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. 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.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.

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.

Inclusion Criteria:

• Patients with a clinical diagnosis of typical or atypical HUS in acute phase

Exclusion Criteria:

• Patient with positive serological screening test for infection with the HIV.
• Patients with a history of cancer.
• Patients who have undergone organ transplantation or bone marrow.
• Patient with a vivid picture of autoimmune thrombotic thrombocytopenic purpura