Asbestos content in the lymph nodes of nonoccupationally exposed individuals

Our plain-English summary of Asbestos content in the lymph nodes of nonoccupationally exposed individuals, by R.F. Dodson, J. Huang, J.R. Bruce (American Journal of Industrial Medicine, 2000).

The study

• Authors: R.F. Dodson, J. Huang, J.R. Bruce
• Journal: American Journal of Industrial Medicine
• Published: 2000;37(2):169-74
• Cited by: 25 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Background: The thoracic lymph nodes are a part of the clearance system from lung tissue. Accumulation of dust in these nodes are known to occur following some types of exposure. However, no information exists as to asbestos content in lymph nodes from the general population.

Methods: The study cohort consisted of 21 individuals previously defined as nonoccupationally exposed to asbestos. Tissue burden of asbestos obtained from lung analysis by analytical electron microscopy was compared with burden in the lymph nodes.

Results: No asbestos fibers were detected in nodes from 8 cases. The majority of the fibers found in lymph nodes were short (<5 microm) and most often noncommercial amphiboles. Ferruginous bodies (FBs) were detected in lymph node from only two samples.

Conclusions: The total asbestos burden in the lung tissue from these individuals was quite low. However, in 12 of the 13 cases that had positive nodes, the tissue burden in the node was appreciably heavier per gram than in the lung. This raises the question as to whether the lymph nodes, though less efficient clearance, may be better indicators of lifetime exposure to dust than lung tissue.

Copyright 2000 Wiley-Liss, Inc.

In plain English

This study measured asbestos in peritracheal lymph nodes taken at autopsy from 21 East Texans considered not occupationally exposed, and compared it with lung measurements from the same people published earlier by the authors. No asbestos fibers were detected in the nodes of 8 people. Ferruginous (coated) bodies appeared in only two nodes, at 193 and 239 per gram of wet tissue. In 12 of the 13 people with asbestos in their nodes, node concentrations per gram were appreciably higher than lung concentrations. Four nodes held 1,000,000 to 1,700,000 fibers per gram of dry tissue; lungs with detectable fibers held 32,000 to 290,000 per gram of dry tissue. Four people had asbestos detected in nodes but not lungs. Anthophyllite was the most common type in nodes (nine people), then tremolite (six); chrysotile, found in eight lungs, was not detected in any node. The authors cautioned that these lung burdens were low compared with many occupationally exposed groups. They concluded that lymph nodes provide useful supplementary data and may in some individuals better indicate lifetime exposure than lung tissue.

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: Autopsy tissue study (case series) comparing asbestos fiber and ferruginous body content of lymph nodes with lung tissue from the same individuals, analyzed by light and analytical electron microscopy. The lung data were reprinted from the authors' earlier 1999 study.
• Who was studied: 21 individuals from East Texas considered nonoccupationally exposed to asbestos, based on work history, lung tissue free of fibrosis or other disease, and fewer than 20 ferruginous bodies per gram wet weight of lung. Per Table I, they were aged 12 to 72, with 17 males and 4 females. Study years are not stated.
• Exposure: No occupational asbestos exposure (general population). The fibers measured in lung and lymph node were chrysotile, amosite, crocidolite, tremolite, actinolite and anthophyllite, along with non-asbestos fibers and ferruginous bodies.
• Main results:
  • No asbestos fibers were detected in the lymph nodes of 8 of the 21 cases.
  • Ferruginous bodies were found in the lymph nodes of only two cases (Cases 20 and 21), at 193 and 239 per gram of wet tissue.
  • Case 21, which had the highest ferruginous body count in a node, had no uncoated asbestos fibers in the node digest.
  • Seven cases (Cases 1 to 7) had no detectable uncoated asbestos fibers in the lung sample.
  • In four cases (Cases 4 to 7), no asbestos fibers were detected in lung tissue, but asbestos was found in the lymph nodes.
  • Among lungs with detectable fibers, total asbestos fiber burden ranged from 32,000 (Case 12) to 290,000 (Case 20) per gram of dry lung tissue.
  • In 12 of the 13 cases with asbestos-positive lymph nodes, fiber concentrations per gram were appreciably heavier in the node than in the lung.
  • Four lymph node samples had over a million asbestos fibers per gram of dry tissue, ranging from 1,000,000 to 1,700,000 per gram dry weight.
  • Anthophyllite was the most common asbestos type in the lymph nodes (nine cases).
  • Tremolite was the second most common asbestos type in the lymph nodes (six cases).
  • Chrysotile was found in the lung tissue of eight cases but was not detected in any lymph node.
  • Amosite was detected in three lymph node samples, at the detection limit of the method.
  • None of the fibers in the lymph nodes met the length and width criteria of the Stanton hypothesis. In lung tissue, 5% of anthophyllite fibers met these criteria.
• The authors' conclusion: The authors concluded that, together with their earlier shipyard-worker findings, the data suggest lymph nodes provide useful supplementary data to lung analysis and may in some individuals be a better indicator of lifetime exposure than lung tissue.
• Limitations the authors state:
  • The authors stated that the data should be considered in light of the low overall lung burden of ferruginous bodies and uncoated asbestos fibers compared with many occupationally exposed cohorts.
  • The authors noted that in two cases (Cases 14 and 15), the asbestos burden was within the detection limit.

Topics

Medical terms in this study, explained in our Lexicon: Amphibole Group, Ferruginous Bodies.

Related studies

• Asbestos content of omentum and mesentery in nonoccupationally exposed individuals — R.F. Dodson, M.F. O'Sullivan, et al. (2001)
• Tissue burden of asbestos in nonoccupationally exposed individuals from east Texas — R.F. Dodson, M.G. Williams, et al. (1999)
• Asbestos content of lung tissue, lymph nodes, and pleural plaques from former shipyard workers — R.F. Dodson, M.G. Williams, et al. (1990)
• Characteristics of asbestos concentration in lung as compared to asbestos concentration in various levels of lymph nodes that collect drainage from the lung — R.F. Dodson, S. Shepherd, et al. (2007)
• The prevalence of enlarged mediastinal lymph nodes in asbestos-exposed individuals: a CT study — C. Sampson, D.M. Hansell (1992)
• Asbestos fibers in para-aortic and mesenteric lymph nodes — T. Uibu, E. Vanhala, et al. (2009)

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