Quantitative Assessment of T-Regulatory Cell Population and FOXP3 Gene Expression in Chronically Exposed Residents of...

The objective is to conduct a pilot study on the quantity of regulatory T-cells (Treg) in the peripheral blood and to assess transcriptional activity of FOXP3 gene in chronically exposed persons. Materials and methods. The study included 77 participants who were divided into two groups: exposed people-45 individuals, with a mean cumulative dose to red bone marrow (RBM) of 641.21 ± 80.41 mGy, and a comparison group-32 individuals, with a mean cumulative RBM dose of 20.38 ± 2.51 mGy. The study on the assessment of the FOXP3 gene expression was conducted in 298 individuals: the exposed group consisted of 163 individuals with a mean cumulative dose to RBM of 702 ± 43.10 mGy; the comparison group included 135 individuals with a mean cumulative dose to RBM of 17.30 ± 1.40 mGy. The study groups did not differ significantly in age, sex, and ethnicity. Quantitative assessment of regulatory T-cells in the peripheral blood was performed using flow cytometry method by the presence of T-helper markers CD3 and CD4, high expression of marker CD25 and low expression of marker CD127. Thus, the phenotype of regulatory T-lymphocytes was described as CD3+CD4+CD25highCD127low. The relative mRNA content of the FOXP3 gene was assessed by PCR-RT. Results. More than 70 years after the onset of chronic exposure, no statistically significant changes in the pool of regulatory T-cells were detected in the exposed persons: the content of absolute and relative number of Treg did not differ statistically significantly between the studied groups (p = 0.91 and p = 0.29, respectively); no statistically significant relationship between Treg indices and the cumulative doses to RBM and thymus and peripheral lymphoid organs were found. No statistically significant differences in FOXP3 gene mRNA expression were found between exposed individuals and the comparison group. A linear positive dependence of FOXP3 gene mRNA expression on the relative number of regulatory T-cells was shown (p = 0.007).