Immune Status of Workers with Professional Risk of Being Affected by Chrysotile Asbestos in Kazakhstan

Our plain-English summary of Immune Status of Workers with Professional Risk of Being Affected by Chrysotile Asbestos in Kazakhstan, by S. Koigeldinova, A. Alexeyev, Z. Zharylkassyn, et al (International Journal of Environmental Research and Public Health, 2022).

The study

• Authors: S. Koigeldinova, A. Alexeyev, Z. Zharylkassyn, Y. Otarov, B. Omarkulov, M. Tilemissov, C. Ismailov
• Journal: International Journal of Environmental Research and Public Health
• Published: 2022;19(21)
• Cited by: 2 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

The purpose of this research was to study the particularities of the immune status of workers in the field of chrysotile asbestos production, depending on their work experience and professional risk of being affected by chrysotile dust. The research covered 125 men, who were workers at the only enterprise dealing with the extraction and beneficiation of chrysotile ores in Kazakhstan. Indicants of cell immunity were detected by flow cytometry; IgA, IgM, and IgG were detected by a multiplex immunological assay. It was found that, among workers impacted by chrysotile asbestos for more than 15 years, compared with individuals who were not impacted by asbestos dust, the level of CD3+ T-cells was decreased (t = -8.76, p < 0.001), as well as the number of CD4+ T-cells (U = 1246.0, p < 0.001). Moreover, CD8+ T-cells increased (t = 5.308, p = 0.001), and neutrophil phagocytic activity also increased, by 1.2 times (U = 305.5, p < 0.001). It was found that working under the condition of professional contact with chrysotile asbestos dust modifies the indicants of humoral immunity, IgA, IgM, and IgG, to a lesser extent than those of cellular immunity.

In plain English

This study compared blood immune measures in 125 men at Kazakhstan's only chrysotile asbestos mining and processing enterprise. All lived in Zhitikara town. Workers with chronic disease, or who had smoked constantly in the last year, were excluded. Fifty-one had worked directly in chrysotile ore extraction and processing for under 15 years, and 39 for over 15 years. Another 35 men without work contact with chrysotile were the comparison group. Workplace certification identified jobs involving asbestos dust contact; exposure degree was judged by years worked, without fiber measurements. Compared with the comparison group, both exposed groups had lower CD3+ and CD4+ T-cell levels and higher CD8+ levels. Both also had about 1.2 times higher neutrophil phagocytic activity, which measures how actively certain white blood cells engulf particles. Longer-serving men also had fewer CD19+ B-cells. A decrease in the CD4+8+ index was not statistically significant. Antibody levels (IgA, IgM, IgG) did not differ noticeably. The authors concluded these cell changes might be an early sign of an unfavorable chrysotile effect. They noted the small sample and possible environmental exposure from the nearby quarry.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: A one-time comparison of blood immune measures across three groups of workers: two chrysotile-exposed groups split by length of work, and one unexposed comparison group
• Who was studied: 125 men working at the only chrysotile ore extraction and processing enterprise in Kazakhstan, all living in Zhitikara town, Kostanay region. Only workers considered healthy were included. Workers with chronic diseases and those with constant tobacco smoking in the last year were excluded. Group 1 had 51 exposed workers with less than 15 years of work. Group 2 had 39 exposed workers with more than 15 years. Group 3 was a control group of 35 workers without professional contact with chrysotile. Ethics approval was dated 2020.
• Exposure: Occupational chrysotile asbestos dust from open-pit mining and ore processing. Which workers had contact was established by mandatory workplace certification. The degree of exposure was assessed by years worked: less than 15 years (average 8.55) or more than 15 years (average 24.54). Fiber exposure was not measured quantitatively.
• Main results:
  • CD3+ T-cells were lower than in the control group in both exposed groups. Group 1 (less than 15 years): t = −6.169. Group 2 (more than 15 years): t = −8.76, p < 0.001.
  • CD4+ T-cells were lower than in the control group in both exposed groups. Group 1: t = −7.792, p < 0.001. Group 2: t = −11.675, p < 0.001.
  • CD8+ T-cells were higher than in the control group in both exposed groups. Group 1: t = 5.551, p < 0.001. Group 2: t = 5.308, p = 0.001.
  • The CD4+8+ immunoregulatory index was lower in both exposed groups, but the difference was not statistically significant. Group 1: p = 0.022, which did not reach the study's threshold. Group 2: p = 0.123.
  • Neutrophil phagocytic activity was about 1.2 times higher than in the control group in both exposed groups. Group 1: U = 428.5, p < 0.001. Group 2: U = 305.5, p < 0.001.
  • CD19+ B-cells were lower than in the control group in group 2 (t = −4.039, p = 0.002). The decrease in group 1 was not significant (p = 0.045).
  • Cells the article labels natural killer (NK) cells (CD3+56/16+) were lower than in the control group in group 1 (t = −1.27, p = 0.011). Cells it labels TNK cells (CD3-56/16+) were higher than in the control group in group 2 (t = 5.893, p = 0.002).
  • Levels of the antibodies IgA, IgM and IgG in the two exposed groups were not noticeably changed compared with the control group. Kruskal–Wallis p-values were 0.443, 0.917 and 0.219.
• The authors' conclusion: The authors concluded that, in apparently healthy workers with long exposure to chrysotile dust, the signs of an effect on the immune system were increased neutrophil phagocytic activity, decreased CD3+ and CD4+ T-cells, increased CD8+ T-cells, and a decreased CD4+8+ index. They suggested these changes might be examined as an early indicator of an unfavorable impact of chrysotile. They also concluded that antibody levels were affected less than cell immunity.
• Limitations the authors state:
  • The sample was relatively small.
  • Asbestos fiber exposure was not measured quantitatively.
  • All workers also had possible environmental exposure from living next to the quarry. The authors believed occupational exposure was much greater.
  • The small sample prevented adjustment for possible confounders.
  • The results cannot easily be applied to other workers.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Chrysotile.

Medical terms in this study, explained in our Lexicon: Chrysotile.

Related studies

• Immune response in shipyard workers with x ray abnormalities consistent with asbestos exposure — H. Anton-Culver, B.D. Culver, et al. (1988)
• Far-reaching consequences of high level air pollution on the developing immune system — T. Turnovska, I. Sirakova, et al. (2001)
• Circulating immune complexes in asbestos workers — J.J. Zone, W.N. Rom (1985)
• An epidemiological survey of immunological abnormalities in asbestos workers. II. Serum immunoglobulin levels — A. Lange (1980)
• A comparative study of the disease burden attributable to asbestos in Brazil, China, Kazakhstan, and Russia between 1990 and 2019 — J. Chen, C. Wang, et al. (2022)
• An epidemiological study of the role of chrysotile asbestos fibre dimensions in determining respiratory disease risk in exposed workers — L. Stayner, E. Kuempel, et al. (2008)

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