Utility of Bronchoalveolar Lavage for the Diagnosis of Asbestos-Related Diseases

Investigation of asbestos concentration in ambient and lavage fluids of patients referred for bronchoscopy, Ahvaz

Introduction

The amount of fibers in the lungs is considered to reflect the cumulative intensity of past asbestos exposure, and bronchoalveolar lavage (BAL) has been proposed to be a good indicator of the presence and quantity of asbestos particles in the lungs. This study evaluated the asbestos concentration in BAL fluids of asbestos-exposed and unexposed pulmonary patients and the environment of Ahvaz city.

Methods

This prospective study was conducted on 80 patients underwent diagnostic fiberoptic bronchoscopy referred to Imam Khomeini Hospital in Ahvaz, Iran, in 2019. Patients with Lung diseases were divided into three groups based on CT scan results: normal (n = 32), lung cancer (n = 40) and Interstitial lung disease (n = 8). The analysis of asbestos fiber concentration in BAL fluid was carried out by Scanning Electron Microscope (SEM).

Results

The positive asbestos test was detected in 69% of all subjects, including 64% of whom had asbestos-related jobs and 74.5% of those with non-related jobs (p = 0.240). The concentrations of asbestos fiber in the BAL in normal patients, lung cancer and interstitial fibrosis (ILD) were 8.13 ± 5.38, 9.66 ± 7.30 and 6.31 ± 1.98 f/ml, respectively (P = 0.492). There was no significant difference between the asbestos levels and exposure history (P = 0.877). The mean concentration of asbestos in the ambient air during the current year was 2.69 ± 0.57 f/ml (2.26-3.70), and the correlation between asbestos levels in BAL and the air was not significant (r = 0.147; P = 0.243).

Conclusions

The exposure of different occupational and non-occupational groups to this carcinogenic substance indicates the need for environmental and individual control measures to reduce and prevent asbestos exposure.

Non-neoplastic respiratory fluid cytology including cell differential counts for interstitial lung disease

Bronchioloalveolar lavage (BAL) is a non-invasive and well-tolerated procedure that plays a key role in the diagnosis of a variety of non-neoplastic pulmonary diseases, including acute respiratory failure, infection, diffuse parenchymal lung disease (DLPD), paediatric and occupational lung disease, and in the evaluation of the lung allograft. A variety of analytic techniques are commonly performed on BAL fluid, including cytology, cell differential count, microbiology and virology, as well as a number of additional techniques in specific circumstances.

Asbestos bodies count and morphometry in bulk lung tissue samples by non-invasive X-ray micro-tomography

The number of the Asbestos Bodies (AB), i.e. asbestos that developed an iron-protein coating during its permanence in biological tissues, is one of the most accessible markers of asbestos exposure in individuals. The approaches developed to perform AB count in biological tissues are based on the manual examination of tissue digests or histological sections by means of light or electron microscopies. Although these approaches are well established and relatively accessible, manual examination is time-consuming and can be reader-dependent. Besides, approximations are applied because of the limitations of 2D readings and to speed up manual counts. In addition, sample preparation using tissue digests require an amount of tissue that can only be obtained by invasive surgery or post-mortem sampling. In this paper, we propose a new approach to AB counting based on non-destructive 3D imaging, which has the potential to overcome most of the limitations of conventional approaches. This method allows automating the AB count and determining their morphometry distribution in bulk tissue samples (ideally non-invasive needle biopsies), with minimal sample preparation and avoiding approximations. Although the results are promising, additional testing on a larger number of AB-containing biological samples would be required to fully validate the method.

Validation of an Asbestos Exposure Questionnaire (QEAS-7) for Clinical Practice

Introduction: The seven-item QEAS-7 questionnaire (exposure to asbestos questionnaire) has been designed as a useful and simple tool to establish the probability of exposure to asbestos. The objective of the present study is to validate the QEAS-7 following the recommended methodology. Methods: The QEAS-7 was prospectively administered to 90 subjects with and without asbestos-related disease (ARD), on two consecutive occasions by two independent researchers. Logical and content validity was evaluated by a committee of experts and construct validity through hypothesis testing. Intra- and interobserver reliability was assessed by calculating Cohen’s Kappa index (κ), which was estimated as weak if below 0.40, moderate if between 0.41 and 0.60 and good/very good if above 0.60. The comparison between proportions was examined using Pearson’s Chi-square test. Results: The majority of participants (88.9%) were male. Mean age was 70.8 years (SD = 8.4) and most of the sample had completed primary education but had not progressed further (62.2%). Forty-three had ARD. The logical, content and construct validity of the QEAS-7 was considered adequate both by a committee of experts and by the users interviewed. The mean administration time was 9 min and 25 s (SD = 3 min and 49 s). The verification of the five hypotheses confirmed the construct validity and the intra- and interobserver reliability to be κ = 0.93 and κ = 0.50 respectively. The concordance in the estimation of asbestos exposure was κ = 0.65. Conclusions: The QEAS-7 is a simple, valid and reliable tool for estimating the probability of exposure to asbestos. Its application in clinical practice appears justified. What is already known about this subject? No studies have been published to date on the validation of specific questionnaires designed to determine asbestos exposure for routine use by healthcare staff in the clinical setting. What are the new findings? This questionnaire can be considered a comprehensible, viable, valid and reliable instrument for identifying exposure to asbestos. Its brevity and simplicity of administration make it ideally suited for use in daily clinical practice. How might this impact on policy or clinical practice in the foreseeable future? This questionnaire can be of help for physicians attending to patients with suspected asbestos-related diseases both in the hospital and in the primary care setting.

Cytological analysis of bronchoalveolar lavage fluid in asbestos-exposed workers

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.