The relationship of systemic inflammation to prior hospitalization in adult patients with cystic fibrosis

CAGE sequencing reveals CFTR-dependent dysregulation of type I IFN signaling in activated cystic fibrosis macrophages

An intense, nonresolving airway inflammatory response leads to destructive lung disease in cystic fibrosis (CF). Dysregulation of macrophage immune function may be a key facet governing the progression of CF lung disease, but the underlying mechanisms are not fully understood. We used 5' end centered transcriptome sequencing to profile P. aeruginosa LPS-activated human CF macrophages, showing that CF and non-CF macrophages deploy substantially distinct transcriptional programs at baseline and following activation. This includes a significantly blunted type I IFN signaling response in activated patient cells relative to healthy controls that was reversible upon in vitro treatment with CFTR modulators in patient cells and by CRISPR-Cas9 gene editing to correct the F508del mutation in patient-derived iPSC macrophages. These findings illustrate a previously unidentified immune defect in human CF macrophages that is CFTR dependent and reversible with CFTR modulators, thus providing new avenues in the search for effective anti-inflammatory interventions in CF.

ROCK STUDY in CF: sustained anti-inflammatory effects of lumacaftor-ivacaftor in sputum and peripheral blood samples of adult patients with cystic fibrosis-an observational study

BACKGROUND

Previous studies showed that the combination of Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) corrector and potentiator, lumacaftor-ivacaftor (LUMA-IVA) provides meaningful clinical benefits in patients with cystic fibrosis who are homozygous for the Phe508del CFTR mutation. However, little is known about the effect of LUMA-IVA on Proinflammatory Cytokines (PICs).

OBJECTIVES

To investigate the impact of LUMA-IVA CFTR modulation on circulatory and airway cytokines before and after 12 months of LUMA-IVA treatment in a real-world setting.

METHODS

We assessed both plasma and sputum PICs, as well as standard clinical outcomes including Forced Expiratory Volume in one second (FEV₁) %predicted, Body Mass Index (BMI), sweat chloride and pulmonary exacerbations at baseline and prospectively for one year post commencement of LUMA-IVA in 44 patients with cystic fibrosis aged 16 years and older homozygous for the Phe508del CFTR mutation.

RESULTS

Significant reduction in plasma cytokines including interleukin (IL)-8 (p<0.05), tumour necrosis factor (TNF)-α (p<0.001), IL-1ß (p<0.001) levels were observed while plasma IL-6 showed no significant change (p=0.599) post-LUMA-IVA therapy. Significant reduction in sputum IL-6 (p<0.05), IL-8 (p<0.01), IL-1ß (p<0.001) and TNF-α (p<0.001) levels were observed after LUMA-IVA therapy. No significant change was noted in anti-inflammatory cytokine IL-10 levels in both plasma and sputum (p=0.305) and (p=0.585) respectively. Clinically significant improvements in FEV₁ %predicted (mean+3.38%, p=0.002), BMI (mean+0.8 kg/m², p<0.001), sweat chloride (mean -19 mmol/L, p<0.001), as well as reduction in intravenous antibiotics usage (mean -0.73, p<0.001) and hospitalisation (mean -0.38, p=0.002) were observed after initiation of LUMA-IVA therapy.

CONCLUSION

This real-world study demonstrates that LUMA-IVA has significant and sustained beneficial effects on both circulatory and airway inflammation. Our findings suggest that LUMA-IVA may improve inflammatory responses, which could potentially contribute to improved standard clinical outcomes.

Regulatory T cell enhancement in adults with cystic fibrosis receiving Elexacaftor/Tezacaftor/Ivacaftor therapy

Introduction

Cystic fibrosis (CF), especially CF lung disease, is characterized by chronic infection, immune dysfunction including impairment of regulatory T cells (Tregs) and an exaggerated inflammatory response. CF transmembrane conductance regulator (CFTR) modulators have shown to improve clinical outcomes in people with CF (PwCF) with a wide range of CFTR mutations. However, it remains unclear whether CFTR modulator therapy also affects CF-associated inflammation. We aimed to examine the effect of elexacaftor/tezacaftor/ivacaftor therapy on lymphocyte subsets and systemic cytokines in PwCF.

Methods

Peripheral blood mononuclear cells and plasma were collected before and at three and six months after the initiation of elexacaftor/tezacaftor/ivacaftor therapy; lymphocyte subsets and systemic cytokines were determined using flow cytometry.

Results

Elexacaftor/tezacaftor/ivacaftor treatment was initiated in 77 PwCF and improved percent predicted FEV1 by 12.5 points (p<0.001) at 3 months. During elexacaftor/tezacaftor/ivacaftor therapy, percentages of Tregs were enhanced (+18.7%, p<0.001), with an increased proportion of Tregs expressing CD39 as a marker of stability (+14.4%, p<0.001). Treg enhancement was more pronounced in PwCF clearing Pseudomonas aeruginosa infection. Only minor, non-significant shifts were observed among Th1-, Th2- and Th17-expressing effector T helper cells. These results were stable at 3- and 6-month follow-up. Cytokine measurements showed a significant decrease in interleukin-6 levels during treatment with elexacaftor/tezacaftor/ivacaftor (-50.2%, p<0.001).

Conclusion

Treatment with elexacaftor/tezacaftor/ivacaftor was associated with an increased percentage of Tregs, especially in PwCF clearing Pseudomonas aeruginosa infection. Targeting Treg homeostasis is a therapeutic option for PwCF with persistent Treg impairment.

Evaluation of Inflammatory Biomarkers in Iranian Patients with Cystic Fibrosis

Background::

Cystic fibrosis (CF) is an autosomal recessive disease characterized by a progressive and recurrent lung infection.

Objective::

This study aimed to evaluate the levels of pro-inflammatory cytokines and their correlations with lung function in CF patients.

Methods::

A matched case-control study was conducted among 18 CF (children and adults) and 18 control patients (age and gender-matched) who were admitted to Masih Daneshvari Hospital (Tehran, Iran). The controls had no obvious inflammatory lung disease. The samples of bronchoalveolar lavage (BAL) fluid, serum, and sputum of participants were collected to determine concentrations of inflammatory cytokines such as interleukins (IL-8, IL-1β) and tumour necrosis factor- alpha (TNF-α) using enzyme-linked immunosorbent assay (ELISA). Spirometry was applied and functional pulmonary indices [forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV1)] were assessed.

Results::

The mean age of CF patients was 15.43 ± 5.970 years (range 4-24). The FVC in a majority of the CF patients (66.7%) was below 60% and only 33.3% of the patients exhibited normal or mild respiratory dysfunction. There were significant differences between FVC and FEV1 measurements before and after bronchoscopy. In addition, IL-8 levels in all three samples (serum, sputum, and BAL) of CF patients and levels of IL-1β and TNF-α in BAL and sputum samples of CF patients were significantly higher than the control group (p<0.001). However, increased cytokine levels were not associated with lung function.

Conclusion::

Increased IL-8 and TNF-α levels seemed to be associated with signs of clinical deterioration and might be useful as diagnostic markers.

Laboratory biomarkers for lung disease severity and progression in cystic fibrosis

Although the clinical outcomes of cystic fibrosis (CF) have been markedly improved through the recent implementation of novel CF transmembrane conductance regulator (CFTR) modulator drugs, robust and reliable biomarkers are still demanded for the early detection of CF lung disease progression, monitoring treatment efficacy and predicting life-threatening clinical complications. Thus, there is an unmet need to identify and validate novel, ideally blood based biomarkers with strong correlations to the severity of CF lung disease, which represents a major contribution to overall CF morbidity and mortality. In this review, we aim to summarize the utility of thus far studied blood-, sputum- and bronchoalveolar lavage (BAL)-based biomarkers to evaluate inflammatory conditions in the lung and to follow treatment efficacy in CF. Measurements of sweat chloride concentrations and the spirometric parameter FEV₁ are currently utilized to monitor CFTR function and the effect of various CF therapies. Nonetheless, both have inherent pitfalls and limitations, thus routinely analyzed biomarkers in blood, sputum or BAL samples are required as surrogates for lung disorders. Recent discovery of new protein (e.g. HE4) and RNA-based biomarkers, such as microRNAs may offer a higher efficacy, which in aggregate may be valuable to evaluate disease prognosis and to substantiate CF drug efficacy.

Glucose ingestion in cystic fibrosis induces severe redox imbalance: A potential role in diabetes

BACKGROUND

Cystic fibrosis related diabetes (CFRD) is the most common co-morbidity associated with cystic fibrosis (CF). Individuals with CF demonstrate airway and systemic oxidation compared to people without CF. Furthermore, systemic oxidation precipitated by hyperglycemia in non-CF diabetes has been shown to lead to enhanced inflammation. We hypothesized that the presence of both CF and diabetes in an individual would result in hyperglycemia-induced redox imbalance to an oxidative state. This in turn would result in enhanced production of pro-inflammatory cytokines.

METHODS

Systemic redox balance and pro-inflammatory cytokines were measured before and following a standard oral glucose tolerance test in healthy controls (HC) and in CF individuals with a spectrum of glucose homeostasis (i.e. normal glucose tolerant - NGT, prediabetes or frank CFRD).

RESULTS

There were no significant differences between groups in terms of basal or glucose-induced levels of inflammatory markers. However, baseline systemic redox potential was significantly more oxidized in CF subjects with prediabetes and CFRD compared to both CF with NGT and HC. Systemic oxidation was significantly worsened, and to a profound degree, two hours following ingestion of glucose in all CF groups (NGT, prediabetes, and CFRD). The level of redox imbalance at the two hour point was the same in all three CF groups and was not associated with the degree of hyperglycemia. There was a significant correlation between worse systemic oxidation and reduced insulin secretion.

CONCLUSIONS

This supports a newly identified abnormality of metabolism in CF - glucose induced redox imbalance to the oxidative state.

C-reactive protein/albumin ratio is associated with lung function among children/adolescents with cystic fibrosis: a three-year longitudinal study

BACKGROUND

Chronic lung infections, inflammation and depletion of nutritional status are considered to be prognostic indicators of morbidity in patients with cystic fibrosis. The aim of this study was to investigate the association between inflammatory markers and lung function, nutritional status and morbidity among children/adolescents with cystic fibrosis.

DESIGN AND SETTINGS

Prospective three-year longitudinal study conducted in an outpatient clinic in southern Brazil.

METHODS

Children/adolescents aged 1-15 years with cystic fibrosis were enrolled. Nutritional status was determined from weight-to-length and body mass index-to-age z-scores and was classified as acceptable, at risk or nutritional failure. Tumor necrosis factor-α, interleukin-1β, myeloperoxidase, C-reactive protein and C-reactive protein/albumin ratio were analyzed. Lung function was evaluated based on the forced expiratory volume in the first second and morbidity according to the number of hospitalizations for pulmonary exacerbation and infections by Pseudomonas aeruginosa. Lung function, nutritional status and morbidity were the outcomes. Odds ratios and 95% confidence intervals were to evaluate the effect of baseline inflammatory markers on the clinical outcomes after three years of follow-up and p-values < 0.05 were considered significant.

RESULTS

We evaluated 38 children/adolescents with cystic fibrosis: 55% female; median age (with interquartile range), 3.75 years (2.71-7.00). Children/adolescents with high C-reactive protein/albumin ratio at baseline had odds of 18 (P = 0.018) of presenting forced expiratory volume in the first second ≤ 70% after three years. The other inflammatory markers were not associated with the outcomes.

CONCLUSION

C-reactive protein/albumin ratio was associated with forced expiratory volume in the first second ≤ 70% after three years.

Mapping targetable inflammation and outcomes with cystic fibrosis biomarkers

Cystic fibrosis is characterized by an overly exuberant neutrophilic inflammatory response to pathogens and other stimuli that starts very early in disease. The overwhelming nature of this response is a primary cause of remodeling and destruction of the airways, suggesting that anti-inflammatory therapies could be beneficial in CF. However, finding therapies that can effectively reduce the inflammatory response without compromising host defenses remains elusive. New approaches towards mapping inflammatory targets promise to aid in developing novel therapeutic strategies and improve outcomes in individuals with CF.

Vitamin D treatment modulates immune activation in cystic fibrosis

Persistent inflammatory response in cystic fibrosis (CF) airways is believed to play a central role in the progression of lung damage. Anti-inflammatory treatment may slow lung disease progression, but adverse side effects have limited its use. Vitamin D has immunoregulatory properties. We randomized 16 CF patients to receive vitamin D2, vitamin D3 or to serve as controls, and investigated the effect of vitamin D supplementation on soluble immunological parameters, myeloid dendritic cells (mDCs) and T cell activation. Three months of vitamin D treatment were followed by two washout months. Vitamin D status at baseline was correlated negatively with haptoglobin, erythrocyte sedimentation rate and immunoglobulin A concentration. Total vitamin D dose per kg bodyweight correlated with the down-modulation of the co-stimulatory receptor CD86 on mDCs. Vitamin D treatment was associated with reduced CD279 (PD-1) expression on CD4⁺ and CD8⁺ T cells, as well as decreased frequency of CD8⁺ T cells co-expressing the activation markers CD38 and human leucocyte antigen D-related (HLA-DR) in a dose-dependent manner. There was a trend towards decreased mucosal-associated invariant T cells (MAIT) cell frequency in patients receiving vitamin D and free serum 25-hydroxyvitamin D (free-s25OHD) correlated positively with CD38 expression by these cells. At the end of intervention, the change in free-s25OHD was correlated negatively with the change in CD279 (PD-1) expression on MAIT cells. Collectively, these data indicate that vitamin D has robust pleiotropic immunomodulatory effects in CF. Larger studies are needed to explore the immunomodulatory treatment potential of vitamin D in CF in more detail.

Phase I Studies of Acebilustat: Biomarker Response and Safety in Patients with Cystic Fibrosis

There is a significant unmet need for safe and effective anti‐inflammatory treatment for cystic fibrosis. The aim of this study was to evaluate the safety of acebilustat, a leukotriene A4 hydrolase inhibitor, and its effect on inflammation biomarkers in patients with cystic fibrosis. Seventeen patients with mild to moderate cystic fibrosis were enrolled and randomized into groups receiving placebo or doses of 50 mg or 100 mg acebilustat administered orally, once daily for 15 days. Sputum neutrophil counts were reduced by 65% over baseline values in patients treated with 100 mg acebilustat. A modestly significant 58% reduction vs. placebo in sputum elastase was observed with acebilustat treatment. Favorable trends were observed for reduction of serum C‐reactive protein and sputum neutrophil DNA in acebilustat‐treated patients. No changes in pulmonary function were observed. Acebilustat was safe and well tolerated. The results of this study support further clinical development of acebilustat for treatment of cystic fibrosis.

Alterations in whole-body arginine metabolism in chronic obstructive pulmonary disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a condition characterized by systemic low-grade inflammation that could increase the production of nitric oxide (NO), of which arginine is the sole precursor. Arginine is derived from the breakdown of protein and through the conversion of citrulline to arginine (de novo arginine production).

OBJECTIVE

Our objective was to study whole-body arginine and citrulline and related metabolism in stable COPD patients.

DESIGN

With the use of stable isotope methodology, we studied whole-body arginine and citrulline rates of appearance, de novo arginine (citrulline-to-arginine flux) and NO (arginine-to-citrulline flux) production, protein synthesis and breakdown rates, and plasma amino acid concentrations in a heterogeneous group of patients with moderate-to-severe COPD [n = 23, mean ± SE age: 65 ± 2 y, forced expiratory volume in 1 s (FEV1): 40% ± 2% of predicted], and a group of healthy older adults (n = 19, mean ± SE age: 64 ± 2 y, FEV1: 95% ± 4% of predicted).

RESULTS

Although plasma arginine and citrulline concentrations were comparable between COPD patients and controls, whole-body arginine (P = 0.015) and citrulline (P = 0.026) rates of appearance were higher in COPD patients and related to a 57% greater de novo arginine production (P < 0.0001). Despite a higher whole-body arginine clearance in COPD patients (P < 0.0001), we found no difference in NO production.

CONCLUSION

In stable patients with moderate-to-severe COPD, endogenous arginine production is upregulated to support a higher arginine utilization that is unrelated to whole-body NO production. This trial was registered at clinicaltrials.gov as NCT01173354 and NCT01172314.

C-Reactive Protein in Stable Cystic Fibrosis: An Additional Indicator of Clinical Disease Activity and Risk of Future Pulmonary Exacerbations

INTRODUCTION

In stable adult cystic fibrosis (CF) patients, we assessed the role of baseline high sensitivity C-reactive protein (hs-CRP) on CF clinical variables and frequency of intravenous (IV) treated pulmonary exacerbations (PExs) 1-year post-baseline.

METHODS

We recruited 51 clinically stable CF patients from our Adult CF Center. We incorporated collected parameters into Matouk CF clinical score and CF questionnaire-revised quality of life score (QOL). We used the clinical minus complications subscores as a clinical disease activity score (CDAS). We dichotomized our patients according to the cohort median baseline hs-CRP of 5.2 mg/L.

RESULTS

Patients in the high hs-CRP group (≥ 5.2 mg/L) demonstrated worse CDAS (r=0.67, p=0.0001) and QOL scores (r=0.57, p=0.0017) at a given FEV₁% predicted. In both hs-CRP groups, prior-year IV-treated PExs and baseline CDASs were significant predictors of future IV-treated PExs. Interestingly, the association between baseline CDAS and future PExs frequency was more robust in the high compared to the low hs-CRP group (r=-0.88, p<0.0001, r=-0.48, p=0.017, respectively) with a steeper regression slope (p=0.001). In addition, a significant interaction was demonstrated between elevated baseline hs-CRP levels and CDASs for the prediction of increased risk of future PExs (p=0.02). This interaction provided an additional indicator of clinical disease activity and added another dimension to the prior year PExs frequency phenotype to identify patients at increased risk for future PExs.

CONCLUSION

Stable CF patients with elevated baseline hs-CRP (≥ 5.2 mg/L) demonstrated worse clinical disease activity and QOL scores at a given level of disease severity (FEV₁% predicted). Elevated baseline hs-CRP values combined with clinical disease activity scores are associated with increased risk for future IV-treated PExs even in those with mild clinical disease activity scores.

Biomarkers in Paediatric Cystic Fibrosis Lung Disease

Biomarkers in cystic fibrosis are used i. for the measurement of cystic fibrosis transmembrane regulator function in order to diagnose cystic fibrosis, and ii. to assess aspects of lung disease severity (e.g. inflammation, infection). Effective biomarkers can aid disease monitoring and contribute to the development of new therapies. The tests of cystic fibrosis transmembrane regulator function each have unique strengths and weaknesses, and biomarkers of inflammation, infection and tissue destruction have the potential to enhance the management of cystic fibrosis through the early detection of disease processes. The development of biomarkers of cystic fibrosis lung disease, in particular airway inflammation and infection, is influenced by the challenges of obtaining relevant samples from infants and children for whom early detection and treatment of disease might have the greatest long term benefits.

Correlations of salivary biomarkers with clinical assessments in patients with cystic fibrosis

RATIONALE

Monitoring clinical disease status in cystic fibrosis frequently requires invasive collection of clinical samples. Due to its noninvasive collection process and direct anatomic relationship with the lower airway, saliva shows great potential as a biological fluid for cystic fibrosis monitoring.

OBJECTIVES

To measure the levels of multiple protein markers in human saliva supernatants and investigate the possibility of utilizing them to provide a more quantitative measure of disease state for use in research and monitoring of patients with cystic fibrosis clinically.

METHODS

Whole saliva samples were collected and processed from cystic fibrosis patients at two distinct time points (2010 and 2013) and measured by two separate platforms. In this cross sectional study, a convenience sample of 71 participants were recruited with samples measured by multiplexed fluorescence microarray (fiber microarray) and another 117 participant samples were measured by an automated, point-of-care, analyzer (SDReader) using a microsphere-based array via fluorescence sandwich immunoassay. For comparison, saliva from 56 and 50 healthy subjects were collected, respectively. The levels of six target proteins were quantified. Various demographic and clinical data, including spirometry, medical history, and clinicians' assessments were also collected from patients with cystic fibrosis on the day of saliva collection.

MEASUREMENTS AND MAIN RESULTS

Similar trends were observed with both platforms and compared with healthy subjects, cystic fibrosis patients had significantly elevated levels of VEGF, IP-10, IL-8, and EGF as well as lower levels of MMP-9 (P ≤ 0.005) using fiber microarray and significantly elevated levels of IP-10, IL-8 with lower levels of MMP-9 and IL-1β (P ≤ 0.02) using the SDReader. The levels of the six proteins correlated with each other significantly, and in some cases, biomarker levels could be used to differentiate between subgroups of patients with different clinical presentations. For example, IP-10 levels significantly correlated with FEV1 and disease severity (as evaluated by clinicians) with both platforms (P < 0.05).

CONCLUSIONS

Significant variations of the levels of six proteins in saliva supernatants, and the correlations of these levels with clinical assessments, demonstrated the potential of saliva for cystic fibrosis research and monitoring.

Sleep-disordered breathing in patients with cystic fibrosis

OBJECTIVE

To test the hypothesis that disease severity in patients with cystic fibrosis (CF) is correlated with an increased risk of sleep apnea.

METHODS

A total of 34 CF patients underwent clinical and functional evaluation, as well as portable polysomnography, spirometry, and determination of IL-1β levels.

RESULTS

Mean apnea-hypopnea index (AHI), SpO2 on room air, and Epworth Sleepiness Scale score were 4.8 ± 2.6, 95.9 ± 1.9%, and 7.6 ± 3.8 points, respectively. Of the 34 patients, 19 were well-nourished, 6 were at nutritional risk, and 9 were malnourished. In the multivariate model to predict the AHI, the following variables remained significant: nutritional status (β = -0.386; p = 0.014); SpO2 (β = -0.453; p = 0.005), and the Epworth Sleepiness Scale score (β = 0.429; p = 0.006). The model explained 51% of the variation in the AHI.

CONCLUSIONS

The major determinants of sleep apnea were nutritional status, SpO2, and daytime sleepiness. This knowledge not only provides an opportunity to define the clinical risk of having sleep apnea but also creates an avenue for the treatment and prevention of the disease.

The chemokine CCL18 characterises Pseudomonas infections in cystic fibrosis lung disease

Cystic fibrosis (CF) lung disease is characterised by chronic Pseudomonas aeruginosa infection and leukocyte infiltration. Chemokines recruit leukocytes to sites of infection. Gene expression analysis identified the chemokine CCL18 as upregulated in CF leukocytes. We hypothesised that CCL18 characterises infection and inflammation in patients with CF lung disease. Therefore, we quantified CCL18 protein levels in the serum and airway fluids of CF patients and healthy controls, and studied CCL18 protein production by airway cells ex vivo. These studies demonstrated that CCL18 levels were increased in the serum and airway fluids from CF patients compared with healthy controls. Within CF patients, CCL18 levels were increased in P. aeruginosa-infected CF patients. CCL18 levels in the airways, but not in serum, correlated with severity of pulmonary obstruction in CF. Airway cells isolated from P. aeruginosa-infected CF patients produced significantly higher amounts of CCL18 protein compared with airway cells from CF patients without P. aeruginosa infection or healthy controls. Collectively, these studies show that CCL18 levels characterise chronic P. aeruginosa infection and pulmonary obstruction in patients with CF. CCL18 may, thus, serve as a potential biomarker and therapeutic target in CF lung disease.

The clinical significance of the gut microbiota in cystic fibrosis and the potential for dietary therapies

Cystic fibrosis (CF) is characterised by many comorbidities related to aberrant mucosa and chronic inflammation in the respiratory and digestive systems. The intestinal mucosa serves as the primary interface between the gut microbiota and endocrine, neural and immune systems. There is emerging evidence that aberrant intestinal mucosa in CF may associate with an altered gut microbiota. Compared to healthy subjects, the overall bacterial abundance and species richness seems to be reduced in CF, accompanied by a trend in suppression of Firmicutes and Bacteroidetes spp. and an augmentation of potentially pathogenic species. There is also some concordance of gut and respiratory microbiotas in CF infants over time. The clinical significance of these observations awaits investigation. The gut microbiota have some potential in CF management by affecting inflammatory and immune responses, and influencing aberrant mucosa. As an important modifiable factor, diet therapies such as probiotics and prebiotics have shown initial promise in improving CF related conditions associated with chronic inflammation. More studies are needed to confirm this, as well as the efficacy of other dietary strategies such as modulating dietary fat and indigestible carbohydrate. Similarly, dietary modification of gut microbiota to optimise nutritional status in CF may be feasible, although more CF-specific studies are warranted.

Impaired functions of macrophage from cystic fibrosis patients: CD11b, TLR-5 decrease and sCD14, inflammatory cytokines increase

BACKGROUND

Early in life, cystic fibrosis (CF) patients are infected with microorganisms. The role of macrophages has largely been underestimated in literature, whereas the focus being mostly on neutrophils and epithelial cells. Macrophages may however play a significant role in the initiating stages of this disease, via an inability to act as a suppressor cell. Yet macrophage dysfunction may be the first step in cascade of events leading to chronic inflammation/infection in CF. Moreover, reports have suggested that CFTR contribute to altered inflammatory response in CF by modification of normal macrophage functions.

OBJECTIVES

In order to highlight possible intrinsic macrophage defects due to impaired CFTR, we have studied inflammatory cytokines secretions, recognition of pathogens and phagocytosis in peripheral blood monocyte-derived macrophages from stable adult CF patients and healthy subjects (non-CF).

RESULTS

In CF macrophage supernatants, concentrations of sCD14, IL-1β, IL-6, TNF-α and IL-10 were strongly raised. Furthermore expression of CD11b and TLR-5 were sorely decreased on CF macrophages. Beside, no difference was observed for mCD14, CD16, CD64, TLR-4 and TLR1/TLR-2 expressions. Moreover, a strong inhibition of phagocytosis was observed for CF macrophages. Elsewhere CFTR inhibition in non-CF macrophages also led to alterations of phagocytosis function as well as CD11b expression.

CONCLUSIONS

Altogether, these findings demonstrate excessive inflammation in CF macrophages, characterized by overproduction of sCD14 and inflammatory cytokines, with decreased expression of CD11b and TLR-5, and impaired phagocytosis. This leads to altered clearance of pathogens and non-resolution of infection by CF macrophages, thereby inducing an exaggerated pro-inflammatory response.

Cytokines in nasal lavages and plasma and their correlation with clinical parameters in cystic fibrosis

BACKGROUND

Because persistent inflammation plays a dominant role in cystic fibrosis (CF), we assessed systemic and local upper airway responses during and after pulmonary exacerbation.

METHODS

We followed a cohort of Pseudomonas aeruginosa-infected adult CF patients (n=16) over time in pulmonary exacerbation and in stable disease. Interleukin (IL)-1β, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-17A, IL-22, interferon-γ and TNFα levels were measured in sputum, nasal lavages and plasma.

RESULTS

In CF patients IL-6 and IL-10 levels in nasal lavages were significantly increased in exacerbation compared with stable disease. Systemic IL-6 significantly correlated with CRP levels and FEV1 (%predicted), independently of disease status. Systemic IL-10 also correlated significantly with CRP and FEV1 (%predicted), but only in exacerbation. Other cytokines tested did not discriminate between exacerbation and stable disease.

CONCLUSIONS

Determination of IL-6 and IL-10 in nasal lavages may provide a minimally invasive tool in the assessment of an exacerbation in CF.

Novel end points for clinical trials in young children with cystic fibrosis

Cystic fibrosis (CF) lung disease commences early in the disease progression and is the most common cause of mortality. While new CF disease-modifying agents are currently undergoing clinical trial evaluation, the implementation of such trials in young children is limited by the lack of age-appropriate clinical trial end points. Advances in infant and preschool lung function testing, imaging of the chest and the development of biochemical biomarkers have led to increased possibility of quantifying mild lung disease in young children with CF and objectively monitoring disease progression over the course of an intervention. Despite this, further standardization and development of these techniques is required to provide robust objective measures for clinical trials in this age group.