Iron and infection

Area of Science:

• Microbiology
• Immunology
• Hematology

Background:

• Iron is a vital nutrient for microbial survival and proliferation.
• Host defense mechanisms have evolved to limit iron availability to pathogens.
• Dysregulation of iron homeostasis can compromise host immunity.

Purpose of the Study:

• To review host mechanisms for restricting iron during infection.
• To examine how iron overload disorders affect infection susceptibility.
• To explain the pathogenesis of anemia of inflammation.

Main Methods:

• Literature review of host-pathogen iron interactions.
• Analysis of iron restriction strategies at mucosal surfaces, in plasma, and within macrophages.
• Examination of the impact of iron overload and inflammation on host defense.

Main Results:

• Infections activate mechanisms to sequester iron in various body compartments.
• Iron overload disorders (e.g., hereditary hemochromatosis, β-thalassemia) impair iron restriction, increasing infection risk.
• Anemia of inflammation results from inflammatory cytokines affecting erythrocyte lifespan, leukocyte production, and iron metabolism via hepcidin.

Conclusions:

• Host iron restriction is a critical antimicrobial defense.
• Impaired iron homeostasis due to overload or inflammation exacerbates infection susceptibility.
• Anemia of inflammation is an unintended consequence of the immune response impacting iron availability and red blood cell turnover.