Alveolitis of pulmonary asbestosis. Bronchoalveolar lavage studies in crocidolite- and chrysotile-exposed individuals

Prognostic Implication of Exfoliative Airway Pathology in Cancer-Free Coal Workers' Pneumoconiosis

BACKGROUND

The purpose of this study is to see if exfoliative pulmonary airway pathology in cancer-free coal workers' pneumoconiosis (CWP) can be used as a biomarker for predicting pulmonary morbidity.

METHODS

We investigated persistent metaplastic changes in bronchoscopic washing cytology and differential cell counts in bronchoalveolar lavages (BAL) in 97 miners with CWP and 80 miners without CWP as the control. Clinicopathological parameters were examined including pulmonary function tests and the presence of progressive massive fibrosis.

RESULTS

When compared to the control group, severe alveolitis, severe goblet cell hyperplasia (GCH), severe hyperplastic epithelial change, and severe squamous metaplasia were the distinguishing biomarkers in CWP. Multivariate analysis revealed that severe alveolitis and severe GCH, along with miner duration and current smoker, were independent predictors of pulmonary mortality. The survival analysis revealed a significantly different survival rate between the three groups: no evidence of severe alveolitis and severe GCH, presence of severe alveolitis or severe GCH but not both, and both severe alveolitis and severe GCH.

CONCLUSIONS

The severities of alveolitis and goblet cell hyperplasia in the bronchoscopic study are independent prognostic factors for CWP. A pathologic grading system based on these two parameters could be used in the stratification and clinical management of CWP patients.

The Wittenoom legacy

The Wittenoom crocidolite (blue asbestos) mine and mill ceased operating in 1966. The impact of this industry on asbestos-related disease in Western Australia has been immense. Use of the employment records of the Australian Blue Asbestos Company and records of the Wittenoom township residents has permitted two cohorts of people with virtually exclusive exposure to crocidolite to be assembled and studied. Follow-up of these two cohorts has been conducted through data linkage with available hospital, mortality and cancer records. The evolution of asbestos-related disease has been recorded and, with the establishment of exposure measurements, quantitative exposure-response relationships have been estimated. There has been an ongoing epidemic of mortality from lung cancer and malignant mesothelioma and, less so, from asbestosis. Wittenoom crocidolite was used extensively in asbestos-cement products in Western Australia. As a result, the state has recorded a higher malignant-mesothelioma mortality rate than in any other Australian state and in any defined general population in the world. Thus, the legacy of Wittenoom has extended beyond the mine and the town, and is still evident more than 50 years after the closure of the mine.

Bronchoalveolar neutrophilia inversely correlates with DLCO at diagnosis in asbestosis but not lung function decline at 1 year

The role of bronchoalveolar lavage (BAL) in the assessment of interstitial lung disease (ILD) remains controversial. Previous studies have demonstrated that BAL cell differential is useful in predicting disease progression in many forms of ILD. We wished to investigate whether BAL had a similar use in predicting disease progression in asbestosis. 21 patients who had significant asbestos exposure, findings of UIP radiologically and BAL performed as part of their investigation were reviewed. There was a significant inverse correlation between percentage BAL neutrophils and percentage predicted DLCO at diagnosis (n=21; P=0.02; r(2)=(-)0.25; CI, (-)0.77(-)0.08), but not with DLCO decline over 1 year. Unlike previous reports in IPF, BAL cell differential is not predictive of decline in classic asbestosis with a UIP pattern and its routine use in this cohort of patients provides little if any additional benefit.

Respiratory Tract and Mediastinum

Normal cytology, abnormal and atypical cells, non-cellular components, and infectious cell changes are largely described together with benign, malignant, and neuroendocrine lesions regarding exfoliative and aspiration cytology of the lung. A separate section broadly addresses diagnostic findings and differential diagnoses in bronchoalveolar washings.

The section ‘Fine needle aspiration biopsy of mediastinal disorders’ covers in particular biopsy techniques, accuracy of liquid-based cytology, and the complex lesions of the thymus gland. Cytodiagnostic algorithms of the major benign and malignant pulmonary and mediastinal lesions and their respective differential diagnoses are additionally presented in synoptic setups.

Bronchoalveoloar lavage fluid cytokines and chemokines as markers and predictors for the outcome of interstitial lung disease in systemic sclerosis patients

Introduction

Interstitial lung disease (ILD) is a frequent manifestation of systemic sclerosis (SSc), and cytokines can contribute to the disease pathology. The aim of the current study was to identify specific changes in cytokine levels that may serve as disease markers and possible targets for therapy.

Methods

Cytokines were measured with bioplex analysis in 38 bronchoalveolar fluids (BALFs) from 32 SSc patients (27 with alveolitis and 11 without alveolitis) and 26 control patients. In the case of SSc patients, cytokines were correlated with the respective bronchoalveolar lavage (BAL) cell differentiation, lung function, and thoracic HR-CT score. For 35 BALF samples derived from 29 SSc patients, follow-up investigations of clinical data, lung-function parameter, or thoracic HR-CT scans were available to evaluate the predictive capacity of BALF cytokines and chemokines.

Results

High IL-7 levels were characteristic of SSc-associated interstitial lung disease (ILD) and, in addition, when compared with ILD-negative SSc patients, ILD-positive SSc patients revealed higher IL-4, IL-6, IL-8, and CCL2 (MCP-1) BALF levels. High CCL2 and IL-8 BALF concentrations were associated with neutrophilic and mixed alveolitis. Cytokine levels of IL-4, IL-8, and CCL2 correlated negatively with lung-function parameters; CCL2 concentrations also correlated with HR-CT scores. High concentrations of several cytokines were associated with the progress of ILD and end-stage ILD. Univariate analyses revealed high IL-2 and tumor necrosis factor-alpha (TNF-α) levels as the best predictors for progressive disease, together with lung-function parameters, young age, and neutrophilic alveolitis. Multivariate analyses partially confirmed these results but did not sufficiently converge because of the limited number of patients.

Conclusions

The association of BALF cytokines with lung fibrosis and its progress suggests that cytokines contribute to the pathogenesis of ILD and hence could be regarded as potential therapeutic targets.

Non-allergic Eosinophilic Inflammation

Much is known about the eosinophilic processes associated with antigens, tumors, and infection, yet data on other causes of eosinophilic inflammation are scarce. This paper investigates the locations and causes of other nonrespiratory eosinophilic inflammation. Although eosinophilic inflammation can involve locomotor, urinary, cardiovascular, nervous, gastrointestinal, and other mucosal surfaces, such inflammation also can accompany tissue trauma, foreign-body reactions, and necrotic or granulomatous processes. Despite their cytolytic/histolytic effects, eosinophil leukocytes are a component of tissue remodeling, can be antigen-presenting cells, and have a role in the reproductive system and in blood coagulation. The study of various types of eosinophilic inflammation may increase our understanding of the biological responses of eosinophil leukocytes to different inflammatory stimuli.

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.

Fibroblast mitogens in bronchoalveolar lavage (BAL) fluid from asbestos-exposed subjects with and without clinical evidence of asbestosis: no evidence for the role of PDGF, TNF-alpha, IGF-1, or IL-1 beta

Asbestosis is a fibrotic lung disease resulting from inhalation of asbestos fibres. Its pathogenesis is poorly understood but probably involves stimulation of fibroblast proliferation and collagen production by mediators released from inflammatory and resident lung cells. In vitro studies have implicate PDGF, TNF-alpha, IGF-1, TGF-beta, and IL-1 in asbestosis, but the role of these mediators in vivo is not known. This study aimed to characterize mediators in bronchoalveolar lavage (BAL) fluid from patients exposed to asbestos with (n = 24) or without (n = 34) asbestosis, compared with ten normal subjects. Human lung fibroblasts were exposed to serial dilutions of BAL fluids and the effects on fibroblast proliferation were assessed. The median mitogenic activity of BAL fluid from asbestos-exposed (17 per cent above medium control, range 3-44 per cent) and asbestosis (14 per cent, range 2-60 per cent) groups was higher than that of BAL fluid from controls (10 per cent, range 2-20 per cent; P < 0.01 and P < 0.05, respectively), but there was no significant difference between the patient groups. The mitogenic activity of BAL fluids was not reduced by incubation with neutralizing antibodies to PDGF-AA, PDGF-AB, PDGF-BB, TNF-alpha, IGF-1, and IL-1 beta. We conclude that BAL fluids from patients exposed to asbestos contain mitogens for human lung fibroblasts, but that PDGF, TNF-alpha, IGF-1, or IL-1 beta do not contribute to this activity.

Bronchoalveolar lavage. Still useful in diagnosing sarcoidosis?

BALF parameters, if evaluated as a diagnostic or prognostic tool, should be based on a full understanding of the clinical profiles and course of pulmonary sarcoidosis. The various markers that have been reported so far are unreliable in determining the prognosis, although BALF lymphocytes and CD4/CD8 ratios are still useful for diagnosing sarcoidosis. It is critical to find feasible markers that relate to a change in disease activity and prognosis, because markers of chronicity may be different from those of progressively worsening sarcoidosis.

Differentiation of the ILO boundary chest roentgenograph (0/1 to 1/0) in asbestosis by high-resolution computed tomography scan, alveolitis, and respiratory impairment

High-resolution computed tomography (HRCT) scans have been advocated as providing greater sensitivity in detecting parenchymal opacities in asbestos-exposed individuals, especially in the presence of pleural fibrosis, and having excellent inter- and intraobserver reader interpretation. We compared the 1980 International Labor Organization (ILO) International Classification of the Radiographs of the Pneumoconioses for asbestosis with the high-resolution CT scan using a grid scoring system to better differentiate normal versus abnormal in the ILO boundary 0/1 to 1/0 chest roentgenograph. We studied 37 asbestos-exposed individuals using the ILO classification, HRCT grid scores, respiratory symptom questionnaires, pulmonary function tests, and bronchoalveolar lavage. We used Pearson correlation coefficients to evaluate the linear relationship between outcome variables and each roentgenographic method. The normal HRCT scan proved to be an excellent predictor of "normality," with pulmonary function values close to 100% for forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), total lung capacity (TLC), and carbon monoxide diffusing capacity (DLCO) and no increase in BAL inflammatory cells. Concordant HRCT/ILO abnormalities were associated with reduced FEV1/FVC ratio, reduced diffusing capacity, and alveolitis consistent with a definition of asbestosis. In our study, the ILO classification and HRCT grid scores were both excellent modalities for the assessment of asbestosis and its association with impaired physiology and alveolitis, with their combined use providing statistical associations with alveolitis and reduced diffusing capacity.

Elevated interleukin-8 in the alveolitis of individuals with asbestos exposure

Asbestosis is a fibrotic and inflammatory interstitial lung disease occurring after chronic occupational exposure to asbestos. An alveolitis has been described with activated alveolar macrophages and increased neutrophils as sampled by bronchoalveolar lavage (BAL). Animal models and in vitro studies demonstrate that asbestos can stimulate alveolar macrophages to release neutrophil chemotactic factor. We performed BAL on 18 nonsmoking individuals with asbestos exposure and observed a twofold increase in percent neutrophils recovered. Alveolar macrophages cultured in vitro from the asbestos-exposed individuals spontaneously released significant amounts of the neutrophil chemotaxin, interleukin-8 (IL-8). In addition, the alveolar macrophages expressed a 2.7-fold increase in steady state mRNA levels compared to unexposed normal controls utilizing the reverse transcriptase/polymerase chain reaction. In vitro experiments confirmed that crocidolite or chrysotile asbestos could stimulate the release of IL-8 from mononuclear phagocytes in a dose-dependent fashion. We conclude that asbestos exposure causes a mild neutrophilic alveolitis, and that IL-8 is one potential mediator capable of contributing to this inflammation in the lower respiratory tract.

Localized inflammatory pulmonary disease in subjects occupationally exposed to asbestos

In reviewing pathology materials from patients occupationally exposed to asbestos, we identified eight patients with either localized nodules in their lung or unusual pathologic changes. The chest radiographs of six patients showed isolated parenchymal nodules thought to represent primary neoplasms. In three cases, pathologic examination of these nodules showed intraluminal fibrosis and inflammation of the distal airways, a pattern of change frequently referred to as "bronchiolitis obliterans organizing pneumonitis." In each instance, asbestos bodies were present in association with the fibroinflammatory tissue. In one case, the nodule showed a desquamative interstitial pneumonitis type pattern, and asbestos bodies were present admixed with the alveolar macrophages and occasionally within their cytoplasm. In one case, the nodule was composed of nonspecific inflammation and fibrosis with focal bronchiolitis obliterans and frequent asbestos bodies scattered throughout the area of inflammation and fibrosis, and in another case, necrotizing inflammation association with Aspergillus fungal organisms was identified. Granulomatous inflammation was the dominant pulmonary pathologic change in one patient, and the other patient's lung biopsy specimen showed a diffuse lymphocyte-plasma cell interstitial pneumonitis. The cases reported suggest that asbestos may cause localized lesions in the lung that clinically and radiographically are misinterpreted as cancer and that pathologically show inflammation and fibrosis of the distal airways. In addition, our observations suggest that asbestos may cause granulomatous inflammation, a desquamative interstitial type pneumonitis, and a lymphocytic interstitial pneumonitis type pattern. Our conclusions that asbestos may cause these pathologic changes are supported by case reports in the clinical and pathologic literature, clinicopathologic studies, and by experimental studies.

Human alveolar macrophage cytokine release in response to in vitro and in vivo asbestos exposure

The lung macrophage is proposed to be involved in the development of asbestos-induced pulmonary fibrosis. Knowledge of the effects of long-term asbestos exposure on lung macrophage cytokine release should better define the role of the macrophage in fibrogenesis. This study examines the effects of acute in vitro asbestos exposure and chronic in vivo asbestos exposure on human alveolar macrophage cytokine release. As indicators of asbestos-induced macrophage activation, the cellular release of IL-1 beta, TNF-alpha, IL-6, GM-CSF, and PGE2 was measured during a 24-h in vitro culture. Alveolar macrophages from normal volunteers were cultured in vitro with chrysotile asbestos. Of the factors measured, only TNF-alpha was elevated in response to asbestos exposure. Alveolar macrophages from asbestos-exposed individuals were placed into one of two groups based on their exposure history. These two groups were matched for age, smoking history, and diagnosis; none met the criteria for asbestosis. Cells isolated from subjects that had been exposed to asbestos for more than 10 years secreted enhanced basal amounts of IL-1 beta, TNF-alpha, IL-6, and PGE2, while those who had been exposed for less than 10 years did not. The results indicate that while asbestos had minimal acute effects on cytokine production by the human alveolar macrophage, intense, chronic exposure to asbestos leads to the enhanced basal release of significant amounts of several cytokines that have activity for the fibroblast, even in the absence of overt fibrosis.

Association between acute inflammatory cells in lavage fluid and bronchial metaplasia

In epidemiologic studies, airway disease and parenchymal injury are known morbid outcomes of occupational exposure to asbestos. However, the relationship of inflammatory events considered to be responsible for parenchymal injury to the subsequent development of airway injury is unknown. To assess this we performed bronchoalveolar lavage (BAL) and airway biopsies on a population of subjects with exposure to asbestos in the workplace. As an index of airway injury, we employed histologic metaplasia seen in mucosal biopsy specimens. Lung BAL fluid was analyzed for two potentially relevant protein markers and for inflammatory cells recovered from the lower respiratory tract. We related metaplasia to demographic features of this study population (eg, smoking history and asbestos exposure data) and also to the protein and cellular markers recovered by BAL. We studied 50 workers and detected keratinizing metaplasia in 15 and varying lesser abnormalities in the other 28. Cigarette smoking was not associated with the presence of metaplasia (p less than 0.2). Smoking status was associated with an increase in BAL cells (p less than 0.02); however, neither the percent nor concentration of acute inflammatory cells was significantly increased. Acute inflammatory cells (percent and cells per milliliter of BAL fluid) were significantly increased among the subjects with severe metaplasia compared with other study subjects. This increase was true of both neutrophils and eosinophils and the sum of these two (p less than 0.02). Stratification of subjects by smoking status demonstrated a persistent association of inflammatory cells with metaplasia. By logistic regression analysis, polymorphonuclear leukocytes per milliliter and eosinophils per milliliter were significantly related to the presence of metaplasia in two independent models (odds ratios, 9.9 and 7.6, respectively). Cigarette smoking and other demographic or BAL variables were not significantly associated with metaplasia in these models.

Evidence of a role for mesothelial cell-derived interleukin 8 in the pathogenesis of asbestos-induced pleurisy in rabbits

Although acute asbestos-induced pleurisy is characterized by an influx of neutrophils, the identity of the factors that attract these cells to the pleural space and the source of the factors are unknown. We found that instillation of crocidolite asbestos into the pleural space of rabbits led to the appearance in pleural liquid of chemotactic activity for neutrophils, and that this chemotactic activity was inhibited significantly by a neutralizing antibody to human interleukin 8 (IL-8). Cultured rabbit pleural mesothelial cells incubated with crocidolite asbestos also released chemotactic activity for neutrophils, which was inhibited significantly by the anti-IL-8 antibody. To determine whether rabbit pleural mesothelial cells synthesize IL-8, we generated a probe for rabbit IL-8 mRNA by amplifying cDNA prepared from stimulated pleural mesothelial cells using the polymerase chain reaction (PCR) and primers based on homologous sequences in human and sheep IL-8 cDNAs. Homology-based PCR yielded a single cDNA fragment with a nucleotide sequence 88% identical to that of a corresponding region of human IL-8 cDNA. With the radiolabeled PCR product as a probe, we demonstrated rapid induction of IL-8 mRNA expression in pleural mesothelial cells exposed to asbestos. As expected, tumor necrosis factor-alpha also led to the appearance of IL-8 in the rabbit pleural space and stimulated cultured pleural mesothelial cells to synthesize and release IL-8. We conclude that asbestos directly stimulates pleural mesothelial cells to synthesize IL-8 and that mesothelial cell-derived IL-8 may play an important role in mediating asbestos-induced pleural inflammation.

Lymphocyte-macrophage alveolitis in nonsmoking individuals occupationally exposed to asbestos

A disordered immunologic activity has been observed in humans and animal models of asbestosis and silicosis. To characterize the lung immunologic response following long-term occupational exposure to asbestos, bronchoalveolar lavage (BAL) was performed on 28 nonsmoking individuals. Increased BAL lymphocytes were observed in one third. Lung lymphocytes were predominantly of the CD4+ helper-inducer subtype with increased CD4+/CD8+ ratio and increased surface expression of DR antigen consistent with the activation phenotype. Histologic evaluation of lung tissue from two individuals with lymphocytic-macrophage alveolitis and asbestos exposure revealed an infiltration of alveolar walls with chronic inflammatory mononuclear cells (lymphocytes). Interferon gamma was spontaneously released by BAL cells from 19 (76 percent) of 25 of the individuals with asbestos exposure and only one of ten normal controls. The release of interferon gamma by BAL cells could be further stimulated with concanavalin A and suppressed by cyclosporine. Although asbestosis is characterized by a predominant alveolar macrophage alveolitis, there is a subgroup with lymphocytic alveolitis and activated lymphocytes participating in the inflammatory response, especially in those without respiratory impairment early in the course of the disease process.

The role of free radicals in asbestos-induced diseases

Asbestos exposure causes pulmonary fibrosis and malignant neoplasms by mechanisms that remain uncertain. In this review, we explore the evidence supporting the hypothesis that free radicals and other reactive oxygen species (ROS) are an important mechanism by which asbestos mediates tissue damage. There appears to be at least two principal mechanisms by which asbestos can induce ROS production; one operates in cell-free systems and the other involves mediation by phagocytic cells. Asbestos and other synthetic mineral fibers can generate free radicals in cell-free systems containing atmospheric oxygen. In particular, the hydroxyl radical often appears to be involved, and the iron content of the fibers has an important role in the generation of this reactive radical. However, asbestos also appears to catalyze electron transfer reactions that do not require iron. Iron chelators either inhibit or augment asbestos-catalyzed generation of the hydroxyl radical and/or pathological changes, depending on the chelator and the nature of the asbestos sample used. The second principal mechanism for asbestos-induced ROS generation involves the activation of phagocytic cells. A variety of mineral fibers have been shown to augment the release of reactive oxygen intermediates from phagocytic cells such as neutrophils and alveolar macrophages. The molecular mechanisms involved are unclear but may involve incomplete phagocytosis with subsequent oxidant release, stimulation of the phospholipase C pathway, and/or IgG-fragment receptor activation. Reactive oxygen species are important mediators of asbestos-induced toxicity to a number of pulmonary cells including alveolar macrophages, epithelial cells, mesothelial cells, and endothelial cells. Reactive oxygen species may contribute to the well-known synergistic effects of asbestos and cigarette smoke on the lung, and the reasons for this synergy are discussed. We conclude that there is strong evidence supporting the premise that reactive oxygen species and/or free radicals contribute to asbestos-induced and cigarette smoke/asbestos-induced lung injury and that strategies aimed at reducing the oxidant stress on pulmonary cells may attenuate the deleterious effects of asbestos.

Development and characterization of a rapid-onset rodent inhalation model of asbestosis for disease prevention

A short-term inhalation model of asbestosis was developed in rodents to examine possible preventive approaches to lung disease. Fischer 344 (F344) rats were exposed for 10 and 20 days to National Institute of Environmental Health Sciences (NIEHS) crocidolite asbestos while sham controls were exposed to air only. To determine quantitative biochemical indicators of asbestos-induced lung disease, bronchoalveolar lavage (BAL) fluids were analyzed for lactic dehydrogenase (LDH), alkaline phosphatase, angiotensin-converting enzyme (ACE), and protein. Total and differential cell counts were performed on cell pellets from BAL. Lungs from additional rats were processed for histopathology, measurement of hydroxyproline, and autoradiography after injection of rats with 3H-thymidine. Exposure to asbestos for 10 and 20 days caused increases in LDH, alkaline phosphatase, and protein in BAL. In contrast, ACE was undetectable in BAL fluids from sham or asbestos-exposed rats. At both time periods, the percentages of polymorphonuclear leukocytes (PMNs) and lymphocytes in BAL were increased in asbestos-exposed rats. Total cell numbers in BAL were increased significantly at 20 days in animals inhaling asbestos. Exposure to asbestos for 10 and 20 days caused elevated amounts of hydroxyproline in lung and the development of fibrotic lesions. Asbestos-exposed rats exhibited increased numbers of interstitial cells and airspace epithelial cells incorporating 3H-thymidine, whereas labeled bronchiolar epithelial cells were not elevated significantly. The quantitative changes in asbestos-associated enzyme levels, cell types and protein in BAL, as well as increases in hydroxyproline and morphologic evidence of fibrosis, are useful indices of asbestos-related lung injury which enable preventive and therapeutic approaches to disease.

In vitro bioactivity of asbestos for the human alveolar macrophage and its modification by IgG

The alveolar macrophage (AM) is likely to play a central role in the initiation and development of the fibrosis associated with asbestos exposure due to its ability to produce factors that modulate cellular functions of the immune system of the lung. In this study, we examine the effects of IgG, albumin, and dipalmitoylphosphatidylcholine (DPPC), the major protein and lipid constituents of alveolar lining fluid, on the interaction between the human AM and chrysotile and crocidolite asbestos, silica, and aluminum beads. We show that both chrysotile and crocidolite asbestos, but not silica and aluminum beads, stimulate the human AM to produce superoxide anion. Preincubating chrysotile and crocidolite asbestos with IgG resulted in an enhancement of their ability to stimulate superoxide anion production. IgG subclasses were studied to determine the subclass specificity of this enhancing effect; on a molar basis, IgG1 was the most potent. After preincubation with IgG, both silica and aluminum also stimulated superoxide anion production to levels similar to the IgG-preincubated asbestos. When albumin and DPPC were included in the preincubation mixture, the IgG-mediated enhancement of superoxide anion production by asbestos was unaffected, while that of silica and aluminum was abolished. In summary, these results indicate that IgG can significantly enhance the bioactivity of particulates for human AM in vitro, and that chrysotile and crocidolite asbestos are unique in their ability to retain this enhancement in the presence of albumin and DPPC. These results are consistent with the suggestion that superoxide anion production by the AM may play an important role in the development of asbestosis.

Asbestos fibers induce release of collagenase by human polymorphonuclear leukocytes

The asbestos fibers chrysotile and crocidolite cause a dose-dependent release of specific granule collagenase by human polymorphonuclear leukocytes (PMNL). Release of azurophil granule elastase was induced by the asbestos fibers at higher concentrations, suggesting that asbestos fibers primarily cause the release of specific granule contents of human PMNL. Wollastonite, a fibrous silicate mineral, causes a weaker collagenase release and no elastase release. The collagenase was released in inactive, latent form. Carboxymethyl cellulose (CMC), an agent known to blunt chrysotile-induced hemolysis and production of reactive oxygen metabolites by human PMNL, specifically inhibits chrysotile-induced release of collagenase. Chrysotile asbestos was found to bind the PMNL serine proteinase cathepsin G. A role of collagenase release, production of reactive oxygen metabolites and cathepsin G binding by chrysotile for the perpetuation of the asbestos-induced alveolitis is suggested.

Asbestos-induced release of a human alveolar macrophage-derived neutrophil chemotactic factor

Neutrophils accumulate in the alveoli of asbestos-exposed individuals. In determining whether asbestos fibers induce the release of neutrophil chemotactic factor (NCF) from human alveolar macrophages, alveolar macrophages (10(6) cell/mL) obtained by bronchoalveolar lavage from six non-asbestos-exposed control subjects were exposed to crocidolite (0.1 and 1 mg/mL), chrysotile (1 mg/mL), or medium alone for 4 h, and NCF activity was measured in the supernatants in a 48-well microchemotaxis chamber with polycarbonate membrane filters (pore size, 3 microns) and purified human neutrophils. Alveolar macrophages in medium alone released negligible amounts of NCF (4 +/- 1 neutrophils per high-power field [N/HPF]). When macrophages were exposed to crocidolite (0.1 and 1 mg/mL), significant NCF release occurred (43 +/- 9 and 105 +/- 32 N/HPF, respectively; p less than 0.01 for each amount compare to alveolar macrophages cultured in medium alone). Chrysotile (1 mg/mL) induced similar NCF release (96 +/- 14 N/HPF; p less than 0.01 compared to unstimulated alveolar macrophages). Partial characterization of the NCF by Sephadex G-25 fine gel filtration demonstrated a molecular size of less than 1,000 daltons. These results show that human alveolar macrophages release NCF after exposure to asbestos. Release of NCF by alveolar macrophages in asbestos-exposed individuals may play a central role in the pathogenesis of asbestosis.

Pulmonary gamma interferon production in patients with fibrosing alveolitis

Patients with fibrosing alveolitis have active inflammation within their lung interstitium. Previous studies have focused on the humoral (immune complex) driven processes. In this study increased pulmonary gamma interferon production has been evaluated. Bronchoalveolar lavage cells were obtained from 40 patients with fibrosing alveolitis, 22 with cryptogenic fibrosing alveolitis, and 18 with connective tissue disease associated (CTD) fibrosing alveolitis. Increased gamma interferon production was seen in 12 (30%) patients and was similar in the two study groups. Up to 512 units/10(6) cells were released over 24 hours, showing that the amounts of gamma interferon released could be as large as those seen in other pulmonary diseases associated with active cellular immune processes, such as sarcoidosis. Spontaneous gamma interferon production was related to increased serum concentrations of IgG and IgM but not to serum IgA, antinuclear antibody, or rheumatoid factor titres. There was no relation between gamma interferon production and pulmonary uptake of gallium-67 citrate. The ratio of helper-inducer (Leu-3) to suppressor-cytotoxic (Leu-2) cells in bronchoalveolar lavage fluid was similar in the two study groups and was similar in patients whose cells produced gamma interferon and those whose cells did not. These data suggest that gamma interferon is released in the lungs of a proportion of individuals with cryptogenic fibrosing alveolitis and CTD-fibrosing alveolitis, suggesting a role for this cytokine in mediating these diseases.

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.

Gallium lung scanning and bronchoalveolar lavage in crocidolite-exposed workers

Gallium lung scanning is widely used to evaluate pulmonary inflammation in patients with interstitial lung disease but has not previously been reported in crocidolite-exposed workers. In order to characterize the pulmonary inflammation caused by crocidolite inhalation, GLS and BAL findings were related to chest x-ray film changes graded according to the ILO classification of roentgenograms of pneumoconioses. In individuals with roentgenographic evidence of asbestosis (CXR greater than or equal to 1/0, n = 15), 13 had a positive GLS and 13 had an abnormal BAL. In asbestos-exposed individuals with equivocal chest x-ray film changes (CXR 0/1, n = 12), six had a positive GLS and six had BAL changes (both GLS and BAL abnormal in three). In individuals with a normal chest x-ray film (CXR 0/0 n = 8), two had a positive GLS and two BAL changes (both abnormal in 1). These data demonstrate that most subjects with crocidolite-induced asbestosis have an abnormal GLS and BAL. In addition, many individuals with asbestos exposure and equivocal or no chest x-ray film changes have an abnormal GLS and/or BAL, suggesting the presence of active subclinical pulmonary inflammation in these individuals.

The role of bronchoalveolar lavage in the assessment of diffuse lung diseases

Bronchoalveolar lavage is a safe and simple technique for sampling the inflammatory cells of the lung. However, while its use in the evaluation of pulmonary pathogenic mechanisms is both well accepted and described, its clinical utility is more controversial. Marked variation in results may occur through variation in the lavage procedure. Standardisation of the lavage technique and laboratory processing of the specimen are essential for reliable results. This review examines the current clinical role of bronchoalveolar lavage in the assessment of patients with diffuse lung diseases, and immunocompromised patients with pulmonary infiltrates. In this latter category, for patients with Acquired Immunodeficiency Syndrome, lavage is of equal efficacy to lung biopsy and can establish the cause of pulmonary infiltrates in over 90% of cases. Bronchoalveolar lavage can detect abnormalities in patients with diffuse lung diseases prior to the development of irreversible fibrosis. Lavage features have been described for sarcoidosis, cryptogenic fibrosing alveolitis, extrinsic allergic alveolitis, connective tissue diseases, and asbestosis. In cryptogenic fibrosing alveolitis lavage data may be used to indicate a subsequent deterioration in the patient's condition, or predict a favourable response to therapy.

Alveolar macrophages from patients with asbestos exposure release increased levels of leukotriene B4

The alveolar influx and subsequent activation of inflammatory cells such as neutrophils and eosinophils are believed to be important in the pathogenesis of many interstitial lung disorders, including asbestosis. Indices of lower respiratory tract abnormalities detected by bronchoalveolar lavage (BAL) were investigated in 93 asbestos-exposed workers as well as in smoking (n = 12) and nonsmoking (n = 10) control subjects. Patients with clinical asbestosis (n = 12) exhibited increases in both BAL neutrophils and BAL eosinophils, expressed as both percentage of total cells and total numbers, when compared to asbestos-exposed workers without asbestosis (n = 81) and control subjects. Significantly greater numbers of BAL neutrophils were also found in asbestos-exposed workers without asbestosis than in either smoking or nonsmoking control subjects. These abnormalities correlated significantly with in vitro BAL alveolar macrophage production of the potent leukocyte chemotaxin, leukotriene B4 (LTB4). For example, basal, unstimulated LTB4 production was 3.1 +/- 0.8 ng/10(6) alveolar macrophages for patients with asbestosis, 1.05 +/- 0.2 ng/10(6) cells in asbestos workers without asbestosis, 0.9 +/- 0.2 ng/10(6) cells in control nonsmokers, and 0.2 +/- 0.05 ng/10(6) cells in control smokers. Stimulated LTB4 release from BAL alveolar macrophages (A23187 or arachidonate) was even more pronounced in asbestos workers with or without asbestosis, suggesting an in vivo priming effect on alveolar macrophage synthesis of LTB4. Cell-free BAL supernatants from asbestos-exposed patients with or without asbestosis also contained significantly greater amounts of LTB4 than did those from control subjects, indicating enhanced in vivo production of this inflammatory mediator.(ABSTRACT TRUNCATED AT 250 WORDS)

Bronchoalveolar lavage in the diagnosis of lipoid pneumonia

Lipoid pneumonia (LP) is an uncommon entity with the characteristic radiographic features and histologic findings of alveoli filled with vacuolated, lipid-laden histiocytes. We questioned whether bronchoalveolar lavage (BAL) could be useful in the confirmation of LP. We examined lipid stains (oil-red O) in BAL specimens from 18 cases, representing a variety of pulmonary disease states, and compared them with an index case of confirmed LP. The index case of LP had a history of chronic intranasal use of mentholated petrolatum with subsequent x-ray findings of progressive air bronchograms. Positive histochemical confirmation (oil-red O) performed on frozen sections of transbronchial lung biopsy was obtained. Eleven of the non-LP cases had no intracellular staining of BAL macrophages with oil-red O stain, whereas the index case of LP exhibited markedly positive intracytoplasmic staining of macrophages for lipid. The remaining seven cases showed minimal to mild lipid staining with only one other case having moderate staining. This study demonstrates that BAL macrophages from patients with a variety of pulmonary states and without suspected LP do not demonstrate significant staining for intracellular lipids, in contrast with the expected strong positivity of LP. Lipid staining of BAL specimens, although not entirely specific, may be a preferred method for confirming the diagnosis of LP, thereby avoiding more invasive procedures.

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.

Neutrophil chemotactic factor release and neutrophil alveolitis in asbestos-exposed individuals

Alveolar neutrophil accumulation occurs in asbestosis. To evaluate a possible role for release of neutrophil chemotactic factor (NCF) in the pathogenesis of asbestosis, spontaneous NCF release from alveolar macrophages obtained by bronchoalveolar lavage (BAL) in eight individuals with asbestosis, 13 asbestos-exposed individuals without asbestosis, and five control subjects has been studied. Alveolar macrophages were incubated in medium (four hours; 37 degrees C), and neutrophil responses to the supernatants were assayed in a microchemotaxis chamber. Alveolar macrophages from subjects with asbestosis released more NCF (97 +/- 19 neutrophils per high-power field [N/HPF]) than controls (3 +/- 1 N/HPF; p less than 0.01). Alveolar macrophages from individuals with asbestos exposure and increased BAL neutrophil proportions (n = 7) released more NCF (93 +/- 24 N/HPF) than individuals with asbestos exposure and normal BAL neutrophil proportions (n = 6; 11 +/- 6 N/HPF; p less than 0.02). The results show that spontaneous NCF release occurs in asbestosis and that NCF release is associated with neutrophil alveolitis in asbestos-exposed individuals without asbestosis, suggesting a pathogenic role for NCF in mediating this neutrophil alveolitis. The results of the study also suggest that the presence of crackles is a better predictor of the presence of neutrophil alveolitis than is an abnormal chest x-ray film.

Increased pulmonary gamma interferon production in asbestosis

In order to determine if disordered cellular immune processes are present in the lungs of persons with asbestosis, we performed bronchoalveolar lavage (BAL) on 26 patients with either crocidolite- or chrysotile-induced pulmonary asbestosis and measured the spontaneous release of gamma interferon (IFN gamma), a marker of increased cellular immune activity. For comparison, 18 control subjects and 7 patients with active pulmonary sarcoidosis were also studied. Recovered BAL cells were cultured for 24 h (5 x 10(6)/ml), and the supernatant was assayed for interferon by determining inhibition of cytopathic effect on encephalomyocarditis virus-induced lysis of WISH cells and characterized by monoclonal anti-IFN gamma antibody inhibition. Nine (35%) patients with asbestosis released increased amounts of IFN gamma, up to 320 units/ml, the levels seen in the sarcoidosis patients. All control subjects released less than or equal to 10 units/ml. All interferon released was IFN gamma. In asbestosis patients, IFN gamma production was not related to a history of cigarette smoking, there was no significant difference in the ratio of helper/inducer (Leu-3) to suppressor/cytotoxic (Leu-2) cells in IFN gamma producers compared to non-IFN gamma producers (p greater than 0.05), and IFN gamma production correlated significantly with serum IgG levels (p less than 0.001) but not with the levels of IgM, IgA, antinuclear factor, or rheumatoid factor. These data suggest that active cellular immune processes are present in the lungs of a proportion of patients with asbestosis.

Correlation of bronchoalveolar lavage cell populations with clinical severity of Pneumocystis carinii pneumonia

We correlated bronchoalveolar lavage (BAL) cell populations with clinical course and outcome in 19 patients with Pneumocystis carinii pneumonia and acquired immunodeficiency syndrome. Twelve patients demonstrated an elevated (greater than or equal to 5 percent) BAL combined neutrophil and eosinophil count, which correlated with the magnitude of the alveolar-arterial PO2 gradient. Patients with elevated BAL granulocytes also had significantly higher serum lactate dehydrogenase levels. Three of the four patients who died had the highest percentage of neutrophil counts observed in lavage fluid. Although no patient was thought to have a concurrent bacterial infection, potential pathogens were cultured from the sputum of patients with the most elevated neutrophil counts. Whether BAL granulocytes reflect an inflammatory process analogous to the adult respiratory distress syndrome or signify concomitant bacterial infection remains to be determined. We conclude that BAL granulocytes are associated with more severe respiratory compromise in patients with Pneumocystis carinii pneumonia.

Comparison of bronchoalveolar lavage helper/suppressor T-cell ratios in sarcoidosis versus other interstitial lung diseases

In order to compare the frequency of elevated lymphocyte proportions and elevated Leu3/Leu2 (helper/inducer to suppressor/cytotoxic) ratios in sarcoidosis with those in clinically similar interstitial lung diseases (ILDs), bronchoalveolar lavage (BAL) lymphocyte proportions and Leu3/Leu2 ratios were determined for 20 patients with sarcoidosis and 30 patients with other (non-sarcoidosis) ILDs [cryptogenic fibrosing alveolitis (seven), lung connective tissue disease (seven), extrinsic allergic alveolitis (four), lymphoproliferative disease (two), and asbestosis (ten)], as well as in eight control subjects. BAL lymphocyte proportions were elevated above control values in 19 (95%) patients with pulmonary sarcoidosis (mean value 36 +/- 3%) but also in 12 (39%) patients with non-sarcoidosis ILDs (mean value 17 +/- 4%). Leu3/Leu2 ratios were over 2.5 in 15 (75%) of the sarcoidosis patients (mean ratio 4.4 +/- 1). In all control subjects, however, and in all but one of the non-sarcoidosis groups, Leu3/Leu2 ratios were below 2.5 (p less than 0.001 for each compared to sarcoidosis patients). Helper/suppressor ratios over 2.5 are found in the majority of our sarcoidosis patients and, unlike raised lymphocyte proportions alone, are not commonly seen in other ILDs, suggesting that evaluation of BAL helper/suppressor cell ratios may be of value in the investigation of patients with ILD.