TY  - JOUR
A1  - Zlamy, Manuela
A1  - Almanzar, Giovanni
A1  - Parson, Walther
A1  - Schmidt, Christian
A1  - Leierer, Johannes
A1  - Weinberger, Birgit
A1  - Jeller, Verena
A1  - Unsinn, Karin
A1  - Eyrich, Matthias
A1  - Würzner, Reinhard
A1  - Prelog, Martina
T1  - Efforts of the human immune system to maintain the peripheral CD8+ T cell compartment after childhood thymectomy
JF  - Immunity & Ageing
N2  - Background
Homeostatic mechanisms to maintain the T cell compartment diversity indicate an ongoing process of thymic activity and peripheral T cell renewal during human life. These processes are expected to be accelerated after childhood thymectomy and by the influence of cytomegalovirus (CMV) inducing a prematurely aged immune system.

The study aimed to investigate proportional changes and replicative history of CD8+ T cells, of recent thymic emigrants (RTEs) and CD103+ T cells (mostly gut-experienced) and the role of Interleukin-(IL)-7 and IL-7 receptor (CD127)-expressing T cells in thymectomized patients compared to young and old healthy controls.

Results
Decreased proportions of naive and CD31 + CD8+ T cells were demonstrated after thymectomy, with higher proliferative activity of CD127-expressing T cells and significantly shorter relative telomere lengths (RTLs) and lower T cell receptor excision circles (TRECs). Increased circulating CD103+ T cells and a skewed T cell receptor (TCR) repertoire were found after thymectomy similar to elderly persons. Naive T cells were influenced by age at thymectomy and further decreased by CMV.

Conclusions
After childhood thymectomy, the immune system demonstrated constant efforts of the peripheral CD8+ T cell compartment to maintain homeostasis. Supposedly it tries to fill the void of RTEs by peripheral T cell proliferation, by at least partly IL-7-mediated mechanisms and by proportional increase of circulating CD103+ T cells, reminiscent of immune aging in elderly. Although other findings were less significant compared to healthy elderly, early thymectomy demonstrated immunological alterations of CD8+ T cells which mimic features of premature immunosenescence in humans.
KW  - thymectomy
KW  - naive T cells
KW  - TRECs
KW  - TCR diversity
KW  - CMV
KW  - CD8
KW  - telomeres
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-146497
VL  - 13
IS  - 3
ER  -