Changes of peripheral lymphocyte subsets and cytokine environment during ageing and deteriorating gastrointestinal tract health status.

Human immune senescence accompanies with the physical and physiological frailty. The functional change and shift of NK, NKT and T cell subsets by ageing have been widely studied. However, it remains largely unclear how the ageing and disease conditions affect the distribution of lymphocytes. In the present study, 233 subjects with age range from 20 to 87 year old, including healthy people, people with chronic gastrointestinal tract disease or cancers were investigated. We found that the proportion of NK cells, CD8+ T cells and NKT cells remained relatively unchanged with ageing. However, NKG2D and CD16 expression level on NK cells decreased with ageing indicating impaired NK cell function. Surprisingly, the proportion of NK, NKT and T cells all declined with deteriorating health status from health to chronic gastrointestinal tract disease and cancer. Furthermore, cytokine and chemokine profiles changed with ageing, but did not vary with different health status. Our results highlight new evidence for a continuum of change during immunologic ageing and show unique data for variations of NK cells, CD8+ T cells, NKT cells, and cytokine microenvironment with human ageing and health status transformation.