Cytokine Levels in Individuals Occupationally Exposed to Ionizing Radiation

Cytokines are proteins produced by various body cells and are intercellular messengers. They perform many functions that are very important for understanding the pathogenesis of early and late effects of radiation exposure, of their prevention and treatment. The purpose of this work was to study the cytokine profile in individuals exposed to chronic occupational irradiation. The main group consisted of the Mayak nuclear plant employees exposed to chronic irradiation as a result of their occupational activities. The control group included residents of the city of Ozyersk near the plant, who did not have chronic exposure by occupation. The cytokine content in blood serumwas determined by the enzyme immunoassay in accordance with instructions of the manufacturers of the test systems. The STATISTICA software package was applied for statistical processing. The analysis to estimate the statistical significance of differences was carried out by the Mann–Whitney method. The presence of correlation dependence was determined using the Spearman’s rank correlation coefficient. Serum levels of IFNγ and TNFα were found to be increased in the occupationally exposed group compared to the control group. It was found in addition that the content of IL-18 and IL-35 in blood serum increased as the dose of internal α-radiation to the red bone marrow (RBM) rose and the concentration of IL-17А, IL-35, and TNFα grew with increasing dose of external γ-irradiation to the RBM. External γ-irradiation suppressed IL-27 secretion in the blood serum of the exposed workers. The content of anti-inflammatory cytokines in the blood serum of exposed individuals did not change. These findings allow to conclude that the expression profile of some cytokines shifted towards the inflammatory side in the long-term after chronic exposure.