Such a significant up-regulation of IFNAR on leukocytes in diseases commonly associated with P. aeruginosa infections (e.g., lung cancer, viral lower respiratory tract infections) (1, 2), prompted us to evaluate the role of type I IFNs in the regulation of antibacterial functions of neutrophils in the model of P. aeruginosa induced pneumonia. This evidence concerns the gene IFNAR1 and susceptibility to pneumonia measurement.