IL17A and infection: We then showed that repeated airway stimulation with intratracheal LPS instillations, mimicking repeated infections, in a mouse lung transplantation model augmented neutrophil and T cell recruitment, airway damage, and airway fibrosis in the context of alloimmunity; it also promoted persistent elevation of IL-17A and upregulation of IL-17RA, expressed on fibroblasts, myofibroblasts, and some immune cells.