Immune response in relation to zinc status, sex and antioxidant defence in Italian elderly population: the ZENITH study

Abstract

Evaluation of some immune markers in Italian elderly population in relation to zinc status, gender and antioxidant defence. Observational study. Italian population. Apparently healthy, free-living subjects, 56 men and 52 women, aged 70-85 y, enrolled in Italy. Lymphocytes were unstimulated or stimulated with the mitogen phytohemoagglutinin (PHA). The proliferative capacity was measured as incorporation of [3H]-thymidine and reported as stimulation index (SI). Cytokine secretion by lymphocytes was determined by ELISA. The antioxidant enzyme activities were measured using commercial kits. Dietary zinc intake, as well as zinc in serum, red blood cells and urine were on the normal range of values and did not show any difference between men and women. The proliferative response showed a high variability without significant differences between men and women. The amount of secreted pro- and anti-inflammatory cytokines was similar in men and women. No differences were found in the activity of antioxidant enzymes in lymphocytes, namely superoxide dismutase, glutathione peroxidase and catalase, between men and women. An association between SI and serum zinc level in men was found. SI resulted negatively correlated with interleukin (IL)-1beta (R2 = 0.036 and P = 0.012) and IL-10 (R2 = 0.34 and P = 0.040) only in men. IL-10 of PHA-stimulated lymphocytes was negatively correlated with red blood zinc in men (R2 = 0.41 and P = 0.008), while IL-10 of unstimulated and PHA-stimulated lymphocytes were negatively correlated with serum zinc in women (R2 = 0.38 and P = 0.020; R2 = 0.31 and P = 0.040, respectively). No correlation was observed between immune markers and antioxidant enzyme activities. Only weak differences on immune response between men and women were observed. However, zinc status appears to have more influence on the ability of lymphocytes to proliferate in men than in women.