Lymphocytic alveolitis and pleural calcifications in nonoccupational asbestos exposure. Protection against neoplasia?

Our plain-English summary of Lymphocytic alveolitis and pleural calcifications in nonoccupational asbestos exposure. Protection against neoplasia?, by S.H. Constantopoulos, Y.A. Dalavanga, K. Sakellariou, et al (The American Review of Respiratory Disease, 1992).

The study

• Authors: S.H. Constantopoulos, Y.A. Dalavanga, K. Sakellariou, J. Goudevenos, O.B. Kotoulas
• Journal: The American Review of Respiratory Disease
• Published: 1992;146(6):1565-70
• Cited by: 10 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Inhabitants of the Metsovo area in Northwest Greece (population, 4,000) have been exposed to asbestos through the use of whitewash containing tremolite. This has resulted in endemic pleural calcifications (PCs) and increased incidence of malignant pleural mesothelioma (MPM). In order to evaluate the lung response to the fiber, bronchoalveolar lavage (BAL) was performed in 25 Metsovites; 14 with PCs, three with PCs and neoplasia, five without PCs, and three without PCs but with established neoplasia. There were no differences between the four groups with regard to age or exposure. Twelve Metsovites had lymphocytic alveolitis (BAL lymphocytes > 15%). Eleven belonged to the group with PCs and one belonged to the group without PCs. None of those with neoplasia had alveolitis. The lymphocytes were mainly helper T-cells, and activation markers were more frequent among those with PCs. We have previously reported on the relative absence of PCs in Metsovites with malignant pleural mesothelioma. This observation and the results of the present study suggest that lymphocytic alveolitis correlates with pleural calcifications, whereas both are rarely present in patients with neoplasia.

In plain English

The authors examined lung washings (bronchoalveolar lavage) from 25 residents of the Metsovo area of northwest Greece, who had been exposed to asbestos through a household whitewash containing tremolite. They formed four groups: 14 with pleural calcifications, three with pleural calcifications and neoplasia (cancer), five with neither, and three with neoplasia but no calcifications. Twelve of the 25 had raised lymphocyte levels in the washings (lymphocytic alveolitis), and 11 of these were in the group with calcifications and no neoplasia. None of those with neoplasia had alveolitis. Asbestos bodies were found in 17 of the 25 residents and in three of 70 comparison subjects. Among 14 Metsovo patients with asbestos-related malignancies that the authors had seen or followed, only four had pleural calcifications. The authors suggested that the alveolitis may have a protective role against neoplasia. They noted that the numbers were small, that they could not measure natural killer cell activity, and that neoplasia itself might have suppressed the lymphocyte response.

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 bronchoalveolar lavage (BAL) study comparing four groups of environmentally exposed residents, with a supplementary tally of thoracic malignancies seen by the authors
• Who was studied: 25 inhabitants of the Metsovo area, Northwest Greece (19 volunteers and 6 who had bronchoscopy for diagnosis of thoracic malignancy), divided into Group A (14 with pleural calcifications), Group B (3 with pleural calcifications and neoplasia), Group C (5 without pleural calcifications or neoplasia) and Group D (3 without pleural calcifications but with neoplasia). There were two control groups: healthy volunteers for alveolitis, and 70 non-Metsovites for asbestos bodies.
• Exposure: Nonoccupational household exposure to tremolite through 'luto' whitewash made from local soil. Group A, for example, had used luto for 36.7 plus or minus 18.15 years and had stopped 28.5 plus or minus 16.29 years before the study.
• Main results:
  • 12 of the 25 Metsovites had BAL lymphocytes above 15.2%, the highest normal value in the authors' laboratory. 11 of these 12 were in Group A (pleural calcifications without neoplasia).
  • Group A's BAL lymphocyte percentage (30.55 plus or minus 20.28) was significantly higher than that of Group B (4.13 plus or minus 0.83), Group C (9.50 plus or minus 6.04) and Group D (11.66 plus or minus 0.94), with p less than 0.01 in all comparisons.
  • None of the Metsovites with neoplasia had alveolitis.
  • The lymphocytes were mainly helper T-cells. Group A showed a borderline increase in DR (activation marker) expression, 37.61% versus 25.61% (p less than 0.05).
  • Asbestos bodies were found in 17 of 25 Metsovites and in three of 70 control subjects. Seven Metsovites had more than 5 asbestos bodies per field, while no control had more than 1 to 2 per field.
  • In the semiquantitative evaluation, the presence and number of asbestos bodies did not correlate with duration of exposure, latency period, or time since last exposure.
  • Of the thoracic malignancies in Metsovites that the authors had seen or followed, 14 were asbestos-related (11 mesotheliomas and three bronchogenic carcinomas), and only four of these 14 patients had pleural calcifications.
• The authors' conclusion: The authors suggested that, rather than being a precursor of asbestosis, the lymphocytic alveolitis seen with pleural calcifications may have a protective role against neoplasia. They presented this as speculation.
• Limitations the authors state:
  • The numbers were small.
  • The authors could not evaluate natural killer cell activity, so they could not reach definite conclusions.
  • Neoplasia itself might have depressed a previously existing BAL lymphocytosis.
  • Asbestos bodies were estimated only semiquantitatively.
  • There were significant gaps in the authors' working hypotheses about mechanism.

Topics

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

Medical terms in this study, explained in our Lexicon: Pleural Calcification, Asbestos Exposure, Whitewash, Tremolite, Endemic, Pleural Mesothelioma, Bronchoalveolar Lavage (BAL).

Related studies

• Additional proteins in BAL fluid of Metsovites environmentally exposed to asbestos: more evidence of "protection" against neoplasia? — V. Galani, S. Constantopoulos, et al. (2002)
• Decreasing prevalence of pleural calcifications among Metsovites with nonoccupational asbestos exposure — C. Manda-Stachouli, Y. Dalavanga, et al. (2004)
• Pleural calcification, pleural mesotheliomas, and bronchial cancers caused by tremolite dust — S. Yazicioglu, R. Ilçayto, et al. (1980)
• Tremolite whitewashing and pleural calcifications — S.H. Constantopoulos, N.A. Saratzis, et al. (1987)
• Metsovo lung: pleural calcification and restrictive lung function in northwestern Greece. Environmental exposure to mineral fiber as etiology — S.H. Constantopoulos, J.A. Goudevenos, et al. (1985)
• Pleural calcification associated with exposure to chrysotile asbestos in southeast Turkey — S. Yazicioglu (1976)

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