Immune function is impaired in iron-deficient, homebound, older women.
BACKGROUND
Aging is often associated with a dysregulation of immune function. Iron deficiency may further impair immunity in older adults. Published reports on iron deficiency and immune response in humans are inconsistent. Most studies are focused on young children in developing countries and are often confounded by comorbid conditions, infections, and nutrient deficiencies.


OBJECTIVE
Our objective was to determine the relation of iron status with immune function in homebound older women, who often have impairments in both iron status and immune response. The subjects were selected according to rigorous exclusion criteria for disease, infection, and deficiencies in key nutrients known to affect immunocompetence.


METHODS
Seventy-two homebound elderly women provided blood for comprehensive evaluation of iron status and cell-mediated and innate immunity. Women were classified as iron-deficient or iron-sufficient on the basis of multiple abnormal iron status test results. Groups were compared with respect to lymphocyte subsets, phagocytosis, oxidative burst capacity, and T cell proliferation upon stimulation with mitogens.


RESULTS
In iron-deficient women, T cell proliferation upon stimulation with concanavalin A and phytohemagglutinin A was only 40-50% of that in iron-sufficient women. Phagocytosis did not differ significantly between the 2 groups, but respiratory burst was significantly less (by 28%) in iron-deficient women than in iron-sufficient women.


CONCLUSIONS
Iron deficiency is associated with impairments in cell-mediated and innate immunity and may render older adults more vulnerable to infections. Further prospective studies using similar exclusion criteria for disease, infection, and concomitant nutrient deficiencies are needed for simultaneous examination of the effects of iron deficiency on immune response and morbidity.
Department of Nutritional Sciences, The Pennsylvania State University, University Park, PA 16802, USA.
Namanjeet
N
Ahluwalia
Jianqin
J
Sun
Deanna
D
Krause
Andrea
A
Mastro
Gordon
G
Handte
D000368:Aged; D000375:Aging / Q000097:blood / Q000276:immunology* / Q000502:physiology; D003208:Concanavalin A / Q000494:pharmacology; D003677:Deficiency Diseases / Q000276:immunology*; D005260:Female; D006801:Humans; D007111:Immunity, Cellular / Q000276:immunology*; D007113:Immunity, Innate / Q000276:immunology*; D007121:Immunocompetence; D007501:Iron / Q000276:immunology; D000090463:Iron Deficiencies; D008213:Lymphocyte Activation; D008875:Middle Aged; D009752:Nutritional Status; D010587:Phagocytosis; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology
D003208:Concanavalin A; D007501:Iron