INFLUENCE OF ZINC SUPPLEMENTATION ON LYMPHOCYTE SUBSETS AND CELL-MEDIATED-IMMUNITY IN ZINC-DEFICIENT HEMODIALYSIS-PATIENTS

Infection is a major cause of morbidity and mortality in patients undergoing hemodialysis for end stage renal disease. Low plasma zinc levels have been associated with immunodepression in these patients. In a randomized, placebo controlled double-blind cross over study, plasma zinc levels, delayed hypersensivity to 7 Antigens (Merieux-Multitest), absolute lymphocyte counts, T- and B-lymphocytes, suppressor-T and helper T-cells and natural killer cells were studied in 25 hemodialysis patients before, during and after intravenous zinc supplementation for 8 weeks. The hemodialysis patients had significantly lower predialysis plasma zinc concentrations compared to 76 healthy controls (74 +/- 12 vs. 126 +/- 28 mcg/dl, p < 0.001). The plasma zinc concentrations increased to the normal range during the treatment period. Lymphocyte subtype analysis showed a significant decrease of suppressor-T cells and an increase of the helper-T/suppressor-T ratio (2.09 +/- 0.26 vs. 3.18 +/- 0.48, p < 0.05) after zinc supplementation. Delayed hypersensivity to intradermal antigens increased significantly only after zinc treatment (2.0 +/- 0.7 vs. 5.8 +/- 1.7, p < 0.05), not after placebo. The changes were reversible after finishing the zinc treatment. It is concluded, that plasma zinc levels are reduced in hemodialysis patients and that the substitution of zinc restores some of the depressed immune functions in these patients.