T cell receptor excision circles as a tool for evaluating thymic function in young children

A. Levy, A. Rangel-Santos, L.C. Torres, G. Silveira-Abreu, F. Agena, M. Carneiro-Sampaio
2019 Brazilian Journal of Medical and Biological Research  
A. Levy 0 0 0 0 -0 0 0 1 -8 2 3 1 -9 1 8 6 1 , A. Rangel-Santos 0 0 0 0 -0 0 0 2 -0 5 7 7 -1 1 1 7 1 , L.C. Torres 0 0 0 0 -0 0 0 3 -3 5 1 7 -6 6 1 5 2 , G. Silveira-Abreu 0 0 0 0 -0 0 0 3 -1 9 1 4 -0 0 7 3 1 , F. Agena 0 0 0 0 -0 0 0 2 -4 5 2 6 -4 8 5 7 3 , and M. Carneiro-Sampaio 0 0 0 0 -0 0 0 2 -1 9 2 4 -4 0 4 3 1 Abstract The thymus is a primary lymphoid organ responsible for the maturation of T cells as well as the immunological central tolerance. It is in the antenatal period and infancy
more » ... period and infancy that it plays its major role. In clinical practice, T cell receptor excision circles (TRECs) are considered a direct and reliable measure of the thymic function. TRECs are a by-product of DNA formation in gene rearrangement of T cell receptors. They are stable and they do not duplicate during mitosis, representing the recent emigrant T cells from the thymus. Despite their importance, TRECs have been neglected by physicians and there is a lack of data regarding thymic function during infancy of healthy children. In order to evaluate thymic function in the first years of life, we propose measuring TRECs as a valuable tool. One hundred and three blood samples from children and adolescents between 3 months and 20 years of age were analyzed. The mean TRECs count was 136.77±96.7 copies of TRECs/mL of DNA. The individuals between 0 and 5 years of age had significantly higher TRECs values than those between 10 and 20 years of age. No significant difference was observed in TRECs values among age groups below 5 years of age. An inverse correlation between TRECs and age was found (r=0.3 P=0.003). These data highlight and validate the evidence of decreased thymus function with age, even during infancy. Awareness should be raised with this important albeit ignored organ.
doi:10.1590/1414-431x20198292 fatcat:lro24yywrbbodbgslbyttmh7eu