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Thymopoiesis and regulatory T cells in healthy children and adolescents.

Arismendi MI, Kallás EG, Santos BA, Carneiro-Sampaio MM, Kayser C - Clinics (Sao Paulo) (2012)

Bottom Line: The analysis of CD4, CD8, CD25, and Foxp3 expression was performed using flow cytometry.Ninety-five healthy controls (46 females and 49 males) ranging in age from 1 to 18 years were analyzed.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.

View Article: PubMed Central - PubMed

Affiliation: Hospital das Clinicas da Faculdade de Medicina da Universidade de São Paulo, Departamento de Pediatria, Instituto da Criança, Brasil.

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 T-cell 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.

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Distribution of TREC levels per µg of DNA among healthy children and adolescents from 1 to 18 years of age. TREC levels per µg of DNA showed a strong inverse correlation with age (r = Spearman's correlation coefficient).
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f1-cln_67p425: Distribution of TREC levels per µg of DNA among healthy children and adolescents from 1 to 18 years of age. TREC levels per µg of DNA showed a strong inverse correlation with age (r = Spearman's correlation coefficient).

Mentions: Ninety-five healthy children and adolescents were analyzed. The mean age of the patients was 9 years (range: 1–18 years). The mean TREC count in PBMCs in all individuals was 8.9×104±3.6×104 TRECs/µg of DNA. The Kolmogorov-Smirnov test revealed that the TREC content of our samples did not display a normal distribution. There were no statistically significant differences in the average TRECs/µg of DNA between female and male patients (8.2±3.3×104 TRECs/µg of DNA versus 9.5±3.9×104 TRECs/µg of DNA, respectively; p = 0.085). Healthy patients between 1 and 9 years of age had significantly higher TREC levels than healthy patients between 10 and 18 years of age (11.2×104 TREC/µg of DNA versus 6.5×104 TREC/µg of DNA, respectively; p<0.001) (Table 1). As shown in Figure 1, there was a strong inverse correlation between age and TREC counts in PBMCs in all individuals (r = -0.846, p<0.001).


Thymopoiesis and regulatory T cells in healthy children and adolescents.

Arismendi MI, Kallás EG, Santos BA, Carneiro-Sampaio MM, Kayser C - Clinics (Sao Paulo) (2012)

Distribution of TREC levels per µg of DNA among healthy children and adolescents from 1 to 18 years of age. TREC levels per µg of DNA showed a strong inverse correlation with age (r = Spearman's correlation coefficient).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3351266&req=5

f1-cln_67p425: Distribution of TREC levels per µg of DNA among healthy children and adolescents from 1 to 18 years of age. TREC levels per µg of DNA showed a strong inverse correlation with age (r = Spearman's correlation coefficient).
Mentions: Ninety-five healthy children and adolescents were analyzed. The mean age of the patients was 9 years (range: 1–18 years). The mean TREC count in PBMCs in all individuals was 8.9×104±3.6×104 TRECs/µg of DNA. The Kolmogorov-Smirnov test revealed that the TREC content of our samples did not display a normal distribution. There were no statistically significant differences in the average TRECs/µg of DNA between female and male patients (8.2±3.3×104 TRECs/µg of DNA versus 9.5±3.9×104 TRECs/µg of DNA, respectively; p = 0.085). Healthy patients between 1 and 9 years of age had significantly higher TREC levels than healthy patients between 10 and 18 years of age (11.2×104 TREC/µg of DNA versus 6.5×104 TREC/µg of DNA, respectively; p<0.001) (Table 1). As shown in Figure 1, there was a strong inverse correlation between age and TREC counts in PBMCs in all individuals (r = -0.846, p<0.001).

Bottom Line: The analysis of CD4, CD8, CD25, and Foxp3 expression was performed using flow cytometry.Ninety-five healthy controls (46 females and 49 males) ranging in age from 1 to 18 years were analyzed.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.

View Article: PubMed Central - PubMed

Affiliation: Hospital das Clinicas da Faculdade de Medicina da Universidade de São Paulo, Departamento de Pediatria, Instituto da Criança, Brasil.

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 T-cell 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.

Show MeSH