Zinc deficiency: changes in cytokine production and T-cell subpopulations in patients with head and neck cancer and in noncancer subjects.

Cell-mediated immune dysfunctions and susceptibility to infections have been observed in zinc-deficient human subjects. In this study, we investigated the production of cytokines and characterized the T-cell subpopulations in three groups of mildly zinc-deficient subjects. These included head and neck cancer patients, healthy volunteers who were found to have a dietary deficiency of zinc, and healthy volunteers in whom we induced zinc deficiency experimentally by dietary means. We used cellular zinc criteria for the diagnosis of zinc deficiency. We assayed enzyme-linked immunosorbent assay the production of cytokines from phytohemagglutinin-stimulated peripheral blood mononuclear cells and assessed by flow cytometry the differences in T-cell subpopulations. Our studies showed that the cytokines produced by TH1 cells were particularly sensitive to zinc status, inasmuch as the production of interleukin-2 (IL-2) and interferon-gamma were decreased even though the deficiency of zinc was mild in our subjects. TH2 cytokines (IL-4, IL-5, and IL-6) were not affected by zinc deficiency. Natural killer cell lytic activity also was decreased in zinc-deficient subjects. Recruitment of naive T cells (CD4+CD45 RA+) and CD8+ CD73+ CD11b-, precursors of cytolytic T cells, were decreased in mildly zinc-deficient subjects. An imbalance between the functions of TH1 and TH2 cells and changes in T-cell subpopulations are most probably responsible for cell-mediated immune dysfunctions in zinc deficiency.