Autoimmunity and asbestos exposure

Our plain-English summary of Autoimmunity and asbestos exposure, by J.C. Pfau, K.M. Serve, C.W. Noonan (Autoimmune Diseases, 2014).

The study

• Authors: J.C. Pfau, K.M. Serve, C.W. Noonan
• Journal: Autoimmune Diseases
• Published: 2014;2014:782045
• Type of article: Review
• Cited by: 46 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Despite a body of evidence supporting an association between asbestos exposure and autoantibodies indicative of systemic autoimmunity, such as antinuclear antibodies (ANA), a strong epidemiological link has never been made to specific autoimmune diseases. This is in contrast with another silicate dust, crystalline silica, for which there is considerable evidence linking exposure to diseases such as systemic lupus erythematosus, systemic sclerosis, and rheumatoid arthritis. Instead, the asbestos literature is heavily focused on cancer, including mesothelioma and pulmonary carcinoma. Possible contributing factors to the absence of a stronger epidemiological association between asbestos and autoimmune disease include (a) a lack of statistical power due to relatively small or diffuse exposure cohorts, (b) exposure misclassification, (c) latency of clinical disease, (d) mild or subclinical entities that remain undetected or masked by other pathologies, or (e) effects that are specific to certain fiber types, so that analyses on mixed exposures do not reach statistical significance. This review summarizes epidemiological, animal model, and in vitro data related to asbestos exposures and autoimmunity. These combined data help build toward a better understanding of the fiber-associated factors contributing to immune dysfunction that may raise the risk of autoimmunity and the possible contribution to asbestos-related pulmonary disease.

In plain English

This was a review article, not a new study. The authors summarized published human, animal and laboratory (in vitro) research on whether asbestos exposure is linked to autoimmunity, where the immune system attacks the body's own tissues. The review reported that several studies of asbestos-exposed groups found more frequent antinuclear antibodies (ANA), a type of autoantibody, but that a strong epidemiological link to specific autoimmune diseases had never been made. In animal studies it described, amphibole asbestos raised ANA in mice and rats. In one mouse study chrysotile did not. No animal study clearly showed fibers causing or worsening systemic autoimmune disease. The review cited a study of people exposed to Libby, Montana amphibole. In that study, exposed people who tested ANA-positive were nearly 3.55 times more likely to have pleural or interstitial abnormalities than exposed people who tested ANA-negative (P = 0.004). The authors noted that many human studies were small, mostly of male workers, often retrospective, and rarely named the fiber type. The authors concluded that the data provide compelling evidence of an association between asbestos exposure and autoimmunity.

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: Review of epidemiological, animal model and in vitro studies (narrative review; no new data collected)
• Who was studied: Published studies: human studies of asbestos-exposed groups (insulation, textile, cement, factory and plant workers, miners, naval personnel, and people exposed to Libby, Montana contaminated vermiculite), plus mouse and rat experiments and cell studies
• Exposure: Chrysotile (serpentine) and amphiboles (tremolite, amosite, crocidolite, actinolite, anthophyllite), and Libby amphibole, a mix including winchite, richterite, tremolite and amosite from contaminated vermiculite. Erionite and nanotubes/nanowires were also discussed.
• Main results:
  • Reviewed human studies described increased ANA frequency with asbestos exposure; a few studies found no increase
  • The review stated that asbestos had not been strongly linked epidemiologically to any specific autoimmune disease
  • A cited nested case-control study in Libby, Montana showed associations of both systemic lupus erythematosus and systemic sclerosis with amphibole exposure
  • In reviewed animal studies, amphibole asbestos increased positive ANA tests in mice and rats
  • In one cited study of C57BL/6 mice, Libby amphibole induced ANA in a significantly higher proportion of mice than saline controls; chrysotile did not
  • The authors stated that, to their knowledge, no animal study clearly showed induction or worsening of systemic autoimmune disease by mineral fibers
  • In a cited follow-up of Libby amphibole-exposed people, those testing ANA-positive were nearly 3.55 times more likely to have pleural or interstitial abnormalities than exposed people testing ANA-negative (P = 0.004)
  • In a cited follow-up of asbestos plant workers (Tamura studies), workers with ANA were more likely to develop radiologic abnormalities than ANA-negative workers
• The authors' conclusion: The authors concluded that the limited number of studies makes conclusions difficult. They nonetheless judged that the data provide compelling evidence of an association between asbestos exposure and autoimmunity, including a possible contribution of autoantibodies to fibrotic disease. They called for future studies to examine specific fiber types.
• Limitations the authors state:
  • The reviewed studies focused mainly on male, occupationally exposed populations, while autoimmune diseases are more common in women
  • Many reviewed studies were retrospective, which limits exposure assessment and the timing between exposure, autoimmune response and lung disease
  • Many human studies were small and had limited exposure data
  • Most studies named the occupation but not the fiber type, so most exposures were mixed and of unknown proportions

Topics

Medical terms in this study, explained in our Lexicon: Asbestos Exposure, Silicate, Crystalline, Mesothelioma, Carcinoma, Latency, Statistical Significance.

Related studies

• Asbestos-induced autoimmunity in C57BL/6 mice — J.C. Pfau, J.J. Sentissi, et al. (2008)
• Silicosis and autoimmunity — S. Lee, H. Hayashi, et al. (2017)
• Silica exposure and altered regulation of autoimmunity — S. Lee, H. Matsuzaki, et al. (2014)
• Centrality of Myeloid-Lineage Phagocytes in Particle-Triggered Inflammation and Autoimmunity — O.K. Favor, J.J. Pestka, et al. (2021)
• Nested case-control study of autoimmune disease in an asbestos-exposed population — C.W. Noonan, J.C. Pfau, et al. (2006)
• Mesothelial cell and anti-nuclear autoantibodies associated with pleural abnormalities in an asbestos exposed population of Libby MT — L.S. Marchand, S. St-Hilaire, et al. (2012)

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