Lymphocyte subsets in subjects exposed to asbestos: changes in circulating natural killer cells

Our plain-English summary of Lymphocyte subsets in subjects exposed to asbestos: changes in circulating natural killer cells, by N. al Jarad, M. Macey, S. Uthayakumar, et al (British Journal of Industrial Medicine, 1992).

The study

• Authors: N. al Jarad, M. Macey, S. Uthayakumar, A.C. Newland, R.M. Rudd
• Journal: British Journal of Industrial Medicine
• Published: 1992;49(11):811-4
• Cited by: 8 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Summary of the article

The authors examined whether circulating lymphocyte subsets, particularly natural killer (NK) cells, differed in people exposed to asbestos. Earlier studies had used only the CD16 antibody to identify NK cells; this study used both CD16 and CD57. The subjects were 16 men with asbestosis, 11 male asbestos workers without asbestosis, and 24 control subjects (two women; 16 smokers and eight non-smokers), studied at hospitals in London. None had clinical evidence of malignancy, radiological evidence of lung cancer, or connective tissue disorders. Blood lymphocytes were separated, frozen and stored, then analysed in batches by flow cytometry with antibodies to CD4, CD8, CD16 and CD57. Absolute counts were also measured. Total lymphocyte numbers were similar in all groups. Compared with controls, the total exposed group had fewer CD16 positive cells (mean 0.21 v 0.31; p = 0.014) and a lower proportion of them (median 11% v 17%; p = 0.048). CD57 positive cells and CD4:CD8 ratios did not differ. No differences were found between workers with and without asbestosis, or between current smokers and non-smokers and ex-smokers combined. CD16 cell numbers correlated inversely with duration of asbestos exposure (r = -0.44, p = 0.026). The authors concluded that circulating CD16 positive cells are reduced in people exposed to asbestos, more so with longer exposure. They suggested this may partly explain asbestos workers' increased susceptibility to malignancies.

PubMed has no abstract for this study, and the article doesn't print one. We wrote this summary from the full article with the help of AI. It is not the authors' wording.

In plain English

This study compared lymphocytes, a type of white blood cell, in the blood of 16 men with asbestosis, 11 male asbestos workers without asbestosis, and 24 control subjects. The article does not name the asbestos fiber types or jobs involved. The authors focused on natural killer (NK) cells, which they described as possibly helping limit tumour growth, and measured them with two markers, CD16 and CD57. Numbers and proportions of CD16 positive cells were lower in the combined exposed group than in controls (p = 0.014 for numbers, p = 0.048 for proportions). CD57 positive cells, total lymphocytes and the CD4:CD8 ratio did not differ. No differences were found between workers with and without asbestosis. Longer duration of asbestos exposure was associated with fewer CD16 positive cells (r = -0.44, p = 0.026). The authors concluded that CD16 positive cells are reduced in people exposed to asbestos. They suggested this reduction may partly explain asbestos workers' increased susceptibility to cancer. They noted that earlier studies conflicted and said larger studies are needed.

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: Cross-sectional comparison of blood lymphocyte subsets (measured by flow cytometry) between asbestos-exposed groups and controls
• Who was studied: 16 male patients with asbestosis, 11 male asbestos workers with no evidence of asbestosis, and 24 control subjects (two of them women). The authors were at the London Chest Hospital and the Royal London Hospital. Dates of the study are not given.
• Exposure: Occupational asbestos exposure. Fiber types, products and jobs are not specified. Duration of exposure was examined in relation to cell counts.
• Main results:
  • Numbers and proportions of CD16 positive (natural killer) cells were reduced in the total asbestos-exposed group (asbestosis plus non-asbestosis workers) compared with the control group (p = 0.014 for numbers and p = 0.048 for proportions).
  • Median proportion of CD16 positive cells was 11 (range 5 to 30) in the total exposed group, compared with 17 (range 1 to 27) in the control group.
  • There were no differences in numbers or proportions of CD57 positive cells between the total exposed group and the control group.
  • No differences were found in any lymphocyte subset between exposed workers with asbestosis and those without.
  • Numbers of CD16 positive cells were inversely correlated with duration of asbestos exposure (r = -0.44, p = 0.026).
  • In the exposed group, no differences in lymphocyte subsets were found between current smokers and non-smokers plus ex-smokers combined. No correlations were found with age or with time since first exposure.
• The authors' conclusion: The authors concluded that circulating CD16 positive cells are reduced in subjects exposed to asbestos, and are lower in those with longer exposure. They suggested this reduction may be at least partially responsible for asbestos workers' increased susceptibility to developing malignancies.
• Limitations the authors state:
  • The authors noted that their findings conflict with earlier studies for reasons that are not clear, and said studies on larger numbers of subjects are needed.

Topics

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

Medical terms in this study, explained in our Lexicon: Lung Cancer, Asbestos Exposure.

Related studies

• Lymphocyte subsets in subjects exposed to asbestos: changes in circulating natural killer cells — P.J. Borm, P.F. Schins (1993)
• Functional Alteration of Natural Killer Cells and Cytotoxic T Lymphocytes upon Asbestos Exposure and in Malignant Mesothelioma Patients — Y. Nishimura, N. Kumagai-Takei, et al. (2015)
• Natural killer cell activity in asbestos workers. Interactive effects of smoking and asbestos exposure — R.D. deShazo, J. Morgan, et al. (1988)
• Asbestos and cancer: human natural killer cell activity is suppressed by asbestos fibers but can be restored by recombinant interleukin-2 — B.W. Robinson (1989)
• Effects of in vitro asbestos exposure on natural killer and antibody-dependent cellular cytotoxicity — R.G. Barbers, J. Oishi (1987)
• Increased frequency of circulating invariant natural killer T cells in malignant pleural mesothelioma patients — E. Altomare, S. Fallarini, et al. (2012)

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