Leukocyte production of IFN-γ and TNF-α in 8- to 12-y-old children with low serum iron levels

• Low serum iron (LSI) was present in 17.5% of 8- to 12-y-old children in our sample.
• Leukocyte numbers were significantly increased in children from the LSI group.
• Neutrophil frequency and numbers were increased in the LSI group; lymphocyte frequency was reduced.
• Interferon (IFN)-γ serum concentrations and production by peripheral blood mononuclear cells were reduced in the LSI group.
• LSI correlates with decreased production of IFN-γ and altered leukocyte populations.

ObjectiveIron deficiency is likely the most common nutritional deficiency worldwide; low iron concentrations have been related to alterations in immune system functions; therefore, the aim of this study was to determine the effect of low serum iron (LSI) concentrations on the production of proinflammatory cytokines by peripheral blood leukocytes in 8- to 12-y-old children from a local community.MethodsWe obtained 120 blood samples and determined full blood counts and serum iron concentrations. An LSI and a control group, paired by age and sex were established using serum iron <60 μg/dL as the cutoff point. Ferritin and C-reactive protein concentrations were quantified. Serum interferon (IFN)-γ and tumor necrosis factor (TNF)-α concentrations were measured in these groups by enzyme-linked immunosorbent assay. A second blood sample was taken from children in both groups to isolate peripheral blood mononuclear cells (PBMCs) and measure IFN-γ and TNF-α production by unstimulated and lipopolysaccharide/phorbol myristate acetate/ionomycin-stimulated leukocytes in vitro.ResultsOf the participants in the present study, 17.5% (21 children) presented LSI, as well as decreased ferritin concentrations. Differential counts from total blood samples showed a significant increase in leukocyte numbers in the LSI group, along with increased neutrophil frequencies and numbers but decreased lymphocyte frequencies. Decreased serum IFN-γ concentrations and decreased in vitro production of IFN-γ by PBMCs were found in the LSI group.ConclusionsThe results of the present study suggest that low iron levels alter leukocyte subpopulations in circulation and have a detrimental effect on leukocyte production of proinflammatory cytokines after an antigenic challenge.