Thymopoiesis and regulatory T cells in healthy children and adolescents

Author(s)

Arismendi, Maria Izabel ^[1] ; Kallas, Esper Georges ^[2] ; Natali dos Santos, Bianca Almeida ^[2] ; Sales Carneiro-Sampaio, Magda Maria ^[1] ; Kayser, Cristiane ^[3]

Affiliation

^[1] Univ Sao Paulo, Fac Med, Dept Pediat, Hosp Clin, Inst Crianca, Sao Paulo - Brazil

^[2] Univ Sao Paulo, Fac Med, Disciplina Imunol Clin & Alergia, Sao Paulo - Brazil

^[3] Univ Fed Sao Paulo, Escola Paulista Med, Disciplina Reumatol, Sao Paulo - Brazil

• Document type: Journal article
• Source: Clinics; v. 67, n. 5, p. 425-429, 2012.
• Web of Science Citations: 2

Abstract

OBJECTIVES: The purpose of this study was to investigate the association between T cell receptor excision circle levels in peripheral blood mononuclear cells and regulatory T cells that co-express CD25 and Foxp3 in healthy children and adolescents of different ages. MATERIALS AND METHODS: The quantification of signal-joint T-cell receptor excision circle levels in the genomic DNA of peripheral blood mononuclear cells was performed using real-time quantitative PCR. The analysis of CD4, CD8, CD25, and Foxp3 expression was performed using flow cytometry. RESULTS: Ninety-five healthy controls (46 females and 49 males) ranging in age from 1 to 18 years were analyzed. The mean T-cell receptor excision circle count in all individuals was 89.095¡36.790 T-cell receptor excision circles per microgram of DNA. There was an inverse correlation between T-cell receptor excision circles counts and age (r = -0.846; p<0.001) as well as between the proportion of CD4+CD25+Foxp3+ T cells and age (r = -0.467; p = 0.04). In addition, we observed a positive correlation between the amount of CD4+CD25+Foxp3+ T cells and the amount of Tcell receptor excision circles per microgram of DNA in individuals of all ages (r = -0.529; p = 0.02). CONCLUSIONS: In this study, we observed a decrease in the thymic function with age based on the fact that the level of T-cell receptor excision circles in the peripheral blood positively correlated with the proportion of regulatory T cells in healthy children and adolescents. These findings indicate that although T-cell receptor excision circles and regulatory T cells levels decrease with age, homeostasis of the immune system and relative regulatory T cells population levels are maintained in the peripheral blood. (AU)

• FAPESP's process: 08/58238-4 - Autoimmunity in children: investigation of the molecular and cellular bases of early onset of autoimmunity
• Grantee: Magda Maria Sales Carneiro-Sampaio
• Support Opportunities: Research Projects - Thematic Grants