Introduction. The influence of adverse factors including ionizing radiation leads to a violation of key transcription factors expression and the ratio of the main types of T-helper cells, which in turn initiates a wide range of immunopathological disorders.Objective. The objective of this research was to study the mRNA expression of the SPI1 and GATA3 genes, as well as the composition of T-helper type 1 and 2 subpopulations, in chronically exposed people during the period of radiation exposure late effects development.Mаterials and methods. The study was carried out on peripheral blood mononuclear cells obtained from 98 residents of the Techa riverside settlements. Two study groups were formed: the group of exposed individuals (average accumulated dose for the red bone marrow radiation was 706.8±62.7 mGy) and the comparison group (radiation dose did not exceed 70 mGy). The median age of the studied individuals at examination was 71.1 ± 0.9 years (58–87 years). The relative mRNA content of the studied genes was assessed using real-time PCR. The number of T-helpers of types 1 and 2 in the populations of T-helpers of central and effector memory was calculated using the flow cytometry method.Results. There was a decrease in the absolute and relative number of type 2 T-helpers included in the T-helpers of central memory in chronically exposed individuals. In people with accumulated doses ≥1000 mGy, an increase in the Th1/Th2 ratio of T-helpers of the central memory (p=0.01), as well as the positive correlation relationship between the relative content of type 2 T-helpers of the effector memory and the expression of the GATA3 gene were registered relative to unexposed individuals.Conclusions. The obtained results indicate that changes in the composition of T-helper cell subpopulations in chronically exposed individuals are not pronounced in the long-term period. However, these changes may directly depend on the total absorbed dose, which in turn determines the prospects for further analysis of the health status of people exposed to chronic high-dose radiation.
