Long-term immune effects of high-level natural radiation on Yangjiang inhabitants in China

Abstract

Purpose: Low dose radiation was found to perturb immune function or inflammatory reactions, which required further study. This study aimed to evaluate the health effects following long-term low dose radiation by detecting levels of peripheral blood lymphocyte subsets and serum cytokines of residents living in the Yangjiang High Background Radiation Area (HBRA).

Materials and methods: Flow cytometry was used to detect peripheral blood T lymphocytes and its subsets (CD4⁺ T, CD8⁺ T lymphocyte) in 100 healthy female residents selected from HBRA and a Control Area (CA), respectively. Thirty cytokines or receptors and CRP levels were measured using antibody arrays in the 40 subjects described above. Subjects were chosen based on an age and BMI match between the two groups. Cytokine expression levels were then verified using ELISA methods.

Result: In comparison to CA, CD8⁺ T lymphocyte numbers were significantly increased with cumulative dose following adjustment to age and BMI. Of the 30 selected targets, 22 indexes were measurable and inflammatory cytokines such as IFN-γ, IL-α, MCP-1, sIL-6R, EGFR, and CRP levels were observed to be significantly up-regulated with cumulative doses. ELISA results confirmed the cytokine array results and found CRP, MCP-1, and sIL-6R levels are linear with cumulative dose following adjustment to age and BMI.

Conclusion: Immune function was found to be affected in humans exposed to long-term low dose radiation. Specifically, we observed an increase in CD8⁺T lymphocyte numbers and an up-regulation of inflammatory biomarkers, including IFN-γ, MCP-1, sIL-6R, EGFR, CRP.

Keywords:

• Immune responses
• low dose effects
• inflammation
• cytokines array

Acknowledgments

We gratefully acknowledge the contribution from workers in the city CDC in Guangdong who provided laboratory management and field investigation.

Disclosure statement

The authors report no conflict of interest. The authors alone are responsible for the content and writing of the paper.

Additional information

Funding

The work was supported by China-Japan Cooperation Research on Radiation Epidemiology in Yangjiang, Guangdong Province, China.

Notes on contributors

Kun Li

Kun Li, PhD, is a physician at the Department of Nuclear Medicine, Shandong Province Qianfoshan Hospital, Jinan, China.

Wen Li

Wen Li, MM, is the director of the Department of Nuclear Medicine, Shandong Province Qianfoshan Hospital, Jinan, China.

Yanying Jia

Yanying Jia, MB, is an assistant director nurse at the Department of Nuclear Medicine, Shandong Province Qianfoshan Hospital, Jinan, China.

Jianxiang Liu

Jianxiang Liu, PhD, is a researcher of Radiobiology at the National Institute for Radiological Protection, Chinese Center for Disease Control and Prevention, Beijing, China.

Guangxiang Tan

Guangxiang Tan, MB, is an assistant director physician at Guangdong Prevention and Treatment Center for Occupational Diseases, Guangzhou, China.

Jianming Zou

Jianming Zou, PhD, is a researcher of Radiobiology at Guangdong Prevention and Treatment Center for Occupational Diseases, Guangzhou, China.

Xiaoliang Li

Xiaoliang Li, PhD, is an assistant researcher of Radiological Protection at the National Institute for Radiological Protection, Chinese Center for Disease Control and Prevention, Beijing, China.

Yinping Su

Yinping Su, PhD, is an associate researcher of Radiological Protection at the National Institute for Radiological Protection, Chinese Center for Disease Control and Prevention, Beijing, China.

Shujie Lei

Shujie Lei, MB, is an associate researcher of Radiological Protection at the National Institute for Radiological Protection, Chinese Center for Disease Control and Prevention, Beijing, China.

Quanfu Sun

Quanfu Sun, PhD, is a senior researcher of Radiological Protection at the National Institute for Radiological Protection, Chinese Center for Disease Control and Prevention, Beijing, China.