The overall goal of HORUS study is to improve our understanding of the host-virus relationship of Cytomegalovirus within immunocompromised solid organ transplant recipients in order to propose both knowledge improvement, and clinical immune signatures for decreasing CMV infections/diseases incidence and avoiding the use of toxic antiviral therapy. HORUS' general goal is to enhance our knowledge on risk factors, disease progression and clinical outcomes by analyzing together immune host characteristics, viral characteristics and immunosuppressive drugs. The constitution of two clinical cohorts (The day 0 of graft cohort and the day 0 of infection cohort) will constitute the aim of HORUS study with clinical data collection and biocollection which will be used in the global HORUS project to identify immune profiles of patients integrating all the actors involved in viral control, viral and clinical parameters associated with a higher risk of CMV replication and an evolution toward a CMV difficult-to-treat disease.~HORUS cohorts is a project of biological samples biobank from solid organ transplant recipients in Hospitals : France (Bordeaux, Toulouse, Paris, Lyon), Spain (Barcelona), Tchequie (Karlova), Italy (Bologna), Switzerland (Lausanne).~Its main objective of this protocol is to collect, prepare, and store~under CRB conditions (NFS96900) longitudinal biological samples from solid organ transplants (heart, kidney, lung, liver), from day 0 of transplantation and followed for the occurrence of CMV infection.~Clinical and sociodemographic data associated with this longitudinal biocollection~The secondary objective is to support for the global HORUS project aiming at:~Studying the longitudinal clinical, viral and immunological profile of solid organ transplants after transplantation with or without CMV disease and if CMV disease with or without a difficult-to-treat (CMV persistence, relapse, antiviral drug resistance)~Defining signatures combining virological data, clinical data, donor/recipient data and immune profile of CMV-specific immunity to identify :i) patients at risk of developing CMV infection and ii) at day 0 of infection to identify patient at risk of developing difficult-to-treat CMV infection. The collection of biological samples, associated with the clinico-biological data, to find the global signature constitutes an indispensable step.
CMV disease remains the most frequent infectious complication post-transplant and it is associated to high morbidity and even mortality. Global efforts from both transplant physicians and researchers in the field is needed to better characterize the host-virus interactions in the transplant setting, with the aim of decreasing the burden of disease and improve the well-being of patients.~HORUS (Casting light on HOst-cytomegaloviRUs interaction in Solid organ transplantation) study is a European research project, funded by the European Commission (Horizon Europe) involving 16 partners in seven European countries (France, Spain, Czech Republic, Belgium, Switzerland, Germany and Italy) aiming to better characterize the host-CMV interactions in SOT recipients. The first aim of HORUS study will be to build a European cohort of SOT recipients including clinical characterization and the constitution of a biocollection, which is the aim of HORUS cohort, in order to perform biological, immunological, gene expression, viral kinetics and deep viral genome characterization in the global European HORUS project to improve our understanding of the development of a CMV immune response in the context of immunosuppression.