Parainfluenza Virus (PIV)

In addition to SarsCov2, the main viral respiratory risks are associated with influenza viruses, respiratory syncytial virus (RSV), human metapneumovirus (hMPV) parainfluenza virus (PIV), adenovirus, rhinovirus, coronavirus and others. HMPV is a respiratory virus discovered in 2001. Like RSV, it appears to be a threat in terms of morbidity and mortality in susceptible populations. Overall, viral infections can cause significant functional decline in older patients, with 67% and 25% reported to be at least temporarily housebound or bedridden, respectively. Respiratory viral infections prevent older patients from functioning and performing their daily tasks. They therefore have a significant impact on the older patients and their families. In addition, respiratory viruses are key factors in the exacerbation of chronic diseases. The aims of this study are to provide a better understanding of the role of hMPV compared to common respiratory viruses on morbimortality, risk of dependency, quality of life alteration in older inpatients.

Bronchiolitis obliterans (BO) is the well-known manifestation of the chronic pulmonary graft-versus-host disease(GVHD) after allogeneic hematopoietic stem cell transplantation (HSCT). The pathophysiology of BO is, however, poorly known. The available data strongly support the role of respiratory viruses, in particular paramyxoviruses (parainfluenzae virus (PIV), respiratory syncytial virus, metapneumovirus). It is likely that the alloimmune response triggered by the respiratory virus is inadequate and leads to the peribronchiolar fibrotic process. The objective is to analyze the kinetics of profiles of the blood and respiratory host responses resulting from a high or low parainfluenza respiratory infection, in order to evaluate if the occurrence of a BO is associated with a specific signature We will evaluate the predictive signature of a BO after a parainfluenza virus infection by characterizing the differences between the patients evolving and those not evolving to a BO at 2 months after the infection.