assay we investigated 58 stroke patients, 21 with and 37 without infection 1 week before acute cerebral ischemia, and compared them to 58 controls with regard to platelet-leukocyte aggregation and platelet activation on admission and on day 7. Patients with previous infection were significantly up-regulated with regard to platelet activation and platelet-leukocyte aggregation compared with patients without infection. On day 7, these increases in the postinfective group had drawn level with the lower values of the other patients. As reported previously, recent infection was associated with a more severe postischemic deficit. CONCLUSIONS These results suggest an important role of intercellular platelet-leukocyte interaction in the pathophysiology of acute cerebral ischemia which may also contribute to the increased incidence and clinical severity of ischemic stroke following infection. This may lead to therapeutic considerations of blocking intercellular adhesion molecules like P-selectin or the P-selectin glycoprotein ligand.