Journal of Clinical Immunology

, Volume 20, Issue 4, pp 250–256

Thymic Involution in Aging

  • Richard Aspinall
  • Deborah Andrew

DOI: 10.1023/A:1006611518223

Cite this article as:
Aspinall, R. & Andrew, D. J Clin Immunol (2000) 20: 250. doi:10.1023/A:1006611518223


The size of the na¨ıve T-cell pool is governed by output from the thymus and not by replication. This pool contributes cells to the activated/memory T-cell pool whose size can be increased through cell multiplication; both pools together constitute the peripheral T-cell pool. Aging is associated with involution of the thymus leading to a reduction in its contribution to the na¨ıve T-cell pool; however, despite this diminished thymic output, there is no significant decline in the total number of T cells in the peripheral T-cell pool. There are, however, considerable shifts in the ratios of both pools of cells, with an increase in the number of activated/memory T cells and the accumulation in older individuals of cells that fail to respond to stimuli as efficiently as T cells from younger individuals. Aging is also associated with a greater susceptibility to some infections and some cancers. An understanding of the causal mechanism of thymic involution could lead to the design of a rational therapy to reverse the loss of thymic tissue, renew thymic function, increase thymic output, and potentially improve immune function in aged individuals.

Thymus atrophy aging involution transgenic mice IL-7 

Copyright information

© Plenum Publishing Corporation 2000

Authors and Affiliations

  • Richard Aspinall
    • 1
  • Deborah Andrew
    • 1
  1. 1.Department of ImmunologyICSTM at Chelsea and Westminster HospitalLondonEngland

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