Mesothelial cell and anti-nuclear autoantibodies associated with pleural abnormalities in an asbestos exposed population of Libby MT

Our plain-English summary of Mesothelial cell and anti-nuclear autoantibodies associated with pleural abnormalities in an asbestos exposed population of Libby MT, by L.S. Marchand, S. St-Hilaire, E.A. Putnam, et al (Toxicology Letters, 2012).

The study

• Authors: L.S. Marchand, S. St-Hilaire, E.A. Putnam, K.M. Serve, J.C. Pfau
• Journal: Toxicology Letters
• Published: 2012;208(2):168-73
• Cited by: 27 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Despite data linking amphibole asbestos exposure with production of autoantibodies, the role of autoantibodies in subsequent disease is unknown. Residents of Libby, Montana have experienced significant exposure to amphibole asbestos due to the mining of asbestos-contaminated vermiculite near the community over several decades. This population predominantly exhibits pleural disease, and an autoimmune-like disorder that has yet to be well defined. This study sought to determine whether autoantibodies from asbestos-exposed subjects were associated with pleural lesions. Serum samples of subjects from Libby were evaluated for anti-nuclear antibodies (ANA) and mesothelial cell autoantibodies (MCAA) using cell based ELISA. The presence of radiographic abnormalities detected during the time frame of serum collection was determined from screening records. In accord with previous studies, 61.3% (76/124) of the Libby samples were ANA positive, a frequency much higher than expected for a healthy population. The odds of having pleural or interstitial abnormalities in Libby was nearly 3.55 times greater for individuals that tested positive for ANA compared with individuals negative for ANA (p=0.004). MCAA were also detected at a strikingly high frequency (18.5%; 23/124) in samples from Libby. Individuals with MCAA had 4.9 times the risk of having pleural abnormalities compared to MCAA-negative subjects (p=0.044). In conclusion, ANA and MCAA were elevated in a study population that was known to have chronic exposure to asbestos, and these autoantibodies were associated with pleural abnormalities, the predominant finding in the asbestos-exposed population of Libby. Additional research is needed to determine the role these autoantibodies may play in pulmonary disease.

Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

In plain English

This study tested stored serum from 124 Libby subjects, randomly selected from a bank of 318 samples. Libby residents were exposed to amphibole asbestos from mining of asbestos-contaminated vermiculite. The authors measured anti-nuclear antibodies (ANA) and antibodies that bind mesothelial cells (MCAA). They used 25 samples from Missoula residents with no known asbestos exposure to set the MCAA cut-off, and compared results with earlier screening radiographs. Of the Libby samples, 76 of 124 (61.3%) were ANA positive and 23 (18.5%) were MCAA positive. ANA-positive subjects had 3.55 times the odds (95% confidence interval 1.49 to 8.43) of any pleural or interstitial abnormality compared with ANA-negative subjects. Compared with MCAA-negative subjects, MCAA-positive subjects had 4.88 times the odds (95% confidence interval 1.05 to 22.77) of pleural abnormalities rather than no radiographic abnormalities. MCAA was not significantly related to interstitial abnormalities. The authors concluded that the data suggest a relationship between these autoantibodies and pleural abnormalities. They noted limits: smoking and individual exposure could not be controlled for, the study cannot show which came first, and the evidence that asbestos caused the antibodies is indirect.

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 laboratory analysis of banked (stored) serum samples, compared with earlier screening radiograph results
• Who was studied: 124 Libby, Montana serum samples randomly selected from a banked set of 318: 65 from females and 59 from males, mean age 50, range 14 to 84 years. A reference group of 25 Missoula, Montana samples (13 male, 12 female, mean age 45) with no known asbestos exposure was used to set the MCAA cut-off.
• Exposure: Amphibole asbestos in vermiculite mined, transported and processed near Libby from 1924 to 1990. Individual exposure details were not available for this analysis.
• Main results:
  • 76 of 124 Libby samples (61.3%, CI 52.1 to 69.9%) were positive for ANA
  • Using the Missoula mean plus three standard deviations as the cut-off, 23 Libby samples (18.5%) were positive for MCAA
  • Among the Libby subjects in this project, 52% had pleural abnormalities and another 25% had interstitial abnormalities
  • In Libby subjects, the odds of any pulmonary abnormality (pleural or interstitial) were 3.55 times greater (95% CI 1.49 to 8.43) for ANA-positive than for ANA-negative individuals, p = 0.004
  • Comparing ANA-positive with ANA-negative subjects, the odds ratio was 3.60 (95% CI 1.44 to 9.01) for pleural abnormalities and 3.44 (95% CI 1.19 to 9.95) for interstitial abnormalities. In each case the comparison was against subjects with no radiographic abnormalities.
  • A higher ANA score was associated with a higher risk of radiographic abnormalities (p = 0.005)
  • 17 of 23 (74%) MCAA-positive samples had pleural abnormalities, compared with 47 of 101 (47%) MCAA-negative individuals
  • Compared with MCAA-negative subjects, the odds of pleural abnormalities were 4.88 times greater (95% CI 1.05 to 22.77) for MCAA-positive individuals, p = 0.044. The analysis compared subjects with pleural abnormalities against subjects with no radiographic abnormalities.
  • In the pleural-abnormality analyses, the comparison group was people with no radiographic evidence of interstitial or pleural abnormalities.
  • There was no significant relationship between MCAA positivity and interstitial abnormalities (p = 0.445)
  • The ANA staining pattern was not related to pleural or interstitial radiographic abnormalities
• The authors' conclusion: The authors concluded that the data suggest a relationship between autoantibodies and pleural abnormalities in Libby amphibole-exposed subjects, and that further research is needed on how MCAA arise and whether they cause damage.
• Limitations the authors state:
  • Smoking history and asbestos exposure were not available for individual subjects, so they could not be controlled for in the analysis.
  • Radiographic data came from the closest screening before serum collection, and reading radiographs carries a risk of misinterpretation.
  • The study does not show whether the antibodies or the lesions came first.
  • The ANA association with abnormalities could simply reflect greater exposure leading to both, without one causing the other.
  • The authors described their data as indirect evidence that asbestos caused these autoantibodies or that the antibodies contribute to pleural disease.

Mines named here

Asbestos mines this study is about. Each mine's page says who ran it, when it worked, and what it produced.

• Libby vermiculite mine, Montana

All asbestos mines

Topics

The National Library of Medicine indexes this study under subjects our site covers: Asbestosis, Pleural plaques and thickening.

Medical terms in this study, explained in our Lexicon: Mesothelial Cells, Amphibole Asbestos, vermiculite, Interstitial.

Related studies

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• Occupational exposure to fluoro-edenite and prevalence of anti-nuclear autoantibodies — V. Rapisarda, C. Loreto, et al. (2018)
• Libby amphibole-induced mesothelial cell autoantibodies bind to surface plasminogen and alter collagen matrix remodeling — R. Hanson, C. Evilia, et al. (2016)
• Libby amphibole-induced mesothelial cell autoantibodies promote collagen deposition in mice — J. Gilmer, K. Serve, et al. (2016)
• Pulmonary abnormalities as a result of exposure to Libby amphibole during childhood and adolescence-The Pre-Adult Latency Study (PALS) — J. Szeinuk, C.W. Noonan, et al. (2017)
• Evaluation of anti-nuclear antibodies and kidney pathology in Lewis rats following exposure to Libby amphibole asbestos — K.D. Salazar, C.B. Copeland, et al. (2013)

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