Objective: To determine effects of vitamin A, zinc and iron deficiency in Indonesian infants on the ability to produce immunoregulatory cytokines.
Design, setting and subjects: Immunological assessment was done in 59 infants participating in a cross-sectional nutritional survey in rural West Java, Indonesia. Production of T-helper cell type-1 (Th1, cell-mediated) cytokines interferon-gamma (IFN-gamma), interleukin-12 (IL-12), interleukin-18 (IL-18) and T-helper cell type-2 (Th2, humoral) cytokine interleukin-6 (IL-6) were measured after stimulation with lipopolysaccharide and phytohemagglutinin in an ex vivo whole blood culture system. Circulating neopterin concentrations were determined as an indicator of in vivo macrophage activity.
Results: Of the infants, 48% were vitamin A deficient, 44% were anemic (with 17% having iron deficiency anemia), and 17% were zinc deficient. Vitamin-A deficient infants had significantly reduced ex vivo production of IFN-gamma, but also significantly higher circulating neopterin concentrations. Production of IFN-gamma and IL-12 were strongly correlated, IFN-gamma and IL-18 production were not. Zinc deficiency was accompanied by significantly reduced white blood cell counts and reduced ex vivo production of IL-6. Iron status was not related to cytokine production.
Conclusions: This study shows that in vitamin A deficiency there is Th1 dominance in a steady state, combined however with impairment of the Th1 response after stimulation, whereas in zinc deficiency, there is a decreased Th2 response. Overall, vitamin A deficiency and zinc deficiency have marked albeit different effects on the immunocompetence of infants, affecting both cell-mediated and humoral components of the immune system.