Peripheral blood mononuclear cells produce cytokines [eg, ILs and tumor necrosis factor (TNF)- ] that assist in the activation of T cells and enhance NK cell activity (51). Supplementation with vitamins C and E results in a transient increase in cytokine production (61). Vitamin C (1 g ascorbic acid), vitamin E (400 mg all-rac- -tocopheryl acetate), vitamins C and E, or placebo were provided for 28 d as part of a randomized trial. On day 14, the combination of vitamins C and E increased IL-1ß and TNF- production 1.8- and 1.5-fold, respectively; small increases were also detected with vitamin E, but vitamin C alone had no effect. However, by day 28, there was no difference in response among the supplement and placebo groups. Other cytokines not measured in this study may be influenced by sustained vitamin supplementation to modulate immune balance, resulting in the transient changes in IL-1ß and TNF- that were observed (61).