Immunologic investigations in asbestos-exposed workers

Our plain-English summary of Immunologic investigations in asbestos-exposed workers, by R.D. deShazo, C.B. Daul, J.E. Morgan, et al (Chest, 1986).

The study

• Authors: R.D. deShazo, C.B. Daul, J.E. Morgan, J.E. Diem, D.J. Hendrick, B.E. Bozelka, R.P. Stankus, R. Jones, J.E. Salvaggio, H. Weill
• Journal: Chest
• Published: 1986;89(3 Suppl):162S-165S
• Cited by: 12 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Summary of the article

The authors examined whether immunologic abnormalities in the blood of asbestos-exposed workers were related to lung fibrosis (asbestosis). They studied asbestos cement workers from two plants in the New Orleans area who were taking part in longitudinal studies at Tulane. Chest x-ray films were classified using the ILO 1980 system by three readers. For humoral immunity, 144 workers were randomly selected from a cohort of 244 (mean age 60 years). Serum IgG was elevated in 61%, IgM in 14% and IgA in 33%, and these elevations were not related to radiographic category. Antinuclear antibodies were found in 22 of 144 workers (15%), rheumatoid factor in 4 (3%), and increased immune complexes in 17 of 140 (12%). For cell-mediated immunity, 29 workers were compared with 52 unexposed controls. Workers had significantly lower lymphocyte counts and lower numbers of total, helper and suppressor T cells, with no difference in helper-suppressor ratios. After adjustment for age, responses to the mitogen PHA did not differ significantly. In vitro, cells from 9 workers with fibrosis and hypergammaglobulinemia produced more spontaneous immunoglobulin than cells from 15 controls, and chrysotile asbestos augmented spontaneous production. No immunologic variable correlated with profusion scores or lung function. T-cell numbers were negatively correlated with time since exposure ceased. The authors concluded that the blood immunologic aberrations were epiphenomena unrelated to the pathogenesis of asbestosis.

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, from Tulane University in New Orleans, examined whether immune abnormalities in the blood of asbestos cement workers were related to lung scarring (asbestosis) seen on chest x-rays. Blood from 144 workers, randomly chosen from a group of 244 at two asbestos cement plants, was tested for antibodies and immunoglobulins. IgG was elevated in 61% of these workers and 15% had positive antinuclear antibody tests, but these findings were not related to x-ray category. A separate group of 29 workers, compared with 52 unexposed controls, had lower lymphocyte counts and lower percentages of some T-cell types, and these abnormalities were similar across x-ray groups. In laboratory cultures, chrysotile asbestos increased spontaneous antibody production by blood cells from both workers and controls. None of the immune measures checked for correlation, including serum IgG and B-cell and T-cell counts, showed a statistically significant correlation with lung function tests or x-ray scores. The authors concluded that the blood immune abnormalities were epiphenomena (by-products) unrelated to how asbestosis develops. They noted that their data could not rule out a role for other immune measures, or show whether the abnormalities are relevant to cancer or autoimmune disease.

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 immunologic study of workers from an existing longitudinal cohort, compared with unexposed controls, plus a laboratory (in vitro) experiment adding chrysotile asbestos to blood cell cultures
• Who was studied: 144 workers randomly selected from a cohort of 244 workers (mean age 60) at two asbestos cement plants in the New Orleans area, tested for humoral immunity. A separate randomly selected group of 29 workers was tested for cell-mediated immunity, most of them (26/29) no longer employed in the industry. Controls were 52 normal subjects (19 female, 33 male), clerical workers and municipal employees with no history of asbestos exposure. In vitro tests used cells from 9 workers with chest x-ray profusion scores of 1/1 or greater and high blood immunoglobulin, and from 15 age- and sex-matched controls.
• Exposure: Asbestos cement dust from work in asbestos cement plants. The 29 workers in the cell-mediated immunity group had a mean exposure of 227 plus or minus 78 months (mean plus or minus standard error), and their time since last known exposure was 9.0 plus or minus 1.2 years. In the laboratory experiments, chrysotile asbestos fibers were added to cell cultures at 125 micrograms per ml.
• Main results:
  • Among the 144 workers, serum IgG was elevated in 61%, IgM in 14% and IgA in 33%. Elevated immunoglobulins were seen in all three x-ray groups and were not related to the category of radiographic abnormality.
  • 22 of 144 workers (15%) had positive antinuclear antibody (ANA) titers: 12% in the 0/0 x-ray group, 18% in the 0/1 group and 24% in the 1/0 or greater group. These proportions were not significantly different between the three groups.
  • Antibodies to double-stranded DNA and to the nonhistone nuclear proteins Sm, RNP and SS-B were not detected in any workers.
  • Rheumatoid factor was detected in 4 of 144 workers (3%).
  • Increased immune complexes were found in the blood of 17 of 140 workers (12%). These were randomly distributed among the three x-ray groups (11%, 18% and 12%).
  • In culture, cells from workers with pulmonary fibrosis produced more immunoglobulin spontaneously than cells from controls, with IgA significantly greater. When stimulated with pokeweed mitogen, control cultures consistently produced more immunoglobulin than workers' cultures.
  • Adding chrysotile asbestos increased spontaneous immunoglobulin production in both control and worker cultures. It inhibited immunoglobulin production at optimal stimulatory doses of pokeweed mitogen.
  • The mean lymphocyte count for the 29 workers (1,543 plus or minus 93 in the text) was significantly less than that of the 52 controls (1,939 plus or minus 78).
  • Compared with controls, all workers had lower percentages of OKT3-positive (total T) cells (47.4 vs 55.8) and OKT4-positive (helper/inducer) cells (30.0 vs 34.5), both marked p less than or equal to 0.05. T-cell abnormalities were similar in the three worker x-ray groups. There were no significant differences in helper-suppressor cell ratios between workers and controls.
  • Without controlling for age, workers' lymphocyte responses to the mitogen PHA appeared significantly lower than controls'. After controlling for age, or for age and OKT4-positive cell numbers, no significant differences were found.
  • The immunologic variables evaluated for correlation (serum IgG levels, percentages and absolute numbers of B-cells and OKT3, OKT4 and OKT8 positive T cells, and T4/T8 ratios) showed no significant correlations with pulmonary function tests or x-ray profusion scores. Absolute numbers of T lymphocytes and T-cell subpopulations were negatively correlated with time elapsed since asbestos exposure ceased.
• The authors' conclusion: The authors concluded that, because none of the immune abnormalities correlated with radiographic or lung function evidence of asbestosis, the abnormalities detected in peripheral blood are epiphenomena unrelated to the pathogenesis of the disease. They suggested that exposure of immune cells to asbestos in the lung likely alters cell functions, producing B-lymphocyte hyperactivity.
• Limitations the authors state:
  • The data do not exclude the possibility that other immunologic variables, such as cytotoxic cell number or function, may be correlated with disease.
  • The data do not allow conclusions about whether the abnormalities are relevant to the development of cancer or autoimmune phenomena associated with asbestosis.

Topics

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

Medical terms in this study, explained in our Lexicon: Fibrosis, Asbestos-Cement, Chest X-Ray, Chrysotile.

Related studies

• Immunologic aberrations in asbestos cement workers: dissociation from asbestosis — R.D. deShazo, D.J. Hendrick, et al. (1983)
• Analysis of depressed cell-mediated immunity in asbestos workers — R.D. deShazo, J. Nordberg, et al. (1983)
• Asbestos toxicity: an immunologic perspective — G.J. Rosenthal, P. Simeonova, et al. (1999)
• Immunologic aspects of pneumoconiosis — R.K. Scheule, A. Holian (1991)
• Investigation of micronucleus frequencies in lymphocytes of inhabitants environmentally exposed to chrysotile asbestos — H. Dönmez-Altuntas, M. Baran, et al. (2007)
• Current concepts about the pathogenesis of silicosis and asbestosis — R.D. deShazo (1982)

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