[Iron and susceptibility to infections].

Iron is essential for proper functioning of the host immune system as well as an essential nutrient for growth of various pathogens. Iron deficiency increases infection susceptibility, specially those due to intracellular pathogens. At the opposite, excess iron stores could increase the virulence of some pathogens. Hepcidin synthesis is increased during the acute inflammation phase; leading to decreased iron intestinal absorption and retention of the metal within macrophages. This is considered to result from a defense mechanism of the child to limit the availability of iron for extracellular pathogens. On the other hand, iron affect innate immune responses by influencing IFN-γ or NF-kB pathways in macrophages. Consequently, iron enhances host resistance to intracellular pathogens but excess iron may alter immune system.