The effect of sex on immune cells in healthy aging: Elderly women have more robust natural killer lymphocytes than do elderly men

Immune gender differences have been reported, but are little studied in elderly humans. We compared monocyte and lymphocyte subsets, along with soluble immune mediators in healthy men and women over the age of 70. We also measured natural killer (NK) lymphocyte cytotoxic granule exocytosis, chemokine synthesis, and cytokine synthesis in response to a variety of stimuli. Elderly women had significantly more circulating B cells than men, whereas men had more CD4 central memory T cells and higher monocyte levels. Plasma adiponectin levels were higher in women, plasma retinol-binding protein 4 levels were higher in men, but there were no significant gender differences in C-reactive protein, IL-15, or sphingosine-1-phosphate. Women had a higher ratio of immature CD56(bright) NK cells to mature CD56(dim) NK cells, indicating a gender difference in NK cell maturation in the elderly. Comparing sexes, female mature NK cells had more vigorous cytotoxic granule responses to K562 leukemia cells and IFN-gamma responses to NKp46 crosslinking. Moreover, female NK cells were more likely to produce MIP-1 beta in response to a variety of stimuli. These data show that gender influences NI( cell activity in elderly humans. (C) 2016 Elsevier Ireland Ltd. All rights reserved.