Evaluation of albumin as a reference marker of dilution in bronchoalveolar lavage fluid from asthmatic and control subjects

The relationship between airway immunoglobulin activity and eosinophils in COPD

In chronic obstructive pulmonary disease (COPD), the effects of inhaled corticosteroids are predicted by blood eosinophil counts. We previously briefly reported increased immunoglobulin (Ig)A and IgM levels in bronchoalveolar lavage (BAL) of COPD patients with higher (eosinophil^high) compared to lower (eosinophil^low) blood eosinophils (>250/μL versus < 150/μL), suggesting differences in adaptive immune function. An inverse relationship exists between eosinophil counts and airway pathogenic bacteria levels. The mechanistic reasons for these associations between eosinophils, corticosteroids and pathogenic bacteria are unclear. IgA, IgM and IgG levels were assessed in BAL, bronchial biopsies and epithelium collected from eosinophil^high (n = 20) and eosinophil^low (n = 21) patients. Bronchial B‐cell numbers were measured by immunohistochemistry. B‐cell activity was assessed in bronchial samples and following exposure to BAL from eosinophil^high and eosinophil^low patients. BAL levels of non‐typeable Haemophilus influenza (NTHi)‐specific immunoglobulins were quantified. Results showed airway expression of IgA, IgG1 and IgM were lower in eosinophil^low compared to eosinophil^high patients, with lower levels of NTHi‐specific IgA and IgM. Bronchial B‐cell numbers were similar in both groups, but B‐cell activity was lower in eosinophil^low patients. In conclusion, COPD eosinophil^low patients show differences in adaptive immune function compared to COPD eosinophil^high patients. These differences may cause different microbiomes in these COPD phenotypes.

Collecting Protein Biomarkers in Breath Using Electret Filters: A Preliminary Method on New Technical Model and Human Study

Biomarkers in exhaled breath are useful for respiratory disease diagnosis in human volunteers. Conventional methods that collect non-volatile biomarkers, however, necessitate an extensive dilution and sanitation processes that lowers collection efficiencies and convenience of use. Electret filter emerged in recent decade to collect virus biomarkers in exhaled breath given its simplicity and effectiveness. To investigate the capability of electret filters to collect protein biomarkers, a model that consists of an atomizer that produces protein aerosol and an electret filter that collects albumin and carcinoembryonic antigen-a typical biomarker in lung cancer development- from the atomizer is developed. A device using electret filter as the collecting medium is designed to collect human albumin from exhaled breath of 6 volunteers. Comparison of the collecting ability between the electret filter method and other 2 reported methods is finally performed based on the amounts of albumin collected from human exhaled breath. In conclusion, a decreasing collection efficiency ranging from 17.6% to 2.3% for atomized albumin aerosol and 42% to 12.5% for atomized carcinoembryonic antigen particles is found; moreover, an optimum volume of sampling human exhaled breath ranging from 100 L to 200 L is also observed; finally, the self-designed collecting device shows a significantly better performance in collecting albumin from human exhaled breath than the exhaled breath condensate method (p<0.05) but is not significantly more effective than reported 3-stage impactor method (p>0.05). In summary, electret filters are potential in collecting non-volatile biomarkers in human exhaled breath not only because it was simpler, cheaper and easier to use than traditional methods but also for its better collecting performance.

Description of an Automated Method for Urea Nitrogen Determination in Bronchoalveolar Lavage Fluid (BALF) of Neonates and Infants

Bronchoalveolar lavage (BAL) partially recovers both the instilled saline and the alveolar fluid, so-called epithelial lining fluid (ELF), but a correction for the dilution due to the BAL technique itself is needed to know the amount of recovered ELF. In this regard, urea nitrogen may be useful and has been proposed to calculate ELF. The aim of the present study was to develop and validate a new method to measure urea nitrogen in BAL fluid (BALF). We used 19 BALF samples obtained from neonates and infants with different respiratory conditions. The urea nitrogen assay was carried out on Cobas c311 analyzer (Roche Diagnostics). A validation study shows that the method is perfectly linear (R(2) = 0.999), sensitive (limit of detection = 0.055 mg/dL; limit of quantification = 0.16 mg/dL), repeatable (low = 0.15 ± 0.02, 13.3%; high = 1.80 ± 0.02, 1.1%), reproducible (low = 0.14 ± 0.02, 14.2 %; high = 1.76 ± 0.04, 2.2 %) with accuracy ranging between 93-96%. Our results support the robustness of validated procedure since the described method appears simple, precise, rapid, and suitable for routine analysis. Thus, it may be used to correct concentration of various noncellular BAL components and calculate their ELF amounts in neonates and infants.

Translational research in pediatrics III: bronchoalveolar lavage

The role of flexible bronchoscopy and bronchoalveolar lavage (BAL) for the care of children with airway and pulmonary diseases is well established, with collected BAL fluid most often used clinically for microbiologic pathogen identification and cellular analyses. More recently, powerful analytic research methods have been used to investigate BAL samples to better understand the pathophysiological basis of pediatric respiratory disease. Investigations have focused on the cellular components contained in BAL fluid, such as macrophages, lymphocytes, neutrophils, eosinophils, and mast cells, as well as the noncellular components such as serum molecules, inflammatory proteins, and surfactant. Molecular techniques are frequently used to investigate BAL fluid for the presence of infectious pathologies and for cellular gene expression. Recent advances in proteomics allow identification of multiple protein expression patterns linked to specific respiratory diseases, whereas newer analytic techniques allow for investigations on surfactant quantification and function. These translational research studies on BAL fluid have aided our understanding of pulmonary inflammation and the injury/repair responses in children. We review the ethics and practices for the execution of BAL in children for translational research purposes, with an emphasis on the optimal handling and processing of BAL samples.

Bronchial brushings for investigating airway inflammation and remodelling

Asthma is the commonest medical cause for hospital admission for children in Australia, affects more than 300 million people worldwide, and is incurable, severe in large number and refractory to treatment in many. However, there have been no new significant treatments despite intense research and billions of dollars. The advancement in our understanding in this disease has been limited due to its heterogeneity, genetic complexity and has severely been hampered particularly in children by the difficulty in obtaining relevant target organ tissue. This review attempts to provide an overview of the currently used and recently developed/adapted techniques used to obtain lung tissue with specific reference to the airway epithelium.

Efficacy of two breath condensers

BACKGROUND

Examination of Exhaled Breath Condensate has been suggested to give information about inflammatory airway diseases.

OBJECTIVES

The aim was to compare efficacy and variability in gain of two commercially available exhaled breath condensers, ECoScreen and RTube in an in vitro set up.

METHODS

Test fluids containing myeloperoxidase (MPO) or human neutrophil lipocalin (HNL) in addition to saline and bovine serum albumin were nebulized and aerosols were transferred by a servo ventilator to either of the two condensers. Analyses of MPO, HNL, or chlorine were done by means of ELISA, RIA, or a modified adsorbed organic halogen technique (AOX), respectively.

RESULTS

Recoveries of HNL were higher when using ECoScreen than RTube (P<0.05). In contrast, there were no significant differences between the two condensers in recoveries of MPO or chlorine. The spread of data was wide regarding all tested compounds.

CONCLUSION

Variability in gain was large and ECoScreen was more efficacious then RTube in condensing the tested solutes of HNL, but not those of MPO or chlorine.

Permeability, inflammation and oxidant status in airspace epithelium exposed to ozone

The aim of the study was to investigate possible mechanisms of epithelial injury in normal subjects exposed to environmentally relevant concentrations of ozone. Fifteen healthy non-smoking subjects (M:F 12:3) were studied. Five of the 15 subjects were exposed to filtered air, six were exposed to ozone 100 parts per billion (ppb) and seven were exposed to ozone 400 ppb with 99mtechnetium labelled diethylene-triamine-penta-acetate (99mTc-DTPA) or bronchoalveolar lavage (BAL) performed 1 or 6 h after exposure as indicated above. All the above studies were performed on different occasions at least 5 days apart. The subjects were exposed on each occasion for 1h during intermittent exercise at a ventilation of 40l min-1. 99mTc-DTPA lung clearance did not change after either level of ozone exposure, but neutrophils increased in BAL 6 h after exposure to 400 ppb. Superoxide anion release from mixed BAL leucocytes decreased 1 h after 100 ppb and 6 h after 400 ppb. Products of lipid peroxidation in epithelial lining fluid decreased both 1 and 6 h after 400 ppb. There was no change in anti-oxidant capacity or glutathione concentrations. Ozone exposure did not increase epithelial permeability, but was associated with neutrophil influx into the airspaces, without evidence of increased oxidative stress.

Increased Levels of Albumin in Bronchial Washing Fluid of Patients with Bronchial Carcinoma. Could Albumin be Considered as a Tumor Marker?

Background

The aim of this study was to evaluate the significance of albumin in bronchial washing fluid (BWF) and its relationship to three tumor markers (CEA, CA 19–9 and NSE).

Methods

Serum and BWF samples were collected in a group of 60 patients. Albumin and tumor markers in the BWF and serum of three groups: a control group (CG), a chronic bronchitis group (CBG) and a lung cancer group (CaG), were analyzed in a prospective cross-sectional study. The diagnostic yields of the tests in each environment (serum and BWF) were evaluated by using as cutoff points the values of the corresponding 90th percentile of CG and CBG taken together.

Results

A significant difference in albumin level (p<0.001) was noted in the BWF of patients with cancer compared with the other two groups. In addition, a significant difference in CEA level (p<0.001) was observed in the serum of cancer patients compared with the other two groups. The cutoff values for CEA in serum and albumin in BWF were 2.20 ng/mL and 2.00 g/dL, respectively. The areas under the corresponding ROC curves were 93% and 97%. Combination of CEA-serum and albumin-BWF by logistic regression analysis increased their diagnostic value.

Conclusion

Measurement of albumin levels in BWF could be a useful additional diagnostic tool to differentiate malignant from non-malignant lung diseases. Moreover, the combined measurement of CEA in serum and albumin in BWF could be of aid in the follow-up of lung cancer patients.

Surfactant function in children with chronic airway inflammation

Pulmonary surfactant is necessary to keep the terminal conducting airways patent. It is unknown whether mild to moderate airway inflammation may influence surfactant function and thus contribute to the pathogenesis of chronic airway inflammation in children. To answer this question, 21 children with chronic obstructive bronchitis and 19 asymptomatic children with long-term tracheostomy and increased numbers of neutrophils in their airways were compared with 15 healthy controls. Bronchoalveolar lavage fluid was separated into large surfactant aggregates (LA) and a supernatant containing inhibitory constituents. Surfactant function of LA, recombinations of LA and supernatant, and recombinations of a defined bovine surfactant and supernatant was assessed in a capillary surfactometer. Compared with controls, the function of the LA surfactant was reduced and there was no difference between children with tracheostomy and chronic obstructive bronchitis. The function of LA-supernatant recombinations was poor in all subjects. This may be explained by the well-known protein influx during the lavage procedure. The activity of bovine surfactant-supernatant reconstitutions was impaired in children with tracheostomy. In all surfactant mixtures assessed, surfactant function was inversely correlated to the number of neutrophils in the lavage fluid. Chronic lower airway inflammation with mild or no clinical symptoms is associated with impaired surfactant function. The dysfunction may contribute to airflow restrictions frequently observed in these children.

Tumour markers in serum, bronchoalveolar lavage and biopsy cytosol in lung carcinoma: what environment lends the optimum diagnostic yield?

BACKGROUND

The aim of this study was to assess the diagnostic yield of the tumour markers carbohydrate antigen (CA 125), carcinoembryonic antigen (CEA), neuron-specific enolase (NSE), squamous cell carcinoma antigen (SCC) and specific tissue polypeptide antigen (TPS) in serum, bronchoalveolar lavage (BAL) and biopsy cytosol in a group of patients with bronchogenic carcinoma.

METHODS

Serum, BAL and biopsy cytosol samples were collected in a group of 85 patients with benign or malignant pulmonary diseases. After appropriate processing, tumour markers were determined by enzyme immunoassay. The diagnostic yields (sensitivity, specificity and accuracy) in each environment (serum, BAL or biopsy) were obtained by using "ROC" curves.

RESULTS

Determined individually, CA 125, NSE and SCC show the greatest diagnostic accuracy in cytosol. CEA and TPS do so in BAL. CEA is the most relevant marker in serum and BAL, and CA 125 in cytosol. When the different tumour markers are associated, they offer better overall yields for all except TPS.

CONCLUSIONS

For the factors evaluated in this study, determination of CEA in BAL was clinically the most useful marker in comparison with serum and cytosol determinations, although the latter may also be helpful in certain situations. Although there is no specific tumour marker for lung cancer, the combination of several can be used to monitor most patients with lung cancer.

Segmental allergen challenge induces plasma protein leakage into the airways of asthmatic subjects at 4 hours but not at 5 minutes after challenge

We have investigated whether increased plasma protein leakage is present early after segmental allergen challenge in allergic asthma. Seven asthmatic subjects with mild allergy (AA group) and 5 non-asthmatic subjects with allergy (ANA group) were challenged with allergen doses based on similar early skin reactions; 5 healthy control subjects without allergy (C group) were challenged with the highest dose applied in the subjects with allergy. Bronchoalveolar lavage (BAL) fluid was obtained before, at 5 minutes after, and at 4 hours after challenge from different segments. Levels of albumin (Alb) and alpha2-macroglobulin (A2M) were measured in BAL fluid and serum. In addition, we calculated the relative coefficient of excretion as follows: RCE = ((A2M in BAL fluid)/(A2M in serum))/((Alb in BAL fluid)/(Alb in serum)). Also, levels of tryptase as a marker of mast cell activation and tumor necrosis factor-alpha (TNF-alpha), a possible inducer of plasma protein leakage, were determined. At 5 minutes after challenge, in none of the groups was a significant change found in the parameters for protein leakage. Levels of tryptase were increased in the subjects with allergy at 5 minutes after challenge only (P = .004). At 4 hours after challenge, levels of Alb (P = .03) and A2M (P = .04) and the RCE (P = .04) were increased in the AA group only. At 4 hours, levels of TNF-alpha were increased, with no significant differences among the three groups. In the asthmatic subjects with allergy, levels of TNF-alpha correlated with levels of Alb (r = 0.85, P = .02). In conclusion, at 4 hours after segmental allergen challenge, plasma protein leakage was increased in the asthmatic subjects only. The increase in levels of TNF-alpha in all groups indicates that the presence of TNF-alpha alone was not sufficient to cause plasma protein leakage within 4 hours after allergen challenge. Our results confirm the concept that plasma exudation after allergen exposure is a pathophysiologic event associated with asthma.

Epithelial permeability, inflammation, and oxidant stress in the air spaces of smokers

The mechanism responsible for the increased air-space permeability in cigarette smokers is unknown. The aim of this study was to assess the acute and chronic effects of cigarette smoking on epithelial permeability, inflammation, and oxidant stress in the air spaces of smokers. Fourteen cigarette smokers underwent 99mTc-diethylenetriamine pentaacetic acid (99mTc-DTPA) lung scans after abstaining from smoking for 12 h (chronic smoking) and 1 h after smoking two cigarettes (acute smoking). Each smoker also underwent bronchoscopy and bronchoalveolar lavage (BAL) after either chronic (n = 8) or acute smoking (n = 7). Seven nonsmokers also underwent bronchoscopy and BAL. The time to 50% clearance of 99mTc-DTPA (t50) after chronic smoking was 16.7 +/- 1. 3 min (mean +/- SE), and was further reduced after acute smoking to 14.8 +/- 1.0 min (p < 0.01). Neutrophil numbers were increased in bronchoalveolar lavage fluid (BALF) in the acute smoking group as compared with the nonsmokers (p < 0.05). Superoxide release from mixed BAL leukocytes was increased after chronic (p < 0.01) and acute (p < 0.001) smoking, as were thiobarbituric acid-reactive species (TBARS), providing evidence of lipid peroxidation in plasma (chronic, p < 0.05; acute, p < 0.05). Trolox equivalent antioxidant capacity (TEAC) was reduced in plasma (p < 0.001) and increased in BALF (p < 0.05) in both smoking groups. The study therefore showed an acute increase in epithelial permeability and an increase in the number of neutrophils in the air spaces of cigarette smokers concomitant with evidence of increased oxidant stress.

Diagnostic value of cytokeratin fragment 19 (CYFRA 21-1) in bronchoalveolar lavage fluid in lung cancer

The aim of this study was to evaluate the diagnostic value of a new tumour marker, cytokeratin fragment 19 (CYFRA 21-1), in bronchoalveolar lavage fluid (BALF) for the diagnosis of lung cancer. The cross-sectional study included 36 patients with lung cancer, 19 with benign lung diseases and 13 control subjects. In the group with cancer, BAL was performed in the cancer-involved lung and in the opposite lung. Results in BALF were expressed both as absolute concentrations (ng ml-1) and referred to total protein (TP) (ng mg-1 TP), and results in plasma were expressed in ng ml-1. In BALF, there was no significant different between cancer and control groups. Using the 95th percentile of levels obtained in benign lung disease in BALF (specificity 95%) as the cut-off point, the sensitivity of CYFRA 21-1 was 13%. Positive and negative predictive values (PPV and NPV) at different pretest probabilities, and positive and negative gains were obtained applying a Bayesian analysis. Results showed low positive gains for PPV (maximal increase of 22%) and almost none for NPV (negative gains < 5%). In plasma, CYFRA 21-1 provided a sensitivity of 65%. The combination of BALF and plasma tumour marker levels showed a sensitivity of 69%. Therefore, measurement of CYFRA 21-1 in BALF has poor diagnostic value in lung cancer.

Immunoglobulin and beta 2-microglobulin concentrations in bronchoalveolar lavage of children and adults

Immunoglobulins play an important role in the pulmonary host defense, but little information is available about immunoglobulin and beta 2-microglobulin concentrations in the lung of normal children. Using bronchoalveolar lavage (BAL) we have studied immunoglobulin and beta 2-microglobulin levels in 30 children 3-15 years old undergoing elective surgery for nonpulmonary illnesses and in 15 healthy adult volunteers. BAL was performed with 3 x 1 ml/kg of body weight normal saline through an endotracheal tube after induction of anesthesia in children and under local anesthesia in adults. Similar concentrations of IgA and IgG were found in BAL fluid of children and adults even though serum levels were lower in children. As comparable results were obtained for albumin, a serum-derived protein, these data suggest that the permeability of the alveolar membrane is higher in children. IgE and IgM were detected in BAL fluid in only a fraction of children. beta 2-microglobulin levels were higher in both blood and BAL fluid of children. These data provide the first reference data for immunoglobulin and beta 2-microglobulin in children and can serve as a basis for future studies of children with pulmonary diseases.

Adjustment of bronchoalveolar lavage volume to body weight in children

To define the amount of epithelial lining fluid (ELF) that is recovered during bronchoalveolar lavage (BAL) in the pediatric age group, we measured albumin and urea concentrations in serum and BAL fluid (BALF) of 37 children aged 3-15 years without bronchopulmonary disease. The children were studied while undergoing elective surgery for non-pulmonary illnesses using a BAL protocol adjusted to body weight. ELF increased with age in proportion to increases in lavage volume. When corrected for the child's weight, approximately 20 mu l ELF/kg body weight were recovered throughout the age range. ELF derived by determining albumin or urea concentrations in BALF were significantly correlated; however, considerable variability was observed in older children when the urea method was used. This was likely due to the increase in dwell time that is known to affect urea concentrations in BALF. In children ELF/100 ml BALF was higher than in adults, suggesting a greater permeability of the alveolar membrane in children. These data show that a BAL protocol adjusted to body weight will yield constant fractions of ELF in children aged 3-15 years. These results should facilitate the comparison of BALF constituents in children of different age groups.

Protein content in bronchoalveolar lavage fluid of patients with asthma and control subjects

BACKGROUND

Secretory component (SC), Clara cell protein (CC10) and to some extent, IgM are proteins locally synthetized in airways. Albumin, alpha 2-macroglobulin and alpha 1-antitrypsin are mainly plasma proteins. In patients with asthma, blood proteins may occur in greater amounts in bronchoalveolar lavage fluid (BALF) than in control subjects because of plasma extravasation. These proteins were measured in BALF to define markers of local synthesis and plasma exudation.

METHODS

Twenty-four patients with asthma (mean age, 40 +/- 3.1 years) and 24 control subjects (mean age, 29 +/- 11 years) were tested. Five aliquots of saline solution (50 ml) were instilled, and the recovered BALF was stored. Clara cell protein was measured by a sensitive immunoassay technique based on the agglutination of latex particles. SC, immunoglobulins, alpha 2-macroglobulin, alpha 1-antitrypsin, and albumin were measured by an immunoradiometric assay. Protein concentrations were normalized to albumin.

RESULTS

In BALF from patients with asthma there was a significant increase in alpha 2-macroglobulin and IgM and a significant decrease of SC, alpha 1-antitrypsin, and Clara cell protein compared with control subjects. Also, the ratio to albumin was significantly increased for alpha 2-macroglobulin and IgM and decreased for SC. There was no correlation between the severity of asthma and the amount of proteins.

CONCLUSIONS

BALF protein content is significantly different in patients with asthma and control subjects, for proteins produced locally and derived from plasma.