This prospective, multicenter, non-interventional trial aims to study the association between TTV viral load and the occurrence of rejection or infection during the first year after transplantation.

The TTV viral loads, taken once a month during the first year after the transplant, will be measured at the end of the study.

TTV (Torque Teno Virus) is a ubiquitous virus that is not associated with any disease. A correlation exists between the level of TTV replication and the subject's immunocompetence: weak or non-existent in immunocompetents, very high in immunocompromised patients. In heart transplant patients, pharmacological dosing of immunosuppressants prevents their toxic manifestations but is not correlated with individual immune competence. Only clinical manifestations of overdose (infections) or under dosage (rejections) currently allow optimization of immunosuppressants. A predictive biomarker of these clinical manifestations upstream of their appearance would revolutionize the management of these patients.

The TTV fulfills the conditions to be an ideal biomarker: classic blood sampling, possible follow-up in all patients, low cost, carrying out the analysis on already existing molecular biology platforms, reproducibility of inter- and intra-laboratory results, defined thresholds for the reliable interpretation of the results.

We believe that this marker will provide the clinician with a useful tool for the management of immunosuppressants and the patient with personalized medicine which will allow their management to be individualized. If this study confirms the expected results, then it will allow, secondly, the setting up of interventional studies to validate the TTV viral load as a biomarker, and a tool for piloting immunosuppressive treatment.

The TTV viral load of heart transplant patients will be follow during the first year after transplantation.

A tube of blood will be taken during the transplant and then once or twice a month.

Samples will be taken at the same time as those taken as part of standard care. The TTV viral load will be measured at the end of the study.

The occurrence of events of interest (infections and rejections) will be collected at each corresponding visit.

Inclusion Criteria:

• Age ≥18 years
• Heart transplant only
• First transplant
• Patient not having objected to carrying out the research
• Affiliated to a French Health Insurance system.

Exclusion Criteria:

• Patient transplanted from more than one solid organ
• Patient who has already been transplanted before
• Patient under guardianship or curatorship
• Patient under legal protection
• Pregnant or breastfeeding woman

Adult patients with first heart transplant

Individual participant data (IPD) that underlie results in publication could be shared. IPD detailed in the protocol of a planned metaanalysis could be shared

Two years after the last publication

Data sharing must be accepted by the sponsor and the PI based on a scientific project and scientific involvement of the PI team. Collaboration will be fostered. Data sharing must respect the agreements made with funders. Teams wishing obtain IPD must meet the sponsor and IP team to present scientific (and commercial) purpose, IPD needed, format of data transmission, and timeframe. Technical feasibility and financial support will be discussed before mandatory contractual agreement. Processing of shared data must comply with European General Data Protection Regulation (GDPR).