Fractional analysis of bronchoalveolar lavage fluid cytology in cystic fibrosis patients with normal lung function. Bronchoalveolar lavage for the evaluation of anti-inflammatory treatment (BEAT) study group

DNA Methylation Profiles of Purified Cell Types in Bronchoalveolar Lavage: Applications for Mixed Cell Paediatric Pulmonary Studies

In epigenome-wide association studies analysing DNA methylation from samples containing multiple cell types, it is essential to adjust the analysis for cell type composition. One well established strategy for achieving this is reference-based cell type deconvolution, which relies on knowledge of the DNA methylation profiles of purified constituent cell types. These are then used to estimate the cell type proportions of each sample, which can then be incorporated to adjust the association analysis. Bronchoalveolar lavage is commonly used to sample the lung in clinical practice and contains a mixture of different cell types that can vary in proportion across samples, affecting the overall methylation profile. A current barrier to the use of bronchoalveolar lavage in DNA methylation-based research is the lack of reference DNA methylation profiles for each of the constituent cell types, thus making reference-based cell composition estimation difficult. Herein, we use bronchoalveolar lavage samples collected from children with cystic fibrosis to define DNA methylation profiles for the four most common and clinically relevant cell types: alveolar macrophages, granulocytes, lymphocytes and alveolar epithelial cells. We then demonstrate the use of these methylation profiles in conjunction with an established reference-based methylation deconvolution method to estimate the cell type composition of two different tissue types; a publicly available dataset derived from artificial blood-based cell mixtures and further bronchoalveolar lavage samples. The reference DNA methylation profiles developed in this work can be used for future reference-based cell type composition estimation of bronchoalveolar lavage. This will facilitate the use of this tissue in studies examining the role of DNA methylation in lung health and disease.

Fractional analysis of bronchoalveolar lavage in systemic sclerosis-associated interstitial lung disease

Background

The utility of bronchoalveolar lavage (BAL) in the evaluation of systemic sclerosis-associated interstitial lung disease (SSc-ILD) remains controversial. Fractional analysis of BAL (FBAL) is a technique that can analyze small airways and alveolar compartments separately and has proven informative in other ILDs. The aim of this study was to explore FBAL characteristics across the spectrum of SSc-ILD severity.

Methods

We retrospectively reviewed patients with SSc-ILD who underwent bronchoscopy with FBAL using three 50 mL aliquots of saline solution. These aliquots were analyzed separately for differential cell composition (FBAL-1, -2, and -3). We compared the FBAL cell composition to the progression of ILD and end-stages of ILD using Cox proportional hazards models.

Results

Sixty-eight patients with SSc-ILD were enrolled in this study. The percentage of neutrophils and eosinophils was lower in FBAL-3 compared to FBAL-1. In contrast, the percentage of macrophages and lymphocytes was higher in FBAL-3. Neutrophils in FBAL-2, -3, and the estimated total FBAL cell fraction (FBAL-total) were negatively correlated with the forced vital capacity % predicted (r=−0.420, −0.362, −0.409, respectively). Although FBAL-total was not linked to the progression and end-stage of ILD, a high percentage of neutrophils in FBAL-3 was significantly associated with the development of end-stage ILD (HR 1.093, 95% CI: 1.003–1.190).

Conclusions

A higher percentage of neutrophils in FBAL-3 is correlated with development of end-stage ILD in SSc-ILD as well as mortality.

Safety of research bronchoscopy with BAL in stable adult patients with cystic fibrosis

Data on adverse events from research bronchoscopy with bronchoalveolar lavage (BAL) in patients with cystic fibrosis (CF) is lacking. As research bronchoscopy with BAL is useful for isolation of immune cells and investigation of CF lung microbiome, we sought to investigate the safety of bronchoscopy in adult patients with CF. Between November 2016 and September 2019, we performed research bronchoscopies on CF subjects (32) and control subjects (82). Control subjects were nonsmokers without respiratory disease. CF subjects had mild or moderate obstructive lung disease (FEV1 > 50% predicted) and no evidence of recent CF pulmonary exacerbation. There was no significant difference in the age or sex of each cohort. Neither group experienced life threatening adverse events. The number of adverse events was similar between CF and control subjects. The most common adverse events were sore throat and cough, which occurred at similar frequencies in control and CF subjects. Fever and headache occurred more frequently in CF subjects. However, the majority of fevers were seen in CF subjects with FEV1 values below 65% predicted. We found that CF subjects had similar adverse event profiles following research bronchoscopy compared to healthy subjects. While CF subjects had a higher rate of fevers, this adverse event occurred with greater frequency in CF subjects with lower FEV1. Our data demonstrate that research bronchoscopy with BAL is safe in CF subjects and that safety profile is improved if bronchoscopies are limited to subjects with an FEV1 > 65% predicted.

Optimizations of In Vitro Mucus and Cell Culture Models to Better Predict In Vivo Gene Transfer in Pathological Lung Respiratory Airways: Cystic Fibrosis as an Example

The respiratory epithelium can be affected by many diseases that could be treated using aerosol gene therapy. Among these, cystic fibrosis (CF) is a lethal inherited disease characterized by airways complications, which determine the life expectancy and the effectiveness of aerosolized treatments. Beside evaluations performed under in vivo settings, cell culture models mimicking in vivo pathophysiological conditions can provide complementary insights into the potential of gene transfer strategies. Such models must consider multiple parameters, following the rationale that proper gene transfer evaluations depend on whether they are performed under experimental conditions close to pathophysiological settings. In addition, the mucus layer, which covers the epithelial cells, constitutes a physical barrier for gene delivery, especially in diseases such as CF. Artificial mucus models featuring physical and biological properties similar to CF mucus allow determining the ability of gene transfer systems to effectively reach the underlying epithelium. In this review, we describe mucus and cellular models relevant for CF aerosol gene therapy, with a particular emphasis on mucus rheology. We strongly believe that combining multiple pathophysiological features in single complex cell culture models could help bridge the gaps between in vitro and in vivo settings, as well as viral and non-viral gene delivery strategies.

Single-Cell Flow Cytometry Profiling of BAL in Children

Childhood pulmonary diseases not only cause childhood morbidity and mortality but also can cause long-term pulmonary impairment. The clinical management of many childhood pulmonary diseases is hampered by a limited understanding of the underlying pathophysiological mechanisms. Flow cytometry, which can be used to phenotype individual cell populations or isolate cells for downstream analysis, represents a crucial technology that can help to elucidate the pathophysiology of these conditions. Here, we describe a flow cytometry-based method for purification and characterization of cell populations in BAL from children. This includes assessment of the effect of cryopreservation on cell phenotype and frequency, a knowledge gap recently identified by an American Thoracic Society report on flow cytometry in lung samples. To our knowledge, this is the first study to simultaneously quantify alveolar macrophages, T cells (CD4 and CD8), B cells, natural killer cells, dendritic cells, granulocytes, and monocytes (CD16⁺/CD16^-) in the BAL of children. The protocols described can be used to advance investigation of the pathophysiology of childhood pulmonary diseases.

Infection and inflammation in induced sputum from preschool children with chronic airways diseases

BACKGROUND

We hypothesized airway inflammation can be detected non-invasively by induced sputum (IS) or peripheral blood eosinophilia, and IS can detect bacterial and viral infection in preschool children with airway disease, with results comparable to broncho-alveolar lavage (BAL).

METHODS

Preschool children with cystic fibrosis, recurrent wheeze, or wet cough underwent IS with nebulized hypertonic saline, chest physiotherapy, and oropharyngeal suction. Samples were analyzed for inflammation by cytology and bacterial culture, viral detection by PCR. Results were compared to BAL and blood in a sub-group undergoing clinically indicated bronchoscopy.

RESULTS

64 children (median age 33 [7-76] months) underwent IS without adverse events. IS was obtained from 61/64. Twenty out of sixty-four underwent BAL and IS, no IS was obtained in 2/23. Thirteen out of twenty-one (62%) had matching bacteria and viruses, 4/21 had positive BAL bacterial growth with negative IS, and 3/21 had negative BAL growth with positive IS. 67% of sputum samples were processed for cytology, 46% had <80% squamous cells; the proportion of squamous cells reduced with increasing age (r = -0.55, P < 0.01). IS was significantly more neutrophilic and less eosinophilic than BAL; 2/21 IS samples contained eosinophils compared to 17/23 BAL. There was a positive correlation between blood and BAL eosinophilia (r = 0.75, P < 0.01).

CONCLUSION

IS from preschool children can be used to assess infection. BAL and IS culture concurred in approximately two-thirds. However, inflammation was measureable in only one-third of IS samples and the cell differential was predominantly neutrophilic compared to BAL. Blood eosinophils may provide a better reflection of lower airway eosinophilia in this age group. Pediatr Pulmonol. 2016;51:778-786. © 2015 WileyPeriodicals, Inc.

[Cystic fibrosis and associated complications]

Cystic fibrosis (CF) is an autosomal recessive inherited metabolic disease. The mutation is located on the long arm of chromosome 7. Due to a defect in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, chloride ion transport is reduced across the cell membrane. As a result, the disease can be described as an exocrinopathy. In all organs with exocrine glands, disorders occur in association with the defective chloride transport. The main impact of this defect is manifested in the lungs. Therefore, the most common cause of death is pulmonary disease with respiratory insufficiency due to recurrent infections. Unfortunately, a cure for the disease is still not available. However, new therapies that may affect the CFTR mutation more specifically give new hope for better therapeutic options in the future. The long-term goal of therapy is to develop a causal therapy for all six different mutation classes and thus for about 2000 mutations.

Changes in airway inflammation during pulmonary exacerbations in patients with cystic fibrosis and primary ciliary dyskinesia

Lung disease in patients with both primary ciliary dyskinesia (PCD) or cystic fibrosis (CF) is associated with impaired mucociliary clearance; however, clinical outcomes are typically worse in CF patients. We assessed whether CF and PCD patients differ in inflammatory response in the airways during pulmonary exacerbation.We first studied clinically stable PCD patients with a spectrum of bacterial pathogens to assess inflammatory response to different pathogens. Subsequently, PCD and CF patients with similar bacterial pathogens were studied at the time of a pulmonary exacerbation and after 21 days of antibiotics treatment. Qualitative and quantitative microbiology, cell counts, interleukin-8 concentrations, and neutrophil elastase activity were assessed in sputum samples obtained before and after treatment.In stable PCD patients, no significant differences were found in sputum inflammatory markers between individuals colonised with different bacterial pathogens. Pulmonary exacerbation severity assessed by a pulmonary exacerbation score and lung function decline from their previous baseline did not differ between CF and PCD patients. Bacterial density for Staphylococcus aureus and Haemophilus influenzae was higher in CF versus PCD (p<0.05), but absolute neutrophil counts were higher in PCD patients (p=0.02). While sputum elastase activity was similar in PCD and CF at the time of exacerbation, it decreased with antibiotic therapy in PCD (p<0.05) but not CF patients.PCD patients differ from those with CF in their responses to treatment of pulmonary exacerbations, with higher neutrophil elastase activity persisting in the CF airways at the end of treatment.

State of progress in treating cystic fibrosis respiratory disease

Since the discovery of the gene associated with cystic fibrosis (CF), there has been tremendous progress in the care of patients with this disease. New therapies have entered the market and are part of the standard treatment of patients with CF, and have been associated with marked improvement in survival. Now there are even more promising therapies directed at different components of the pathophysiology of this disease. In this review, our current knowledge of the pathophysiology of lung disease in patients with CF is described, along with the current treatment of CF lung disease, and the therapies in development that offer great promise to our patients.

Outcome measures for clinical trials assessing treatment of cystic fibrosis lung disease

Cystic fibrosis (CF) is a complex genetic disease characterized by death from loss of lung function. Therapies target pathophysiologic changes associated with pulmonary disease progression. Although therapeutic mechanisms differ, efficacy demonstration is limited to a few accepted outcome measures, each with shortcomings that are becoming more pronounced as CF population health improves. Pulmonary function improvement (as forced expiratory volume in 1 s [FEV₁]) and reduction of pulmonary exacerbation risk are commonly used outcomes. Changes in FEV₁ decline rate, quality of life, linear growth and/or weight gain are less utilized outcomes. Validated outcomes tend to work best in subjects with more aggressive or advanced lung disease and less so in healthier subjects. Assays of effects on primary therapeutic targets have yet to be validated as surrogate measures of clinical efficacy. As CF population health improves, it will become increasingly difficult to employ current clinical outcome measures to demonstrate efficacy.

Bronchoscopy in cystic fibrosis infants diagnosed by newborn screening

BACKGROUND

There is evidence of early functional and structural changes in babies with cystic fibrosis (CF) diagnosed on newborn screening (NBS). The aim of the present study was to determine the yield of bronchoalveolar lavage (BAL) microbiology and cytology, and 24 hr pH monitoring in a group of CF infants diagnosed on NBS.

METHODS

Infants referred to a tertiary pediatric respiratory center between July 2007 and November 2009 underwent surveillance fiber-optic bronchoscopy (FOB), BAL, and insertion of a 24 hr dual pH probe under a single general anesthetic.

RESULTS

We studied 33 infants, median age of 100 days (47-215 days) at the time of FOB. In 9 of 33 (27%) bacterial organisms were identified. Seven of the nine patients (78%) were asymptomatic and only one had had a positive cough swab prior to FOB. Neutrophilia was identified in 18/27 (67%) cases with a median of 11% (6-73%). 13/31 (42%) had an abnormal pH study with a pH index >12%.

CONCLUSIONS

The high yield of microbiology, cytology, and pH probe investigations in NBS infants justifies invasive surveillance. Longitudinal studies to determine if early aggressive treatment results in improved outcome are awaited.

Assessment of surfactant protein A (SP-A) dependent agglutination

BACKGROUND

Monomers of the collectin surfactant associated protein-A (SP-A) are arranged in trimers and higher oligomers. The state of oligomerization differs between individuals and likely affects SP-A's functional properties. SP-A can form aggregates together with other SP-A molecules. Here we report and assess a test system for the aggregate forming properties of SP-A in serum and broncho-alveolar lavage samples.

METHODS

Anti-SP-A antibodies fixed to latex beads bound SP-A at its N-terminal end and allowed the interaction with other SP-A molecules in a given sample by their C-terminal carbohydrate recognition domain (CRD) to agglutinate the beads to aggregates, which were quantified by light microscopy.

RESULTS

SP-A aggregation was dependent on its concentration, the presence of calcium, and was dose-dependently inhibited by mannose. Unaffected by the presence of SP-D no aggregation was observed in absence of SP-A. The more complex the oligomeric structure of SP-A present in a particular sample, the better was its capability to induce aggregation at a given total concentration of SP-A. SP-A in serum agglutinated independently of the pulmonary disease; in contrast SP-A in lung lavage fluid was clearly inferior in patients with chronic bronchitis and particularly with cystic fibrosis compared to controls.

CONCLUSIONS

The functional status of SP-A with respect to its aggregating properties in serum and lavage samples can be easily assessed. SP-A in lung lavage fluid in patients with severe neutrophilic bronchitis was inferior.

Expression, regulation and clinical significance of soluble and membrane CD14 receptors in pediatric inflammatory lung diseases

Background

Inflammatory lung diseases are a major morbidity factor in children. Therefore, novel strategies for early detection of inflammatory lung diseases are of high interest. Bacterial lipopolysaccharide (LPS) is recognized via Toll-like receptors and CD14. CD14 exists as a soluble (sCD14) and membrane-associated (mCD14) protein, present on the surface of leukocytes. Previous studies suggest sCD14 as potential marker for inflammatory diseases, but their potential role in pediatric lung diseases remained elusive. Therefore, we examined the expression, regulation and significance of sCD14 and mCD14 in pediatric lung diseases.

Methods

sCD14 levels were quantified in serum and bronchoalveolar lavage fluid (BALF) of children with infective (pneumonia, cystic fibrosis, CF) and non-infective (asthma) inflammatory lung diseases and healthy control subjects by ELISA. Membrane CD14 expression levels on monocytes in peripheral blood and on alveolar macrophages in BALF were quantified by flow cytometry. In vitro studies were performed to investigate which factors regulate sCD14 release and mCD14 expression.

Results

sCD14 serum levels were specifically increased in serum of children with pneumonia compared to CF, asthma and control subjects. In vitro, CpG induced the release of sCD14 levels in a protease-independent manner, whereas LPS-mediated mCD14 shedding was prevented by serine protease inhibition.

Conclusions

This study demonstrates for the first time the expression, regulation and clinical significance of soluble and membrane CD14 receptors in pediatric inflammatory lung diseases and suggests sCD14 as potential marker for pneumonia in children.

Disease surveillance using bronchoalveolar lavage

The role of pulmonary infection and inflammation in the pathogenesis of destructive lung disease in cystic fibrosis (CF) is undisputed. The use of bronchoscopy and bronchoalveolar lavage (BAL) has demonstrated that these processes may begin early in life and be present in the absence of overt clinical symptoms. Some children diagnosed following newborn screening can be infected with Pseudomonas aeruginosa in infancy. Studies using BAL have demonstrated a relationship between lower airway inflammation and bacterial load in the lungs; however, inflammation may occur in the absence of obvious current infection. BAL has the potential to provide a greater understanding of the pathogenesis of CF lung disease and microbiological surveillance provides the opportunity for early detection and eradication of P. aeruginosa. Lack of standardization inhibits the ability to compare data from different centres and to optimize treatment strategies. This review discusses the recommendations from a workshop held in early 2007 aimed at achieving a standardized approach to BAL in infants and young children with CF.

Clinical trials in cystic fibrosis

In patients with cystic fibrosis (CF), clinical trials are of paramount importance. Here, the current status of drug development in CF is discussed and future directions highlighted. Methods for pre-clinical testing of drugs with potential activity in CF patients including relevant animal models are described. Study design options for phase II and phase III studies involving CF patients are provided, including required patient numbers, safety issues and surrogate end point parameters for drugs, tested for different disease manifestations. Finally, regulatory issues for licensing new therapies for CF patients are discussed, including new directives of the European Union and the structure of a European clinical trial network for clinical studies involving CF patients is proposed.

Lower airway inflammation in infants with cystic fibrosis detected by newborn screening

Controversy exists over whether the lower airway inflammation that characterizes cystic fibrosis (CF) is initiated primarily by the genetic defect. To determine if inflammation precedes infection, we examined bronchoalveolar lavage (BAL) fluid cytology, cytokines (interleukin (IL)-1beta, IL-4, IL-5, IL-6, IL-8, IL-10, and tumor necrosis factor-alpha), and free neutrophil elastase activity from 70 CF (aged 1.5-71 months) children detected by newborn screening and 19 (aged 2.0-48 months) controls with chronic stridor. CF subjects were selected and categorized as pristine (13 aged </= 6 months, lacking prior respiratory symptoms and exposure to antibiotics, and without respiratory pathogens on BAL), infected (42 with viruses or >/= 10(5) colony-forming units/ml of pathogenic bacteria in BAL), and uninfected (15 aged > 6 months, asymptomatic, not taking antibiotics at bronchoscopy, and free of pathogens in their BAL). To further resolve if inflammation develops without infection, inflammatory mediators in paired annual BAL samples from 38 CF subjects were measured, and results were grouped according to whether BAL showed persistence (n = 6), acquisition (n = 8), clearance (n = 13), or absence (n = 11) of infection. While pristine, uninfected, and control subjects had similar BAL profiles, infected patients showed elevated inflammatory indices, including increased IL-10 (P < 0.001). Pristine subjects had the fewest signs of inflammation. Analysis of BAL pairs found differences between the four infection groups for changes in neutrophil percentages, IL-8 (P < 0.001), and free neutrophil elastase (P = 0.009). Infection was associated with elevated inflammatory mediators in BAL fluid. In contrast, minimal or reduced signs of inflammation accompanied absence of eradication of infection from BAL fluid. We conclude that in CF, infection initiates and sustains airway inflammation.

Sequential analysis of surfactant, lung function and inflammation in cystic fibrosis patients

BACKGROUND

In a cross-sectional analysis of cystic fibrosis (CF) patients with mild lung disease, reduced surfactant activity was correlated to increased neutrophilic airway inflammation, but not to lung function. So far, longitudinal measurements of surfactant function in CF patients are lacking and it remains unclear how these alterations relate to the progression of airway inflammation as well as decline in pulmonary function over time.

METHODS

As part of the BEAT trial, a longitudinal study to assess the course of airway inflammation in CF, we studied lung function, surfactant function and endobronchial inflammation using bronchoalveolar lavage fluid from 20 CF patients with normal pulmonary function (median FEV1 94% of predicted) at three times over a three year period.

RESULTS

There was a progressive loss of surfactant function, assessed as minimal surface tension. The decline in surfactant function was negatively correlated to an increase in neutrophilic inflammation and a decrease in lung function, assessed by FEV1, MEF(75/25%VC), and MEF(25%VC). The concentrations of the surfactant specific proteins A, C and D did not change, whereas SP-B increased during this time period.

CONCLUSION

Our findings suggest a link between loss of surfactant function driven by progressive airway inflammation and loss of small airway function in CF patients with limited lung disease.

Early detection of lung disease in preschool children with cystic fibrosis

PURPOSE OF REVIEW

Babies with cystic fibrosis are born with essentially normal lungs but rapidly develop inflammation and infection. Evaluation is generally based on history and physical examination until school age, when children become able to perform spirometry. In these 'silent years', however, unrecognized lung damage can occur. Recently, techniques to improve the evaluation of preschool children have been developed, and an assessment of where they fit into clinical and research practice is now needed. This is particularly urgent to select groups of children for new, phenotype-specific therapies, and monitor their effects.

RECENT FINDINGS

The techniques in which there have been major recent advances include physiologic methods, particularly indices of gas mixing; imaging techniques, especially high-resolution computed tomographic scanning; and bronchoscopic studies. The clinical roles of these techniques need to be explored, as do comparisons between techniques.

SUMMARY

The preschool years need no longer be silent. Some simple techniques such as spirometry can be performed in much younger children than conventionally believed to be practical. Others currently require sophisticated apparatus (lung clearance index) or carry potential risks (radiation, high-resolution computed tomographic scanning). We need good long-term, prospective comparisons of these techniques, with measurement of inflammatory markers. We also need to know which are sufficiently reproducible, and indicative of prognosis, for use as endpoints in clinical trials.

DNA concentrations in BAL fluid of cystic fibrosis patients with early lung disease: influence of treatment with dornase alpha

Recombinant DNase (dornase alpha) was shown to improve lung function and reduce pulmonary exacerbations in cystic fibrosis (CF) patients, but its effects on DNA concentrations in the lower airways remain unclear at the present time. As part of the Bronchoalveolar Lavage in the Evaluation of Anti-Inflammatory Treatment (BEAT) Study, a multicenter open study to evaluate the evolution of inflammation in CF patients with early lung disease and its modulation by dornase alpha treatment, we studied DNA concentrations in the bronchoalveolar lavage (BAL) fluid of 48 CF patients with mild lung disease. After the initial BAL, 29 patients received daily treatment with 2.5 mg of dornase alpha; 19 patients served as controls. BAL was repeated after 18 months in all patients. Mean BAL fluid DNA concentrations were not different between groups at baseline (mean +/- SD, 14.1 +/- 6.9 microg/ml for controls, and 17.6 +/- 11.2 microg/ml for the dornase alpha group), but higher than previously reported for infants with CF. A weak but positive correlation (P <0.01) was observed between the percentage of neutrophils in BAL fluid and DNA levels. On reassessment after 18 months, the percentage of neutrophils was not different between the two groups, but DNA had increased in controls, whereas decreased levels were observed in treated patients (P <0.03, t-test). DNA concentrations increased by more than 10 microg/ml in 7 of 19 controls compared to 2 of 29 CF patients treated with rhDNase (P=0.01, Fisher's test). Therefore, treatment with dornase alpha over 18 months reduces DNA load in BAL fluid, which may have a positive effect on the clearance of lower airway secretions.

Beta-defensins and LL-37 in bronchoalveolar lavage fluid of patients with cystic fibrosis

BACKGROUND

The antimicrobial peptides human beta-defensin 1 and 2 (hBD-1 and 2) and the cathelicidin LL-37/hCAP-18 are key factors in innate immune responses of the respiratory tract. The aim of this study was to determine the concentrations of these peptides in airway surface fluid of CF patients with mild lung disease.

METHODS

We measured the concentrations of hBD-1, hBD-2, and LL-37 in bronchoalveolar lavage fluid of 20 patients (5-34 years) participating in the prospective BEAT-study (bronchoalveolar lavage for the evaluation of anti-inflammatory treatment) using an immuno-dot blot-assay.

RESULTS

All three peptides could be detected in lavage fluid of the study population. Increased levels of inflammatory markers in bronchoalveolar lavage fluid were associated with elevated concentrations of LL-37/hCAP-18 (total cell count, P = 0.006; relative neutrophil count, P = 0.002). Deterioration of lung function, measured by MEF25 (maximal flow rate at 25% of residual forced vital capacity), correlated with decreased hBD-2 (P = 0.026), but increased LL-37/hCAP-18 concentrations (P = 0.016).

CONCLUSIONS

The data suggest that concentrations of antimicrobial peptides are correlated with severity of CF lung disease: Levels of LL-37/hCAP-18 are associated with bronchial inflammation and, therefore disease severity, whereas decreased levels of beta-defensins in advanced lung disease likely contribute to a secondary defect of the local host defense.

Pulmonary Surfactant, Lung Function, and Endobronchial Inflammation in Cystic Fibrosis

Cystic fibrosis (CF) lung disease is primarily a disease of the small airways. We hypothesized that even in patients with normal lung function, a reduced surfactant function would be present and favor small airway obstruction. Bronchoalveolar lavages from 76 patients with CF (5-31 years, median 11) with well-conserved lung function (FEV1 94% predicted, range 78-121) and from 10 healthy control subjects were investigated. The deviation of the biophysical surfactant performance from normal, assessed in a bubble surfactometer, was small; however, the ability of the surfactant to maintain the patency of a narrow airway (% open) was significantly reduced. Surfactant protein (SP)-C level was increased, SP-B and SP-D were unchanged, whereas SP-A was decreased. Among the patients with CF, neutrophilic inflammation was modestly related to a poorer surfactant activity, but not to lung function. SP-D was reduced in proportion to the degree of inflammation and in the presence of bacteria. These findings in a large cohort of patients with CF with normal lung function show that the endobronchial airway inflammation is linked to early perturbations of the biophysical properties and immunologic components of pulmonary surfactant and opens fields for novel therapeutic interventions.

Glutathione and glutathione peroxidase in sputum samples of adult patients with cystic fibrosis

BACKGROUND

Reduced glutathione (GSH) is a major antioxidant in the lung. In cystic fibrosis (CF) patients, extracellular GSH levels of lower airways, obtained by bronchoalveolar lavage (BAL), were reported to be lower than non-CF individuals.

METHODS

Upper airway secretions of stable adult CF patients (29 spontaneous and 13 induced sputum) and non-CF individuals (14 healthy and 12 asthmatics; all induced sputum) were analyzed for total glutathione (i.e. the sum of reduced, GSH, and oxidized, GSSG, forms), GSH and GSSG levels by enzymatic kinetic assay.

RESULTS

In CF, both spontaneous and induced sputum samples were comparable in total glutathione levels which were surprisingly high (median concentration of 9.2 (range 1.4-65.2) and 11.6 (1.1-69.8) microM, respectively). In non-CF individuals, total glutathione levels were significantly lower (healthy 2.8 (1.0-12.3), asthmatics (5.3 (1.3-19.2) microM; p<0.001, both vs. CF). In CF, more than 90% of total glutathione was represented by GSH, whereas in non-CF controls, GSH made up less than 50% of total glutathione (p<0.001).

CONCLUSIONS

In contrast to BAL, CF sputum contains high levels of GSH. Sputum induction is a potentially useful procedure to monitor antioxidant levels in upper airways of CF patients.

Effect of Treatment with Dornase Alpha on Airway Inflammation in Patients with Cystic Fibrosis

Recombinant human deoxyribonuclease (rhDNase) has been shown to improve lung function and reduce the number of pulmonary exacerbations in patients with cystic fibrosis (CF), but its long-term effect on airway inflammation remains unknown. In this study, we used bronchoalveolar lavage (BAL) to investigate the long-term effect of rhDNase on inflammation in patients with CF having mild lung disease. A total of 105 patients with CF (> or =5 years of age) having normal lung function were randomized to receive rhDNase (2.5 mg/day) or no rhDNase. Patients with a normal percentage of neutrophils in BAL fluid at baseline were not randomized and served as the control group. The percentage of neutrophils in the pooled BAL sample was similar in both randomized groups at baseline. A significant increase in neutrophils was observed over the 3-year study period in both untreated patients and control subjects, whereas neutrophils remained unchanged in patients treated with rhDNase. Elastase activities and interleukin-8 concentrations also increased in untreated patients and remained stable in patients on rhDNase. We conclude that in patients with CF, an increase in neutrophilic airway inflammation is found that is positively influenced by rhDNase treatment.

BPI-ANCA of pediatric cystic fibrosis patients can impair BPI-mediated killing of E. coli DH5alpha in vitro

Gram-negative bacterial lung infections and chronic bacterial colonization are major threats for pediatric cystic fibrosis (CF) patients. Besides impeded mucociliary clearance, other mechanisms that contribute to increased susceptibility to infections are presumed. The bactericidal/permeability-increasing protein (BPI), which is delivered by neutrophil granulocytes and mucosal epithelial cells, is one of the most potent innate antibiotics against Gram-negative bacteria and endotoxin. Antineutrophil cytoplasmic autoantibodies against BPI (BPI-ANCA) have been found in up to 90% of CF patients, and titers correlated inversely with lung function parameters. As major pulmonary damage is mediated by Gram-negative bacteria and their products, the question was raised as to whether BPI-ANCA can inhibit the antibiotic function of BPI in these patients. Sera of 23 pediatric CF patients were analyzed for the presence of BPI-ANCA by indirect immunofluorescence, ELISA, epitope mapping, and Western blotting. Patients' IgG were tested in a bacterial growth inhibition assay with recombinant BPI (rBPI) and an amino-terminal fragment of BPI (rBPI(21)) that retains antibiotic activity for inhibition of the antibiotic function of BPI against E. coli DH5alpha in vitro. BPI was recognized by 21 of 23 patients' sera in our detection assays. Thirteen of 23 patients' BPI-ANCA (56%) could inhibit the antibiotic function in vitro. Moreover, epitope mapping over the whole BPI sequence revealed that more patients' BPI-ANCA recognize the amino-terminal part of BPI than can be detected by ELISA. Thus, in pediatric CF patients, BPI-ANCA may contribute to diminished bacterial clearance by inhibiting the antibiotic function of BPI.

BPI-ANCA in transporter associated with antigen presentation (TAP) deficiency: possible role in susceptibility to Gram-negative bacterial infections

Although HLA class I expression is diminished in patients with defects in the transporter associated with antigen presentation (TAP), recurrent Gram-negative bacterial lung infections are found from childhood onwards. As MHC class II-mediated responses are normal, other mechanisms that contribute to susceptibility to infections are presumed. The bactericidal/permeability-increasing protein (BPI) is a potent neutrophil antibiotic that neutralizes endotoxin efficiently. As antineutrophil cytoplasmic autoantibodies (ANCA) against BPI were found in the majority of cystic fibrosis patients and correlate with disease severity we examined the prevalence of BPI-ANCA and their contribution to susceptibility to bacterial infections in six TAP-deficient patients. Although only two patients showed ANCA in indirect immunofluorescence, BPI-ANCA occurred in five of six patients in ELISA. Purified IgG from BPI-ANCA-positive sera (five of six) inhibited the antimicrobial function of BPI in vitro. Epitope mapping revealed binding sites not only on the C-terminal but also on the antibiotic N-terminal portion of BPI, indicating that short linear BPI peptide fragments may be long-lived enough to become immunogens. In conclusion, BPI-ANCA are associated strongly with TAP deficiency. Inhibition of the antimicrobial BPI function by BPI-ANCA demonstrates a possible mechanism of how autoantibodies may contribute to increased susceptibility for pulmonary Gram-negative bacterial infections by diminished bacterial clearance.

Analysis of sequential aliquots of hypertonic saline solution-induced sputum from clinically stable patients with cystic fibrosis

STUDY OBJECTIVES

Sputum induction (SI) is a noninvasive tool for sampling inflamed airways. The purpose of this study was to determine the optimal duration of collection in patients with cystic fibrosis (CF). The hypothesis was that the duration of SI collection would quantitatively and qualitatively alter the content of the induced sputum.

METHODS

In 10 clinically stable patients with CF (mean +/- SD age, 28 +/- 7 years; mean FEV(1), 2.6 +/- 0.7 L), SI was performed with 3% hypertonic saline solution at five time points over 20 min.

RESULTS

SI was well tolerated, with an average maximum fall in FEV(1) of 7 +/- 7%. The sample volumes, urea concentrations, interleukin-8 concentrations, total cell counts, and nonsquamous cell counts remained constant (p > 0.05). The percentage of neutrophils decreased from 89 +/- 5% to 86 +/- 4% (p = 0.03), and the percentage of alveolar macrophages increased 5 +/- 2% to 8 +/- 4% (p < 0.01). The mean quantitative microbiological counts of nonmucoid Pseudomonas aeruginosa and Staphylococcus aureus decreased over the 20-min time period each by half a log (p = 0.05 and p < 0.01, respectively). Surfactant protein-A concentration increased from 1.6 +/- 0.3 to 2.4 +/- 0.4 ng/mL (log(10); p < 0.001).

CONCLUSIONS

We conclude that aliquots of induced sputum are similar in clinically stable patients with CF during 4-min intervals, although there is more alveolar sampling after 20 min. When induced-sputum samples are fractionated for research monitoring of inflammatory or microbiologic indexes, power calculations accounting for these variations over time are required.

Matrix metalloproteases in BAL fluid of patients with cystic fibrosis and their modulation by treatment with dornase alpha

BACKGROUND

Matrix metalloproteinases (MMPs) are involved in the remodelling and degradation of extracellular matrix and may play a role in pulmonary tissue destruction in cystic fibrosis (CF).

METHODS

Bronchoalveolar lavage (BAL) fluid levels of MMP-8, MMP-9, and their natural inhibitor TIMP-1 were measured on two occasions within 18 months in 23 children with mild CF, 13 of whom were treated with DNase.

RESULTS

MMP-8 (39.3 (6.8) v 0.12 (0.01) ng/ml), MMP-9 (58.0 (11.4) v 0.5 (0.02) ng/ml), and the molar ratio of MMP-9/TIMP-1 (0.36 (0.05) v 0.048 (0.01)) were significantly higher in patients with CF than in control children without lung disease. Gelatine zymography showed the typical banding pattern of neutrophil derived MMP-9, including 130 kDa NGAL-MMP-9 complex and 92 kDa latent MMP-9 bands; 85 kDa bands (corresponding to active MMP-9) were seen in all patients. There was a close correlation between BAL fluid concentrations of MMPs and alpha(2)-macroglobulin, a marker of alveolocapillary leakage. After 18 months MMP levels were increased in untreated patients and decreased in patients treated with DNase.

CONCLUSIONS

Uninhibited MMPs may contribute to pulmonary tissue destruction even in CF patients with mild lung disease that may be positively affected by treatment with DNase.

Interlobar differences in bronchoalveolar lavage fluid from children with cystic fibrosis

Bronchoalveolar lavage (BAL) performed in specialist centres has improved the understanding of infant cystic fibrosis (CF) lung disease. As most researchers sample from a single lobe, it was determined whether BAL results could be generalized to other lung segments. Thirty-three CF children, aged 1.5-57 months, underwent in random order sequential BAL of their right middle and lingula lobes. Specimens from each lobe had separate quantitative bacteriology, cytology and cytokine analysis. Bacterial counts > or = 1 x 10(5) colony forming units (cfu) x mL(-1) were observed in nine (27%) subjects, including six involving only the right middle lobe. These six children had similar inflammatory indices in their right middle and lingula lobes, and interleukin (IL)-8 concentrations in the latter were significantly higher than that observed within the lingula lobes of the 24 CF children with bacterial counts < 1 x 10(5) cfu x mL(-1). Lingula neutrophil and IL-8 levels correlated best with right middle lobe bacteria numbers. This observational study in cystic fibrosis children suggests that while inflammation is detected in both lungs, bacterial distribution may be more inhomogeneous. Bronchoalveolar lavage microbiological findings from a single lobe may therefore, not be generalized to other lung segments. When performing bronchoalveolar lavage in cystic fibrosis children, it is important to sample from multiple sites.

Changes in strategies for optimal antibacterial therapy in cystic fibrosis

Aggressive antibiotic therapy of bacterial airway infection is one of the main reasons for the dramatic increase in life expectancy over the last few decades. Staphylococcus aureus and Haemophilus influenzae are the predominant pathogens in younger patients, but the choice of antibiotic therapy against these pathogens remains highly controversial. There is general agreement that patients with pulmonary exacerbations should be treated and many cystic fibrosis (CF) centres will also try to eradicate bacteria in the absence of symptoms. Prophylactic antibiotic therapy, with anti-staphylococcal medications started at the time of diagnosis, is advocated by some groups but its positive effect remains unproven. In fact, recent studies have suggested that continuous prophylactic treatment with anti-staphylococcal antibiotics may increase the risk of early colonisation with Pseudomonas aeruginosa. P. aeruginosa is the main pathogen in older children with CF. While chronic airway infection with mucoid P. aeruginosa is considered irreversible, both the combination of oral ciprofloxacin with inhaled colistin and inhaled tobramycin alone has been used successfully in the early phase of colonisation. In patients chronically infected with P. aeruginosa, standard treatment of pulmonary exacerbations consists of intravenous combination therapy for 2-3 weeks. Controversy exists whether this treatment should be performed routinely every 3 months or only in the presence of a pulmonary exacerbation. Inhaled antibiotics such as tobramycin have been shown to improve lung function and reduce sputum density of P. aeruginosa, but both the optimal dose and the duration of therapy are unclear at the present time.

Pediatric bronchoscopy

Diagnostic flexible endoscopy for pediatric respiratory diseases is performed in many centers. Technical advances have resulted in performance of interventional bronchoscopies, and new diagnostic indications are being explored. Indications with documented clinical benefit include congenital or acquired progressive or unexplained airway obstruction. Pulmonary infections in immunodeficient children who do not respond to empirical antibiotic treatment may be diagnosed by bronchoscopy and bronchoalveolar lavage (BAL). The potential usefulness of bronchoscopy and BAL for managing chronic cough, wheeze, or selected cases with asthma or cystic fibrosis requires further study. The use of transbronchial biopsies (TBB) is established in pediatric lung transplantation. The role of TBB in the diagnosis of chronic interstitial lung disease in children remains to be determined. For a number of interventional applications, rigid endoscopy is required, and pediatric bronchoscopists should be trained in its use. Complications in pediatric bronchoscopy are rare, but severe nosocomial infection or overdosing with local anesthetics has occurred. The issues of quality control, video documentation, interobserver variability of findings, and educational standards will have to be addressed in the future as bronchoscopy use becomes less restricted to only large pediatric pulmonary units.