Age- and sex-associated differences in immune cell populations.

Aging is associated with the risk of increased infection severity and altered immune responses. In this study we investigated age- and sex-specific differences in immune cell composition in a subset of the population-based CoNAN study using a cross-sectional analysis. We identified a significant age × sex interaction in memory B cells and observed age-related declines in naive lymphocytes and an increase in CD8(+) effector memory T cells in men. Additionally, numbers of dendritic cell subpopulations decreased with age in both sexes. This study provides new insights into complex dependencies of the immune cell composition on age and sex (e.g., age × sex interaction effects) and could enhance our understanding of immune status variations among different ages. However, further studies are needed to assess the functional implications of these compositional differences.