Clinical observations link respiratory virus infection and P. aeruginosa colonization to disease progression in CF patients. Given that type I and III Interferons (IFN) exert protective antiviral but also deleterious effects, it is very important to delineate specific IFN signatures in CF patients. The project aims to better understand the dynamics between bacteria and viruses in CF patients and to ascertain whether virus– bacteria coinfection compromise the IFN response. The researchers will examine a large series of respiratory samples – up to 1800 – from CF patients. On these samples, the researchers will investigate the simultaneous presence of bacteria and viruses, and from the cells of the same samples they will analyze the expression of the Interferon genes. The collected data are to be correlated with the clinical status of patients. The project aims to identify the patients at risk of developing serious respiratory complications, based on the IFN response profile and bacterial/viral coinfections. Furthermore, identification of IFN genes could be a potential target for the development of new therapeutic approaches.