Research

Direct analysis of thymic function in children with Down's syndrome

Nicole Prada^1* , Milena Nasi^2* , Leonarda Troiano² , Erika Roat² , Marcello Pinti² , Elisa Nemes² , Enrico Lugli² , Roberta Ferraresi² , Luigi Ciacci³ , Davide Bertoni³ , Ornella Biagioni⁴ , Milena Gibertoni⁴ , Cristina Cornia⁴ , Liviana Meschiari⁴ , Elisabetta Gramazio⁴ , Mauro Mariotti⁴ , Ugo Consolo³ , Fiorella Balli⁵ and Andrea Cossarizza²

¹  Dipartimento di Biopatologia e Metodologie Biomediche, Università di Palermo, via Tukory 211, 90134 Palermo, Italy

²  Cattedra di Immunologia, Dipartimento di Scienze Biomediche, Università di Modena e Reggio Emilia, via Campi 287, 41100 Modena, Italy

³  Clinica Odontoiatrica, Università di Modena e Reggio Emilia, via del Pozzo 71, 41100 Modena, Italy

⁴  Servizio di Neuropsichiatria Infantile, AUSL Modena, via Cardarelli 45, 41100 Modena, Italy

⁵  Clinica Pediatrica, Università di Modena e Reggio Emilia, via del Pozzo 71, 41100 Modena, Italy

author email corresponding author email* Contributed equally

Immunity & Ageing 2005, 2:4doi:10.1186/1742-4933-2-4

Published:	16 February 2005

Abstract

Background

Down's syndrome (DS) is characterized by several immunological defects, especially regarding T cell compartment. DS is considered the best example of accelerated ageing in humans. Direct observations of the thymus have shown that in DS this organ undergoes severe histological and morphological changes. However, no data on its capacity to generate T cells are present in the literature. Here, using a new technology based upon real time PCR, we have investigated the capacity of the thymus to produce and release newly generated T lymphocytes (the so called "recent thymic emigrants", RTE) in children with DS.

Methods

We studied 8 children affected by DS, aged 2–7 years, compared with 8 age- and sex-matched healthy controls. Flow cytometry was used to determine different lymphocytes subsets. Real time PCR with the Taqman system was used to quantify the amount of RTE, i.e. peripheral blood lymphocytes that express the T cell receptor rearrangement excision circles (TREC).

Results

In comparison with control children, those with DS had a significant lower number of TREC+ peripheral blood cells. Moreover, in DS children but not in controls, a strong negative correlation between age and the levels of TREC+ cells was found.

Conclusions

The direct measure of thymic output indicates that the impairment of the organ results in a reduced production of newly generated T cells. This observation could suggest that cytokines able to modulate thymic function, such as interleukins, could be useful to improve the functionality of the organ and to treat the immunodeficiency present in DS subjects.