Immune response to influenza vaccine in healthy elderly: lack of association with plasma beta-carotene, retinol, alpha-tocopherol, or zinc.

Immunity and nutritional status are compromised with age, yet the relationship between them is unclear. Immune responses and plasma micronutrient levels of 61 healthy elderly (mean 81 years) and 27 young (mean 27 years) were assessed before and after immunization with trivalent influenza vaccine (FLU). FLU-induced proliferation and IFN-gamma levels of elderly were lower than young before and after immunization.

Effects of N-(4-hydroxyphenyl)-retinamide on the number and cytotoxicity of natural killer cells in vitamin-A-sufficient and -deficient rats.

N-(4-hydroxyphenyl)retinamide (4-HPR), a synthetic retinoid with anticarcinogenic activity, has been shown to lower the plasma retinol level rapidly and significantly. We reported previously that vitamin A-deficient rats (plasma retinol < 0.175 mumol/l) have a low number of natural killer (NK) cells in peripheral blood.