Immune Status of a Man Long after Chronic Radiation Exposure

Abstract

Purpose: Assessment of major parameters of the system immunity in 376 Techa riverside residents affected by external γ- and internal (mainly due to 90Sr) irradiation 60–68 years after the onset of exposure. Material and methods: The study involved 376 residents of the settlements located in the basin of the Techa River which was contaminated due to releases of liquid radioactive waste of Mayak Production Association. Red bone marrow received the largest doses that reached 4457.1 mGy, mean dose value was 1080.8 ± 38.4 mGy. Doses to the thymus and peripheral organs of the immune system in the exposed individuals were much lower; mean dose value was 65.3 ± 4.9 mGy. The study of the systemic immunity included the analysis of the parameters that characterize functional status of adaptive and innate immunity, as well as of the cytokine system. Results: Pro-inflammatory changes of the cytokines spectrum (decrease of IL-4 in blood serum, increase of TNFα and IFNγ) were observed in exposed people with a background of involution changes. Conclusion: Persistent reduction in the number of neutrophils in blood against normal levels of granulocyte colony-stimulating and granulocyte-macrophage colony-stimulating factors in blood serum could be indicative of certain inefficiency of hematopoietic stem cell pool. The most distinct features of immunity in exposed persons concerned the cytokine spectrum which were inflammatory in nature and on the one hand could be involved in the mechanisms of development of long-term effects of radiation and on the other could have a protective effect on the protection of the body from cells carrying sublethal abnormalities.