Iron and Immunity

Abstract

Farthing, M. J. G. (Department of Gastroenterology, St Bartholomew's Hospital, London, ECIA 7BE, UK). Iron and immunity. Review of animal and human studies concerning the impact of iron deficiency on immune function in vivo indicates that in many instances there is no firm consensus of opinion as to the relationship between iron status and immunity. One major problem with almost all human studies is that other micro‐ and macronutrient deficiencies are inadequately controlled for and thus it is often unclear as to whether reported abnormalities of immune function can be attributed specifically to iron deficiency. Even when abnormalities of immune function have been detected it is often uncertain as to the biological and clinical relevance that these may have for the host. Within these restraints the available studies suggest that iron deficiency may at least contribute to impaired T lymphocyte function as judged by DTH responses in skin and impaired mitogen‐induced proliferation. As in protein energy malnutrition, humoral immunity is largely spared in humans, the balance of evidence suggesting that immunoglobulin production and function is normal, as are serum concentrations of complement. The only other abnormality of non‐specific immunity which has been reported consistently to be abnormal is that of reduced bactericidal activity of polymorphonuclear leucocytes. The clinical relevance of these abnormalities remains to be established. There is, however, no evidence to suggest that individuals with iron deficiency suffer the devastating infective complications of the well defined immunodeficiency syndromes either congenital or acquired. It seems likely therefore that despite the fundamental importance of iron in maintaining the integrity of immune function, humans can tolerate the extremes of deficiency and excess and survive in a relatively healthy state.

Nano-Fe as feed additive improves the hematological and immunological parameters of fish, Labeo rohita H.

“…Several reports showed that a deficiency of iron may contribute to several immunodeficiency syndromes such as impaired T cell functioning, atrophy in lymph organs, etc. in both humans and animals (Farthing 1989). In this study, no immune suppression was observed in all the treated groups.…”

“…The in vitro effects of magnetic iron oxide nanoparticles on dendritic cell activation (Goya et al 2008) and enhanced production of interleukins, cytokines, through intravenous administrations in rat (Chen et al 2011) support our findings. Iron deficiency also causes decreased myeloperoxidase activity, bactericidal activity, neutrophil functions and NBT reductions (Dhur et al 1989;Farthing 1989;Oppenheimer and Hendrickse 1983;Scrimshaw and San Giovanni 1997). However, alternative complement activity was not significantly influenced by dietary nano-Fe administration in Labeo rohita H. Similarly, in Atlantic salmon, specific hemolytic complement activities were not influenced by the administration of dietary iron sources (both organic and inorganic form) up to 20 weeks (Andersen et al 1998).…”

Altered Iron Metabolism in Children With Human Immunodeficiency Virus Disease

“…Although hepcidin was not measured in this study, levels of this recently identified regulator of iron metabolism are known to be elevated in inflammatory states, leading to decreased iron absorption [33], which may be the case in this sample. Because iron deficiency is linked to developmental delay, poor growth, and impaired immune function, it should be treated promptly, even before anemia develops [24,34,35]. It is important to note that, while a low hemoglobin would likely trigger investigation and treatment of anemia, iron deficiency often goes unnoticed as it is not identifiable on a routine blood count.…”

Micronutrient Supplementation and Infection: A Double-Edged Sword?

“…Twenty-eight percent of 153 Peruvian infants had elevated C-reactive protein concentrations or leucocytosis associated with elevated ferritin concentrations, resulting in an underestimation of iron deficiency by 12% (6). Impaired T-cell proliferation, impaired delayed-type hypersensitivity, and decreased bactericidal activity of polymorphonuclear leukocytes have been consistently reported in iron deficiency (7). Neutrophils and macrophages require iron for phagocytosis and for generation of toxic oxygen intermediates to kill bacteria.…”