Cytological analysis of bronchoalveolar lavage fluid in asbestos-exposed workers

Our plain-English summary of Cytological analysis of bronchoalveolar lavage fluid in asbestos-exposed workers, by P. Sartorelli, S. Indini, F. Bianchi, et al (La Medicina del Lavoro, 2020).

The study

• Authors: P. Sartorelli, S. Indini, F. Bianchi, M. D'Alessandro, L. Bergantini, P. Cameli, M.A. Mazzei, G. Scancarello, L. Barabesi, E. Bargagli
• Journal: La Medicina del Lavoro
• Published: 2020;111(5):379-387
• Cited by: 9 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Background: Asbestos-related lung diseases are a group of heterogeneous disorders with different pathogenesis and prognosis. Very few studies investigated the BALF cell profile of asbestos exposed workers. The existence of a relationship between bronchoalveolar lavage fluid (BALF) cellular pattern and specific diagnosis and/or asbestos exposure biomarkers would allow the identification of effect biomarkers useful in the follow up of asbestos-exposed workers and in the diagnosis of asbestos-related diseases.

Objectives: To assess BALF cell profile in formerly asbestos-exposed workers and its relationship with asbestos fibre (amphibole and chrysotile) and asbestos body (AB) concentrations.

Methods: 113 male workers formerly exposed to asbestos underwent bronchoscopy with bronchoalveolar lavage and were retrospectively enrolled. 35 of them were affected by pleural plaques and 10 were affected by asbestosis. Pulmonary functional tests (PFT), BALF cellular pattern, BALF mineralogical analysis with asbestos fibres and AB counting were performed in each patient. A statistical analysis with a multivariate linear regression model was adopted.

Results: From the statistical analysis of data a direct correlation between pack-years and BALF macrophages was found. Inversely correlation between pack-years and BALF lymphocytes was detected. There was not relationship among BALF cellular pattern, PFT values, specific diagnosis, BALF AB count or BALF asbestos fibre concentration.

Discussion: BALF cellular pattern does not seem to be related to asbestos exposure biomarkers like AB and asbestos fibre concentration in BALF. Instead, smoke habit can induce an increase in BALF macrophages and a decrease of BALF lymphocytes count.

In plain English

This retrospective study from Siena, Italy, looked at 113 men who had formerly been exposed to asbestos at work. They were hospitalized between 2010 and 2018 because asbestos-related disease was suspected. Each had bronchoalveolar lavage, a procedure that washes fluid into the lungs and recovers cells. The authors counted the cell types in this fluid and measured chrysotile fibres, amphibole fibres and asbestos bodies in it. Based on imaging and clinical findings, 35 men had pleural plaques and 10 had asbestosis. In the statistical models, smoking (measured in pack-years) was the only significant factor (p = 0.02). More smoking went with more macrophages and fewer lymphocytes. Fibre and asbestos body levels were not related to the cell counts, and neither were lung function or, in the authors' words, diagnosis, which did not seem to affect them. The authors concluded that asbestos exposure was not associated with any specific cell pattern. They said mineralogical analysis of the fluid, which here meant counting asbestos bodies and fibres, should be considered essential, at least in workers not heavily exposed. They noted that exposure in this group was relatively low and that only 10 men had asbestosis.

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: Retrospective study of workers who underwent bronchoscopy with bronchoalveolar lavage, analysed with multivariate linear regression and zero-inflated Poisson regression models
• Who was studied: 113 male workers formerly exposed to asbestos, suspected of asbestos-related disease, hospitalized 2010-2018 at the Occupational Medicine Unit of the University Hospital of Siena, Italy; mean age 55 years (range 42-72); 19 smokers, 36 former smokers, 58 non-smokers. Patients with certain other lung and immune diseases were excluded
• Exposure: Past occupational asbestos exposure documented by occupational history, in industries including railway insulation removal and rolling stock production (13), building (12), shipbuilding (4), metal foundry (25), engineering (13), transport (5), electric energy production (24) and others (17). Chrysotile fibres, amphibole fibres and asbestos bodies were measured in the lavage fluid. The authors described exposure as medium/low
• Main results:
  • 45 of the 113 workers (40%) had non-malignant asbestos-related disease: 35 with pleural plaques and 10 with asbestosis with or without pleural plaques
  • In the whole group, geometric mean concentrations in lavage fluid were 1.11 asbestos bodies/ml, 332.44 chrysotile fibres/ml and 458.07 amphibole fibres/ml. Chrysotile was below the detection limit in 73 of 113 workers, amphiboles in 49 of 113, and asbestos bodies were undetectable in 69 of 113
  • In the multivariate linear regression (macrophages, lymphocytes, CD4/CD8 ratio), only the smoking (pack-years) coefficient was significant (p = 0.02). It was positive for macrophages and negative for lymphocytes
  • In the zero-inflated Poisson models for neutrophils and eosinophils, no coefficient was significant
  • Concentrations of asbestos bodies, chrysotile and amphibole fibres were not related to the number or types of lavage cells, nor to years since the beginning of exposure
  • There were no statistically significant correlations between lung function measurements and lavage cell findings
  • The authors described the group's lavage cell profile as normal by their laboratory's parameters, with a non-significant trend toward more lymphocytes and fewer macrophages (mean macrophages 78.54% plus or minus 16.91; mean lymphocytes 17.72% plus or minus 15.78)
• The authors' conclusion: The authors concluded that asbestos exposure was not associated with any specific lavage cell profile. Smoking modified the cell profile. Mineralogical analysis of lavage fluid should be considered essential, because cytology alone does not give enough information on asbestos exposure or on diagnosis of non-malignant asbestos-related diseases, at least in workers who were not heavily exposed
• Limitations the authors state:
  • The results may have been influenced by the relatively low asbestos exposure of the studied population
  • The asbestosis subgroup was small (10 patients), and most asbestosis cases were early CT findings in patients without symptoms
  • More than half of the group was apparently healthy and most were without symptoms, which the authors used to explain the lack of correlation with lung function
  • Exposure dated back many years for most workers, and it is unclear whether cell responses to fibres change over time. Asbestos effects on lavage cells may also be qualitative and functional, which counts do not capture

Topics

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

Medical terms in this study, explained in our Lexicon: Bronchoalveolar Lavage (BAL), Prognosis, Asbestos Exposure, Biomarker, Amphibole Group, Chrysotile, Asbestos Body Formation, Bronchoscopy.

Related studies

• Asbestos exposure assessment by mineralogical analysis of bronchoalveolar lavage fluid — P. Sartorelli, G. Scancarello, et al. (2001)
• Asbestos bodies in bronchoalveolar lavage fluids of brake lining and asbestos cement workers — P. Dumortier, P. De Vuyst, et al. (1990)
• Bronchoalveolar lavage fluid cellular profile in workers exposed to chrysotile asbestos — F.P. Kokkinis, D. Bouros, et al. (2011)
• Measurement of asbestos fibre concentrations in fluid of repeated bro-choalveolar lavages of exposed workers — P. Sartorelli, R. Romeo, et al. (2007)
• Lymphocyte subpopulations in bronchoalveolar lavage fluid in asbestos workers — A.R. Gellert, M.G. Macey, et al. (1985)
• Comparative analysis of induced sputum and bronchoalveolar lavage fluid (BALF) profile in asbestos exposed workers — E.C. Alexopoulos, D. Bouros, et al. (2011)

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