High circulating levels of tumor necrosis factor-alpha in centenarians are not associated with increased production in T lymphocytes.
BACKGROUND
Aging is characterized by increased inflammatory activity reflected by increased plasma levels of proinflammatory cytokines, concomitant with an altered cytokine profile of T lymphocytes. High plasma levels of tumor necrosis factor (TNF)-alpha are strongly associated with morbidity and mortality in elderly humans. However, the cellular source and mechanisms for the increased circulating TNF-alpha levels are unknown.


OBJECTIVE
The aim of the present study was to investigate if high plasma levels of TNF-alpha are associated with increased production of TNF-alpha by T lymphocytes in elderly humans.


METHODS
TNF-alpha production by CD4+ and CD8+ T lymphocytes was measured by flow cytometry following stimulation with phorbol 12-myristate 13-acetate and ionomycin in 28 young controls, 14, 81-year-olds and 25 centenarians.


RESULTS
Plasma levels of TNF-alpha increased with increasing age. An increased percentage and number of T lymphocytes from the 81 year olds expressed TNF-alpha, whereas centenarians did not show this altered TNF-alpha secretion profile.


CONCLUSIONS
T cells may contribute to the elevated levels of plasma TNF-alpha in healthy elderly subjects, whereas other mechanisms are responsible in very old individuals.
Sandmand
Marie
M
The Department of Infectious Diseases, Rigshospitalet, University of Copenhagen, Denmark.
Bruunsgaard
Helle
H
Kemp
Kåre
K
Andersen-Ranberg
Karen
K
Schroll
Marianne
M
Jeune
Bernard
B
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over / Q000502:physiology*; D005260:Female; D006801:Humans; D008213:Lymphocyte Activation / Q000187:drug effects* / Q000502:physiology; D008297:Male; D013601:T-Lymphocytes / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis*
D014409:Tumor Necrosis Factor-alpha