Age-related changes in the cellular composition of the thymus in children - 18/08/11
Rotterdam, The Netherlands
Abstract |
Background |
T-cell development in the thymus is an extensively studied subject, mainly in mice. Nevertheless, the normal composition and cell numbers of the noninvoluted human thymus are largely unknown.
Objective |
We aimed to gain insight into age-related changes in different thymic subpopulations and to provide reference values for the distribution of thymocyte subsets. The composition of the normal thymus may serve as a reference for thymi in pathological conditions and may aid diagnoses of immunodeficiency diseases.
Methods |
Thymic lobes of 70 children (58 immunologically normal and 12 diseased), ranging in age from 8 days to 8 years old, were studied by 4-color flow-cytometric analysis. Detailed staining and gating strategies allowed us to dissect small subsets, including immature CD4−CD8− populations and thymic B, natural killer, and T-cell receptor γδ+ cells.
Results |
We demonstrate that distribution of thymocyte subsets changes with age and correlates with age-related fluctuations of T-lymphocyte counts in peripheral blood. Thymi of children 3 to 6 months old appear to be the most active: they have high numbers of total thymocytes, the highest percentage of double-positive cells, and large numbers of CD34+ progenitors in their thymi. Furthermore, we show that the human thymus is a site for B-cell development, because all B-cell progenitor stages that can be found in the bone marrow are also present in the thymus.
Conclusion |
We conclude that T-cell development in children is a dynamic process, answering the demands of a maturing and expanding immune system.
Le texte complet de cet article est disponible en PDF.Key words : Thymus, thymocyte development, childhood, T lymphocytes, B lymphocytes, NK cells, Down syndrome, Williams syndrome
Abbreviations used : APC, DN, DP, FITC, ISP, NK, SP, TCR
Plan
Mr de Haas was supported by a grant from the Netherlands Organization for Scientific Research-Stigon. Ms Naber was supported by a grant from the Dutch Heart Foundation. |
Vol 115 - N° 4
P. 834-840 - avril 2005 Retour au numéroBienvenue sur EM-consulte, la référence des professionnels de santé.
L’accès au texte intégral de cet article nécessite un abonnement.
Déjà abonné à cette revue ?