Direct analysis of thymic function in children with Down's syndrome.
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.
Prada
Nicole
N
Dipartimento di Biopatologia e Metodologie Biomediche, Università di Palermo, via Tukory 211, 90134 Palermo, Italy.
Nasi
Milena
M
Cattedra di Immunologia, Dipartimento di Scienze Biomediche, Università di Modena e Reggio Emilia, via Campi 287, 41100 Modena, Italy.
Troiano
Leonarda
L
Cattedra di Immunologia, Dipartimento di Scienze Biomediche, Università di Modena e Reggio Emilia, via Campi 287, 41100 Modena, Italy.
Roat
Erika
E
Cattedra di Immunologia, Dipartimento di Scienze Biomediche, Università di Modena e Reggio Emilia, via Campi 287, 41100 Modena, Italy.
Pinti
Marcello
M
Cattedra di Immunologia, Dipartimento di Scienze Biomediche, Università di Modena e Reggio Emilia, via Campi 287, 41100 Modena, Italy.
Nemes
Elisa
E
Cattedra di Immunologia, Dipartimento di Scienze Biomediche, Università di Modena e Reggio Emilia, via Campi 287, 41100 Modena, Italy.
Lugli
Enrico
E
Cattedra di Immunologia, Dipartimento di Scienze Biomediche, Università di Modena e Reggio Emilia, via Campi 287, 41100 Modena, Italy.
Ferraresi
Roberta
R
Cattedra di Immunologia, Dipartimento di Scienze Biomediche, Università di Modena e Reggio Emilia, via Campi 287, 41100 Modena, Italy.
Ciacci
Luigi
L
Clinica Odontoiatrica, Università di Modena e Reggio Emilia, via del Pozzo 71, 41100 Modena, Italy.
Bertoni
Davide
D
Clinica Odontoiatrica, Università di Modena e Reggio Emilia, via del Pozzo 71, 41100 Modena, Italy.
Biagioni
Ornella
O
Servizio di Neuropsichiatria Infantile, AUSL Modena, via Cardarelli 45, 41100 Modena, Italy.
Gibertoni
Milena
M
Servizio di Neuropsichiatria Infantile, AUSL Modena, via Cardarelli 45, 41100 Modena, Italy.
Cornia
Cristina
C
Servizio di Neuropsichiatria Infantile, AUSL Modena, via Cardarelli 45, 41100 Modena, Italy.
Meschiari
Liviana
L
Servizio di Neuropsichiatria Infantile, AUSL Modena, via Cardarelli 45, 41100 Modena, Italy.
Gramazio
Elisabetta
E
Servizio di Neuropsichiatria Infantile, AUSL Modena, via Cardarelli 45, 41100 Modena, Italy.
Mariotti
Mauro
M
Servizio di Neuropsichiatria Infantile, AUSL Modena, via Cardarelli 45, 41100 Modena, Italy.
Consolo
Ugo
U
Clinica Odontoiatrica, Università di Modena e Reggio Emilia, via del Pozzo 71, 41100 Modena, Italy.
Balli
Fiorella
F
Clinica Pediatrica, Università di Modena e Reggio Emilia, via del Pozzo 71, 41100 Modena, Italy.
Cossarizza
Andrea
A
Cattedra di Immunologia, Dipartimento di Scienze Biomediche, Università di Modena e Reggio Emilia, via Campi 287, 41100 Modena, Italy.
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