Subpopulations of cytotoxic T-lymphocytes in human peripheral blood in the long-term period after the onset of chronic exposure

«Radiation and Risk», 2026, vol. 35, No. 1, pp.138-150

DOI: 10.21870/0131-3878-2026-35-1-138-150

Authors

Khomenko P.O. – Jun. Researcher
Kodintseva E.A. – Lead. Researcher, Head of the Shared Research Facilities, C. Sc., Biol. URCRM FMBA of Russia. Contacts: 68-A Vorovsky Str., Chelyabinsk, 454141, Russia; e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it. .
Urals Research Center for Radiation Medicine of the FMBA of Russia, Chelyabinsk

Abstract

To clarify certain pathogenetic mechanisms of radiation-induced carcinogenesis it is important to investigate functional activity and differentiation of cytotoxic T-lymphocytes in chronically exposed population from the Techa River Cohort. The objective of the study is to perform quantitative assessment of activated cytotoxic T-lymphocytes and cells in subpopulations of cytotoxic T-lymphocytes in chronically exposed people-members of the Techa River Cohort in the long-term period after the onset of radiation exposure. The main group consisted of 53 members of the Techa River Cohort: mean age was 74.9 years, mean dose to the red bone marrow (RBM) made up 567.8+-57.3 mGy. Patients were subdivided into three subgroups by dose calculated to the RBM: the first group – 70-270 mGy (n=18); the second group – 271-650 mGy (n=17); the third one – >650 mGy (n=16). The comparison group consisted of 19 people similar in age, sex, ethnicity who resided in ecologically-friendly rural areas. The fraction of CD16+ cytotoxic T-lymphocytes in people from the 3rd subgroup (99.25%) exceeded that in people from the 1st and 2nd subgroups: 94.50% (p=0.015) and 95.54% (p=0.037), respectively. In the 2nd subgroup the absolute number of naïve cytotoxic T-lymphocytes (0.026x10⁹/l) and central memory T-lymphocytes (0.072x10⁹/l) was lower than that in the members of the 1st subgroup – 0.040x10⁹/l (р=0.047) and 0.099x109/l (р=0.031), respectively. No statistically significant correlations between the studied parameters and accumulated doses were revealed. Correlations between sex and relative (SR=-0.32, p=0.022) and absolute (SR=-0.32, p=0.026) number of cytotoxic central memory T-lymphocytes, ethnicity and fraction of terminally differentiated cytotoxic T-cells (SR=-0.37, p=0.007), ethnicity and absolute number of the cytotoxic central memory T-lymphocytes (SR=0.38, p=0.006) and cytotoxic effector memory T cells (SR=0.31, p=0.028) were established in the main group. The specific features of activation and differentiation of cytotoxic T-lymphocytes in apparently healthy (within the age-appropriate normal value range) chronically exposed individuals indicate some potential differences in the functioning of the main effector-cells of adaptive immune response and could be partially involved in the development of radio-resistance in the studied people. The results are preliminary.

Key words
chronic radiation exposure, Techa River, population, long-term period, antitumor immunity, cytotoxic T-lymphocytes, flow cytometry, differentiation markers, activation molecules, radiation factors, non-radiation factors, radiobiology

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