Ann Decraene

Elevated expression of both mRNA and protein levels of IL-17A in sputum of stable Cystic Fibrosis patients

BackgroundT helper 17 (Th17) cells can recruit neutrophils to inflammatory sites through production of IL-17, which induces chemokine release. IL-23 is an important inducer of IL-17 and IL-22 production. Our aim was to study the role of Th17 cells in cystic fibrosis (CF) lung disease by measuring IL-17 protein and mRNA levels and IL-22 and IL-23 mRNA in sputum of clinically stable CF patients and by comparing these levels with healthy controls.MethodsSputum induction was performed in adult CF patients outside of an exacerbation and healthy control subjects. IL-17A protein levels were measured in supernatants with cytometric bead array (CBA) and RNA was isolated and quantitative RT-PCR was performed for IL-17A, IL-22 and IL-23.ResultsWe found significantly higher levels of IL-17A protein and mRNA levels (both: p < 0.0001) and IL-23 mRNA levels (p < 0.0001) in the sputum of CF group as compared to controls. We found very low levels of IL-22 mRNA in the CF group. The levels of IL-17 and IL-23 mRNA were higher in patients chronically infected with Pseudomonas aeruginosa (P. aeruginosa) as compared to those who were not chronically infected with P. aeruginosa. The presence of Staphylococcus aureus (S. aureus) on sputum did not affect the IL-17 or IL-23 levels. There was no correlation between IL-17 or IL-23 levels and FEV1 nor sputum neutrophilia.ConclusionThe elevated levels of IL-17 and IL-23 might indicate that Th17 cells are implicated in the persistent neutrophil infiltration in CF lung disease and chronic infection with P. aeruginosa.

Type III IFN‐λ mRNA expression in sputum of adult and school‐aged asthmatics

Background The increased susceptibility of asthmatics to rhinovirus infection has recently been related to deficient IFN‐λ1 (IL‐29) and IFN‐λ2/3 (IL‐28) production by bronchial epithelial cells and macrophages.

Bile Acids in Sputum and Increased Airway Inflammation in Patients With Cystic Fibrosis

BACKGROUND Up to 80% of patients with cystic fibrosis (CF) may have increased gastroesophageal reflux and aspiration of duodenogastric contents into the lungs. We aimed to assess aspiration in patients with CF by measuring duodenogastric components in induced sputum and to investigate whether the presence of bile acids (BAs) in sputum was correlated with disease severity and markers of inflammation. METHODS In 41 patients with CF, 15 healthy volunteers, 29 patients with asthma, and 28 patients with chronic cough, sputum was obtained after inhalation of hypertonic saline. Sputum supernatant was tested for BA and neutrophil elastase. Spirometry and BMI were assessed on the day of sputum collection. RESULTS Two of 15 healthy patients (13%), eight of 29 patients (28%) with asthma, four of 28 patients (14%) with chronic cough, and 23 of 41 patients (56%) with CF had BA in sputum. BA concentrations were similar in patients who are positive for BA with genotype F508del homozygote, F508del heterozygote, and other CF mutations and were not related with BMI and age. Patients with CF with BA in sputum had a higher concentration of neutrophil elastase compared with patients without BA in sputum (31.25 [20.33-54.78] μg/mL vs 14.45 [7.11-27.88] μg/mL, P < .05). There was a significant correlation between BA concentrations and dynamic lung volumes (FEV(1) % predicted [r = -0.53, P < .01], FVC% [r = -0.59, P < .01]) as well as with number of days of antibiotic IV treatment (r = 0.58, P < .01). CONCLUSIONS BAs are present in the sputum of more than one-half of patients with CF, suggesting aspiration of duodenogastric contents. Aspiration of BA was associated with increased airway inflammation. In patients with BA aspiration, the levels of BA were clearly associated with the degree of lung function impairment as well as the need for IV antibiotic treatment.

The Sputum Colour Chart as a predictor of lung inflammation, proteolysis and damage in non-cystic fibrosis bronchiectasis: a case-control analysis.

Non‐cystic fibrosis bronchiectasis (NCFB) is characterized by a vicious cycle of airway infection, inflammation and structural damage with inappropriate mucus clearance. Our aim was to relate the value of proteolytic enzymes, proteolytic enzyme activity and inflammatory markers to disease severity and symptoms in patients with NCFB.

Airway inflammation in patients with chronic non-asthmatic cough

Introduction Chronic non-asthmatic cough (CC) is a clinical challenge and underlying pathophysiological mechanisms remain still not completely understood. One of the most common comorbidities in CC is gastro-oesophageal reflux disease (GORD). Airway epithelium damage can contribute to airway inflammation in CC. Aims We studied airway inflammation in patients with CC compared to healthy controls. Patients with GORD were treated with proton pump inhibitors (PPI) and cough response to PPI was evaluated. Patients and methods Sputum was induced in 41 adults with CC and 20 healthy non-smokers who were age and sex matched. We compared sputum differential cell count by cytospin and cytokine and chemokine production at the mRNA and/or protein levels by real-time (RT)-PCR and cytokine bead array (CBA), between patients with CC and healthy subjects. Furthermore we studied airway inflammation in patients with different comorbidities. Results No differences in sputum differential cell counts were observed between patients with CC and healthy subjects. Sputum monocyte chemoattractant protein-1 (MCP-1) protein levels were significantly higher in patients when compared to controls. Thymic stromal lymphopoietin (TSLP) mRNA was significantly more often expressed in sputum of patients with CC than from healthy controls. Sputum transforming growth factor (TGF)-β levels did not differ between patients and controls, but were significantly lower in the PPI responders compared to the non-responders; p=0.047. There is no evidence for impaired T helper cell (Th)1/Th2/Th17 balance in CC. Patients with reflux oesophagitis (RO) have significantly more sputum eosinophils than patients without RO. Conclusions CC is a condition presenting with different disease phenotypes. High sputum MCP-1 levels are present in a large group of patients with CC and a majority of these patients with CC have increased sputum TSLP levels, most likely produced by damaged airway epithelial cells.

IL-17A in Human Respiratory Diseases: Innate or Adaptive Immunity? Clinical Implications

Since the discovery of IL-17 in 1995 as a T-cell cytokine, inducing IL-6 and IL-8 production by fibroblasts, and the report of a separate T-cell lineage producing IL-17(A), called Th17 cells, in 2005, the role of IL-17 has been studied in several inflammatory diseases. By inducing IL-8 production and subsequent neutrophil attraction towards the site of inflammation, IL-17A can link adaptive and innate immune responses. More specifically, its role in respiratory diseases has intensively been investigated. We here review its role in human respiratory diseases and try to unravel the question whether IL-17A only provides a link between the adaptive and innate respiratory immunity or whether this cytokine might also be locally produced by innate immune cells. We furthermore briefly discuss the possibility to reduce local IL-17A production as a treatment option for respiratory diseases.

Sputum “IL-5, IL-17A, IL-25-high” pattern is associated with uncontrolled asthma and worse lung function

The “IL-5-high” asthma profile (n=13) merged with the “IL-25-high” (10/13) and surprisingly also with the “IL-17A-high” (11/13) profile. A sputum “IL-25-high” profile was even restricted to patients with an “IL-5-high” profile. Only a minority of “IL-5-high” patients were found to be “IL-4-high” (n=6), whereas 17 other patients had an “IL-4-high” profile without being “IL-5-high”. Patients with an “IL-5-high”, Il-17A-high” and/or “IL-25 high” cytokine pattern had worse lung function parameters (FEV1%pred., PEF, FEF25-75%). Uncontrolled asthmatics had significantly higher sputum IL-5, IL-17A and IL-25 mRNA levels. Conclusion Airway cytokine expression is highly heterogeneous amongst patients and their exact contribution to asthma pathogenesis is debated. Uncontrolled asthma was associated with higher levels of IL-5, IL-17A and IL-25 in the airways of asthmatics. Identifying patients’ aberrant cytokine expression in the airways by non-invasive techniques might help to define responders to current and future therapies.

Elevated IL-17 and IL-23 mRNA levels in sputum of stable CF patients

The role of the innate immunity in lung inflammation of cystic fibrosis (CF) has been well described but T lymphocytes might also be important. In particular, T helper 17 (Th17) cells can recruit neutrophils to an inflammatory site through production of IL-17, which induces chemokine release. IL-23 is an important inducer of IL-17 production. Elevated protein levels of IL-17 and IL-23 were found in bronchoalveolar lavage (BAL) fluid and sputum of CF patients during exacerbation (McAllister et al., J Immunol 2005;175:404). Our aim was to study the role of Th17 cells in CF lung disease by measuring IL-17 and IL-23 mRNA in sputum of stable CF patients and by comparing these levels with healthy controls. Sputum induction was performed in 39 stable adult CF patients (age: 25.6±6.2 years; FEV1: 65.8±18.6% predicted) outside of exacerbation and 11 controls (age: 27.5±10.9 years). Neutrophil counts ranged from 91.6±8.3% in the CF group and 42±23.7% in the controls. RNA was isolated and quantitative real-time RT-PCR was performed. mRNA levels were normalised to the house keeping gene 18s rRNA. We found significantly higher levels of IL-17 (p< 0.0001) and IL-23 (p< 0.0001) in the CF group compared to controls. There was a correlation between IL-17 and IL-23 mRNA expression in the CF group (p< 0.0001) and to a lesser extent in the controls (p = 0.0426). The elevated levels of IL-17 and IL-23 mRNA could explain the persistent neutrophil infiltration present in sputum of stable CF patients. The correlation between IL-17 and IL-23 mRNA supports the potential role of the IL-23-IL-17 axis in the pathophysiology of CF lung disease.