Bronchoalveolar Lavage Neutrophil Elastase Research Articles

COMBATing airway inflammation in infants with cystic fibrosis

Cystic fibrosis lung disease is characterised by a progressive cycle of mucus obstruction, airway infection, and inflammation. The Australian Respiratory Early Surveillance Team for Cystic Fibrosis (AREST CF) 1 Sly PD Gangell CL Chen L et al. Risk factors for bronchiectasis in children with cystic fibrosis. N Engl J Med. 2013; 368: 1963-1970 Crossref PubMed Scopus (401) Google Scholar intensive surveillance programme has provided strong evidence that this process starts early in infancy, before respiratory symptoms. In a landmark study, the team reported that free neutrophil elastase in bronchoalveolar lavage done in infancy predicts the subsequent development of bronchiectasis by age 3 years, rendering airway inflammation a key target to modulate disease progression early in life. 1 Sly PD Gangell CL Chen L et al. Risk factors for bronchiectasis in children with cystic fibrosis. N Engl J Med. 2013; 368: 1963-1970 Crossref PubMed Scopus (401) Google Scholar The effect of azithromycin on structural lung disease in infants with cystic fibrosis (COMBAT CF): a phase 3, randomised, double-blind, placebo-controlled clinical trialAzithromycin treatment from diagnosis of cystic fibrosis did not reduce the extent of structural lung disease at 36 months of age; however, it did reduce airway inflammation, morbidity including pulmonary exacerbations in the first year of life and hospitalisations, and improved some clinical outcomes associated with cystic fibrosis lung disease. Therefore we suggest thrice-weekly azithromycin is a strategy that could be considered for the routine early management of paediatric patients with cystic fibrosis. Full-Text PDF

Increased MUC1 plus a larger quantity and complex size for MUC5AC in the peripheral airway lumen of long-term tobacco smokers.

There is little information on mucins versus potential regulatory factors in the peripheral airway lumen of long-term smokers with (LTS+) and without (LTS-) chronic obstructive pulmonary disease (COPD). We explored these matters in bronchoalveolar lavage (BAL) samples from two study materials, both including LTS+ and LTS- with a very similar historic exposure to tobacco smoke, and healthy non-smokers (HNSs; n=4-20/group). Utilizing slot blot and immunodetection of processed (filtered and centrifuged), as well as unprocessed BAL samples from one of the materials, we compared the quantity and fraction of large complexes of mucins. All LTS displayed an enhanced (median) level of MUC5AC compared with HNS. LTS- displayed a higher level of large MUC5AC complexes than HNS while LTS+ displayed a similar trend. In all LTS, total MUC5AC correlated with blood leukocytes, BAL neutrophil elastase and net gelatinase activity. Large mucin complexes accounted for most MUC5B, without clear group differences. In all LTS, total MUC5B correlated with total MUC5AC and local bacteria. In the same groups, large MUC5B complexes correlated with serum cotinine. MUC1 was increased and correlated with BAL leukocytes in all LTS whereas MUC2 was very low and without clear group differences. Thus, the main part of MUC5AC and MUC5B is present as large complexes in the peripheral airway lumen and historic as well as current exposure to tobacco smoke emerge as potential regulatory factors, regardless of COPD per se. Bacteria, leukocytes and proteinases also constitute potential regulatory factors, of interest for future therapeutic strategies.

Minimal change in structural, functional and inflammatory markers of lung disease in newborn screened infants with cystic fibrosis at one year

BackgroundWith the widespread introduction of newborn screening for cystic fibrosis (CF), there has been considerable emphasis on the need to develop objective markers of lung health that can be used during infancy. We hypothesised that in a newborn screened (NBS) UK cohort, evidence of airway inflammation and infection at one year would be associated with adverse structural and functional outcomes at the same age. MethodsInfants underwent lung function testing, chest CT scan and bronchoscopy with bronchoalveolar lavage (BAL) at 1 year of age when clinically well. Microbiology cultures were also available from routine cough swabs. Results65 infants had lung function, CT and BAL. Mean (SD) lung clearance index and forced expiratory volume in 0.5 s z-scores were 0.9(1.2) and -0.6(1.1) respectively; median Brody II CF-CT air trapping score on chest CT =0 (interquartile range 0–1, maximum possible score 27). Infants isolating any significant pathogen by 1 yr of age had higher LCI z-score (mean difference 0.9; 95%CI:0.4–1.4; p = 0.001) and a trend towards higher air trapping scores on CT (p = 0.06). BAL neutrophil elastase was detectable in 23% (10/43) infants in whom BAL supernatant was available. This did not relate to air trapping score on CT. ConclusionsIn this UK NBS cohort at one year of age, lung and airway damage is much milder and associations between inflammation, abnormal physiology and structural changes were at best weak, contrary to our hypothesis and previously published reports. Continued follow-up will clarify longer term implications of these very mild structural, functional and inflammatory changes.

The clinical significance of oropharyngeal cultures in young children with cystic fibrosis.

In children with cystic fibrosis (CF) the associations between oropharyngeal swabs (OPSs) for detection of Pseudomonas and lung disease have not been evaluated.OPS and bronchoalveolar lavage (BAL) samples were obtained annually in children with CF from 2005 to 2017. OPS test characteristics were calculated using BAL as "gold standard". Results were related to lung inflammation (BAL neutrophil elastase and interleukin-8), structural lung disease (chest computed tomography PRAGMA-CF (Perth-Rotterdam Annotated Grid Morphometric Analysis for CF) scores), respiratory exacerbations and future detection of Pseudomonas on BAL.From 181 patients, 690 paired OPS-BAL cultures were obtained. Prevalence of Pseudomonas in BAL was 7.4%. OPS sensitivity was 23.0% and specificity was 91.4%, reducing the post-test probability for a positive BAL following a negative OPS to 6.3%. Pseudomonas on OPS was not associated with lung inflammation or respiratory exacerbations, but was weakly associated with current PRAGMA-CF %Disease score (p=0.043). Pseudomonas on BAL was associated with positive neutrophil elastase (OR 4.17, 95% CI 2.04-8.53; p<0.001), increased interleukin-8 (p<0.001), increased all baseline PRAGMA computed tomography scores (p<0.001), progression of PRAGMA computed tomography scores (p<0.05) and increased risk of respiratory exacerbations (incidence rate ratio 2.11, 95% CI 1.15-3.87; p=0.017).In children with CF OPSs only marginally change the probability of detecting lower airway Pseudomonas and are not associated with lung disease indices nor exacerbations risk.

Evolution of cystic fibrosis lung function in the early years.

Most treatment of newborn screening-diagnosed cystic fibrosis is not evidence-based; there are very few randomized controlled trials (RCTs). Furthermore, the advent of novel molecular therapies, which could be started at diagnosis, mandates performing RCTs in very young children. However, unless the natural history of early cystic fibrosis lung disease is known, RCTs are impossible. Here, we review the results of two large prospective cohorts of these infants - London Cystic Fibrosis Collaboration (LCFC) (London, UK) and Australian Respiratory Early Surveillance Team for Cystic Fibrosis (AREST-CF) (Australia). Nutritional status remained excellent in both the cohorts. Both cohorts reported abnormal lung function aged at 3 months. AREST-CF, which previously reported rapidly declining preschool lung function, now report good conventional school-age spirometry. LCFC reported improvement between 3 months and 1 year, and stability in the second year. AREST-CF also reported a high prevalence of high resolution computed tomographic abnormalities related to free neutrophil elastase in bronchoalveolar lavage; LCFC reported high resolution computed tomographic changes at 1 year, which were too mild to be scored reproducibly. At least in the first 2 years of life, lung function is not a good end-point for RCTs; routine bronchoalveolar lavage and HRCT cannot be justified. Newborn screening has greatly improved outcomes, but we need better point-of-care biomarkers.

Stability of interleukin 8 and neutrophil elastase in bronchoalveolar lavage fluid following long-term storage

Background Interleukin-8 (IL-8) and neutrophil elastase (NE) are commonly measured markers of inflammation in bronchoalveolar lavage (BAL) fluid from patients with cystic fibrosis. Longitudinal analysis assumes uniform stability during storage, however the effect of extended low-temperature storage on these markers remains unclear. Methods BAL fluid from 104 children with cystic fibrosis was assayed for IL-8 and NE after storage at 4 °C for 7 days and − 80 °C for up to 6 years and compared with the initial assays performed soon after collection. Results IL-8 levels were stable after any measured length of time at − 80 °C or 4 °C. NE levels were stable for 6 months at − 80 °C but decreased beyond that or after 7 days at 4 °C. Conclusions Our data support the stability of IL-8 in BAL stored at − 80 °C for prolonged periods. NE in BAL decreases with storage and should be assayed as soon as practical after collection.

Reactive Oxygen Species Regulate Neutrophil Recruitment and Survival in Pneumococcal Pneumonia

The role of NADPH oxidase activation in pneumonia is complex because reactive oxygen species contribute to both microbial killing and regulation of the acute pulmonary infiltrate. The relative importance of each role remains poorly defined in community-acquired pneumonia. We evaluated the contribution of NADPH oxidase-derived reactive oxygen species to the pathogenesis of pneumococcal pneumonia, addressing both the contribution to microbial killing and regulation of the inflammatory response. Mice deficient in the gp91(phox) component of the phagocyte NADPH oxidase were studied after pneumococcal challenge. gp91(phox)(-/-) mice demonstrated no defect in microbial clearance as compared with wild-type C57BL/6 mice. A significant increase in bacterial clearance from the lungs of gp91(phox)(-/-) mice was associated with increased numbers of neutrophils in the lung, lower rates of neutrophil apoptosis, and enhanced activation. Marked alterations in pulmonary cytokine/chemokine expression were also noted in the lungs of gp91(phox)(-/-) mice, characterized by elevated levels of tumor necrosis factor-alpha, KC, macrophage inflammatory protein-2, monocyte chemotactic protein-1, and IL-6. The greater numbers of neutrophils in gp91(phox)(-/-) mice were not associated with increased lung injury. Levels of neutrophil elastase in bronchoalveolar lavage were not decreased in gp91(phox)(-/-) mice. During pneumococcal pneumonia, NADPH oxidase-derived reactive oxygen species are redundant for host defense but limit neutrophil recruitment and survival. Decreased NADPH oxidase-dependent reactive oxygen species production is well tolerated and improves disease outcome during pneumococcal pneumonia by removing neutrophils from the tight constraints of reactive oxygen species-mediated regulation.

Unopposed neutrophil elastase in bronchoalveolar lavage from transplant recipients with cystic fibrosis.

Large numbers of neutrophils with unopposed neutrophil elastase (NE) proteolytic activity are found in lower respiratory tract secretions from most patients with advanced cystic fibrosis (CF). To determine whether antielastase defenses may be overwhelmed in epithelial lining fluid after lung transplantation, we measured NE activity (cleavage of the specific substrate, MeO-Suc-Ala-Ala-Pro-Val-pNA) in bronchoalveolar lavage fluids (BALF) obtained for surveillance or diagnostic purposes at various intervals (1 mo to 7 yr after transplantation) from 52 recipients who had undergone double or bilateral lung transplantation for end-stage CF. Unopposed NE activity was found in BALF from 14 recipients, most of whom also had >= 10(5) colony forming units (cfu) of Pseudomonas aeruginosa in BALF. Ten of the 14 recipients with unopposed NE in bronchoalveolar lavage (BAL) had developed obliterative bronchiolitis (OB), but only 8 of the 38 subjects without unopposed NE activity had OB (p = 0. 002; Fisher exact test). We conclude that antiprotease defenses in lower respiratory tract secretions of CF patients receiving lung allografts are sufficient in the majority of patients to prevent unopposed NE activity. However, the presence of unopposed NE activity in BAL from lung allografts of patients with CF is associated with progressive, irreversible OB and graft failure.