DEMONSTRATION OF RICKETTSIA-CONORII-INDUCED COAGULATIVE AND PLATELET ACTIVATION IN-VIVO IN PATIENTS WITH MEDITERRANEAN SPOTTED-FEVER

Endothelial injury in vivo induced by Rickettsia Conorii, the etiologi c agent of Mediterranean Spotted Fever (MSF) has been recently demonst rated. We sought to determine whether platelet and/or coagulative acti vation in vivo can be demonstrated in the acute phase of MSF, through measurements of a major metabolite of thromboxane (TX) in the urine (1 1-dehydro-TXB(2)) and of plasma prothrombin fragment 1+2, whose levels reflect activation of prothrombin to thrombin. Moreover, we measured plasma endothelin-1 as marker of endothelial dysfunction. Our results provide biochemical evidence for the occurrence of TXA(2)-dependent pl atelet activation and thrombin generation in vivo, together with endot helial dysfunction. These phenomena could account for clinical manifes tations of MSF, such as vasculitis and focal micro-thrombus formation. These results could also provide a rationale for testing the efficacy of aspirin or heparin in reducing the prothrombotic status of Rickett siae diseases.