Age-Related Changes in CCR9 super(+) Circulating Lymphocytes: Are CCR9 super(+) Naive T Cells Recent Thymic Emigrants?

The chemokine receptor CCR9 is reported to be predominantly expressed by thymocytes as well as by circulating gut-homing and resident T cells in the small intestinal mucosa. Its ligand thymus-expressed chemokine (TECK) is produced by thymic and small intestinal epithelium. Here we report that the pr...

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Bibliographic Details
Published in:Scandinavian journal of immunology 2001-11, Vol.54 (5), p.435-439
Main Authors: Olaussen, R W, Farstad, IN, Brandtzaeg, P, Rugtveit, J
Format: Article
Language:English
Subjects:
CCR9 protein
Human immunodeficiency virus
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Summary:The chemokine receptor CCR9 is reported to be predominantly expressed by thymocytes as well as by circulating gut-homing and resident T cells in the small intestinal mucosa. Its ligand thymus-expressed chemokine (TECK) is produced by thymic and small intestinal epithelium. Here we report that the proportion of circulating CCR9 super(+) naive T cells (mostly CD4 super(+)) declines with age, from approximately 15% of all T cells at birth to around 1% in adults. The proportion of CCR9 super(+) T cells lacking the classical gut-homing receptor alpha 4 beta 7, was much higher in children than in adults. Therefore, circulating CD3 super(+)CCR9 super(+)CD45RA super(+) cells have most likely left the thymus quite recently. This notion was supported by the small number of CCR9 super(+) naive T cells which was present shortly after thymectomy. Establishing a phenotypic marker for recent thymic emigrants might provide a powerful tool in the clinical assessment and follow-up after cancer chemotherapy, hematopoietic stem cell transplantation, and during antiretroviral treatment of human immunodeficiency virus (HIV)-infected patients.
ISSN:0300-9475
DOI:10.1046/j.1365-3083.2001.01008.x