Diagnostic value of asbestos bodies in bronchoalveolar lavage fluid

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.

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.

Asbestos exposure biomarkers in the follow-up of asbestos-exposed workers

Health surveillance of asbestos exposed workers should be stratified according to the exposure level. Unfortunately there is a lack of information regarding asbestos exposure in many working places and markers of asbestos exposure are often needed. The aim of the study was to assess the reliability of different dose and effect biomarkers in the follow up of asbestos-exposed workers. Mineralogical analysis of bronchoalveolar lavage fluid (BALF) as a biomarker of asbestos fibre burden was performed in a population of 307 male subjects occupationally exposed to asbestos. Using nonparametric statistical methods 8 variables were analyzed with respect to asbestos-related diseases and working sectors. The existence of a relationship between serum soluble mesothelin-related peptides (SMRP) and asbestos exposure levels was also investigated. Concentrations of amphiboles, chrysotile and asbestos bodies in BALF were higher in patients with asbestosis as well as in railway industry workers. A correlation between the onset of non malignant asbestos-related diseases and the levels of SMRP concentration was not found. This study confirms that fibre concentration in BALF may be considered as a reliable biomarker of previous asbestos exposure, whereas SMRP does not appear to be influenced by asbestos exposure levels.

The utility of electron microscopy in detecting asbestos fibers and particles in BALF in diffuse lung diseases

Background

In patients with diffuse lung diseases, differentiating occupational lung diseases from other diseases is clinically important. However, the value of assessing asbestos and particles in bronchoalveolar lavage fluid (BALF) in diffuse lung diseases by electron microscopy (EM) remains unclear. We evaluated the utility of EM in detecting asbestos fibers and particles in patients with diffuse lung diseases.

Methods

The BALF specimens of 107 patients with diffuse lung diseases were evaluated. First, detection of asbestos by EM and light microscopy (LM) were compared. Second, the detection of asbestos using surgically obtained lung tissues of 8 of 107 patients were compared with the results of EM and LM in BALF. Third, we compared the results of mineralogical components of particles in patients with (n = 48) and without (n = 59) a history of occupational exposure to inorganic dust.

Results

BALF asbestos were detected in 11 of 48 patients with a history of occupational exposure by EM; whereas asbestos as asbestos bodies (ABs) were detected in BALF in 4 of these 11 patients by LM. Eight of 107 patients in whom lung tissue samples were surgically obtained, EM detected BALF asbestos at a level of >1,000 fibers/ml in all three patients who had ABs in lung tissue samples by LM at a level of >1,000 fibers/g. The BALF asbestos concentration by EM and in lung tissue by LM were positively correlated. The particle fractions of iron and phosphorus were increased in patients with a history of occupational exposure and both correlated with a history of occupational exposure by a multiple regression analysis.

Conclusions

EM using BALF seemed to be superior to LM using BALF and displayed a similar sensitivity to LM using surgically-obtained lung tissue samples in the detection of asbestos. Our results also suggest that detection of elements, such as iron and phosphorus in particles, is useful for evaluating occupational exposure. We conclude that the detection of asbestos and iron and phosphorus in particles in BALF by EM is very useful for the evaluation of occupational exposure.

Asbestos bodies in bronchoalveolar lavage in the 21st century: a time-trend analysis in a clinical population

OBJECTIVES

Asbestos bodies (AB) in bronchoalveolar lavage (BAL) can be detected by light microscopy and their concentration is indicative of past cumulative asbestos exposure. We assessed clinical and exposure characteristics, as well as possible time trends, among patients in whom AB had been quantified in BAL.

METHODS

BAL samples obtained from 578 participants between January 1997 and December 2014 were available for analysis. The processing of samples and the microscopic analysis were performed by a single expert and 76% of samples came from a single tertiary care hospital, allowing clinical and exposure data to be extracted from patient files.

RESULTS

The study population (95% males) had a mean age of 62.5 (±12.4) years. AB were detected in 55.2% of the samples, giving a median concentration of 0.5 AB/mL (95th centile: 23.6 AB/mL; highest value: 164.5 AB/mL). The AB concentration exceeded 1 AB/mL in 39.4% and 5 AB/mL in 17.8%. A significant decrease from a geometric mean of 0.93 AB/mL in 1997 to 0.2 AB/mL in 2014 was apparent. High AB concentrations generally corresponded with occupations with (presumed) high asbestos exposure. AB concentrations were higher among patients with asbestosis and pleural plaques, when compared with other disease groups. Nevertheless, a substantial proportion of participants with likely exposure to asbestos did not exhibit high AB counts.

CONCLUSIONS

This retrospective study of a large clinical population supports the value of counting AB in BAL as a complementary approach to assess past exposure to asbestos.

Occupational asbestos exposure and lung cancer--a systematic review of the literature

The objective of this study was to evaluate the scientific literature concerning asbestos and lung cancer, emphasizing low-level exposure. A literature search in PubMed and Embase resulted in 5,864 citations. Information from included studies was extracted using SIGN. Twenty-one statements were evidence graded. The results show that histology and location are not helpful in differentiating asbestos-related lung cancer. Pleural plaques, asbestos bodies, or asbestos fibers are useful as markers of asbestos exposure. The interaction between asbestos and smoking regarding lung cancer risk is between additive and multiplicative. The findings indicate that the association between asbestos exposure and lung cancer risk is basically linear, but may level off at very high exposures. The relative risk for lung cancer increases between 1% and 4% per fiber-year (f-y)/mL, corresponding to a doubling of risk at 25-100 f-y/mL. However, one high-quality case-control study showed a doubling at 4 f-y/mL.

[Exposition markers: mineralogical analysis in the sputum and the bronchoalveolar lavage--asbestos bodies--uncoated fibres]

The aim of mineralogical analysis of lung tissue, bronchoalveolar lavage (BAL) and sputum is to characterize individuals' exposure to asbestos fibres by identifying markers of this; asbestos bodies (AB) and uncoated fibres. The techniques of mineralogical analysis, habitually used to identify AB and uncoated fibres, are respectively optical microscopy (OM) and analytical electronic microscopy (EM). Correlations between levels of retention of AB in lung tissue, BAL and sputum have been established and validated threshold values indicating a high probability of significant exposure exist. These results must be interpreted in the context of clinical and occupational information. Mineralogical analysis is not suitable for use in routine medical screening but it can be considered when a source of exposure is not evident from the questionnaire since a positive analysis of BAL or of sputum is highly specific and thus useful to confirm an important retention of asbestos in the lung, which justifies medical follow-up. A negative result does not exclude previous significant asbestos exposure (frequent false negatives occur especially in sputum and biopersistence of chrysotile is lower than for amphiboles). Thus it can be a complementary tool for the assessment of asbestos exposure but its use imposes conditions for the collection and handling of samples.

Mesothelioma: you do not have to work for it

Asbestos pollution is a global problem. Asbestos exposure induced mesothelioma does not require an 'occupational' type of exposure. Bystander exposures may result in earlier age of disease onset and more aggressive disease progression as described in the following 3 case reports.

Il lavaggio broncoalveolare nelle pneumopatie infiltrative diffuse

Le pneumopatie infiltrative diffuse costituiscono un gruppo eterogeneo di malattie caratterizzate, istologicamente, dalla presenza di un danno a carico della parete alveolare che puÒ essere infiltrata da cellule infiammatorie/neoplastiche/fluidi/tessuto connettivo. Si parla di forme “diffuse” per sottolineare l’interessamento non solo dell’interstizio, ma anche delle strutture acinari e bronchiolari.

An update on the detoxification processes for silica particles and asbestos fibers: successess and limitations

Inhalation of asbestos fibers and crystalline silica produces a number of diseases including fibrosis and cancer. Investigations into the mechanisms involved in mineral particle-induced toxicity indicated the importance of their surfaces in the pathological consequences. Masking of the surface sites has therefore featured prominently in a number of detoxification processes that have been investigated. The majority of the detoxification processes were, however, conducted to elucidate the involvement of a particular surface site in the toxicity of a specific mineral. Others were investigated with the aim of large industrial applications to be applied during mining, handling, processing, transporting, and disposing of minerals. It can be concluded that, to date, there is no single detoxification process that could be applied universally to all different types of mineral particles. Those that have shown some success could not completely abolish all adverse effects. Further elucidation of mechanisms of particle-induced toxicity may open new possibilities for detoxification processes.

Clinical Correlation of Asbestos Bodies in BAL Fluid

BACKGROUND

Asbestos bodies (AB) in BAL cells are specific markers of asbestos exposure.

METHODS

We retrospectively reviewed BAL cytocentrifuge slides of 30 utility workers with a history of asbestos exposure and 30 normal volunteers. BAL cytocentrifuge slides were blinded and scanned under 40 x light microscope.

RESULTS

AB were found more frequently in subjects with a history of asbestos exposure compared to normal volunteers (10 of 30 subjects, 33%, vs 0 of 30 subjects). The mean number of AB seen in the AB-positive group was 2.7 per slide. Demographic data were comparable including age, gender, and smoking. Exposure histories were also similar: duration > 20 years, onset > 30 years ago, and time since last exposure > 7 years. More AB-positive patients reported respiratory symptoms (70% vs 26%, p < 0.05). High-resolution CT scans of AB-positive patients revealed a higher prevalence of parenchymal disease (70% vs 26%, p < 0.05). AB-positive subjects had reduced pulmonary function compared to AB-negative subjects: FVC (86% vs 97% predicted), FEV(1) (77% vs 92% predicted, p < 0.05), and diffusion capacity of the lung for carbon monoxide (76% vs 104% predicted, p < 0.01).

CONCLUSION

In individuals with a history of asbestos exposure, the presence of AB in BAL cells is associated with higher prevalence of parenchymal abnormalities, respiratory symptoms, and reduced pulmonary function.

Asbestos exposure assessment by mineralogical analysis of bronchoalveolar lavage fluid

Mineralogical analysis of bronchoalveolar lavage fluid (BALF) by electron microscopy can represent the most suitable method for assessing asbestos exposure. However, it has been claimed that no standardized or systematic approach to the subject of mineralogical analysis exists. This study aimed to evaluate BALF mineralogical analysis by transmission electron microscopy as biomarker of asbestos fiber load. BALF was examined in 108 exposed workers and 57 patients who underwent diagnostic fiberoptic bronchoscopy for various clinical purposes. Asbestos bodies in BALF were counted with a phase-contrast microscope. Fibers were counted and analyzed by transmission electron microscopy, which showed a significant difference between the two populations and positive results for all exposed subjects. Only 82.2% of the exposed population tested positive for asbestos bodies. Subjects with long-term exposure had higher concentrations of fibers than did those with more recent exposure, probably because of the higher workplace exposure levels in the past. The results of the study confirm that fiber concentration in BALF can be considered as a reliable biomarker of past asbestos exposure, even many years after the end of exposure.

Pseudoasbestos bodies and fibers in bronchoalveolar lavage of refractory ceramic fiber users

Refractory ceramic fibers (RCF) are widely used to replace asbestos in applications requiring high heat resistance. Ferruginous bodies mimicking asbestos bodies (ABs) have been detected in the lungs of RCF production workers. This raises the question about their presence in other occupational groups and whether "typical ABs" still reflect past asbestos exposures in all settings. An AB counting by phase-contrast light microscopy and a screening test by analytical electron microscopy were systematically performed on all bronchoalveolar lavage fluids (BALF) submitted to our laboratory in 1992 through 1997 (n = 1,800). When RCF were detected in electron microscopy, the structures considered as "typical ABs" were marked under light microscopy and prepared for further chemical and structural analysis. Pseudo-ABs on RCF were detected in samples from nine subjects (0.5%). All of them had worked either as foundry workers, steel workers, or welders. In these subjects, alumino-silicate fibers compatible with RCF accounted for 42% of the core fibers analyzed, other nonasbestos fibers for 28%, and asbestos fibers for 30%. ABs thus remain a valid marker of asbestos retention but attention must be paid to a possible occurrence of pseudo-asbestos bodies on RCF and other nonasbestos fibers in end-users of refractory fibers.

Role of bronchoalveolar lavage in interstitial lung disease

Bronchoalveolar lavage remains an important research tool in understanding ILD. It is still an important part of the clinical management of patients with ILD. It is most useful in detecting unusual forms of ILD. It helps the clinician narrow down the possible causes of the interstitial pattern. It also can confirm a clinical impression of certain conditions. Although rarely diagnostic, it is often supportive. In conjunction with high-resolution CT scan, most patients with ILD can be diagnosed using relatively noninvasive methods.

The role of environmental and occupational exposures in Turkish immigrants with fibre-related disease

Environmental exposure to tremolite and erionite causes endemic diseases of the lung and pleura in Turkey. This study aimed to evaluate the impact of these exposures and further occupational exposures on fibre-related diseases in Turkish immigrants living in Belgium. The study included 51 males and 17 females that emigrated < 1-38 yrs ago. Most of them (n=46) had nonmalignant pleural lesions, one had asbestosis and one had mesothelioma. Environmental asbestos exposure was likely for the majority of patients (60%), but there were also reports of possible occupational asbestos (n = 14) and erionite (n = 2) exposure. Tremolite was the main fibre type in bronchoalveolar lavage fluid (BALF). Elevated concentrations of amosite or crocidolite were detected in only two patients. The delay elapsed since the end of the environmental exposure had no influence on the asbestos body or the tremolite fibre concentrations in the BALF of Turkish immigrants. Most fibre-related diseases in Turkish immigrants are probably due to environmental rather than occupational exposure. Precise information about geographical origin and occupation should be obtained when investigating these patients. Mineralogical analysis of bronchoalveolar lavage fluid gives valuable information on the type and intensity of exposure, especially in patients with both environmental and occupational exposure.

Erionite bodies and fibres in bronchoalveolar lavage fluid (BALF) of residents from Tuzköy, Cappadocia, Turkey

OBJECTIVES

The high incidence of malignant mesothelioma in some villages of Cappadocia (Turkey) is due to environmental exposure to erionite fibres. The aim was to evaluate the fibre burden in bronchoalveolar lavage fluid (BALF) from inhabitants of an erionite village and compare it with Turkish subjects with or without environmental exposure to tremolite asbestos.

METHODS

Ferruginous bodies (FBs) and fibres were measured and analyzed by light and transmission electron microscopy (TEM) in the BALF of 16 subjects originating from Tuzköy.

RESULTS

FBs were detected in the BALF of 12 subjects, with concentrations above 1 FB/ml in seven of them. Erionite was the central fibre of 95.7% of FBs. Erionite fibres were found in the BALF of all subjects, by TEM, and these fibres were low in Mg, K, and Ca compared with erionite from Tuzköy soil. The mean concentration of erionite fibres in BALF was similar to that of tremolite fibres in Turks with environmental exposure to tremolite. The proportion of fibres longer than 8 microm in BALF represented 35.6% for erionite compared with 14.0% for tremolite. The asbestos fibre concentrations in erionite villagers was not different from that in Turks without environmental exposure to tremolite.

CONCLUSION

Analysis of BALF gives information about fibre retention in populations environmentally exposed to erionite for whom data on fibre burden from lung tissue samples are scarce. This may apply to exposed Turks having emigrated to other countries.

Medical examination for asbestos-related disease

There are millions of workers whose exposure to asbestos dust prior to the implementation of asbestos regulation and improved control measures places them at risk of asbestos-related disease today. In addition, workers are still being exposed to significant amounts of asbestos, when asbestos materials in place are disturbed during renovation, repair, or demolition. Given the continued presence of asbestos-containing materials in industrial, commercial, and residential settings throughout the U.S., a sizeable population remains at risk of asbestos-related disease. This article reviews the health effects associated with exposure to asbestos and delineates the steps necessary for the comprehensive screening and clinical assessment for asbestos-related disease, in order to assist physicians in identifying and preventing illness associated with exposure to asbestos among their patients.

Assessment of environmental asbestos exposure in Turkey by bronchoalveolar lavage

Environmental or domestic exposure to asbestos fibers originating from local soil is responsible for a high incidence of diseases in large rural areas of Turkey. Bronchoalveolar lavage fluids (BALF) were obtained for 65 Turkish subjects originating from these areas and for 42 Turkish controls. Asbestos bodies (ABs) and uncovered fibers (UFs) were quantified by phase contrast light microscopy. Total fiber burden was determined by transmission electron microscopy. The main asbestos types disclosed were tremolite and to a lesser extent chrysotile. AB and fiber concentrations were higher in environmentally exposed subjects (geometric mean [geometric standard deviation]: 5.20 [6.22] AB/ml, 444 [11.6] tremolite fibers/ml) than in control subjects (0.22 [1.45] AB/ml, 12.0 [15.4] tremolite fibers/ml) (p < 0.001). In subjects environmentally exposed in Turkey, AB burdens on tremolite were in the same range as those on commercial amphiboles in subjects occupationally exposed in Belgium. In Turkish subjects, values above either 1 AB/ml, 3 uncovered fiber/ml in light microscopy, or 300 fibers/ml in electron microscopy indicated usually an abnormal alveolar retention reflecting a significant cumulative exposure from environmental or domestic origin. These observations are probably valid for other areas in the world where diseases associated with environmental exposure to soil- derived asbestos fibers occur and for immigrants originating from these areas.

Electron microscopic microanalysis of bronchoalveolar lavage: a way to identify exposure to silica and silicate dust

OBJECTIVES

The diagnostic implications of finding non-fibrous inorganic particles in bronchoalveolar lavage (BAL) fluid has not been fully assessed. The aim of this study has been to measure the silica and non-fibrous silicates in BAL fluid from populations with different exposures to inorganic dust, and to find whether such measurement is useful for diagnostic purposes.

MATERIALS AND METHODS

BAL samples from 19 subjects with only environmental exposure to inorganic dust (group A, mean (SD) age 50.7 (15.2)), 23 subjects with normal chest x ray films exposed to silica or silicates at work (group B, mean (SD) age 52.0 (12.4)), and 15 subjects with a previous diagnosis of silicosis (group C, mean (SD) age 68.0 (6.5)) were studied. Absolute and relative cell counts were found, and the samples were prepared for microanalysis by electron microscopy (EM). Firstly, semiquantitative x ray microanalysis was performed to find the level of silicon (Si) (peak/background Si) and this was followed by microanalysis of individual particles by EM. Variables related to the level of Si detected were assessed with multivariate analysis.

RESULTS

Detected levels were higher in group B (2.09, 95% confidence interval (95% CI) 1.56 to 2.82) and C (1.50, 95% CI 1.07 to 2.12) than in group A (0.87, 95% CI 0.66 to 1.16) (P < 0.05, Dunett t test). A first multivariate analysis showed that exposure to silica or silicates was the only determinant of the level of Si expressed as log peak/background Si, when adjusted for age, sex, smoking habit, and cell count. A second multivariate analysis with microanalysis of individual particles as an independent variable showed the silica count to be the main predictor of detected concentration of Si. Silica and non-aluminium silicates together explain 55.5% (R2) of the variation in detected levels of Si.

CONCLUSIONS

Detected levels of Si in BAL fluid depend on silica count and are higher in subjects with exposure to inorganic dust at work, but will not discriminate between exposed subjects with and without silicosis. Because semiquantitative x ray microanalysis does not accurately define exposure to non-silica inorganic particles, this measurement must be followed by EM microanalysis of individual particles in most cases, especially when exposure to silicates or metal dust is suspected.

Respiratory disease as a result of talc inhalation

Three cases of respiratory disease in workers with occupational exposure to talc containing asbestos fibers are reported. Standard chest roentgenographs, high-resolution computed tomography, respiratory function tests, morphologic study of bronchoalveolar lavage fluid (BAL), light microscopic examination, and mineralogical analysis by transmission electron microscopy (TEM) of BAL was performed. All subjects showed bilateral pleural plaques, and in two subjects the study of BAL revealed lymphocytic alveolitis with an increased T4/T8 ratio. Mineralogical analysis of BAL detected asbestos-fiber concentrations of 510, 2039, and 3392 fibers/mL and many asbestos bodies. In one patient, mineralogical analysis of lung tissue was also performed; a concentration of 3,659,000 fibers/g dry tissue was found. Simultaneously, we performed a mineralogical study of 12 commercial talc samples, including those used by the patients during the last phase of their working lives. TEM revealed asbestos fibers in five samples. Two subjects used two of these talc powders. The study presented here confirms the need to perform all relevant clinical tests together with the study of BAL and mineralogical analysis of the materials to which the patients are or were exposed to determine occupational exposure to fibers, including those associated with talc, which are often misidentified.

Asbestos bodies in bronchoalveolar lavage fluid in relation to occupational history

Concentrations of asbestos bodies (AB) were assessed by optical microscopy of 10 ml iron-stained samples and compared with the exposure history acquired by personal interview for 156 patients. Concentrations equalling or exceeding 1 AB/ml were found in 85% of patients who had been heavily exposed to asbestos and only 7% of those who were unlikely to have been exposed. Elevated AB concentrations were observed among primary asbestos, shipyard and construction workers. Smoking was not found to affect the AB concentrations. The use of Papanicolaou-stained cytological Millipore preparations during routine screening was a less sensitive method for the assessment of AB concentrations than that involving iron-stained preparations. The expression of AB concentration as AB/ml or AB/million cells were found to be equally useful indicators of exposure. The correlation between AB concentration and exposure history was greater than in earlier studies on workers exposed to chrysotile. Concentrations exceeding 1 AB/ml were indicative of a nontrivial exposure to asbestos. Despite the observed correlation between AB concentration and exposure history, the individual variability of AB counts, methodological differences and laboratory-bound reference values are important in the interpretation of AB concentrations in bronchoalveolar lavage (BAL) fluid at individual level.

Pleural plaques, asbestos exposure, and asbestos bodies in bronchoalveolar lavage fluid

The profiles of occupational asbestos exposure were investigated in a series of 66 hospital patients in whom pleural plaques constituted the only asbestos-induced abnormality. The relationship between a radiological semiquantitative score of pleural plaques and indices of asbestos exposure was also examined. On the basis of a standardized occupational questionnaire, four classes of asbestos exposure were distinguished in our study population: no evidence of exposure, low-level exposure, sporadic exposure at higher levels, and a remaining group of individuals with substantial exposure. Asbestos body count in bronchoalveolar lavage fluid (BALF) was used as an objective indicator of cumulative lung retention of asbestos. Our results support the data indicating that pleural plaques may occur in subjects with low-level or sporadic asbestos exposure. Although it is admitted that pleural plaques are strongly associated with past asbestos exposure, our data suggest that the stage of pleural plaques was not correlated to the level, frequency, duration of exposure nor to the amount of asbestos bodies in the BALF in subjects free of any lung parenchymal abnormalities on high resolution computerized tomography.

Use of anti-TNF-alpha antiserum to investigate toxic alveolitis arising from cotton dust exposure

Cotton dust has been associated with byssinosis and toxic alveolitis. A murine animal model has been developed with which to investigate the pathogenesis of these disorders. Studies with the model have reproduced the neutrophilic inflammation characteristic of the alveolitis, and have shown the presence of tumor necrosis factor-alpha (TNF-alpha) in the bronchoalveolar lavage (BAL) fluid. The current study investigated the role of TNF-alpha in the inflammatory response by use of a polyclonal antiserum to recombinant murine TNF-alpha. Following a 4-h exposure to cotton dust, experimental animals showed a 40-fold increase in BAL cells with 92% neutrophils. There was a 24-fold increase in TNF-alpha in the BAL fluid. Up regulation of TNF-alpha mRNA expression was detected in BAL cells. Mice pretreated with anti-TNA-alpha antiserum displayed a marked attenuation of the neutrophilic inflammation; however, the level of TNF-alpha mRNA expression was not reduced in these mice. These studies support a major role of TNF-alpha in the toxic alveolitis induced by cotton dust inhalation.

Retention of asbestos bodies in the lungs of welders

Examination of asbestos bodies (AB) retained in the lungs is a useful way of assessing past occupational exposure to this material. AB retention has been extensively studied in workers directly exposed to asbestos, but less so in those end users, such as welders, who use asbestos-containing products. We therefore retrospectively studied AB retention in 211 welders, for whom biological testing procedures had been requested by a chest physician, between 1988 and 1991. Optical microscopy of AB was performed on samples of sputum (40 subjects), bronchoalveolar lavage fluid (BAL) (147 subjects), and lung tissue obtained after thoracotomy (38 subjects). Information on previous jobs and exposure was obtained using a questionnaire (the mean duration of welding activities was 16.6 years). Eighty-two subjects (38.9%) had elevated lung retention of AB in all the samples studied. Significant AB retention occurred in only 30% of sputum samples, but in 40.1% of BAL samples and 39.5% of lung tissue samples. The duration of welding activities correlated with the density of AB in BAL or lung tissue (r = 0.31, p < 0.01 and r = 0.49, p < 0.05, respectively). On the basis of the questionnaire, only two of the welders with significant AB retention had other occupational exposure to asbestos. Our findings suggest that welding activities may increase lung retention of AB, and consequently might produce higher risks of fibrotic and/or malignant pulmonary diseases. These potential risks need to be brought to the attention of doctors; a longitudinal follow-up may also be warranted in such populations, even after individuals have ceased their welding jobs.

Pleural mesothelioma and exposure to asbestos: evaluation from work histories and analysis of asbestos bodies in bronchoalveolar lavage fluid or lung tissue in 131 patients

Exposure to asbestos was evaluated in 131 patients with pleural malignant mesothelioma in the Paris area between 1986 and 1992 using data from a detailed specific questionnaire and light microscopy analysis of the retention of asbestos bodies in bronchoalveolar lavage fluid or lung tissue. Probable or definite exposure to significant levels of asbestos dust was identified in only 48 (36.6%) subjects, and significant asbestos body counts (above 1 asbestos body/ml in bronchoalveolar lavage fluid or 1000 asbestos bodies/g of dry lung tissue) were found in only 45 (34.3%) subjects. Overall 50 subjects had experienced exposure to only low levels of asbestos or no exposure at all and showed no significant retention of asbestos bodies in the biological sample analysed. Previous studies have shown that light microscopy may be useful in the identification of subjects with previous exposure to asbestos. In this study, apart from cases with obvious exposure to asbestos, a large group of subjects seemed to have a history of exposure or lung retention of asbestos bodies suggestive of very low levels of cumulative exposure, similar to those described in the general population.

Analysis of ferruginous bodies in bronchoalveolar lavage from foundry workers

Classical ferruginous bodies in tissue samples are considered to be markers of past exposure to asbestos. Recent studies have shown that the presence of ferruginous bodies in bronchoalveolar lavage (BAL) fluid correlates with past exposure to asbestos and offers a more sensitive reference than occupational history. Lavage samples from five subjects who had worked in foundries were evaluated by light microscopy for the presence of ferruginous bodies and by transmission electron microscopy for both characterisation of the uncoated fibre burden and analysis of the cores of the ferruginous bodies. All samples at lower magnification (light microscopy (200 x)) contained ferruginous bodies that were externally consistent with asbestos bodies. At higher magnification (400 x), a separate population from this group could be identified by the presence of a thin black ribbon. Transmission electron microscopy of the core materials of ferruginous bodies and comparable uncoated particulates supported the reliability of higher magnification light microscopy for distinguishing most of those non-asbestos cores; however, a population of transparent non-asbestos cored ferruginous bodies were also shown to exist.

Distribution of asbestos bodies in the human lung as determined by bronchoalveolar lavage

Asbestos-related lung diseases tend to have distinct local distributions, for example, asbestosis first appears and tends to be more severe in the peripheral parts of the lower lung zones. The risk for asbestosis is related to the total asbestos burden of the lung. This suggests that the lower lobes in asbestos-exposed individuals may contain more asbestos than the other lobes. To test whether such topographic differences exist, we compared the number of retrieved asbestos bodies (AB) per ml BAL fluid in three groups of occupationally asbestos-exposed subjects who underwent BAL at different sampling sites. In Group 1 (n = 24) we performed BAL at three sites, namely in a segment of the right upper, right middle, and right lower lobe, to evaluate differences in asbestos body burden from lung apex to basis. There was a distinct increase in BAL asbestos body concentrations from the upper (21.2 +/- 9.1 AB/ml BAL fluid) to the middle (30.4 +/- 12.8 AB/ml BAL fluid) and to the lower lobe (56.0 +/- 20.2 AB/ml BAL fluid), all differences being significant (p < 0.01). In Group 2 (n = 40), we found good interlobar correlations for asbestos body counts between the right middle lobe (21.0 +/- 5.8 AB/ml BAL fluid) and the lingula (22.4 +/- 5.9 AB/ml BAL fluid) (r = 0.941, p < 0.001) and, in Group 3 (n = 15), between the ventral basal segment of the right (41.2 +/- 13.6 AB/ml BAL fluid) and left lung (39.0 +/- 13.6 AB/ml BAL fluid) (r = 0.966, p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Cellular and biochemical indices of bronchoalveolar lavage for detection of lung injury following insult by airborne toxicants

Cellular and biochemical profiles of bronchoalveolar lavage (BAL) material after inhalation or intratracheal exposure to various airborne toxicants clearly reflect that BAL has the potential of being a useful tool for the rapid screening of lung injury. The cellular and biochemical responses not only predict inflammation, extent of tissue damage and toxic nature of the substances, but could also help in understanding the molecular mechanisms of pathogenicity. Depending upon the changes of BAL in animals acutely exposed to a pulmonary toxicant, future in-depth studies along with complete histopathological evaluations could be made. Also, the assessment of macromolecules of pharmacological importance in the lavage, especially the secretory products of alveolar macrophages and other lung cell types, could be very useful in predicting the toxic potential of various airborne substances and could also serve as important indicators of developing chronic lung diseases and, therefore, necessitate further studies.

The clinical utility and reliability of asbestos bodies in bronchoalveolar fluid

Although asbestos bodies are easily identified in bronchoalveolar lavage (BAL) fluid and are thought to be strongly associated with the asbestos body burden in the lung parenchyma, the clinical utility and reliability of this biologic measure of exposure has not been sufficiently studied. To assess the clinical relevance of BAL asbestos bodies we compared this bioassay of exposure to other measures of exposure and also indices of lung disease in asbestos-exposed workers (n = 71). The median concentration of asbestos bodies was 0.8 bodies per ml of BAL fluid (range 0 to 34.3). Seven workers or 9.9% had zero asbestos bodies identified in the BAL fluid. The concentration of BAL asbestos bodies was not associated with the duration of exposure (r = -0.02), the time from first exposure to asbestos (r = 0.12), or the time since last exposure to asbestos (r = 0.05). Moreover, radiographic and physiologic measures of asbestos-induced lung disease were not found to be associated with the concentration of BAL asbestos bodies. In fact, of the seven study subjects with zero BAL asbestos bodies, the mean duration of exposure was 32 yr, and six of these subjects had radiographic evidence of asbestos-induced lung disease. To assess the reliability of measuring BAL asbestos bodies, we performed a second bronchoscopy on 54 subjects and directly compared the concentration of BAL asbestos bodies from both the first and second BAL samples. Within these 54 subjects, the concentration of BAL asbestos bodies was found to be a very reliable measure (r = 0.76; p = 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

The usefulness of bronchoalveolar lavage in identifying past occupational exposure to asbestos: a light and electron microscopy study

Fiberoptic bronchoscopy has permitted the development of lavage procedures for the collection of lung washes. In certain disease states this material may contain large numbers of phagocytic cells (macrophages and neutrophils). Since these phagocytes are the predominant "dust scavenger cells" in the lung, the assessment of their particulate burden as well as that of the overall lavage material has been suggested as a potentially important diagnostic tool. The studies to date have shown that the presence of ferruginous bodies is an indication of past occupational exposure. In the present study, a digestion procedure was carried out on bronchoalveolar lavage material collected from individuals who were occupationally exposed to asbestos and from samples obtained from the general population. The parameters used for distinguishing the source of these samples included both light microscopy assessment of the filters for the presence of ferruginous bodies and electron microscopic screening for the presence of uncoated fibers.

Clinical role of bronchoalveolar lavage in adults with pulmonary disease

BAL remains a powerful investigative tool. In a short span of 20 yr, it has helped tremendously in understanding some of the aspects of the pathogenesis of diseases involving the lower respiratory tract. To realize its full potential in the diagnosis and management of diseases involving the lower respiratory tract, there is a great need for standardization of the technical aspects of BAL as well as processing and analysis of the BAL cellular- and fluid-phase components. Despite these hurdles, BAL has been found to be diagnostic in several infectious and noninfectious diseases involving the lower respiratory tract, and it provides valuable information that may be helpful in characterizing the prognosis and response to therapy in certain interstitial diseases of the lung. It is expected that with future research, in particular long-term prospective epidemiologic and clinical studies in pneumoconioses and in other interstitial lung disease, BAL will prove more valuable in the diagnosis and management of such disease.

Asbestos bodies in bronchoalveolar lavage fluids of brake lining and asbestos cement workers

Asbestos body (AB) concentrations in bronchoalveolar lavage samples of 15 brake lining (BL) workers exposed only to chrysotile have been determined and compared with those from 44 asbestos cement (AC) workers extensively exposed to amphiboles. The mean AB concentrations (263 +/- 802 and 842 +/- 2086 AB/ml respectively) for those groups did not differ significantly but were much higher than those found in control groups. Analytical electron microscopy of asbestos body cores showed that in the BL group 95.6% were chrysotile fibres whereas in the AC group amphiboles accounted for 93.1%. The size characteristics of the central fibres differed for chrysotile and amphibole AB, the former being shorter and thinner. Examination of repeated bronchoalveolar lavage samples showed that the mechanisms of clearance of chrysotile fibres do not affect AB concentration for at least 10 months after cessation of exposure. It thus appears that routine counting of ABs in BAL allows the assessment of current or recent occupational exposures to asbestos. Exposures to chrysotile lead to AB concentrations comparable with those encountered in exposures to amphiboles.

Bronchoalveolar lavage

The technique of BAL performed through the fiberoptic bronchoscope has, in two decades, provided clinicians and researchers with the ability to safely sample the inflammatory-immune cell milieu of the human lung. Standardized BAL and processing of the lavage constituents provides assistance in determining the optimal care of patients with a variety of lung diseases, and renders diagnosis in selected cases. It has become indispensable in the diagnosis of pulmonary infiltrates in immunocompromised patients, and plays an important role in improving clinical management. Finally, it continues to yield an ever increasing amount of data for the researchers studying the mechanisms and pathogenesis of lung disease. It is likely that BAL will become an even more valuable tool with increasing relevance to the practice of chest medicine in the 1990s.

Asbestosis occurring after brief inhalational exposure: usefulness of bronchoalveolar lavage in diagnosis

A case of clinically and radiologically typical asbestosis manifesting in a 55 year old man occurred 36 years after a brief exposure period of less than one year. A transbronchial lung biopsy was performed but the samples were considered non-diagnostic. The diagnosis was supported by the use of bronchoalveolar lavage to obtain alveolar samples and scanning electron microscopy-energy dispersive x ray analysis of fibres found in the bronchoalveolar lavage fluid which showed a predominance of amosite.

Bronchoalveolar lavage cell and lymphocyte phenotype profiles in healthy asbestos-exposed shipyard workers

The cellular and lymphocyte phenotypic composition of bronchoalveolar lavage (BAL) fluid and peripheral blood (PB) from 15 healthy, nonsmoking, asbestos-exposed shipyard workers (AEW) and 10 nonsmoking, age-matched unexposed workers (UEW) were compared. None of the AEW had clinical, radiographic, or physiologic evidence of asbestosis, but six had radiographic evidence of pleural plaques and/or thickening. The mean duration of asbestos exposure was 16.3 +/- 2.3 yr, and the mean period since exposure was 10.8 +/- 0.5 yr. All but three of the AEW and none of the UEW had asbestos bodies detected in the first 20 ml of BAL fluid recovered (0.1 to 35 asbestos bodies/ml). The AEW had a significantly higher mean percentage (19.1 +/- 2.8% versus 9.7 +/- 1.6%) and concentration (31.6 +/- 5.2 x 10(3) cells/ml versus 14.7 +/- 2.5 x 10(3) cells/ml) of BAL lymphocytes compared with that in the UEW, with an increased mean concentration of each phenotype measured. In PB, the mean lymphocyte concentration was also higher in the AEW than in the UEW (2.0 +/- 0.3 x 10(3) cells/ml versus 1.5 +/- 0.3 x 10(3) cells/ml), but the difference was not statistically significant, and there was no increase of any phenotype measured. BAL lymphocytosis did not correlate with exposure history or BAL asbestos body count, but was greater in AEW with pleural abnormality (30.1 +/- 2.9% versus 11.8 +/- 1.6%). BAL concentrations of CD-20, CD-3, and CD-4, but not of CD-8 cells were significantly increased compared with those in the AEW without pleural abnormality. Further longitudinal studies are needed to determine the prognostic significance of these findings.