Purpose: Long-term exposure to low dose radiation may trigger immune response and stimulate hormesis. Interleukin-2 (IL-2) and interleukin-2 receptor (IL-2R) play a crucial role in immune function. We aimed to explore the possible association of IL-2 and IL-2R gene polymorphisms with low dose radiation exposure, as well as the relationship with IL-2 gene expression in people residing in areas with a high background radiation in Yangjiang, China.
Materials and methods: We recruited and assigned 54 native men residing in Yangxi County, Yangjiang city to the high natural background radiation (HNBR) group, and 53 native men residing in Hengpi County, Enping city to the control area (CA) group. All the participants wore a thermoluminescent dosimeter (TLD) for 90 days, and answered questionnaires. The serum levels of IL2, IL4, IL5, sIL2R, and tumor growth factor (TGF), and expression levels of IL2RA, IL2RB, IL2RG, and IL2 were also analyzed. Additionally, we tested 10 polymorphic loci associated with the IL-2 gene.
Results: The annual effective radiation doses in the HNBR and CA groups were 6.24 mSv y-1 and 1.95 mSv y-1, respectively. After adjusting for potential confounding factors, the serum levels of IL-2 and IL-5 were higher in the HNBR group than the CA group (p < .05), while the serum level of TGFβ was lower in the HNBR group (p < .05). The IL-2 gene mRNA expression level was higher in the HNBR group than the CA group (p < .05). The IL-2RB rs76206423 AA allele showed significant variations in the HNBR group (p = .0381).
Conclusions: Long-term exposure to low dose radiation may enhance immune function, and IL-2RB rs76206423 may be related to the expression of IL-2 by other coding variants. Moreover, our data provide a better understanding of the molecular mechanism of the immune response to low dose radiation.
Keywords: IL-2; IL-2R; Polymorphism; high background radiation; immune function; low dose radiation.