Study of 'Vascular Competence' Profile and Endothelial Activation in the Hemolytic Uremic Syndrome in Children and Adults

The Hemolytic Uremic Syndrome (HUS) is a rare thrombotic microangiopathy (TMA), affecting both children and adults. HUS is characterized by the abnormal occurrence of diffuse thrombosis in the microcirculation resulting in the occurrence of ischemic events affecting especially the kidneys and is associated with hemolytic anemia.Its prognosis is severe, with a mortality of 1% in children, 10% in adults and the occurrence of renal failure in 50% of cases.In its typical form, HUS occurs in the aftermath of a diarrheic intestinal infection by bacteria which produce a Shiga toxin. In its unusual shape, which affects both children and adults, there are genetic abnormalities alternate way of regulating complement proteins explaining frequent relapses.One of the major problems encountered in the management of HUS is the absence of reliable marker of treatment response or relapse; conventional hematological markers being too insensitive to judge therapeutic efficacy or identify early relapse. Data from the literature suggest that the endothelial cell is a major target of this syndrome. Our hypothesis is that an initial micro-endothelial activation plays a critical role in the initiation and / or relapse of the disease through the sudden release of high molecular weight ultralarge von Willebrand factor (UL-vWHf) and procoagulant endothelial microparticles.The main objective of this study is to define a "vascular competence" profile in a population of patients with typical or atypical HUS; both in the acute phase and in remission of the disease.