Clinical Correlation of Asbestos Bodies in BAL Fluid

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.

Bronchoalveolar lavage as a diagnostic procedure: a review of known cellular and molecular findings in various lung diseases

Bronchoalveolar lavage (BAL) is a commonly used procedure in the evaluation of lung disease as it allows for sampling of the lower respiratory tract. In many circumstances, BAL differential cell counts have been reported to be typical of specific lung disorders. In addition, more specific diagnostic tests including molecular assays such as polymerase chain reaction (PCR) or enzyme-linked immunosorbent assay, special cytopathologic stains, or particular microscopic findings have been described as part of BAL fluid analysis. This review focuses on common cellular and molecular findings of BAL in a wide range of lung diseases. Since the performance of the first lung irrigation in 1927, BAL has become a common and important diagnostic tool. While some pulmonary disorders have a highly characteristic signature of BAL findings, BAL results alone often lack specificity and require interpretation along with other clinical and radiographic details. Development of new diagnostic assays is certain to reinforce the utility of BAL in the future. Our review of the BAL literature is intended to serve as a resource to assist clinicians in the care of patients with lung disorders.

Imaging of Occupational Lung Disease

Occupational lung diseases span a variety of pulmonary disorders caused by inhalation of dusts or chemical antigens in a vocational setting. Included in these are the classic mineral pneumoconioses of silicosis, coal worker's pneumoconiosis, and asbestos-related diseases as well as many immune-mediated and airway-centric diseases, and new and emerging disorders. Although some of these have characteristic imaging appearances, a multidisciplinary approach with focus on occupational exposure history is essential to proper diagnosis.

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.

Reduced lung function in smokers in a lung cancer screening cohort with asbestos exposure and pleural plaques

BACKGROUND

While low dose computed tomography (LDCT) screening for lung cancer is recommended for high-risk smokers, ages 55-74 years, information about asbestos exposure may not be routinely elicited. Asbestos exposure is associated with declining respiratory function over time; however, the effect of a history of asbestos exposure in LDCT screening cohorts is limited. We report the relationship between asbestos exposure and pulmonary function in a cohort of heavy smokers with a history of occupational asbestos exposure, hypothesizing that these subjects will have additional decreased pulmonary function. We also examined relationships between spirometric measurements and the presence of isolated pleural plaques.

METHODS

A cross-sectional study was performed using data from the NYU Lung Cancer Biomarker Center cohort to compare study subjects with a history asbestos exposure primarily in the period since 1970 when tighter federal standards were in place (n = 359) to those without asbestos exposure (n = 1038) with respect to pulmonary function, LDCT lung imaging findings, and clinical symptoms. We further classified individuals with asbestos exposure by length of exposure time to examine the effect of duration of exposure on pulmonary function. Lastly, for asbestos-exposed participants, we examined the association of spirometric measurements with the presence of absence of isolated pleural plaques.

RESULTS

Individuals with asbestos exposure had decreased FVC % predicted compared to those with no asbestos exposure (76% vs. 85% predicted, P < 0.01) and FEV1 % predicted (64% vs. 67% predicted, P < 0.01). Since there was no change in FEV1 /FVC ratio, the findings are consistent with restrictive impairment. Those with ≥20 years of exposure had a lower mean FVC % predicted compared to those with less than 20 years of exposure (74% vs. 78% predicted, P = 0.017). Individuals with asbestos exposure were more likely to have pleural plaques (P < 0.001) on CT. Those with isolated pleural plaques had lower mean % predicted FEV1 (P = 0.005) and FVC (P = 0.001) compared to those without pleural plaques.

CONCLUSIONS

Occupational asbestos exposure in a cohort of heavy smokers was associated with a significant restrictive decline in pulmonary function, with longer duration of exposure associated with greater decline. The presence of isolated pleural plaques was also associated with reduced lung function.

A review on airway biomarkers: exposure, effect and susceptibility

Current research in pulmonology requires the use of biomarkers to investigate airway exposure and diseases, for both diagnostic and prognostic purposes. The traditional approach based on invasive approaches (lung lavages and biopsies) can now be replaced, at least in part, through the use of non invasively collected specimens (sputum and breath), in which biomarkers of exposure, effect and susceptibility can be searched. The discovery of specific lung-related proteins, which can spill over in blood or excreted in urine, further enhanced the spectrum of airway specific biomarkers to be studied. The recent introduction of high-performance 'omic' technologies - genomics, proteomics and metabolomics, and the rate at which biomarker candidates are being discovered, will permit the use of a combination of biomarkers for a more precise selection of patient with different outcomes and responses to therapies. The aim of this review is to critically evaluate the use of airway biomarkers in the context of research and clinical practice.

Asbestos-related pleuropulmonary diseases: benign and malignant

Asbestos is known for its desirable properties of thermal and heat resistance along with excellent strength and durability. It was widely used in many industries since the late 19th century, until its adverse effects on health were recognized. The occurrence of pleuropulmonary changes from exposure to asbestos often has a latency period of 20 to 30 years. The use of asbestos has been banned, regulated, and minimized in many countries, but in several developing countries, the use of asbestos in industries is still a common practice. In this article, the benign and malignant clinical manifestations of asbestos exposure are discussed.

Bronchoalveolar lavage fluid cellular profile in workers exposed to chrysotile asbestos

The cellular profile of bronchoalveolar lavage fluid (BALF) in asbestos-exposed population remains controversial. We, therefore, aimed to investigate BALF in apparently healthy individuals that were exposed in asbestos-related work for a long period of time. Participants were selected among employees of a car brakes and clutches factory that used chrysotile asbestos. Selection criteria were an employment history of ≥15 years and the absence of severe respiratory disease. The total number and type of BALF cells, the existence of dust cells, iron-laden macrophages and asbestos bodies were assessed. Thirty-nine workers (25 men), with a mean age of 46.2 ± 4.2 years and a mean employment time of 23.5 ± 4 years, participated. Asbestos bodies were observed in 14 out of 39 (36%) specimens, dust cells in 37 and iron-laden macrophages in all. Those with asbestos bodies had at least 3 times higher probability to have lymphocytosis (lymphocytes > 11%: 64% vs 28%, p = 0.027) and had an increased percentage of iron-laden macrophages compared to those without asbestos bodies (median values: 42% vs 13%, p = 0.08). Smokers (36%) had less lymphocytes compared to non and ex-smokers (median values: 6% vs. 13%, p = 0.002), and iron-laden macrophages count had a positive relation (r = 0.31, p = 0.05) to lymphocyte count. Asbestos-exposed asymptomatic individuals with the presence of asbestos bodies in the BALF are more likely to have lymphocytic alveolitis while concurrent dust exposure and smoking habits hold a significant role.

Padrões tomográficos das doenças intersticiais pulmonares difusas com correlação clínica e patológica

A tomografia de alta resolução (TCAR) é a técnica de imagem radiológica que reflete mais de perto as alterações da estrutura pulmonar. Os vários achados tomográficos podem ser combinados para formar padrões típicos. Estes, conjuntamente com a distribuição anatômica dos achados, e com os dados clínicos, podem estreitar o diagnóstico das doenças intersticiais pulmonares difusas, e em vários casos sugerir o diagnóstico correto com alto grau de acurácia. Os padrões mais comuns das doenças intersticiais pulmonares difusas na TCAR são o nodular, linear e reticular, lesões císticas, opacidades em vidro fosco e consolidações. Este artigo revisa as correlações entre os padrões tomográficos na TCAR e os achados patológicos e resume as causas mais comuns e os métodos de investigação para se atingir um diagnóstico nas doenças pulmonares crônicas difusas mais comuns.

Cytology of nonneoplastic occupational and environmental diseases of the lung and pleura

CONTEXT

Cytologic examination of the respiratory tract has been a useful diagnostic tool when evaluating neoplastic lesions of the respiratory tract. However, we have limited experience in the application of this technique in the management of nonneoplastic occupational and environmental diseases of the lung and pleura. This review focuses on the cytologic characteristics of a variety of occupational lung diseases, grouping them into 2 broad diagnostic categories: reactive cellular changes and noncellular elements. The former includes entities such as reactive mesothelial proliferation, goblet cell metaplasia, Creola bodies, and reserve cell hyperplasia, and the latter encompasses Curschmann spirals, Charcot-Leyden crystals, and asbestos bodies.

OBJECTIVE

To illustrate the cytologic features of several nonneoplastic occupational and environmental diseases and correlate the cytology with various etiologic agents.

DATA SOURCES

Case-derived material and literature review.

CONCLUSIONS

The role of cytology in the diagnosis of nonneoplastic occupational and environmental lung diseases is limited. This may be because more than one agent can elicit a similar host reaction and/or the offending agent can be associated with more than one pathologic process. However, in the appropriate clinical and radiographic setting, the cytology can render valuable diagnostic information. Examples include pulmonary alveolar proteinosis in patients with acute silicoproteinosis and asbestos bodies in bronchoalveolar lavage samples of patients with asbestos exposure.

Pneumoconiosis: comparison of imaging and pathologic findings

Pneumoconiosis may be classified as either fibrotic or nonfibrotic, according to the presence or absence of fibrosis. Silicosis, coal worker pneumoconiosis, asbestosis, berylliosis, and talcosis are examples of fibrotic pneumoconiosis. Siderosis, stannosis, and baritosis are nonfibrotic forms of pneumoconiosis that result from inhalation of iron oxide, tin oxide, and barium sulfate particles, respectively. In an individual who has a history of exposure to silica or coal dust, a finding of nodular or reticulonodular lesions at chest radiography or small nodules with a perilymphatic distribution at thin-section computed tomography (CT), with or without eggshell calcifications, is suggestive of silicosis or coal worker pneumoconiosis. Magnetic resonance imaging is helpful for distinguishing between progressive massive fibrosis and lung cancer. CT and histopathologic findings in asbestosis are similar to those in idiopathic pulmonary fibrosis, but the presence of asbestos bodies in histopathologic specimens is specific for the diagnosis of asbestosis. Giant cell interstitial pneumonia due to exposure to hard metals is classified as a fibrotic form of pneumoconiosis and appears on CT images as mixed ground-glass opacities and reticulation. Berylliosis simulates pulmonary sarcoidosis on CT images. CT findings in talcosis include small centrilobular and subpleural nodules or heterogeneous conglomerate masses that contain foci of high attenuation indicating talc deposition. Siderosis is nonfibrotic and is indicated by a CT finding of poorly defined centrilobular nodules or ground-glass opacities.

[Contribution of bronchoalveolar lavage to the management of interstitial lung disease]

Bronchoalveolar lavage (BAL) is a minimally invasive method for exploring the distal lung. It enables collection of free cellular and acellular material present in the alveoli. Over the last two decades BAL has become a fundamental tool for positive diagnosis of interstitial lung disease and even more for differential diagnosis. It has contributed greatly to the diagnosis of lung infections, particularly in immunosuppressed patients. In the context of non-infectious infiltrative disease, the diagnostic contribution of BAL is limited due to the lack of a specific cell profile. It remains a fundamental tool for the differential diagnosis of idiopathic interstitial pneumonia. With BAL, a number of infectious or tumoral diseases can be ruled out with precision. It is also an important element for the evaluation of possible iatrogenic disease. BAL has transformed the diagnosis of interstitial lung disease and considerably reduced the indications for surgical biopsy.