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

Cattedra di Immunologia, Dipartimento di Scienze Biomediche, Università di Modena e Reggio Emilia, via Campi 287, 41100 Modena, Italy. .
Immunity & Ageing (Impact Factor: 3.54). 03/2005; 2(1):4. DOI: 10.1186/1742-4933-2-4
Source: PubMed


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.

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).

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.

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.

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Available from: Marcello Pinti, Oct 02, 2015
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    • "In recent years attempts have been made to quantify thymic output by using T-cell receptor excision circle (TREC) content of cells. Lower percentages of TREC positive lymphocytes have been shown in children with DS, which showed an agerelated decrease in contrast to healthy controls [54] [55]. Low TREC content, however, might rather be explained by lower percentage of naı¨ve T-cells in DS, the main cell type containing TRECs. "
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