Dysregulation between TH1 and TH2 T cell subpopulations in the elderly.

We investigated the influence of zinc and its binding proteins on the immune system in 21 elderly and 20 young subjects. We detected a deficiency of zinc in the serum of the elderly. Albumin levels were within physiological range, but alpha 2-macroglobulin was significantly increased in the serum of elderly subjects. Using a whole blood assay, we found decreased production of interferon-gamma (IFN-gamma) and soluble interleukin-2 receptors (SIL-2R) in the elderly, whereas interleukin-10 (IL-10) production was greater than in the young controls. To exclude cellular defects, we measured lymphocyte subpopulations. In elderly subjects, we detected lower quantities of CD8+, CD8+/CD45RA+ and CD4+/CD45RO+ cells, but not CD4+ cells, than in young subjects. Other lymphocyte subpopulations were comparable for both groups. These findings suggest a dysregulation between TH1 cells and TH2 cells in the elderly, which may be a result of long-term zinc deficiency. Zinc reconstitution showed no beneficial effects as measured by T cell activity.