title: Cytokine production and lymphocyte subpopulations in aged humans. An assessment during nocturnal sleep.
abstract: The view of a general impairment of immune functions associated with aging has been challenged by recent studies including a more detailed evaluation of various cytokines and lymphocyte subsets. In the present human study, effects of age on the production of cytokines by T cells and monocytes were assessed, together with age-dependent changes in subset populations of mononuclear cells (MNC). Blood was collected every 30 min during nocturnal sleep in 16 aged (mean: 79.6 +/- 7.5 years) and in 16 young controls (mean: 24.6 +/- 3.1 years). Nocturnal sleep was chosen as a well-defined period within the 24-h cycle with minimal exogenous influences. The in vitro production of interleukin-1 beta (IL-1 beta) and tumor necrosis factor-alpha (TNF-alpha) was measured after mitogen stimulation with lipopolisaccharide from E. coli (LPS). Production of interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) was measured after stimulation with phytohemagglutinin (PHA). Regarding MNC subsets, monocytes, lymphocytes, CD3+, CD4+, CD8+, HLA-DR, CD16+, CD25+, and CD19+ were determined. Advanced age was associated with a decreased number of T cells (CD3+) and decreases in the major T cell subsets (CD4+, CD8+, P < 0.001). Production of IL-2 was not affected. However, production of IFN-gamma tended to be enhanced, and numbers of activated T cells (HLA-DR/CD3+), natural killer cells (CD16+), and T cells expressing IL-2 receptors (CD25+/CD3+) were markedly increased in the aged. While monocyte counts were unchanged in the elderly production of IL-1 beta and TNF-alpha mainly derived from these cells, was enhanced (p < 0.05). Results indicate a state of enhanced responsiveness of the T cell compartment and of monocytes in aged which may compensate for the substantial decrease in T cells.
authors.affiliation: Clinical Neuroendocrinology, University of Lübeck, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Born
authors.forename: D
authors.initials: D
authors.lastname: Uthgenannt
authors.forename: C
authors.initials: C
authors.lastname: Dodt
authors.forename: D
authors.initials: D
authors.lastname: Nünninghoff
authors.forename: E
authors.initials: E
authors.lastname: Ringvolt
authors.forename: T
authors.initials: T
authors.lastname: Wagner
authors.forename: H L
authors.initials: HL
authors.lastname: Fehm
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000097:blood*; D002940:Circadian Rhythm / Q000502:physiology*; D016207:Cytokines / Q000096:biosynthesis*; D005069:Evaluation Studies as Topic; D005260:Female; D006403:Hematologic Tests; D006801:Humans; D016131:Lymphocyte Subsets / Q000378:metabolism*; D008297:Male; D012016:Reference Values; D012890:Sleep / Q000502:physiology*
chemical_list: D016207:Cytokines