Induced sputum compared to bronchoalveolar lavage for evaluating patients with sarcoidosis and non-granulomatous interstitial lung disease

Sputum quantitative cytometry in patients with interstitial lung disease and chronic cough

BACKGROUND

Chronic cough frequently occurs in patients with diffuse interstitial lung diseases (ILDs), and can have negative effects on quality-of-life. While there are multiple possible contributors to cough in this setting, the contribution and consequences of airway inflammation have not been previously measured. We aimed to estimate the prevalence of airway cellular inflammation in patients with chronic cough and ILD, and examine the interaction between airway inflammation and changes in lung function.

METHODS

We examined all patients with physician-diagnosed ILD and chronic cough who had sputum quantitative cytometry ordered between 2004 and 2018. The prevalence of airway inflammation was estimated by applying previously established criteria for bronchitis. FEV₁ and FVC were compared between individuals based on the presence of airway inflammation. The changes in FEV₁ and FVC were compared between individuals who had their treatment tailored to their sputum result, and those who did not.

RESULTS

Airway inflammation was present in 50% of patients (n = 173), and was associated with lower FEV₁ (1.87 vs 2.05 L, p = 0.043) and FVC (2.39 vs 2.71, p = 0.024). Sputum-guided management of airway eosinophilia was associated with improvements in FEV₁ (+120 vs -205mL, p < 0.0001) and stability of FVC (+13 vs -284mL, p = 0.003).

CONCLUSIONS

Airway inflammation is common in patients with chronic cough and ILD, and its presence may negatively affect lung function. Further research is required to understand if there is a role for quantitative sputum cytometry in this population, particularly if sputum-guided management of airway inflammation could lead to improvements in cough and other ILD outcomes.

Mucosal-associated invariant T cells and Vδ2+ γδ T cells in community acquired pneumonia: association of abundance in sputum with clinical severity and outcome

Mucosal-associated invariant T (MAIT) cells and Vδ2+ γδ T cells are anti-bacterial innate-like lymphocytes (ILLs) that are enriched in blood and mucosa. ILLs have been implicated in control of infection. However, the role of ILLs in community-acquired pneumonia (CAP) is unknown. Using sputum samples from a well-characterized CAP cohort, MAIT cell and Vδ2+ T cell abundance was determined by quantitative polymerase chain reaction (qPCR). Cytokine and chemokine concentrations in sputum were measured. The capacity of bacteria in sputum to produce activating ligands for MAIT cells and Vδ2+ T cells was inferred by 16S rRNA sequencing. MAIT cell abundance in sputum was higher in patients with less severe pneumonia; duration of hospital admission was inversely correlated with both MAIT and Vδ2+ T cell abundance. The abundance of both ILLs was higher in patients with a confirmed bacterial aetiology; however, there was no correlation with total bacterial load or the predicted capacity of bacteria to produce activating ligands. Sputum MAIT cell abundance was associated with interferon (IFN)-α, IFN-γ, and sputum neutrophil abundance, while Vδ2+ T cell abundance was associated with CXCL11 and IFN-γ. Therefore, MAIT and Vδ2+ T cells can be detected in sputum in CAP, where they may contribute to improved clinical outcome.

Is Induced Sputum A Useful Noninvasive Tool in the Diagnosis of Pulmonary Sarcoidosis?

OBJECTIVES

In patients with pulmonary sarcoidosis, the provocation of sputum expectoration through the inhalation of hypertonic saline has been investigated as an alternative diagnostic tool for invasive procedures. We aimed to assess the diagnostic value of induced sputum (IS) by observing its cell distribution in patients with a confirmed histopathological diagnosis of sarcoidosis.

MATERIALS AND METHODS

In this prospective, cross-sectional study, we compared the IS results of 20 patients with a histopathologically confirmed pulmonary sarcoidosis diagnosis and 24 healthy volunteers. The percentages of macrophages, lymphocytes, neutrophils, and eosinophils in IS and the CD4/CD8 ratio were compared.

RESULTS

The percentage of lymphocytes in IS was significantly higher in the pulmonary sarcoidosis patients compared to the control group (41.6% vs 8.9%, p<0.001). There were no significant differences in the other IS cell percentages and CD4+/CD8+ ratio between the groups. Sputum induction was well tolerated.

CONCLUSION

Sputum induced by the inhalation of hypertonic saline is a safe, inexpensive, less invasive, and easily repeated method and can be a valuable alternative to other invasive methods in the diagnosis of pulmonary sarcoidosis.

Sputum Anticitrullinated Protein Antibodies in Patients With Long-standing Rheumatoid Arthritis

OBJECTIVE

The aim of this study was to evaluate the presence of autoantibodies to cyclic citrullinated synthetic peptides (ACPAs) in the sputum of patients with long-standing rheumatoid arthritis (RA).

METHODS

Nineteen consecutive RA patients and 16 age- and sex-matched control subjects participated in this cross-sectional study. All underwent complete lung function tests and provided induced sputum. Antibodies to citrullinated (CitP) and the corresponding norleucine-containing (NorP) peptides in the sputum of the RA patients and control subjects, as well as in the serum of the RA patients, were determined by enzyme-linked immunosorbent assay.

RESULTS

Patients with RA had the following characteristics: mean disease duration of 12 years, Disease Activity Score for 28 joints of 3.44, and Sharp-van der Heijde score of 57.5. Ten of the 19 RA patients showed high titers of ACPAs in their sera. Four of the seropositive (40%), none of the seronegative RA patients, and only 1 of the control subjects showed detectable levels of ACPAs in their sputum. The ratio between the reactivity with CitP and NorP peptides in the sputum was significantly higher in RA sputum than in control sputum (1.33 ± 1.2 vs. 0.64 ± 0.14, P = 0.02). A positive correlation was found between sputum ACPAs and age, serum ACPAs, sputum anti-NorP, serum anti-CitP/NorP reactivity ratio, and the proportion of neutrophils and lymphocytes in the sputum. No significant correlation was found between sputum ACPAs and disease severity, history of smoking, lung function tests, or treatment for RA.

CONCLUSIONS

Anticitrullinated protein/peptide antibodies can be detected in the sputum of RA patients and are correlated with the presence in the serum.

Sputum biomarkers in IPF: Evidence for raised gene expression and protein level of IGFBP-2, IL-8 and MMP-7

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a rare lung disease of unknown origin leading rapidly to death. This paper addresses the issue of whether sputum induction is a suitable tool to study respiratory tract inflammation and potential biomarkers in IPF compared to COPD, a fibrosing airway wall disease.

METHODS

In a cross-sectional analysis, 15 IPF patients, 32 COPD and 30 healthy subjects underwent sputum induction. Total sputum cell counts and the amount of TGF- β, IGF-1, IGF-2, IGFBP-1, IGFBP-2, IGFBP-3, IL-8, IL-13, MMP-7, MMP-9, YKL-40, TNF-α and KL-6 in sputum supernatant were analysed. We also profiled gene expression of cells in the induced sputum for TGF-β, MMP-7, YKL-40, IGFBP-2, IL-6, IL-8 and TNF-α.

RESULTS

IPF patients, like COPD, had increased sputum absolute number of neutrophils, eosinophils, macrophages and epithelial cells compared to HS. IPF sputum supernatants had increased concentrations of IGFBP-2, IL-8, TGF-β, MMP-7, MMP-9 and KL-6 (p<0.05, p<0.0001, p<0.05, p<0.05, p<0.0001, p<0.05 respectively) when compared to healthy subjects where COPD had higher IL-6 and TNF-α levels than IPF (p<0.05 and p<0.05 respectively) and HS (p<0.0001 and p<0.001 respectively) and higher IL-8 and MMP-9 than HS (p<0.0001 and p<0.001 respectively). Conversely to IL-6 and TNF-α, MMP-7 was increased in IPF compared to COPD (p<0.05). The KL-6 and MMP-7 protein levels in sputum were inversely correlated with total lung capacity (TLC, % of predicted) in IPF patients (r = -0.73 and r = -0.53 respectively). Sputum gene expression analysis identified a significant increase for IGFBP-2, IL-6, IL-8 and MMP-7 in IPF compared to HS (p<0.05, p<0.01, p<0.05 and p<0.0001 respectively) and for IGFBP-2, YKL-40, IL-6, IL-8 and MMP-7 compared to COPD (p<0.01, p<0.01, p<0.05, p<0.01 and p<0.0001 respectively). Furthermore, gene expression of TGF-β was increased in IPF compared to COPD (p<0.001) but not to HS.

CONCLUSION

Our data show clear increase in expression and production of IGFBP-2, IL-8 and MMP-7 in sputum from patients with IPF that may contribute to the disease.

Diagnostic Performance of Bronchoalveolar Lavage Fluid CD4/CD8 Ratio for Sarcoidosis: A Meta-analysis

BACKGROUND

The usefulness of bronchoalveolar lavage fluid (BALF) CD4/CD8 ratio for diagnosing sarcoidosis has been reported in many studies with variable results. Therefore, we performed a meta-analysis to estimate the overall diagnostic accuracy of BALF CD4/CD8 ratio based on the bulk of published evidence.

METHODS

Studies published prior to June 2015 and indexed in PubMed, OVID, Web of Science, Scopus and other databases were evaluated for inclusion. Data on sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), and diagnostic odds ratio (DOR) were pooled from included studies. Summary receiver operating characteristic (SROC) curves were used to summarize overall test performance. Deeks's funnel plot was used to detect publication bias.

RESULTS

Sixteen publications with 1885 subjects met our inclusion criteria and were included in this meta-analysis. Summary estimates of the diagnostic performance of the BALF CD4/CD8 ratio were as follows: sensitivity, 0.70 (95%CI 0.64-0.75); specificity, 0.83 (95%CI 0.78-0.86); PLR, 4.04 (95%CI 3.13-5.20); NLR, 0.36 (95%CI 0.30-0.44); and DOR, 11.17 (95%CI 7.31-17.07). The area under the SROC curve was 0.84 (95%CI 0.81-0.87). There was no evidence of publication bias.

CONCLUSION

Measuring the BALF CD4/CD8 ratio may assist in the diagnosis of sarcoidosis when interpreted in parallel with other diagnostic factors.

Biological exposure metrics of beryllium-exposed dental technicians

Beryllium is commonly used in the dental industry. This study investigates the association between particle size and shape in induced sputum (IS) with beryllium exposure and oxidative stress in 83 dental technicians. Particle size and shape were defined by laser and video, whereas beryllium exposure data came from self-reports and beryllium lymphocyte proliferation test (BeLPT) results. Heme oxygenase-1 (HO1) gene expression in IS was evaluated by quantitative polymerase chain reaction. A high content of particles (92%) in IS >5 μ in size is correlated to a positive BeLPT risk (odds ratio [OR] = 3.4, 95% confidence interval [CI]: 0.9-13). Use of masks, hoods, and type of exposure yielded differences in the transparency of IS particles (gray level) and modulate HO1 levels. These results indicate that parameters of size and shape of particles in IS are sensitive to workplace hygiene, affect the level of oxidative stress, and may be potential markers for monitoring hazardous dust exposures.

A novel alternative to environmental monitoring to detect workers at risk for beryllium exposure-related health effects

The purpose of this study was to describe a methodology for surveillance and monitoring of beryllium exposure using biological monitoring to complement environmental monitoring. Eighty-three Israeli dental technicians (mean age 41.6 ± 1.36 years) and 80 American nuclear machining workers (54.9 ± 1.21 years) were enrolled. Biological monitoring was carried out by analyzing particle size (laser technique) and shape (image analysis) in 131/163 (80.3%) induced sputum samples (Dipa Analyser, Donner Tech, Or Aquiva, Israel). Environmental monitoring was carried out only in the United States (Sioutas impactor, SKC, Inc., Eighty Four, Pa.). Pulmonary function testing performance and induced sputum retrieval were done by conventional methods. Sixty-three Israeli workers and 37 American workers were followed up for at least 2 years. Biological monitoring by induced sputum indicated that a >92% accumulation of <5 μm particles correlated significantly to a positive beryllium lymphocyte proliferation test result (OR 3.8, 95% CI 1.2-11.4, p = 0.015) among all participants. Environmental monitoring showed that beryllium particles were <1 μm, and this small fraction (0.1-1 μ) was significantly more highly accumulated in nuclear machining workers compared to dental technicians. The small fractions positively correlated with induced sputum macrophages (r = 0.21 p = 0.01) and negatively correlated with diffusion lung carbon monoxide single breath (DLCO-SB r = 0.180 p = 0.04) in all subjects. Years of exposure were positively correlated to the number of accumulated particles 2-3 μ in diameter (r = 0.2, p = 0.02) and negatively correlated to forced expiratory volume in one second/forced vital capacity findings (r = -0.18, p = 0.02). DLCO was decreased in both groups after two years of monitoring. Biological monitoring is more informative than environmental monitoring in the surveillance and monitoring of workers in beryllium industries. Induced sputum is a feasible and promising biomonitoring method that should be included in the surveillance of exposed workers.

Induced sputum in interstitial lung diseases - A pilot study

INTRODUCTION

Induced sputum with hypertonic saline has been suggested as a safer and cheaper alternative to bronchoalveolar lavage for evaluation of patients with interstitial lung diseases (ILD).

OBJECTIVE

To evaluate the safety and feasibility of sputum induction in ILD and to compare sputum cellular profiles with paired bronchoalveolar lavage fluid results.

MATERIAL AND METHODS

Twenty patients underwent sputum induction with 4.5% saline within 2 weeks of bronchoalveolar lavage. Total, differential cell counts and cellular viability were assessed. Wilcoxon test and Spearman's rank correlation coefficient were used and a p<0,05 was considered statistically significant.

RESULTS

From a total of 20 subjects (mean age 49.4±16.4 years, 70% male) a satisfactory sputum sample was obtained in 15 subjects (75%). Induction was stopped in one subject, due to a significant decrease in PEF. The cell profiles for induced sputum and bronchoalveolar lavage fluid (BALF) were different (P <.05), except for eosinophils, and there were no significant correlations between the two methods. Compared to sputum reference values there was an increase of lymphocytes (3.2% vs 0.5%) and eosinophils (1.4% vs 0.0%). Comparing sarcoidosis and hypersensitivity pneumonitis sputum, both diseases had an increase in lymphocytes (4.4 vs 3.9%), with a significant higher neutrophil count in hypersensitivity pneumonitis (65.4% vs 10.6% P <0.05), a finding also seen in BALF.

CONCLUSION

Induced sputum is feasible and safe in interstitial lung diseases. Although sputum cellular counts are not correlated with bronchoalveolar lavage fluid, sputum cellular profiles may help to distinguish different ILD.

Ultrafine and nanoparticles-induced oxidative stress: the role of heme oxygenase-1 and carbon monoxide as anti-inflammatory pathways

INTRODUCTION

Particulate matter (PM) is an environmental factor that has been associated with increased respiratory morbidity and mortality. The major effect of ambient PM on the pulmonary system is that it promotes inflammation in susceptible people. One of the mechanisms by which ambient PM exerts its proinflammatory effects is by generating increased oxidative stress induced by chemical compounds and metal constituents. Cellular responses to PM-induced oxidative stress include activation of antioxidant defense. OBJECTIVE. To investigate the anti-inflammatory and anti-apoptotic roles of heme oxygenase-1 (HO-1) and carbon monoxide (CO) in the PM-induced oxidative stress arm, inflammation, and toxicity. Methods. Particle size analyses were performed according to a laser technique based on the time of transition theory using an Eyetech Analyzer (Donner Technologies Ltd., Israel). HO-1 was analyzed by quantitative reverse transcriptase polymerase chain reaction (RT-PCR) in induced sputum (IS) samples.

RESULTS

We demonstrate the feasibility of measuring micro- and nanoparticles in IS samples of exposed individuals in and out of the workplace to determine the protective role of HO-1 and CO.

CONCLUSIONS

Ongoing studies will further elucidate the protective role of HO-1 and CO in the PM-induced oxidative stress model.

Induced sputum proteome in healthy subjects and asthmatic patients

BACKGROUND

Asthma is a heterogeneous disease characterized by abnormal airway pathophysiology and susceptibility to different stimuli, as exemplified by a subset of patients with exercise-induced bronchoconstriction. Induced sputum provides a noninvasive method to sample airway biofluids that are enriched in proteins.

OBJECTIVE

We hypothesized that novel mechanisms in the pathogenesis of asthma might be revealed by studying the patterns of protein expression in induced sputum.

METHODS

We used shotgun proteomics to analyze induced sputum from 5 healthy subjects and 10 asthmatic patients, including 5 with exercise-induced bronchoconstriction. Differential protein expression among asthmatic patients, asthma subphenotypes, and control subjects was determined by using spectral counting and computational methods.

RESULTS

Using Gene Ontology analysis, we defined the functional landscape of the induced sputum proteome and applied network analysis to construct a protein interaction map for this airway compartment. Shotgun proteomics analysis identified a number of proteins the differential enrichment or depletion of which robustly distinguished asthmatic patients from healthy control subjects and captured the effects of exercise on induced sputum proteome. Functional and network analysis identified key processes, including proteolytic activity, that are known contributors to airway remodeling. Importantly, this approach highlighted previously unrecognized roles for differentially expressed proteins in pathways implicated in asthma, such as modulation of phospholipase A(2) by secretoglobin, a putative role for S100A8/9 in human asthma, and selective upregulation of complement component 3a in response to exercise in asthmatic patients.

CONCLUSION

Computationally intensive analysis of induced sputum proteome is a powerful approach to understanding the pathophysiology of asthma and a promising methodology to investigating other diseases of the airways.

Induced sputum as a method for detection of systemic sclerosis-related interstitial lung disease

Inducted sputum (IS) is a non-invasive procedure that can be used for collection of airway secretions. The aim of our study is to evaluate the clinical usefulness of IS for detection of airway inflammation in systemic sclerosis (SSc). Bronchoalveolar lavage and IS were performed to 20 patients with SSc. Eighteen patients who were referred to pulmonary medicine for bronchoalveolar lavage due to other reasons were also recruited for cell counts comparisons. Spirometry, echocardiography and thorax CT (HRCT) imaging were also performed to all patients. Mean macrophage and lymphocyte counts were found to be increased in IS of SSc patients compared with that of control (58.4 ± 14.5% vs. 31.3 ± 16.3%, 30.2 ± 15.4% vs. 15.0 ± 11.5% P < 0.001), whereas mean neutrophil count was lower in the SSc patients (4.1 ± 4.5% vs. 17.2 ± 13.1%, P < 0.05). Significant correlations were noted between BAL and IS findings for macrophage (r = 0.55, P = 0.02) lymphocyte (r = 0.65, P < 0.01) and total cell counts (r = 0.45, P = 0.06). IS is an easy and reliable method for the detection of alveolitis and can be used for early detection of lung involvement in scleroderma.

High extracellular induced sputum haem oxygenase-1 in sarcoidosis and chronic beryllium disease

BACKGROUND

Sarcoidosis and chronic beryllium disease (CBD) are inflammatory conditions in which oxidative stress state may be crucial for disease outcome. This study compares haem oxygenase-1 (HO-1) extracellular activity for the first time in patients with sarcoidosis or CBD and in healthy controls.

MATERIALS AND METHODS

Induced sputum was recovered using a standard protocol. Pulmonary function tests (PFT) were performed by conventional methods. T lymphocyte subsets (CD4 and CD8) were measured by flow activated cell shorter (FACS). The HO-1 and nitrite levels were measured by a bilirubin-biliverdin reductase-dependent reaction and Greiss reaction respectively. Ferritin and iron levels were measured by enzymatic reaction and chemiluminometric immunoassay respectively.

RESULTS

The mean percentage of lymphocytes was significantly higher in the 36 sarcoid patients compared with that in the 17 controls (P=0.001). The mean CD4/CD8 ratio was significantly higher in the sarcoid and the 10 CBD patients compared to that in controls (P=0.000 and 0.002 respectively), as was the mean HO-1 activity (P=0.045 and 0.041 respectively). The HO-1 activity did not differ with the sarcoidosis stage. The HO-1 level and PFT parameters were negatively correlated. The differences in mean nitrite, ferritin and iron levels were non-significant between the three groups. The HO-1 and ferritin levels were correlated (P=0.008).

CONCLUSIONS

We succeeded in non-invasively measuring the activity of HO-1 from cells of airways in spite of its being an intracellular enzyme. The HO-1 levels in sarcoidosis and CBD were abnormally elevated.

Induced sputum and occupational diseases other than asthma

PURPOSE OF REVIEW

Induced sputum noninvasively provides information on cellular and soluble material from airways. It has been successfully applied for assessing airway inflammation in asthma and chronic obstructive pulmonary disease, producing reliable results comparable to biopsy and bronchoalveolar lavage. Induced sputum research in the field of occupational medicine has mainly focused upon occupational asthma, and less to other types of occupational diseases.

RECENT FINDINGS

Particulate size distribution in induced sputum samples points to accumulation over time, leading to the consideration that this measurement may serve as a time-dependent marker for biological monitoring. Qualitative analysis of chemical composition of induced sputum particles is well correlated to the chemical elements spectrum in bronchoalveolar lavage lung cells and in biopsy thin sections. T cell subsets in induced sputum can be used as a marker of granulomatosis in chronic beryllium disease. Cytokines retrieved from induced sputum samples in exposed workers show a differential pattern compared to nonexposed workers.

SUMMARY

Induced sputum is a well tolerated, noninvasive technique that is opening a new window in the field of occupational diseases of the lung and can be integrated into the well established criteria for diagnosing and monitoring these diseases, especially when invasive techniques are clinically contraindicated or impractical.

Relationship between induced sputum cytology and inflammatory status with lung structural and functional abnormalities in asbestosis

BACKGROUND

Asbestosis is associated with lung cellular and immunological abnormalities. Induced sputum cytology and local and systemic markers of inflammation may be helpful to characterize disease status and progression in these patients.

METHODS

Thirty-nine ex-workers with asbestosis on high-resolution CT (HRCT) and 21 non-exposed controls were evaluated. Sputum cytology and IL-8 in serum and sputum were related to lung function impairment.

RESULTS

Subjects with asbestosis had reduced sputum cellularity but higher macrophage/neutrophil ratio and % macrophage as compared with controls. Sputum and serum IL-8 were also higher in patients with asbestosis (P < 0.05). In addition, evidence of lung architectural distorption on HRCT was associated with increased levels of serum IL-8. Interestingly, absolute macrophage number was negatively correlated with total lung capacity (r = -0.40; P = 0.04) and serum IL-8 to lung diffusing capacity (r = -0.45; P = 0.01).

CONCLUSIONS

Occupationally exposed subjects with asbestosis on HRCT have cytologic abnormalities in induced sputum and increased local and systemic pro-inflammatory status which are correlated to functional impairment.

Rapid diagnosis of smear-negative tuberculosis using immunology and microbiology with induced sputum in HIV-infected and uninfected individuals

Rationale and Objectives

Blood-based studies have demonstrated the potential of immunological assays to detect tuberculosis. However lung fluid sampling may prove superior as it enables simultaneous microbiological detection of mycobacteria to be performed. Until now this has only been possible using the expensive and invasive technique of broncho-alveolar lavage. We sought to evaluate an immunoassay using non-invasive induced-sputum to diagnose active tuberculosis.

Methods and Results

Prospective cohort study of forty-two spontaneous sputum smear-negative or sputum non-producing adults under investigation for tuberculosis. CD4 lymphocytes specific to purified-protein-derivative of Mycobacterium tuberculosis actively synthesising interferon-gamma were measured by flow cytometry and final diagnosis compared to immunoassay using a cut-off of 0.5%. Sixteen subjects (38%) were HIV-infected (median CD4 count [range] = 332 cells/µl [103–748]). Thirty-eight (90%) were BCG-vaccinated. In 27 subjects diagnosed with active tuberculosis, the median [range] percentage of interferon-gamma synthetic CD4+ lymphocytes was 2.77% [0–23.93%] versus 0% [0–2.10%] in 15 negative for active infection (p<0.0001). Sensitivity and specificity of the immunoassay versus final diagnosis of active tuberculosis were 89% (24 of 27) and 80% (12 of 15) respectively. The 3 positive assays in the latter group occurred in subjects diagnosed with quiescent/latent tuberculosis. Assay performance was unaffected by HIV-status, BCG-vaccination or disease site. Combining this approach with traditional microbiological methods increased the diagnostic yield to 93% (25 of 27) alongside acid-fast bacilli smear and 96% (26 of 27) alongside tuberculosis culture.

Conclusions

These data demonstrate for the first time that a rapid immunological assay to diagnose active tuberculosis can be performed successfully in combination with microbiological methods on a single induced-sputum sample.

Hydrogen peroxide in exhaled breath condensate (EBC) vs eosinophil count in induced sputum (IS) in parenchymal vs airways lung diseases

We compared exhaled breath condensate (EBC) and induced sputum (IS) for assessing inflammation in pulmonary diseases in patients with obstructive lung disease (n = 20), persistent cough >6 months (n = 20), interstitial lung disease (n = 25) and controls (n = 10). EBC was collected by suspending a Teflon perfluoroalkoxy tube installed in an ice-filled container and connected to a polypropylene test tube. IS was recovered after 20' inhalation of 3% saline with an ultrasonic nebulizer, and 300 cells were differentially counted in cytospin Giemsa-stained slides. H(2)0(2) was measured by a method based on oxidation of phenolsulfonphthalein (phenol red) mediated by horseradish peroxidases and H(2)0(2). Pulmonary function tests were performed by conventional methods. H(2)0(2) levels in EBC and % eosinophils in IS were significantly different between groups. A positive and significant correlation was found between % eosinophils in IS and the levels of H(2)0(2) in EBC for each group and for all patients combined.

Induced sputum as a tool for early detection of airway inflammation in connective diseases-related lung involvement

BACKGROUND

Induced sputum (IS) sampling is a safe and validated approach to study bronchial inflammation in chronic obstructive lung diseases. Although promising results have also been reported in various diffuse interstitial lung disorders, the potential use of IS in the assessment of connective tissue diseases (CTD)-related lung involvement has not yet been investigated.

AIM OF THE STUDY

To evaluate the clinical usefulness of IS in the early management of patients suffering from rheumatoid arthritis (RA) and systemic sclerosis (SSc) at the onset of respiratory symptoms.

PATIENTS AND METHODS

The study population included 19 patients (RA=12; SSc=7) and 14 age- and sex-matched healthy volunteers. Lung function testing, high resolution computed tomography (HRCT) of the thorax and IS collection were performed in all cases. Broncho-alveolar lavage (BAL) was obtained in selected patients.

RESULTS

IS samples from patients contained a significantly higher percentage of neutrophils and a lower percentage of macrophages compared to healthy subjects (p=0.002 and 0.001, respectively), while the total cell number showed no differences. In addition, sputa yielded both higher cell counts and higher neutrophils than BAL samples (p=0.02 in all instances). No correlations were found between IS findings and lung function parameters, HRCT and BAL findings.

CONCLUSIONS

This is the first study investigating the inflammatory cell pattern in IS from CTD patients with early clinical evidence of lung involvement. Future studies are needed to determine whether the assessment of airway inflammation adds significant information that may result in a relevant improvement of disease management.

Induced sputum in interstitial lung diseases

PURPOSE OF REVIEW

Induced sputum is a particularly useful procedure since it provides information on the cellular and molecular constituents in inflammation. Extensive work has demonstrated the application of induced sputum in the management of asthma, chronic obstructive pulmonary disease and chronic bronchitis, but less attention has been paid to its efficacy in diagnosing interstitial lung diseases. This review analyzes the applications of induced sputum in the assessment of sarcoidosis, nongranulomatous interstitial lung diseases, occupational lung diseases and other systemic diseases with or without lung involvement.

RECENT FINDINGS

T cell subsets in induced sputum in combination with pulmonary function testing can serve as predictors with high specificity and sensitivity in diagnosing sarcoidosis, using multivariate logistic regression models which can be easily implemented in clinical practice. Differential cell counts in induced sputum are as useful as bronchoalveolar lavage for identifying neutrophilic inflammation in patients with nongranulomatous interstitial lung diseases (e.g. idiopathic pulmonary fibrosis) and detecting chronic rejection in bronchiolitis obliterans syndrome. Sputum analysis has also been shown to be a useful tool for diagnosing, assessing and monitoring occupational lung disorders.

SUMMARY

We suggest integrating induced sputum technology to the well-established criteria for the diagnosis of interstitial lung diseases, especially when there are clinical contraindications for performing bronchoscopy or when tissue confirmation is absent for any reason.

The role of induced sputum in amiodarone-associated interstitial lung diseases

Amiodarone, a highly effective medication for suppressing cardiac rhythm disturbances, may cause pulmonary injury, such as chronic interstitial lung diseases, in 5-15% of the patients who take it. We applied induced sputum (IS), a non-invasive technique, for diagnosing amiodarone-induced pulmonary toxicity. Four patients with interstitial lung disease who were treated by amiodarone for ischemic heart diseases were evaluated by a conventional clinical workup. All four patients showed marked interstitial pattern on computerized tomography and decreased diffusion capacity (DLCO-SB 51-76%). IS showed lymphocytosis, a high CD4 or CD8 count, eosinophilia and amiodarone in 3 of 4 patients. IS may be a useful tool for assessing amiodarone toxicity in patients with ischemic heart diseases and concomitant pulmonary side effects.

Combined CD4/CD8 ratio in induced sputum and pulmonary function testing for non-invasive identification of sarcoidosis

Induced sputum is a useful noninvasive method for assessing parenchymal diseases. This retrospective study investigated its potential application in combination with functional parameters to differentiate sarcoidosis from non-sarcoid interstitial lung disease (NSA-ILD), especially when bronchoscopy is clinically contraindicated. All 120 study patients (67 sarcoidosis and 53 NSA-ILD) underwent both bronchoalveolar lavage (flexible fiberoptic video bronchoscope; Pentax, Japan) and induced sputum testing (3% NaCl, selecting plugs method, 300 cells differentially counted in Giemsa stained cytopreps). CD4/CD8 subsets were identified by a fluorescence-activator cell sorter. All patients underwent high-resolution computerized tomography and 103 of 120 underwent transbronchial biopsy. Multivariate logistic regression models were applied to the data to predict the probability of having the sarcoidosis as a function of the explanatory variables: Model I contained demographic and induced sputum data, and Model II included demographic data and combined sputum and pulmonary function test results. The area under the curve was 0.899 for induced sputum parameters alone and 0.914 for induced sputum and pulmonary function parameters.

CONCLUSION

The results derived from the combination of noninvasive induced sputum approach can be used as predictors with high specificity and sensitivity in the differential diagnosis of sarcoidosis.

Th1/Th2 cytokine pattern in bronchoalveolar lavage fluid and induced sputum in pulmonary sarcoidosis

Background

Sarcoidosis is thought to be a T-helper type 1 cytokine (Th2 cytokine) mediated disorder. Induced sputum (IS) has been proposed as a useful non-invasive method, mainly for the assessment of the airway diseases. The aim of this study was to explore induced sputum (IS) CD4⁺Th1 T-lymphocyte subpopulation and to compare them with those of bronchoalveolar lavage fluid (BALF) in patients with sarcoidosis.

Methods

We studied prospectively 21 patients (12 female, 9 male) of median age 46 yr (range, 25–65) with sarcoidosis and 10 normal subjects (5 female, 5 male) of median age 39 yr (range, 26–60). IS was performed with hypertonic saline solution using an ultrasonic nebulizer. BALF was performed within 10 days of IS. After stimulation of sputum lymphocytes with phorbol-myristate-acetate, we used double immunocytochemical methods to identify CD4⁺ IFN-γ positive and IL-4 positive cells (Th1 and Th2, respectively).

Results

Sarcoidosis patients had an increased number of CD4+ -IFN-γ producing cells in IS (p = 0.003) and BALF (p = 0.01) in comparison with normal subjects. No significant differences were detected between CD4+ -IL-4 cells in BALF (p = 0.053, NS) and IS (p = 0.46, NS) between sarcoidosis patients and healthy controls. The ratio of Th1 to Th2 cells in BALF and IS was statistically different in sarcoidosis when compared with normal subjects (p = 0.007 in BALF and IS). A significant correlation was found between CD4+ IFN-γ positive cells in IS and those in BALF in sarcoidosis patients (r = 0.685, p = 0.0006).

Conclusion

These data suggests that a Th1-like cytokine pattern can be observed in CD4+ T-lymphocytes in IS in patients with pulmonary sarcoidosis. Further studies are needed to explore the value of IS vs BALF in the follow-up of these patients.

Induced sputum versus bronchoalveolar lavage fluid in the evaluation of patients with idiopathic pulmonary fibrosis

BACKGROUND

Induced sputum (IS) has been proposed as a useful noninvasive method for the assessment of airway diseases. Bronchoalveolar lavage fluid (BALF), an important tool for evaluating interstitial lung diseases, has limited utility due to its invasiveness and the difficulties of performing it in severely ill patients, while it is impractical for follow-up evaluation.

OBJECTIVES

The aim of this study was to investigate the differences and the possible correlation of cell differential and lymphocyte subpopulations between BALF and IS samples in patients with idiopathic pulmonary fibrosis (IPF).

METHODS

We studied prospectively 20 patients (18 male, 2 female) of median age 67 years (range 40-75) with IPF and 10 normal subjects (5 female, 5 male) of median age 59 years (range 36-70). IS was performed with hypertonic saline solution using an ultrasonic nebulizer (Ultraneb 2000). BALF was performed by a conventional procedure using fiberoptic bronchoscopy within 3 days from IS. May-Grunewald-Giemsa-stained preps were differentially counted and T-lymphocyte subsets were analyzed by a flow-activated cell sorter.

RESULTS

The percentage of macrophages was significantly lower in IS than in BALF (p < 0.0001), while the neutrophils were lower in BALF (p < 0.0001). A significant correlation was found between BALF and IS eosinophil counts (r = 0.54, p = 0.01) and CD4+/CD8+ ratio (r = 0.74, p < 0.0001).

CONCLUSION

Our data suggest that different information is obtained by IS and BALF and thus, the two methods are complementary in IPF.

Induced sputum and bronchoalveolar lavage from patients with hypersensitivity pneumonitis

BACKGROUND AND AIM

Hypersensitivity pneumonitis (HP) is an immunologically induced inflammation of the lung parenchyma, though bronchial airways may be also involved. The aim of this study was to compare the cellular profiles of induced sputum (IS) in patients with newly diagnosed HP to that of healthy subjects, and to examine the relationship between inflammatory cells from IS and BAL.

METHODS

Nine HP patients and 9 healthy volunteers were studied. IS was obtained by inhalation of hypertonic saline solution in all subjects. Bronchoscopy was performed on a different occasion in all patients and in five controls.

RESULTS

IS was well tolerated and preferred to BAL by all subjects. Both IS and BAL from HP patients showed a significant increase in total cells (P < 0.02 and P < 0.001) and in lymphocytes (P < 0.02 and P < 0.001) and a significant decrease in macrophages (P < 0.05 and P < 0.001), when compared with normal subjects. In HP patients, total cells number in IS was higher than that in BAL (P < 0.02). Moreover, the percentage of lymphocytes was significantly lower in IS than in BAL (P < 0.001). No significant relationship was found between total cells or inflammatory cells from IS and the corresponding ones from BAL and wide limits of agreement were found between lymphocytes from IS and BAL.

CONCLUSIONS

This study demonstrated that both BAL and IS from newly diagnosed HP patients contained significantly more total cells and lymphocytes, when compared to healthy subjects. Moreover, differential cell counts in HP patients showed that IS and BAL reflected different compartments of inflammation. Thus, IS could represent a complementary, but not alternative tool to bronchoscopy both in research and in the clinical monitoring of HP patients.

Induced sputum assessment in New York City firefighters exposed to World Trade Center dust

New York City Firefighters (FDNY-FFs) were exposed to particulate matter and combustion/pyrolysis products during and after the World Trade Center (WTC) collapse. Ten months after the collapse, induced sputum (IS) samples were obtained from 39 highly exposed FDNY-FFs (caught in the dust cloud during the collapse on 11 September 2001) and compared to controls to determine whether a unique pattern of inflammation and particulate matter deposition, compatible with WTC dust, was present. Control subjects were 12 Tel-Aviv, Israel, firefighters (TA-FFs) and 8 Israeli healthcare workers who were not exposed to WTC dust. All controls volunteered for this study, had never smoked, and did not have respiratory illness. IS was processed by conventional methods. Retrieved cells were differentially counted, and metalloproteinase-9 (MMP-9), particle size distribution (PSD), and mineral composition were measured. Differential cell counts of FDNY-FF IS differed from those of health care worker controls (p < 0.05) but not from those of TA-FFs. Percentages of neutrophils and eosinophils increased with greater intensity of WTC exposure (< 10 workdays or greater than or equal to 10 workdays; neutrophils p = 0.046; eosinophils p = 0.038). MMP-9 levels positively correlated to neutrophil counts (p = 0.002; r = 0.449). Particles were larger and more irregularly shaped in FDNY-FFs (1-50 microm; zinc, mercury, gold, tin, silver) than in TA-FFs (1-10 microm; silica, clays). PSD was similar to that of WTC dust samples. In conclusion, IS from highly exposed FDNY-FFs demonstrated inflammation, PSD, and particle composition that was different from nonexposed controls and consistent with WTC dust exposure.

Induced-sputum particle size distribution and pulmonary function in foundry workers

The authors studied and determined a correlation between the distribution of particle size in induced sputum and pulmonary function tests among 54 foundry workers, of whom 34 had been exposed to a variety of metals. Sputum was induced with an ultrasonic nebulizer and processed by conventional methods; a particle scanner was used to measure particle size. All participants underwent spirometry to measure their flow rates. There were significant differences between the exposed and nonexposed groups with respect to the proportion of particles with diameters greater than 2 microm and with diameters greater than 5 microm. A positive correlation was found between the proportion of particles greater than 5 microm in diameter and the ratio of forced expiratory volume in 1 sec (FEV1.0) to forced vital capacity (FVC) (i.e., FEV1.0/FVC) for all 54 workers, and there was a significant correlation for non-smokers. Correlations by work categories revealed a significant negative correlation among casting workers between particles with diameters greater than 5 microm and percentage of FVC. These findings indicate the value of measuring particle size in induced-sputum specimens as a tool for differentiating between exposed and nonexposed workers. Also indicated was a tendency toward a restrictive pattern in pulmonary function tests among workers who had exposure to higher percentages of large particles.

Induced sputum-retrieved matrix metalloproteinase 9 and tissue metalloproteinase inhibitor 1 in granulomatous diseases

Matrix metalloproteinases (MMPs) capable of degrading various components of connective tissue matrices, and tissue inhibitor metalloproteinases (TIMPs) are considered important in lung parenchymal remodeling and repair processes in pulmonary diseases. Induced sputum (IS) is a reliable noninvasive method to investigate pathogenesis, pathophysiology and treatment of lung disease. This study was designed to determine whether IS-MMP9/TIMP1 levels demonstrate lung parenchymal remodeling in sarcoidosis (SA) and Crohn's disease (CRD) patients. Sputum was induced and processed conventionally in 13 SA patients, 18 CRD patients and 9 controls. Two-hundred cells were counted on Giemsa-stained cytopreps, and T lymphocytes subsets (CD4 = T helper and CD8 = T suppressor cytotoxic cells) were analysed by FACS using monoclonal antibodies.MMP-9 and TIMP-1 were measured using commercial ELISA kits. MMP-9 concentrations, but not those of TIMP-1, were significantly greater in the sputum supernatant in SA and CRD patients compared to controls (P = 0.018 and P = 0.0019, respectively). The molar ratio, MMP-9/TIMP-1, was significantly higher in SA and CRD patients compared to controls (P = 0.008 and P = 0.024, respectively). Gelatinase species having a molecular weight similar to that of MMP-9 were demonstrated by zymographic analysis. MMP-9 levels were highly correlated with the CD4/CD8 ratio and DLCO capacity in SA but less in CRD patients. MMP-9 levels in IS provide a sensitive marker for pulmonary damage.

Induced sputum for identifying sarcoidosis in patients with uveitis

OBJECTIVE

To evaluate the value of the induced sputum technique in diagnosing sarcoidosis as the cause of uveitis.

DESIGN

Comparative case series.

PARTICIPANTS

Seventeen patients with uveitis. Two control groups were used. The first included 10 patients with sarcoid without uveitis; the second included 5 healthy volunteers.

TESTING

Sputum was induced by a 20-minute inhalation of 3.5% saline using an ultrasonic nebulizer. Samples were studied by differential counts of 200 cells on cytopreps stained by Giemsa. T lymphocyte subset analyses were done by fluorescence-activated cell sorter using the monoclonal antibodies CD4 (T helper cells) and CD8 (T suppressor-cytotoxic cells). Angiotensin-converting enzyme (ACE) serum levels were obtained.

MAIN OUTCOME MEASURES

A CD4/CD8 ratio >2.5 and an ACE level >145 microl/ml/minute were considered to be abnormal.

RESULTS

The difference in the CD4/CD8 ratios in the induced sputum examination between the group of patients with an elevated ACE level and the group of patients with an ACE level within normal limits was statistically significant (P = 0.0001).

CONCLUSIONS

The induced sputum examination showed increased CD4/CD8 ratios in patients with uveitis who also had elevated ACE levels, suggesting the presence of sarcoidosis.

Age-related quantitative alterations in lymphocyte subsets and immunoglobulin isotypes in healthy horses

OBJECTIVE

To characterize age-associated changes in lymphocyte population subsets and immunoglobulin isotypes.

ANIMALS

30 healthy young light-breed horses (5 to 12 years old) and 30 healthy aged light-breed horses (> 20 years old).

PROCEDURE

Lymphocyte subset populations were identified, using monoclonal antibodies to cell surface markers CD5, CD4, CD8, and IgG. Subset populations were quantitated by use of flow cytometric analysis of antibody-stained cells. Serum immunoglobulin concentration was determined using single radial immunodiffusion.

RESULTS

Absolute cell counts of total lymphocytes, T cells, CD4+ and CD8+ T cells, and B cells were decreased in aged horses, compared with young horses. There was a significant decrease in the percentage of CD8+ cells and an increase in the CD4+-to-CD8+ cell ratio in the aged population, compared with young horses. However, serum concentration of IgG, IgG(T), IgM, or IgA did not differ with age.

CONCLUSIONS AND CLINICAL RELEVANCE

In horses, total lymphocyte count and lymphocyte subset cell counts decrease with age. Age-matched control values are necessary for optimal evaluation of hematologic variables in aged horses. The decrease in lymphocyte subset cell counts in healthy aged horses mimics that seen in other species and may contribute to an age-associated decrease in immunocompetency.

Induced sputum: diagnostic value in interstitial lung disease

Induced sputum by inhalation of hypertonic saline solution is a noninvasive technique used to collect cellular and soluble material from lung airways. During the past decade, this method has been widely used to assess airway inflammation in asthma and chronic obstructive pulmonary disease, since it produces reliable results and compares favorably to other invasive techniques, such as biopsy and bronchoalveolar lavage (BAL). Induced sputum has been recently used to study interstitial lung disease (ILD), more specifically pneumoconiosis, sarcoidosis, and nongranulomatous ILD. Moreover, results from induced sputum supplied information comparable to BAL findings for occupational lung disease and were able to distinguish sarcoidosis patients from healthy subjects and from patients with nongranulomatous ILD. Although induced sputum had previously provided promising results in assessing patients with ILD, its diagnostic role has not yet been well defined. Further studies of the evaluation by induced sputum of grading of severity, follow-up of disease, and effects of treatment are needed. Additionally, to date no specific studies have been undertaken to evaluate the safety and functional effects of sputum induction on patients with ILD. In conclusion, we think that induced sputum can be used as a complementary tool to BAL both in research and in clinical monitoring of patients with ILD.

The use of induced sputum in the assessment of pulmonary involvement in Crohn's disease

OBJECTIVE

Our aim was to evaluate lung involvement in Crohn's disease (CRD) patients by induced sputum (IS). Extraintestinal manifestations are frequent in CRD, but lung involvement is rare. Induced sputum is a reliable noninvasive method of investigating the pathogenesis, pathophysiology, and treatment of lung disease.

METHODS

Twenty-four CRD patients and nine control subjects (all nonsmokers) without respiratory symptoms were tested. Sputum was induced by 20' inhalation of 3.5% saline using ultrasonic nebulizer. Samples were studied by differential counts of 200 cells on cytopreps stained by Giemsa. T-lymphocyte subset analyses were done by FACS using three monoclonal antibodies: CD3 = total T cells, CD4 = T helper cells, and CD8 = T suppressor-cytotoxic cells. CD4/CD8 >2.5 was considered abnormal.

RESULTS

Four patients did not produce sputum. Of the remaining 20 patients, seven had active CRD and 13 were in remission. They were divided into two groups: Group A patients had abnormal CD4/CD8 ratio of 6.7 +/- 2.5; Group B (seven patients) had normal CD4/CD8 ratio of 1.7 +/- 0.52 (p = 0.0001). The differential counts of IS samples were similar in both groups, but lymphocyte count was significantly higher in CRD patients than in the control group (13.2 +/- 11.2 vs 4.8 +/- 3.6, p = 0.036). There were no differences in spirometry, treatment, extent, or activity of CRD.

CONCLUSION

Using a simple noninvasive method, we found that among CRD patients without respiratory symptoms there was a high (65%) incidence of lung involvement.