Hepatitis E is a worldwide disease. It is the leading or second leading cause of acute hepatitis in adults in developing countries from sub-Saharan Africa or Southeast Asia, where it is hyperendemic and principally water-borne. In industrialised western countries, hepatitis E was until recently considered as imported from hyperendemic geographical areas, but is currently an emerging autochthonous infectious disease. A growing body of data from Europe, America, Australia, and Asia strongly indicate that pigs represent a major Hepatitis E Virus (HEV) reservoir and might be a source of zoonotic transmission to humans through direct or indirect exposure. Hepatitis E typically causes self-limited acute infection. However, the overall death rate is 1-4%, and it can reach 20% in pregnant women and might be still higher in patients with underlying chronic liver disease. To date, no preventive or curative treatment of hepatitis E is available.

Therefore, the major goal of the study is to analyse for the first time the host responses in kidney-transplant recipients with chronic HEV infection and to compare them to the host responses in kidney-transplant recipients without viral infection (controls), to identify a specific peripheral signature using blood microarray-based gene expression profiling.

Other minor goals are :

1. to assess the incidence of HEV infection in kidney-transplant recipients from south-eastern France, to study the risk factors, and to describe the clinical features and outcomes of chronic HEV infection in kidney-transplant recipients,
2. to compare the peripheral signature to a liver signature in the cases where a liver biopsy is available. If peripheral and liver signatures are parallel, peripheral signature may become a non-invasive tool of exploration of chronic HEV infection in kidney-transplant recipients.

Inclusion Criteria:

• Age > 18 years
• Transplanted by a functional kidney
• affected by a hepatitis E chronic
• Benefiting from a follow-up in the Center of Nephrology and renal Transplantation or in the service of Hépato-gastro-entérologie of the CHU The Conception in Marseille
• Having signed a consent informed about participation in the study

Exclusion Criteria:

• Affected by another sharp or chronic viral infection