Effect of age on the gastrointestinalassociated mucosal immune response of humans

Age-related changes in gastrointestinal-associated mucosal immune response have not been well studied. Thus, we investigated the effect of age on this response and compared these re-sponses to those of peripheral immune cells. Saliva, blood, and intestinal biopsies were collected from young and old healthy subjects to determine immunoglobulin (Ig) levels and to isolate pe-ripheral blood mononuclear cells, intraepithelial lymphocytes (IELs), and lamina propria lym-phocytes (LPLs). Although subject age did not influence the level of total IgA found in saliva, IgA levels in serum increased ( p.05) with age. Older subjects ’ peripheral blood mononuclear cell proliferation and IL-2 production were significantly lower than those of young subjects. LPLs from older subjects produced significantly less IL-2 in response to all stimuli than did that from the young. IEL’s ability to proliferate and produce IL-2 was not affected by subject age. Thus, LPL but not IEL demonstrated an age-related decline in immune function similar to that seen in peripheral lymphocytes. HE well documented age-associated decline in the sys-temic immune response (1) contributes to decreased re