Interleukin-8 concentrations are elevated in bronchoalveolar lavage, sputum, and sera of children with cystic fibrosis

Cystic fibrosis and the use of pharmacogenomics to determine surrogate endpoints for drug discovery

Cystic fibrosis (CF) is caused by a mutation in the CFTR gene, encoding a chloride channel. For the most common mutation, Delta F508, the basis of the deficit is the failure of the mutant CFTR channel protein to traffic properly to the apical plasma membrane of the affected epithelial cell. The trafficking failure results in loss of the cyclic adenosine monophosphate (cAMP)-activated chloride channel function of the CFTR protein in the plasma membrane. The lung is the principal site affecting patient morbidity and mortality in CF. The main reason is that the CF airway epithelial cells also secrete high levels of the proinflammatory cytokine interleukin (IL)-8, resulting in massive cellular inflammation, infection, tissue damage and lung destruction. The relationship between the trafficking defect, the loss of chloride channel activity, and inflammation is not known. However, gene therapy of CF lung epithelial cells with the wild-type CFTR gene can repair the chloride channel defect, as well as suppress the intrinsic hypersecretion of IL-8. Repair of both defective channels and high IL-8 secretion can also be effected by treatment with the candidate CF drug CPX, which is in clinical trials in CF patients. CPX acts by binding to the mutant CFTR protein, and helps the protein to mature and gain access to the plasma membrane. CPX also suppresses the synthesis and secretion of IL-8 from CF epithelial cells, presumably by virtue of its repair of the trafficking defect of mutant CFTR. To guide pharmacogenomic experiments we have therefore hypothesized that the genomic signature of CF epithelial cells treated with CPX should resemble the signature of the same cells repaired by gene therapy. We have developed two algorithms for identifying genes modified by repair of CFTR defects. The GRASP algorithm uses a statistical test to identify the most profoundly changing genes. The GENESAVER algorithm allows us to identify those genes whose pattern of expression changes in-phase or out-of-phase with IL-8 secretion by CF cells. For the latter algorithm we modified IL-8 secretion from CF cells by treatment with wild-type CFTR, with CPX, or by exposure to bacteria. The results have supported the hypothesis, and have provided a basis for considering the common pharmacogenomic expression signature as a surrogate endpoint for CF drug discovery. Significantly, the nature of the hypothesis, as well as the algorithm developed for this study, can be easily applied to pharmacogenomic studies with other goals.

Relationship between sputum inflammatory markers, lung function, and lung pathology on high-resolution computed tomography in children with cystic fibrosis

High-resolution computed tomography (HRCT) is a sensitive technique for early visualisation and location of cystic fibrosis (CF) bronchopathology, and has been shown to detect acute reversible and chronic changes. It would be expected to correlate with markers of the underlying pathological processes, such as sputum cytokines and cytology, as well as with pulmonary function tests (PFTs). Our aim was to study the relationship between PFTs, sputum cytology, and sputum cytokine interleukin-8 (IL-8) and HRCT in CF patients. Prospective standardized collection of sputum samples was performed at the time of routine annual high-resolution CT scans. Forced expired volume in 1 sec (FEV(1)) and forced vital capacity (FVC) were recorded. Sputum processing was selective, with dispersal by the three-enzyme technique. IL-8 measurements were by kit assay. HRCT scans were scored by a pediatric radiologist, blinded to clinical condition, using a modified Bhalla score.Forty-three CT scans were performed on 34 children with CF between March 1998 and April 2000. Mean age was 12.3 years (range, 6-21 years), FEV(1) (% predicted) was 67% (range, 23-120%), and mean modified Bhalla score was 11.2 (range, 0-22). Sputum IL-8 concentration (mean, 86; range, 4-150 ng/mL) and total cell count (mean, 31.9 x 10(6)/mL; range, 21.8-42.0 x 10(6)/mL) were high. FEV(1) and FVC correlated with modified Bhalla score (r = -0.66, P < 0.0001 for both), and most individual components of the score, especially mosaic perfusion (r = -0.64, r = -0.61 respectively, P < 0.0001) and extent of bronchiectasis (r = -0.61, P < 0.0001 for both). The combination of these two predicted 58% of the variability in FEV(1) on analysis of variance (P < 0.0001). Sputum total cell count correlated weakly with modified Bhalla score (r = 0.38, P < 0.05) and with FEV(1) and FVC (r = -0.36, P < 0.05; and r = -0.46, P < 0.01). Differential cell counts, cell viability, and IL-8 did not correlate with modified Bhalla scores, or with reversible components such as mucus plugging, centrilobular nodules, or peribronchial thickening. In conclusion, pathological changes on HRCT correlated with lung function but not with sputum markers of inflammation.

Fate of swallowed interleukin 8 and TNFα, and effect on the Wistar rat gut

To evaluate the passage of cytokines through the gastrointestinal tract, we investigated the digestion of interleukin-8 (IL-8) and tumour necrosis factor alpha (TNF alpha), in vitro and in vivo, and their propensity to induce intestinal inflammation. We serially immuno-assayed IL-8 and TNF alpha solutions co-incubated with each of three pancreatin preparations at pH 4.5 and pH 8. We gavaged IL-8, TNF alpha and marker into 15 Wistar rats, and measured their faecal cytokine concentrations by ELISA and histologically examined their guts. IL-8 immunoreactivity was extinguished by all pancreatin preparations after 1 h of incubation at 37 degrees C. TNF alpha concentration progressively fell from 1 to 4 h with all enzyme preparations. Buffer control samples maintained their cytokine concentrations throughout incubation. No IL-8 or TNF alpha was detected in any rat faecal pellets. There was no significant proinflammatory effect of the gavaged cytokines on rat intestine. IL-8 and TNF alpha in aqueous solution could well be fully digested in the CF gut when transit time is normal and exogenous enzymes are provided, although cytokines swallowed in viscous sputum may be protected from such digestion.

Airway neutrophil inflammation in nonasthmatic patients with food allergy

BACKGROUND

Patients with food allergy (FA) have been recently shown to develop bronchial hyperresponsiveness (BHR), despite the absence of any concomitant asthmatic manifestation. In order to explain this observation, we sought to examine the presence of a bronchial inflammation in induced sputum of nonasthmatic patients with FA.

METHODS

Twelve nonasthmatic patients with FA (urticaria, digestive symptoms, anaphylaxis) were included in the study. Results were compared to these obtained from eight asthmatic patients without food allergy and eight healthy controls. Diagnosis of FA was based on double-blind placebo-controlled challenge. Sputum cells and fluid-phase eosinophil cationic protein (ECP), myeloperoxidase (MPO) and interleukin-8 (IL-8) were measured in induced sputum. BHR was evaluated using methacholine inhalation.

RESULTS

Sputum from asthmatics, in comparison with the sputum of healthy subjects and patients with FA contained a higher proportion of eosinophils and higher levels of ECP (< 0.001). In marked contrast, patients with FA exhibited an increased proportion of neutrophils and IL-8 in comparison with asthmatics and controls (P < 0.05 for neutrophils and P < 0.001 for IL-8). There was a significant correlation between sputum neutrophils and IL-8 (r = 0.68, P < 0.001). MPO levels were not different between the groups. There was a trend toward higher levels of IL-8 and ECP in food allergic patients with BHR in comparison with patients with FA without BHR.

CONCLUSION

Our results demonstrate that a subclinical neutrophil airway inflammation is present in patients with food allergy free of clinical respiratory symptoms and that IL-8 may be an important mediator of this neutrophilia.

Serum hyaluronic acid concentrations are increased in cystic fibrosis patients with liver disease

AIM

To determine whether serum hyaluronic acid (HA) concentrations are abnormal in patients with cystic fibrosis (CF) liver disease, and if so, whether the abnormality is associated with disease severity.

METHODS

A total of 74 patients with CF were assessed for evidence of liver involvement as indicated by clinical, ultrasound, and biochemical findings. Serum hyaluronic acid concentrations were measured and compared with concentrations in 293 normal controls. Lung function in the CF patients was also recorded.

RESULTS

Thirty four CF patients had no evidence of liver disease; in these, serum HA concentrations were similar to those in healthy controls (median (range): 16.1 (9.4-75.1) v 15 (1-77) microg/l). Nineteen CF patients had established liver disease detected by clinical and ultrasound examination, with significantly increased HA concentrations (56.1 (26-355) microg/l). Serum HA concentrations were also significantly increased, although to a lesser extent, in 21 CF patients with an abnormal liver ultrasound scan alone (22.4 (9.5-43.4) microg/l). There was no correlation between serum HA concentration and lung function.

CONCLUSION

Serum HA concentrations were significantly increased in children with clinical or ultrasound evidence of liver disease, being higher in those with more advanced hepatic damage. Despite the inflammation and fibrosis present in CF lungs there was no correlation between HA concentration and lung function, suggesting that high concentrations were a failure of hepatic clearance rather than overproduction in the lung. Longitudinal measurement of HA concentrations may prove a useful marker for the development of significant liver damage in CF patients.

Airway inflammation in children with cystic fibrosis and healthy children assessed by sputum induction

A noninvasive method to characterize inflammation and infection in the airways of nonexpectorating children with cystic fibrosis (CF) is needed for clinical and research purposes. Accordingly, we performed sputum inductions by administering 3% saline to 11 healthy control children and 20 children with CF, composed of 7 sputum producers (capable of spontaneously expectorating sputum) and 13 nonproducers. Induced sputum weights were comparable in each group, whereas the amount of induced sputum collected from the CF producers was over 10-fold higher than the spontaneously expectorated samples. We found a significant increase in indices of airway inflammation, including total cell counts, absolute neutrophil counts, interleukin-8 (IL-8) levels, and neutrophil elastase activity in the CF subjects compared with the healthy control subjects. These same indices in the induced sputum specimens from CF producers were significantly correlated with levels in the matched expectorated sputum specimens. Sputum total protein concentration was elevated in the CF groups, whereas urea and albumin levels were not significantly different. Salivary analysis, performed separately, revealed higher levels of IL-8 and total protein in the CF groups. Airway infection, as assessed by quantitative counts of CF-related bacterial pathogens, was also higher in the CF subjects. The same bacterial pathogens, in similar colony counts, were isolated from both the induced and expectorated sputum samples from the CF producers. We conclude that airway inflammation and infection, assessed through sputum induction, are significantly increased in children with CF as compared with healthy children. Furthermore, induced sputum samples are similar to spontaneously expectorated samples in describing both inflammation and infection in the CF airway.

IL-8 released constitutively by primary bronchial epithelial cells in culture forms an inactive complex with secretory component

The bronchial epithelium is a source of both alpha and beta chemokines and, uniquely, of secretory component (SC), the extracellular ligand-binding domain of the polymeric IgA receptor. Ig superfamily relatives of SC, such as IgG and alpha(2)-macroglobulin, bind IL-8. Therefore, we tested the hypothesis that SC binds IL-8, modifying its activity as a neutrophil chemoattractant. Primary bronchial epithelial cells were cultured under conditions to optimize SC synthesis. The chemokines IL-8, epithelial neutrophil-activating peptide-78, growth-related oncogene alpha, and RANTES were released constitutively by epithelial cells from both normal and asthmatic donors and detected in high m.w. complexes with SC. There were no qualitative differences in the production of SC-chemokine complexes by epithelial cells from normal or asthmatic donors, and in all cases this was the only form of chemokine detected. SC contains 15% N-linked carbohydrate, and complete deglycosylation with peptide N-glycosidase F abolished IL-8 binding. In micro-Boyden chamber assays, no IL-8-dependent neutrophil chemotactic responses to epithelial culture supernatants could be demonstrated. SC dose-dependently (IC(50) approximately 0.3 nM) inhibited the neutrophil chemotactic response to rIL-8 (10 nM) in micro-Boyden chamber assays and also inhibited IL-8-mediated neutrophil transendothelial migration. SC inhibited the binding of IL-8 to nonspecific binding sites on polycarbonate filters and endothelial cell monolayers, and therefore the formation of haptotactic gradients, without effects on IL-8 binding to specific receptors on neutrophils. The data indicate that in the airways IL-8 may be solubilized and inactivated by binding to SC.

Sputum processing for evaluation of inflammatory mediators

Neutrophil-dominated inflammation is prominent in the cystic fibrosis (CF) and chronic bronchitis (CB) airways. We assessed the degree of airway inflammation by measuring the sputum concentrations of interleukin (IL)-8, myeloperoxidase (MPO), and deoxyribonucleic acid (DNA). We determined the relationship among the concentrations of these mediators and investigated methodological problems that may be responsible for reported variability in measurements. Sputa obtained from 31 patients were solubilized with phosphate-buffered saline, dithiothreitol (DTT) (0.1% or 1%), or dornase alfa (0.2 mg/mL). The sputum concentration of IL-8 and MPO was measured by enzyme-linked immunosorbent assay (ELISA), and DNA was measured using microfluorimetry. There was a significant relationship among sputum IL-8, MPO, and DNA. For MPO (means +/- SD), CF was 1,392 +/- 771 vs. CB at 75 +/- 65 mcg/mL; P < 0.0001. For IL-8: CF was 239 +/- 154 vs. CB at 121 +/- 108 ng/mL; P = 0.0002. For DNA, CF was 1.707 +/- 1.25 vs. CB at 0.184 +/- 0.272 mg/mL; P < 0.0001. The MPO concentration in CF sputum was approximately double after in vitro treatment with dornase alfa (P < 0.0001). There is a greater concentration of IL-8, MPO, and DNA in CF than in CB sputa. There is a significant relationship among these inflammatory markers in sputum. DNA polymers bind myeloperoxidase in the sputum, and we speculate that treatment with dornase alfa may remove a source of MPO inhibition.

Model systems for investigating mucin gene expression in airway diseases

Overproduction of mucus and of mucin glycoproteins and goblet cell hyperplasia occurs in chronic obstructive airway diseases, including asthma and cystic fibrosis. Mucus overproduction results from alterations in several cellular processes, including altered regulation of airway mucin genes on exposure to environmental and infectious agents and to inflammatory mediators. Seven of the nine identified MUC genes (which encode the protein backbone of mucins) are normally expressed in human respiratory tract tissues. Several inflammatory mediators have now been shown to regulate expression of MUC2, MUC5AC, and MUC5B genes. Importantly, mucin gene expression can be regulated both transcriptionally and posttranscriptionally. Current information on airway mucin gene expression is summarized in this review along with an overview of airway epithelial model systems. In vitro model systems include airway epithelial carcinoma cell lines and primary normal human bronchial epithelial (NHBE) cells. In vivo systems include human respiratory tract tissues and rodent airways. Our laboratory has begun to investigate the role of cytokines on mucin gene expression in vitro and in vivo and on goblet cell metaplasia in vivo. Because cytokines can alter cell proliferation, we characterized the effect of interleukin (IL)-4 and IL-13 on the proliferation of NHBE cells and three human lung carcinoma cell lines--A549, NCI-H292, and Calu-3--that are frequently used for analyses of airway mucin gene expression. Both IL-4 and IL-13 had cell-specific effects. They increased proliferation moderately (1.2-3.0-fold) in NHBE and Calu-3 cells, but markedly inhibited proliferation of A549 cells in a dose-dependent manner. IL-4 increased proliferation of NCI-H292 cells moderately, although IL-13 had no significant effect. We also examined the role of IL-13 and IL-4 on MUC5AC messenger RNA (mRNA) expression in A549, Calu-3, and H292 cell lines and did not observe any significant effect. However, we recently showed an increase in Muc-5ac mRNA and protein expression in a murine model of ovalbumin-induced allergic asthma and in murine airways when IL-13 was delivered intranasally (Alimam, N.Z., et al. Am J. Respir. Cell Mol. Biol. 22:253--260). Thus, we speculate that IL-13 plays a role in the differentiation of murine airway epithelial cells into goblet cells, which then express Muc-5ac mRNA. A detailed analysis of the role of cytokines in airway cell differentiation and mucin gene expression both in vitro and in vivo is required to elucidate the roles of mucins in airway health and diseases. Identification of Muc-5ac as a major gene and gene product in goblet cell metaplasia should facilitate delineation of the molecular mechanisms underlying the induction and reversal of airway goblet cell metaplasia and goblet cell hyperplasia.

Eosinophil cationic protein and interleukin-8 levels in bronchial lavage fluid from children with asthma and infantile wheeze

It has been shown previously that airway eosinophils characterize childhood asthma and neutrophils contribute to the pathophysiology of both infantile wheezing and asthma. Therefore, eosinophil cationic protein (ECP) and interleukin-8 (IL-8) levels in bronchoalveolar lavage fluid (BALF) from asthmatics (n = 16) and infantile wheezers (n = 30) were analyzed as markers of eosinophil- and neutrophil-mediated inflammation. To aid the interpretation, a control group of children (n = 10) with no lower airway pathology were included. Disease severity was assessed by using a symptom score. Surprisingly, no significant difference was found in IL-8 or ECP levels among asthma, infantile wheeze, and control groups. Asthma was characterized by: a correlation between ECP levels and eosinophil counts (r = 0.618, p = 0.014); a correlation between neutrophil number and IL-8 levels (r = 0.747, p = 0.002); and increasing IL-8 levels with symptom score (p = 0.03). In infantile wheezers, IL-8 levels were poorly related to neutrophil number but were significantly increased when neutrophils were > 10%. Although detectable levels were found in all but one symptomatic infant, IL-8 concentrations did not reflect the symptom score in infantile wheeze. ECP was unexpectedly correlated to neutrophil percentages (Rho = 0.832, p = 0.001), and a threshold of ECP>20 ng/ml was associated with persistent symptoms in these infantile wheezers. Hence, in accordance with BALF cellularity, activation of eosinophils was suggested by raised levels of ECP in childhood asthma, but not in infantile wheeze. Neutrophil-mediated inflammation appeared to better reflect the severity of asthma than that of infantile wheeze. Although its meaning remains to be elucidated, ECP was suggested to be a helpful indicator of persistent infantile wheeze. However, its utility as a marker predicting ongoing asthma remains to be established.

Inflammation in cystic fibrosis airways: relationship to increased bacterial adherence

It is unclear whether inflammation in the cystic fibrosis (CF) lung relates predominantly to bacterial infection, or occurs as a direct consequence of mutant cystic fibrosis transmembrane conductance regulator (CFTR) protein. Interleukin (IL)-8 secretion from CF and non-CF cell lines, and from CF and non-CF human primary nasal epithelial cells incubated with or without Pseudomonas aeruginosa, was measured. Activation of nuclear factor-kappaB (NF-kappaB) in unstimulated CF and non-CF nasal epithelial cells, cell lines and murine tissues was measured by gel-shift assays. No significant difference in basal IL-8 production or NF-kappaB activation was observed between CF and non-CF primary nasal cells. However, CF cells exhibited a significantly (p<0.01) increased IL-8 secretion following P. aeruginosa stimulation. Equalization of the increased P. aeruginosa adherence observed in CF cells, to non-CF levels, resulted in comparable IL-8 secretion. Further, IL-8 production did not differ with mutations which result in either correctly localized CFTR, or in partial/total mislocalization of this protein. Similar levels of NF-kappaB activation were observed in a number of organs of wildtype and CF mice. Finally, IL-8 secretion and NF-kappaB activity were not consistently increased in CF cell lines. Cos-7 cell transfection with plasmids expressing deltaF508 or G551D mutant CFTR protein resulted in increased activation of a p50-containing NF-kappaB complex, but IL-8 secretion was similar to wild-type cells. The authors conclude that the stimulus produced by Pseudomonas aeruginosa is the predominant inflammatory trigger in their models.

Levels of IL-8 and myeloperoxidase in the lungs of pneumonia patients

Interleukin-8 (IL-8) is considered as the major polymorphonuclear neutrophils (PMNs) chemoattractant cytokine in lung diseases such as asthma and adult respiratory distress syndrome (ARDS). However, controversial results were obtained regarding the involvement of IL-8 in the pathogenesis of pneumonia. This study examines the role of IL-8 in the recruitment and activation of PMNs in the lung of pneumonia patients. The interesting aspect of this study is that it is a site- specific analysis of the infected and uninfected lungs of the same patient. The level of IL-8 mRNA, protein and myeloperoxidase present in the cells of the bronchioalveolar lavages (BALs) taken from the areas of known pneumonic consolidations on chest X-ray (infected lung) are compared with the BALs obtained from areas of no obvious infiltrate (non-infected lung). The results obtained from the infected and non-infected lungs of pneumonic patients were further compared with that of a control group of non-smoking patients. The level of IL-8 mRNA and protein were determined by RT-PCR and ELISA respectively. There was a significant increase in the level of IL-8 mRNA in the infected lung as compared to its level in the non-infected lung (p < 0.001). In correlation with the increase in mRNA, IL-8 protein concentrations in BAL fluids from the infected lung were 6 fold higher than those taken from the non-infected lung (p < 0.0001). This pattern was also consistent with MPO activity in the BALs (4.5 fold more MPO activity in the infected lung as compared to that of the non-infected lung), indicating that IL-8 is directly implicated in neutrophil accumulation that follows acute respiratory infection. The results of the present study, therefore, indicate the involvement of IL-8 in the pathogenesis of pneumonia.

DNA and actin bind and inhibit interleukin-8 function in cystic fibrosis sputa: in vitro effects of mucolytics

Infection of the cystic fibrosis (CF) airways elicits an exaggerated, interleukin-8 (IL-8) mediated, neutrophil inflammatory response. Necrosing neutrophils release DNA and actin into the airways, increasing the viscoelasticity of airway secretions. Mucolytics aim to improve airway clearance by reducing this viscoelasticity. DNase I reduces the viscoelasticity of CF sputum, and a human recombinant form of this enzyme is widely administered to patients with CF. Gelsolin, which cleaves actin polymers, is also known to reduce CF sputum viscosity in vitro, and it has been proposed as a future mucolytic agent. We have shown that the anionic polymers DNA and actin bind and mask immunologic recognition of the basic peptide IL-8 and prevent this chemokine from binding to neutrophil receptors. Reduction of CF sputum viscosity by DNase I or gelsolin in vitro was demonstrated to increase the proportion of free IL-8 and the IL-8-dependent neutrophil chemotactic activity of sputum supernatants. We hypothesize that an electrostatic interaction between polymer and chemokine may limit the inflammatory potential of the latter, but that this interaction may be weakened by polymer cleavage. The potential risk of increased inflammation via this mechanism suggests a caveat should be attendant on treatment of patients with CF with these mucolytic agents.

Evaluation of serum interleukin-8 as a marker of disease activity in acute asthma in children

Cytokine-mediated interactions among the inflammatory cells may play a role in the pathogenesis of bronchial asthma. Interleukin-8 (IL-8) is a major cytokine in the recruitment of neutrophils to the area of inflammation. Serum IL-8 is a marker of disease activity and treatment efficacy in bronchial asthma. To understand the role of IL-8 in disease activity in acute asthma, changes in serum concentrations of IL-8 elaborated by activated eosinophil before and after prednisolone therapy with clinical improvement were determined in the present study. Circulating levels of IL-8 in 15 normal control subjects and in sera from 20 allergic asthmatic children with acute exacerbation and in stable condition were determined by using commercially available assay kits. The mean concentration of serum IL-8 was statistically significantly higher in asthmatic children with acute exacerbation (63.62 +/- 11.41 pg/mL) and in stable asthmatics (64.22 +/- 10.31 pg/mL) compared to the control group subjects (50.40 +/- 30.70 pg/mL; p < 0.01). However, the difference was not statistically significant between the acute exacerbation and stable asthmatics groups (p > 0.05). Serum IL-8 is a poor indicator of disease activity in acute asthma; therefore, monitoring by serum IL-8 concentration is of limited value. The clinical value of serum IL-8 as a marker of disease activity remains to be established.

Elevated levels of interleukin-8 and transforming growth factor-beta in bronchoalveolar lavage fluid from patients with bronchiolitis obliterans syndrome: proinflammatory role of bronchial epithelial cells. Munich Lung Transplant Group

BACKGROUND

Obliterative bronchiolitis (OB), the most important long-term complication after lung transplantation, is thought to be a manifestation of chronic rejection within the airways, with the hallmarks inflammation and fibroproliferation.

METHODS

To characterize the inflammatory process in the context of OB we quantified tumor necrosis factor-alpha, interleukin (IL)-8, IL-10, and transforming growth factor (TGF)-beta on the protein and mRNA level in bronchoalveolar lavage fluid samples obtained from patients with bronchiolitis obliterans syndrome (BOS) and without BOS. In addition, bronchial cells sampled by bronchial brushing were analyzed for mRNA expression.

RESULTS

In respiratory epithelial lining fluid (ELF) from BOS patients the protein levels of IL-8 (52.4+/-22.2 vs. 4.4+/-0.9 pg/ml ELF, P<0.005) and TGF-beta (5.6+/-1.9 vs. 0.9+/-0.2 ng/ml ELF, P<0.005) were significantly elevated. In addition, bronchoalveolar lavage fluid cells of BOS patients showed increased expression of TGF-beta (1.13+/-0.44 vs. 0.45+/-0.16, optical density [O.D.]/O.D. glyceraldehyde-3-phosphate dehydrogenase [GAPDH], P=0.11) and IL-8 (0.25+/-0.13 vs. 0.09+/-0.03 O.D/O.D. GAPDH, P=0.53) without the differences reaching statistical significance. In contrast, IL-8 mRNA expression of bronchial cells was significantly higher in the BOS group (0.85+/-0.40 vs. 0.22+/-0.10 O.D./O.D. GAPDH, P<0.05).

CONCLUSIONS

We assume that IL-8 and TGF-beta may act as key mediators for airway inflammation and fibroproliferation in the pathogenesis of OB, with bronchial epithelial cells serving as a relevant source of IL-8.

Intestinal inflammation in cystic fibrosis

BACKGROUND

There is controversy about whether the inflammatory response observed in the cystic fibrosis (CF) lung occurs secondary to bacterial infection or is caused by a dysregulation of the inflammatory response associated with the basic cellular defect of CF.

AIMS

To study the inflammatory response in the gastrointestinal tract of children with CF; and to investigate whether there is increased inflammation in the gastrointestinal tract of CF children with fibrosing colonopathy.

METHODS

Whole gut lavage was performed on 21 pancreatic insufficient children with CF, who were clinically well, five children with CF and fibrosing colonopathy, and 12 controls. Intestinal outputs of plasma derived proteins (albumin, alpha(1) antitrypsin, IgG), secretory immunoglobulins (IgA and IgM), cellular constituents (eosinophil cationic protein and neutrophil elastase), and cytokines (interleukin 8 and interleukin 1beta) were measured.

RESULTS

Compared to controls, the 21 CF patients, with no intestinal complications, had increased intestinal outputs of albumin, IgG, IgM, eosinophil cationic protein, neutrophil elastase, interleukin 1beta, and interleukin 8. Similar values were obtained for the CF patients with fibrosing colonopathy.

CONCLUSIONS

These data suggest that there is immune activation in the gastrointestinal mucosa of children with cystic fibrosis, which may result from the basic cellular defect. Fibrosing colonopathy does not appear to be associated with increased inflammation.

Bronchoalveolar lavage

Bronchoalveolar lavage is a technique for sampling the epithelial lining fluid of the respiratory tract. Analysis of cellular and non-cellular components of returned fluid has the potential to provide valuable information about airways inflammation. Because of the invasive nature of the investigation, there are few conditions for which repeat sampling can be justified. Bronchoalveolar lavage has been used to study immune mechanisms in cystic fibrosis, interstitial lung diseases and asthma. This article reviews the usefulness of BAL assessments for lung inflammation in paediatric practice.

Evidence of chronic inflammation in morphologically normal small intestine of cystic fibrosis patients

Cystic fibrosis (CF) is caused by mutations in the CF transmembrane conductance regulator gene and characteristically leads to prominent lung and pancreatic malfunctions. Although an inflammatory reaction is normally observed in the CF airways, no studies have been performed to establish whether a chronic inflammatory response is also present in the CF intestine. We have investigated whether immunologic alterations and signs of inflammation are observed in CF small intestine. Fourteen CF, 20 negative, and four disease controls underwent duodenal endoscopy for diagnostic purposes. Two CF patients were rebiopsied, one after 3 mo of an elemental diet and the other after 2 wk of pancreatic enzyme withdrawal. In three CF and 10 controls, in vitro small intestine organ cultures were also performed. Expression of ICAM-1, IL-2 receptor, IL-2, IFN-gamma, CD80, and transferrin receptor was studied by immunohistochemistry before and after in vitro organ culture. In CF small intestine, an increased number of lamina propria mononuclear cells express ICAM-1 [mean 114 (SD 82.8), p < 0.001 versus controls], CD25 [20.2 (18.7), p < 0.01], IL-2 [23.6 (13.7), p < 0.05], and IFN-gamma [19 (15.9), p < 0.05], whereas villus enterocytes highly express transferrin receptor. Reduced expression of immunologic markers was observed after 24 h of in vitro culture in all three CF patients as well as in the patient kept on elemental diet for 3 mo. These results indicate that chronic inflammation is observed in CF duodenum and suggest that the perturbation of local mucosal immune response may contribute to the overall clinical picture in CF patients.

Anti-inflammatory gene therapy directed at the airway epithelium

Cystic fibrosis (CF) is characterised by chronic airway inflammation. Pro-inflammatory mediators in the lung are regulated by the transcription factor nuclear factor kappa B (NFkappaB). We have assessed the effect of adenovirus and liposome-mediated overexpression of the NFkappaB inhibitor IkappaBalpha, as well as liposome-mediated transfection with oligonucleotides resembling NFkappaB consensus binding sites (decoys) in a cystic fibrosis airway epithelial cell line (CFTE). Electrophoretic mobility shift assays (EMSA) were used to assess NFkappaB activity and secretion of the pro-inflammatory cytokine interleukin-8 (IL-8) was measured by ELISA. At a MOI of 30, Ad-IkappaBalpha significantly decreased IL-8 secretion to 60% and 43% of control unstimulated and TNF-alpha stimulated cells, respectively. At this MOI, approximately 70% of cells are transduced. EMSA showed an approximately 50% decrease in NFkappaB activation. Liposome-mediated transfection of IkappaBalpha did not reduce IL-8 secretion, probably due to low transfection efficiency (approximately 5% of cells). Liposome-mediated transfection of CFTE cells with rhodamine-labeled decoy oligonucleotides indicated a transfection efficiency close to 100%. TNF-alpha stimulated IL-8 secretion was reduced by approximately 40% using this approach. EMSA confirmed a significant decrease of NFkappaB activation. Decoy oligonucleotides may be a promising approach for reduction of NFkappaB-mediated pulmonary inflammation. Gene Therapy (2000) 7, 306-313.

Asthma: A disease of inflammation and repair

Mucosal inflammation and more recently airway remodeling continue to be a focus of interest when considering both the pathophysiology and treatment of asthma. Although a number of candidate genes relevant to inflammatory cell action have been identified and linked to atopy and airway hyperresponsiveness, it is important to understand genetic factors that might determine the extent of tissue remodeling. The mechanisms regulating the allergic responses in the airways are complex, involving antigen presenting cells and T lymphocytes, which process antigens and orchestrate the response, and mast cells and eosinophils as effector cells. Abundant evidence also points to a proinflammatory role for structural cells, including epithelial and endothelial cells, and smooth muscle. Because of the complex nature of the inflammatory changes in asthma, the exact relation between individual inflammatory cells and their mediators on the one hand and hyperresponsiveness of the airways and clinical manifestations on the other remains unclear. The same applies to the phenomenon of airway remodeling because it is uncertain exactly how the different components of restructuring affect the airway physiology. If progress is to be made in the treatment of asthma, further efforts will be needed to understand the regulation and link between the mechanisms causing inflammation and those leading to fibrotic changes.

Production of the potent neutrophil chemokine, growth-related protein alpha (GROalpha), is not elevated in cystic fibrosis children

Progressive neutrophil-mediated lung damage causes much of the morbidity and mortality in cystic fibrosis (CF). Neutrophil chemoattractants implicated in CF include interleukin (IL-)8, tumour necrosis factor (TNFalpha) and leukotriene (LT)B4, but growth-related protein alpha (GROalpha), a highly potent neutrophil chemokine, has not been investigated. Atopic status has been considered to contribute to the marked heterogeneity of pulmonary disease in CF. We hypothesized that GROalpha may be produced in biologically-significant amounts in the CF lung, and that enhanced production of GROalpha, IL-8 or LTB4 may contribute to the poorer lung function seen in atopic CF patients compared to non-atopic CF patients. GROalpha, IL-8 and LTB4 levels in the sputum of atopic and non-atopic CF patients were assessed by immunoassays, and GROalpha and IL-8 levels were also assessed in the plasma of CF patients and normal controls. As expected, there were high levels of IL-8 and LTB4 in most CF sputum samples, and IL-8 levels were higher in CF plasma than in control plasma (P=0.02). In contrast, GROalpha was undetectable (< 5 pg ml(-1)) in the sputum of 21 out of 25 CF patients, with low levels (range 144-825 pg ml(-1)) in the remainder, and median levels of GROalpha in CF plasma (33 pg ml(-1), n=24) were not significantly different from controls (34 pg ml(-1), n=25). Lung function [forced expiratory volume in 1 sec (FEV1) and forced vital capacity (FVC)] was significantly poorer in atopic CF compared to non-atopic CF patients (P<0.02), but sputum levels of GROalpha, IL-8 and LTB4 were not different between the subgroups. Our results suggest that unlike LTB4 and IL-8, GROalpha does not contribute to neutrophilic inflammation in the CF lung, and other factors must determine the impaired lung function observed in atopic CF patients. These results may have important implications in the development of chemokine receptor antagonists as novel anti-inflammatory agents in CF.

Reduced interleukin-8 production by cystic fibrosis airway epithelial cells

The acquisition of Pseudomonas aeruginosa in the airways of patients with cystic fibrosis (CF) is the initial event leading to bronchiectasis and lung disease. Although the host factors that permit initial airway colonization are largely unknown, recent studies suggest that secretion of interleukin (IL)-8 by airway epithelia and local recruitment of neutrophils is the final pathway in a pulmonary cytokine network. To determine whether differences in cytokine production exist between normal and CF airway epithelia, secretion of immunoreactive IL-8 and IL-10 as well as specific messenger RNA (mRNA) abundance were compared in airway epithelia expressing normal and mutant CF transmembrane regulator. After induction with IL-1beta, a CF airway cell line engineered to express the wild-type CF gene (CFT1-LCFSN) secreted significantly more immunoreactive IL-8 than did its isogenic parent that expressed the mutant CF gene (CFT1) or an isogenic vector control line (CFT1-LC3). Further studies with the three related cell lines demonstrated that expression of CFT1-LCFSN was associated with a significant increase in uninduced secretion of immunoreactive IL-8 as well as a 10- to 20-fold increase in IL-8 mRNA abundance when compared with the isogenic lines expressing the mutant gene. IL-1beta induction and intracellular accumulation of IL-8 appeared to be unaffected by CF genotype. These studies suggest that IL-8 secretion by CF airway epithelial cells is defective and may contribute to Pseudomonas persistence in the CF airway. Further studies are needed to confirm this difference in other cell lines and determine the linkage between IL-8 production and CF gene expression.

Cytokines and inflammatory mediators do not indicate acute infection in cystic fibrosis

Various treatment regimens and difficulties with research design are encountered with cystic fibrosis (CF) because no standard diagnostic criteria exist for defining acute respiratory exacerbations. This study evaluated the role of serial monitoring of concentrations of selected cytokines and inflammatory mediators in serum and sputum as predictors of respiratory exacerbation, as useful outcome measures for CF, and to guide therapy. Interleukin-8 (IL-8), tumor necrosis factor alpha (TNF-alpha), neutrophil elastase-alpha-1-protease inhibitor complex (NE complex), protein, and alpha-1-protease inhibitor (alpha-1-PI) were measured in serum and sputum collected from CF patients during respiratory exacerbations and periods of well-being. Levels of NE complex, protein, and alpha-1-PI in sputum rose during respiratory exacerbations and fell after institution of antibiotic therapy (P = 0.078, 0.001, and 0.002, respectively). Mean (+/- standard error of the mean) levels of IL-8 and TNF-alpha were extremely high in sputum (13,780 +/- 916 and 249.4 +/- 23.5 ng/liter, respectively) but did not change significantly with clinical deterioration of the patient (P > 0.23). IL-8 and TNF-alpha were generally undetectable in serum, and therefore these measures were unhelpful. Drop in forced expiratory volume in 1 s was the only clinical or laboratory parameter that was close to being a determinant of respiratory exacerbation (P = 0.055). This study provides evidence of intense immunological activity occurring continually within the lungs of adult CF patients. Measurement of cytokines and inflammatory mediators in CF sputum is not helpful for identifying acute respiratory exacerbations.

The effect of chloride concentration on human neutrophil functions: potential relevance to cystic fibrosis

Recently, some investigators have observed elevated concentrations of chloride in the airway surface fluid (ASF) overlying respiratory epithelia from cystic fibrosis (CF) patients compared with ASF overlying non-CF epithelia. Others have shown that this elevated ASF salt concentration can inactivate human beta-defensin-1, an antimicrobial peptide secreted by respiratory epithelia. This could impair the primary epithelial defense against bacteria in the CF airway, thereby forcing a greater reliance on polymorphonuclear leukocyte (PMN)-mediated defenses. Pseudomonas aeruginosa (Psa) flourishes in the CF airway despite the presence of abundant PMN. We therefore investigated whether elevated ASF chloride concentration in CF might also compromise PMN function. We employed a cell-culture model in which halide concentrations and osmolarity were varied independently. We examined the effects of chloride concentration on three aspects of PMN function: recruitment of PMN to the airway (production of interleukin-8 [IL-8]), PMN antimicrobial activity (killing of Psa), and PMN clearance from the airways (apoptosis and lysis). We found that exposure to elevated chloride concentration increased PMN synthesis of IL-8, decreased PMN killing of Psa, and accelerated PMN apoptosis and lysis. In CF airways, elevated chloride therefore could contribute to the increased number of PMN recruited into the airways, the increased survival of Psa, and the increased quantity of toxic mediators released by PMN into the airways. These effects of elevated chloride on PMN function may provide another causal link between loss of cystic fibrosis transmembrane conductance regulator function and CF lung disease.

Selective up-regulation of chemokine IL-8 expression in cystic fibrosis bronchial gland cells in vivo and in vitro

Accumulating evidence suggests that the early pulmonary inflammation pathogenesis in cystic fibrosis (CF) may be associated with an abnormal increase in the production of pro-inflammatory cytokines in the CF lung, even in the absence of infectious stimuli. We have postulated that if baseline abnormalities in airway epithelial cell production of cytokines occur in CF, they should be manifested in the CF bronchial submucosal glands, which are known to express high levels of CFTR (cystic fibrosis transmembrane conductance regulator) protein, the gene product mutated in CF disease. Immunohistochemical analyses showed that CF bronchial submucosal glands in patients homozygous for the deltaF508 deletion expressed elevated levels of the endogenous chemokine interleukin (IL)-8 but not the pro-inflammatory cytokines IL-1beta and IL-6, compared with non-CF bronchial glands. Moreover, basal protein and mRNA expression of IL-8 were constitutively up-regulated in cultured deltaF508 homozygous CF human bronchial gland cells, in an unstimulated state, compared with non-CF bronchial gland cells. Furthermore, the exposure of CF and non-CF bronchial gland cells to an elevated extracellular Cl- concentration markedly increased the release of IL-8, which can be corrected in CF gland cells by reducing the extracellular Cl- concentration. We also found that, in contrast to non-CF gland cells, dexamethasone did not inhibit the release of IL-8 by cultured CF gland cells. The selective up-regulation of bronchial submucosal gland IL-8 could represent a primary event that initiates early airway submucosal inflammation in CF patients. These findings are relevant to the pathogenesis of CF and suggest a novel pathophysiological concept for the early and sustained airway inflammation in CF patients.

Interleukin-8 production by cystic fibrosis nasal epithelial cells after tumor necrosis factor-alpha and respiratory syncytial virus stimulation

High levels of neutrophils and the neutrophil-attracting chemokine interleukin (IL)-8 have been observed in the airways of patients with cystic fibrosis (CF). We hypothesized that CF respiratory epithelium produces excessive amounts of IL-8 either at baseline or after stimulation. To test this hypothesis we compared immunoreactive IL-8 release by primary nasal epithelial cell (NEC) cultures established from young children with or without CF, at several time points after stimulation of cultures with tumor necrosis factor-alpha (TNF-alpha) or infection with respiratory syncytial virus (RSV). Both stimuli induced significantly increased IL-8 release by both CF and control cultures. However, there was no difference between CF and control cells in either the magnitude or duration of the IL-8 response. The effect of transduction of CF cells with Ad5-CBCFTR, an adenovirus vector mediating expression of cystic fibrosis transmembrane regulator (CFTR), on IL-8 production was also determined. TNF-alpha stimulated IL-8 production was not different in Ad5-CBCFTR-transduced, -untransduced, or Ad5-CMVLacZ-transduced control cells. Lastly, immortalized CF tracheal epithelial cell lines, both uncorrected and retrovirally corrected with CFTR, were compared. Again, TNF-alpha-stimulated IL-8 production did not differ significantly between cell lines with and without functioning CFTR. Our data suggest that isolated CF NECs cultured under these conditions do not produce more IL-8 than do non-CF control cultures, either at baseline or after incubation with the nonspecific stimuli TNF-alpha and RSV. We conclude that the absence of functioning CFTR alone is not sufficient to cause excessive production of IL-8.

Neutrophil adhesion molecule surface expression and responsiveness in cystic fibrosis

The neutrophil-dominated inflammation of the lung in cystic fibrosis (CF) has traditionally been seen as a physiological response to continuous opportunistic infection. Recent studies suggest, however, that regulation of the inflammatory response itself may be altered in CF. Neutrophil migration from the bloodstream involves alterations in surface expression of the adhesion molecules L-selectin and Mac-1 (CD11b/CD18). The aim of this study was to assess neutrophil adhesion molecule expression and responsiveness in CF. Neutrophils from chronic (n = 16) and acutely infected (n = 13) CF patients and 15 normal control subjects were directly assessed by Fluorescence-activated cell sorter (FACS) analysis for surface expression of L-selectin and CD11b before and after stimulation with interleukin 8 (IL-8) or f-Met-Leu-Phe (fMLP). Neutrophils from stable (n = 5) and acutely infected (n = 5) non-CF bronchiectasis patients were also assessed. Surface upregulation of CD11b was similar in all groups. Basal levels of L-selectin were also comparable among all groups, however, when stimulated, neutrophils from both stable and acutely infected CF patients shed significantly less L-selectin than those from control subjects (p < 0.05 and p < 0.01, respectively). This decreased responsiveness was not observed in either stable or acutely infected non-CF bronchiectasis patients. These results add to the accumulating evidence suggestive of a defective inflammatory response in CF.

Nitric oxide metabolites in cystic fibrosis lung disease

Although the activity of nitric oxide (NO) synthases are increased in lung tissue of patients with cystic fibrosis, the concentrations of nasal and exhaled NO have recently been found to be decreased in cystic fibrosis. This could either be due to reduced NO formation or metabolism of NO within airway fluids. In this study, the stable NO metabolites, nitrate and nitrite, were determined in the saliva and sputum of 18 stable cystic fibrosis patients, 21 cystic fibrosis patients during a pulmonary exacerbation, and in saliva and endotracheal secretions of normal controls. Median saliva concentrations of NO metabolites (nitrate plus nitrite) were 704 mumol/l (95% confidence interval (CI) 419 to 1477) in stable cystic fibrosis patients, 629 mumol/l (95% CI 382 to 1392) in cystic fibrosis patients presenting with pulmonary exacerbation, and 313 mumol/l (95% CI 312 to 454) in controls. Median sputum NO metabolite concentration in stable cystic fibrosis was 346 mumol/l (95% CI 311 to 504). This was not significantly different from cystic fibrosis patients presenting with pulmonary exacerbation (median 184 mumol/l, 95% CI 249 to 572), but significantly higher than in endotracheal secretions of controls (median 144 mumol/l, 95% CI 96 to 260). Sputum NO metabolite concentration in cystic fibrosis pulmonary exacerbation significantly increased during antibiotic treatment. A positive correlation was observed between sputum NO metabolites and lung function in stable cystic fibrosis, suggesting less airway NO formation in cystic fibrosis patients with more severe lung disease. These data indicate that decreased exhaled NO concentrations in cystic fibrosis patients may be due to retention and metabolism of NO within the airway secretions. However, sputum NO metabolites are not a useful marker of airway inflammation in cystic fibrosis lung disease.

Interleukin-8 Expression in Human Nasal Polyps

The cytokine Interleukin 8 (IL-8) has been shown to be a potent mediator of leukocyte recruitment and neovascularization in inflammatory and neoplastic diseases. In this study we hypothesize that IL-8 produced in the nasal polyp microenvironment is responsible for the leukocyte recruitment seen in nasal polyposis. To test this hypothesis we evaluated nasal polyps for distribution and content of IL-8 antigen with immunohistochemical techniques and radioimmunoassay to determine tissue levels of IL-8. The immunohistochemical results demonstrated that IL-8 antigen staining occurred predominantly within inflammatory cells and epithelium. IL-8 was detected in all nasal polyp tissue homogenates (a mean value of 1767 ± 1633 pg/mg total protein (TP) with a range of 134 to 3668 pg/mg TP vs control specimens with a mean value of 77 pg/mg TP with a range of 0.09 to 255 pg/mg TP). These data demonstrate the presence and distribution and levels of IL-8 antigen in nasal polyps in vivo, supporting our hypothesis that local production of IL-8 could be an important factor in the sustained recruitment of leukocytes in nasal polyposis. Thus IL-8 likely plays a significant role in the pathogenesis of this disease process and therefore is a potential target for therapeutic intervention.

Controlled trial of inhaled budesonide in patients with cystic fibrosis and chronic bronchopulmonary Psuedomonas aeruginosa infection

The efficacy and safety of anti-inflammatory treatment with inhaled glucocorticosteroids in patients with cystic fibrosis (CF) and complicating chronic Pseudomonas aeruginosa (P.a.) lung infection was studied in a placebo-controlled, parallel, double-blind single center trial. Active treatment consisted of budesonide dry powder, 800 microg twice daily, delivered from a Turbuhaler. The study period covered two successive 3-mo intervals between elective courses of intravenous anti-Pseudomonas antibiotics. Fifty-five patients entered the study, with a mean age of 20 yr and a mean FEV1 of 63% of predicted. Analysis of all patients entered, irrespective of trial adherence ("intention to treat"), showed a decrease in FEV1 in the first period of -0.032 L in patients on budesonide versus -0.187 L in patients on placebo (p = 0.08). The corresponding figures for the patients adhering to the protocol during the first period were -0.017 L versus -0.198 L (p < 0.05, confidence interval of the difference: -0.035 to +0.327 L). For all patients entered, as well as for patients adhering to the trial, there was always a trend in favor of budesonide, as judged by changes in FEV1 and FVC in both 3-mo periods. None of the patients had asthma, but the patients on budesonide had a mean improvement in histamine reactivity of +1.15 dose steps over the entire 6-mo period, as opposed to +0.017 dose steps in patients on placebo (p < 0.05). There was also a significant (p = 0.01) correlation between pre-trial histamine reactivity and the change in FEV1 in the first period in patients on budesonide. We conclude that inhaled glucocorticosteroids can be of short-term benefit in patients with CF and chronic P.a. infection and that those patients most likely to benefit from this treatment are patients with hyperreactive airways. Prolonged studies in larger number of patients are necessary to determine the long-term efficacy of this treatment.

Lower airway inflammation in infants and young children with cystic fibrosis

Airway inflammation is an important component of cystic fibrosis (CF) lung disease. To determine whether this begins early in the illness, before the onset of infection, we examined bronchoalveolar lavage (BAL) fluid from 46 newly diagnosed infants with CF under the age of 6 mo identified by a neonatal screening program. These infants were divided into three groups: 10 had not experienced respiratory symptoms or received antibiotics and pathogens were absent in their BAL fluid; 18 had clear evidence of lower respiratory viral or bacterial (> or = 10(5) CFU/ml) infection; and the remaining 18 had either respiratory symptoms, taken antibiotics, or had < 10(5) CFU/ml of respiratory pathogens. Their BAL cytology, interleukin-8, and elastolytic activity were compared with those from 13 control subjects. In a longitudinal study to assess if inflammation develops or persists in the absence of infection, the results of 56 paired annual BAL specimens from 44 CF infants were grouped according to whether they showed absence, development, clearance, or persistence of infection. In newly diagnosed infants with CF, those without infection had BAL profiles comparable with control subjects while those with a lower respiratory infection had evidence of airway inflammation. In older children, the development and persistence of infection was accompanied by increased inflammatory markers, whereas these were decreased in the absence, or with the clearance, of infection. We conclude that airway inflammation follows respiratory infection and, in young children, improves when pathogens are eradicated from the airways.

Decreased concentration of exhaled nitric oxide (NO) in patients with cystic fibrosis

Nitric oxide (NO) is produced by various cell types in the human respiratory tract. Endogenously produced nitric oxide is detectable in the exhaled air of healthy individuals. Exhaled NO has been shown to be increased in airway inflammation, most probably due to cytokine-mediated activation of NO synthases. To assess whether NO can serve as a marker of inflammation in cystic fibrosis (CF) lung disease, we measured exhaled NO in CF patients with a chemiluminescence analyser. Single breath measurements were performed in 27 stable CF patients (age range, 6-40 years) and 30 non-smoking controls (age range, 6-37 years). Exhaled NO concentrations were 9.1 +/- 3.6 ppb in the controls and 5.9 +/- 2.6 ppb (P < 0.001) in CF patients. To account for room air NO concentrations on the measurement of exhaled NO, we also calculated the difference between exhaled NO and ambient NO concentrations. Difference values were also significantly lower in CF compared with controls (P < 0.0001). In CF patients there was a positive correlation between exhaled NO and forced vital capacity (r = 0.43, P = 0.033), suggesting that exhaled NO is lower in patients with severe lung disease than in those with mild disease. We conclude that measurements of exhaled NO in CF does not reflect activity of CF airway inflammation. The decreased concentrations of exhaled NO may be due to inhibitory effects of inflammatory cytokines on NO syntheses in the airways and alveolar epithelial cells or to increased retention in airway secretions.

Airway inflammation in COPD assessed by sputum levels of interleukin-8

STUDY OBJECTIVE

To assess the characteristics of airway inflammation in patients with COPD.

METHODS

We measured the sputum concentration of interleukin-8 (IL-8), a chemokine involved in the migration and activation of neutrophils and eosinophils. We also measured myeloperoxidase (MPO) as a parameter of neutrophil activity and eosinophil cationic protein (ECP) as a parameter of eosinophil activity. Spontaneous sputum samples were obtained from 33 patients with stable COPD and 30 patients with asthma. Induced sputum samples were obtained from 12 normal control subjects.

RESULTS

The sputum concentration of IL-8 was significantly higher in the patients with COPD than in the patients with asthma or in the control subjects (p<0.0001). Concentrations of MPO and ECP were significantly higher in the patients with COPD than in the control subjects but did not differ significantly between the patients with COPD and those with asthma. In the patients with COPD, the sputum concentration of IL-8 was significantly correlated with the concentration of MPO (r=0.55, p<0.001) and of ECP (r=0.53, p<0.01). The sputum concentration of IL-8 was negatively correlated with FEV1/FVC (r=-0.78, p<0.0001) in the COPD group.

CONCLUSIONS

Results suggest the activation of both neutrophils and eosinophils in the airways of patients with COPD. It appears that IL-8 plays a primary role in this activation. The sputum concentration of IL-8 appeared to be closely associated with the degree of airflow obstruction in patients with COPD and may serve as a marker in evaluating the severity of airway inflammation, which is a risk factor for COPD.

Randomised controlled trial of inhaled corticosteroids (fluticasone propionate) in cystic fibrosis

BACKGROUND

Controlling lung inflammation may be the key to improving morbidity and mortality in cystic fibrosis.

OBJECTIVE

To assess the effects of inhaled corticosteroids on lung inflammation in cystic fibrosis.

DESIGN

Double blind placebo controlled randomised sequence crossover trial. Fluticasone propionate (400 micrograms/day) was given as a dry powder inhaler for six weeks with a four week washout period before crossover.

OUTCOME MEASURES

Sputum inflammatory markers (interleukin-8, tumour necrosis factor-alpha (TNF-alpha) and neutrophil elastase-both free and bound to alpha 1-antiprotease), sputum interleukin-10, lung function, and symptomatology.

SUBJECTS

Twenty three children from a regional cystic fibrosis centre were enrolled into the study, with mean age 10.3 years (range 7 to 17 years) and mean baseline forced expiratory volume in one second (FEV1) of 64% (range 21% to 102%) predicted for sex and height. One patient was excluded for non-compliance to the study protocol.

RESULTS

No significant benefit was shown for the use of fluticasone propionate in any of the outcomes. For sputum interleukin-8 there was an estimated true treatment median difference of 142 pg/ml (95% confidence interval (CI) 8 to 2866 pg/ml) in favour of placebo; while for maximal expiratory flow at 25% (MEF25%) remaining forced vital capacity predicted for sex and height there was a 15 percentage points (pp) (95% CI 4 to 26 pp) mean treatment difference in favour of placebo. Sputum interleukin-10 was undetected in any samples and unaffected by fluticasone propionate. Neither atopic status, baseline FEV1, nor concomitant DNase therapy had any effect on response to treatment.

CONCLUSIONS

Lack of benefit from fluticasone propionate was most likely due to failure of the drug to penetrate the viscid mucus lining the airways. It is suggested a large multicentre trial with higher doses given for a longer time by a different delivery system is required to assess efficacy.

Interleukin-8 and leukotriene B4 in bronchoalveolar lavage fluid from HIV-infected patients with bacterial pneumonia

Human immunodeficiency virus (HIV)-infected patients are at increased risk of contracting bacterial infections, mainly pneumonia. Despite this, little is known about immunopathogenic mechanisms in HIV-related bacterial pneumonia. This paper investigates the presence of the neutrophil chemotactic mediators, interleukin-8 (IL_8) and leukotriene B4 (LTB4), in bronchoalveolar lavage (BAL) fluid from 27 HIV-infected patients with bacterial pneumonia. Significantly elevated levels of IL-8 were found in BAL fluid of patients with bacterial pneumonia [529 pg ml-1 (296-1161 pg ml-1)] compared to matched patients with Pneumocystis carinii pneumonia (PCP) [59 pg ml-1 (42-254 pg ml-1)] and healthy controls [58 pg ml-1 (37-82 pg ml-1)]. Levels of LTB4 were not elevated during bacterial pneumonia when compared to PCP patients and healthy controls. Furthermore, a positive correlation was found between IL-8 levels in BAL fluid and relative BAL neutrophilia (r = 0.60, P = 0.001) in bacterial pneumonia. In conclusion, elevated IL-8 levels in BAL fluid were found in patients suffering from bacterial pneumonia, which may account for the influx of neutrophils to the lung, whereas LTB4 appears not to be an important chemotactic factor in this setting.

Induction of biologically active interleukin-8 from lung epithelial cells by Burkholderia (Pseudomonas) cepacia products

The frequency of isolation of Burkholderia cepacia from the sputum of cystic fibrosis (CF) patients is increasing. Using the human A549 lung epithelial cell line, we have investigated the ability of B. cepacia exoproducts to stimulate interleukin-8 (IL-8) release. Cell-free supernatants from a panel of CF clinical, non-CF clinical, and nonclinical B. cepacia isolates were found to stimulate IL-8 release, with levels ranging from 11.8 +/- 2.8 to 80.0 +/- 3.5 ng/ml. A similar pattern was seen at the level of the IL-8 mRNA. The bioactivity of the IL-8 was confirmed by examining its effect on the intracellular free calcium in neutrophils and inhibition by a neutralizing anti-IL-8 antibody. B. cepacia lipopolysaccharide, which was able to stimulate IL-8 release from monocytes, did not release IL-8 from the A549 cells. Furthermore, the stimulating ability of the bacterial cell-free supernatant was not diminished by polymyxin B, was markedly reduced by boiling, and appeared unrelated to N-acylhomoserine lactones. The ability of B. cepacia to elicit IL-8 release from epithelial cells may be important in the pathology of CF.

The diagnostic value of bronchoalveolar lavage in immunocompetent children with chronic diffuse pulmonary infiltrates

We have investigated the diagnostic value of (BAL) in 29 immunocompetent children (ages 1 month to 18 years) with chronic diffuse pulmonary infiltrates on chest radiograph who presented for evaluation over a 3-year period. The median age at the time of the BAL was 20 months with a range of 1-210 months. Positive results (1) diagnostic of a primary disorder; (2) consistent with a diagnosis; or (3) diagnostic of a secondary disorder, were obtained in 20/29 patients (13 with a single positive BAL finding and 7 with more than one finding). BAL was diagnostic of a primary disorder in only 5 patients (17%) with aspiration detected in 3 and infection in 2. The differential diagnosis was narrowed in 15 patients by the presence of lymphocytosis, neutrophilia, or eosinophilia. A secondary disorder was uncovered in 8 patients. Negative results were obtained in 9 additional patients. We conclude that BAL provided useful information in children with chronic diffuse infiltrates, but its ability to determine the primary cause was limited.

Potential of preventing Pseudomonas aeruginosa lung infections in cystic fibrosis patients: experimental studies in animals

In patients with cystic fibrosis (CF), respiratory tract infections caused by Staphylococcus aureus and Haemophilus influenzae are followed by Pseudomonas aeruginosa with increasing age. Chronic endobronchial lung infection with P. aeruginosa is the leading cause of morbidity and mortality. In Danish CF patients we noted that both onset of initial colonization and chronic lung infection with P. aeruginosa peaked during the winter months which is the season for respiratory virus infections. Virus may therefore pave the way for P. aeruginosa. We established a chronic P. aeruginosa lung infection in rats by embedding mucoid bacteria in seaweed alginate and installing the beads intratracheally into the lower part of the left lung. Although the rats did not suffer from CF, the antibody responses and the pathologic changes of the lungs mimicked the findings in CF patients. By using this model in normal and athymic rats we showed that the T-cell response during the "natural" course of the infection played no major role. In a model of acute P. aeruginosa pneumonia we found that the macroscopic inflammatory response of the lungs was immense and that the natural capacity to clear P. aeruginosa was very efficient and could not be improved by immunization, although high serum levels of IgM, IgG and IgA antibodies to P. aeruginosa alginate, LPS, exotoxin A and sonicate were induced. We developed a method for collecting and measuring IgA in saliva and noted that mucosal IgA antibodies were induced by vaccination; they did not significantly prevent inflammation, however. In the chronic rat model we succeeded to improve the survival significantly and to change the inflammatory response subsequent to vaccination from an acute type inflammation dominated by polymorphonuclear leukocytes (PMNs) as in CF patients to a chronic type inflammation dominated by mononuclear leukocytes. Furthermore, we found that rats immunized with an alginate containing vaccine had a significantly earlier cellular shift to a chronic type inflammation as well as a significant reduction in the severity of the macroscopic inflammation compared to two other vaccine groups and to nonimmunized controls. Similar results were obtained in rats treated with the TH1 cytokine, interferon-gamma (IFN-gamma). Several authors have shown that the lung tissue damage during chronic infection in CF patients is caused by a type III hypersensitivity reaction leading to release of elastase by PMNs surrounding the bacterial microcolonies. The cellular shift we have induced by vaccination and by IFN-gamma treatment therefore offers a possible new strategy for improving the clinical course in chronically infected CF patients.

Bronchiectasis and related disorders

Bronchiectasis is defined in current medical parlance as the abnormal and permanent dilatation of one or more bronchi, and in clinical practice, the condition is often characterized by features of chronic bronchial infection. Apart from occurring as a primary lung disease, bronchiectasis is a major component of two other disease entities, cystic fibrosis and diffuse panbronchiolitis. Although the three conditions have distinctly different underlying causes, they share the similarity of a predominantly neutrophilic airways inflammation, and the persistent bronchial infection by bacteria, in particular Pseudomonas aeruginosa. Hence, new knowledge in one disease may be explored and applied in the others.

Bronchoalveolar lavage or oropharyngeal cultures to identify lower respiratory pathogens in infants with cystic fibrosis

As collections of lower respiratory tract specimens from young children with cystic fibrosis (CF) are difficult, we determined whether oropharyngeal cultures predicted lower airway pathogens. During 1992-1994, 75 of 90 (83%) infants with CF diagnosed by neonatal screening had 150 simultaneous bronchoalveolar lavage (BAL) and oropharyngeal specimens collected for quantitative bacterial culture at a mean age of 17 months (range, 1-52). Ten children undergoing bronchoscopy for stridor served as controls. Total and differential cell counts and interleukin-8 concentrations were measured in BAL fluid. A subset of bacterial pathogens were typed by pulsed field gel electrophoresis. A non-linear relationship with inflammatory markers supported a diagnosis of lower airway infection when > or = 10(5) colony-forming units/ml were detected. This criterion was met in 47 (31%) BAL cultures from 37 (49%) children. Staphylococcus aureus (19%), Pseudomonas aeruginosa (11%), and Hemophilus influenzae (8%) were the major lower airway pathogens. In oropharyngeal cultures, S. aureus (47%), Escherichia coli (23%), H. influenzae (15%), and P. aeruginosa (13%) predominated. The sensitivity, specificity, and positive and negative predictive values of oropharyngeal cultures for pathogens causing lower respiratory infections were 82%, 83%, 41%, and 97%, respectively. When there was agreement between paired oropharyngeal and BAL cultures, genetic fingerprinting showed some strains of the same organism were unrelated. We conclude that oropharyngeal cultures do not reliably predict the presence of bacterial pathogens in the lower airways of young CF children.

TNF-alpha, IL-8, soluble ICAM-1, and neutrophils in sputum of cystic fibrosis patients

The cytokines tumor necrosis factor-alpha (TNF-alpha), interleukin-8 (IL-8), and intercellular adhesion molecule-1 (ICAM-1) have important roles in regulating neutrophil migration and the inflammatory response. To determine whether the concentration of these cytokines and soluble ICAM-1 (sICAM-1) in sputum was increased in patients with cystic fibrosis during acute exacerbations, we conducted (1) a cross-sectional study of 40 patients, 22 who were clinically well and 18 with acute pulmonary exacerbations; and (2) an 11 months longitudinal study of 16 patients. Significant differences in clinical scores, pulmonary function, and sputum neutrophil density were found between the acutely ill and the well group. There was a strong linear relationship (P < 0.0005) between TNF-alpha and IL-8 concentrations in sputum, but no association between clinical status and cytokine concentrations. The concentration of sICAM-1 was lower in acutely ill compared with well patients in the cross-sectional study. Recovery of exogenous IL-8 added to sputum was complete, while recovery of TNF-alpha averaged 70%. Recovery of exogenous sICAM-1 was only 43%, and the recoveries were lower in sputum samples from acutely ill patients than those from stable patients (P = 0.018). These data indicate that in cystic fibrosis patients, sputum concentrations of TNF-alpha and IL-8 are not increased during acute exacerbations of pulmonary inflammation.

Contribution of specific Pseudomonas aeruginosa virulence factors to pathogenesis of pneumonia in a neonatal mouse model of infection

We sought to identify which Pseudomonas aeruginosa products are involved initiating respiratory tract infection. Defined mutants derived from strain PAO i.e., PAOR1 (lasR),PAO-pmm (algC) (an LPS mutant), and AK1152 (which is Fla- and lacks functional pili), were significantly less virulent than PAO1 in a BALBc/ByJ neonatal mouse model of infection as measured by their abilities to cause acute pneumonia, bacteremia, and death. All three mutants were also less adherent to epithelial cells in an in vitro binding assay. PAOR1 and AK1152 were less able to elicit epithelial production of interleukin-8 than PAO1. LasR was found to be required for the optimal expression of neuraminidase under conditions of increased osmolarity, as might be present in certain pathological conditions. PAO-exsA::omega,, which lacks exoenzyme S expression, was fully virulent, causing at least as much pathology as PAO1. The expression of several P. aeruginosa virulence factors appears to be required to establish pulmonary infection in the neonatal mouse.

Diverse Pseudomonas aeruginosa gene products stimulate respiratory epithelial cells to produce interleukin-8

Respiratory epithelial cells play a crucial role in the inflammatory response during Pseudomonas aeruginosa infection in the lungs of patients with cystic fibrosis. In this study, we determined whether the binding of specific Pseudomonas gene products (pilin, flagellin) to their receptors on respiratory epithelial cells would result in production of the neutrophil chemoattractant IL-8. Piliated wild-type organisms, purified pili, or antibody to the pilin receptor (asialoGM1) evoked significant production of IL-8 by immortalized airway epithelial cells, whereas nonpiliated organisms were less able to bind to respiratory epithelial cells and stimulated much less IL-8 secretion (P < 0.01). A piliated, nonflagellated strain was also associated with decreased binding and a diminished level of IL-8 production when compared to wild-type organisms. Isogenic, nonadherent rpoN mutants, lacking pilin and flagellin, did not bind or elicit an IL-8 response. In addition, the IL-8 response was four-fold higher in a cystic fibrosis cell line compared with its corrected cell line. The Pseudomonas autoinducer, an exoproduct secreted during chronic infection, was found to stimulate IL-8 in a dose-dependent manner. P. aeruginosa adhesins, which are necessary for initial infection, directly stimulate IL-8 production by respiratory epithelial cells and therefore play a major role in the pathogenesis of Pseudomonas infection in patients with cystic fibrosis. The inflammatory response is subsequently perpetuated by Pseudomonas autoinducer which is secreted during chronic infection.