Iron in respiratory immunity and infection

Iron is essential for the survival of both humans and pathogens, creating intense competition for the metal during infection. Whilst hosts seek to restrict access to iron via nutritional immunity, microbes including bacteria, viruses, and fungi have adapted unique mechanisms to acquire it. The lungs function as a key battleground in this contest, with local iron homeostasis mediated by tissue-resident alveolar macrophages. Systemic iron status-either overload or deficiency-also dictates the efficacy of innate and adaptive immunity, thus directly influencing the outcomes of respiratory disease. This review will examine our current understanding of the host-iron-pathogen axis in the lung, as well as consider how it could be exploited to improve health outcomes in respiratory infection.