Unravelling the role of Pneumocystis jirovecii in utero infection in early and late pulmonary diseases of very preterm infants.

Very preterm birth represent about 1% of livebirths in Europe each year and is associated with 58% of neonatal deaths and substantial lifetime health problems.

Pneumocystis jirovecii is an ubiquitous microfungus commonly known for causing a severe interstitialpneumonia in immunosuppressed subjects.

However, this could be the tip of the iceberg and compelling new evidences suggest thatthis infection may be pathogenic to certain groups of infants.In utero transmission of P. jirovecii in humans has been recently proven.

The fungus has been found in the lungs of 14-25%preterm newborns, associated with an increased risk of respiratory distress syndrome (RDS) and bronchopulmonary dysplasia.

Theability of P. jirovecii to change the pulmonary environment has been demonstrated in other contexts, inducing a modification of thehost immune response, pulmonary dysbiosis and thickening of pulmonary alveoli.

Genetic polymorphisms have also beenindependently implicated in both an increased risk of preterm bi or neonatal RDS and a susceptibility to P. jirovecii.Hence, JIROborn aims to address the impact of P. jirovecii in utero infection on the preterm infants lungs alteration and on thedevelopment of subsequent early or late diseases, constructing a predictive model for monitoring preterm infants relatedpulmonary complications.JIROborn is a nested case control study using a prospective cohort of 596 infected and uninfected preterm infants and their mothers.First, the clinical impact of P. jirovecii infection will be evaluated for early and later lung complications.

Then, biological effects of theinfection will be studied focusing on the immune parameters, the microbiota and on surfactant and mucus production.

Genetic andepigenetic susceptibilities to P. jirovecii colonization and/or to the development of pulmonary diseases will be evaluated.

Finally, alldata will be analysed to build a predictive model for the monitoring of preterm infants pulmonary complications.