Systemic cytokine signaling via IL-17 in smokers with obstructive pulmonary disease: a link to bacterial colonization?

Pathogenicity and virulence of Aspergillus fumigatus

Pulmonary infections caused by the mould pathogen Aspergillus fumigatus are a major cause of morbidity and mortality globally. Compromised lung defences arising from immunosuppression, chronic respiratory conditions or more recently, concomitant viral or bacterial pulmonary infections are recognised risks factors for the development of pulmonary aspergillosis. In this review, we will summarise our current knowledge of the mechanistic basis of pulmonary aspergillosis with a focus on emerging at-risk populations.

An inhibitor of RORγ for chronic pulmonary obstructive disease treatment

The role of RORγ as a transcription factor for Th17 cell differentiation and thereby regulation of IL-17 levels is well known. Increased RORγ expression along with IL-17A levels was observed in animal models, immune cells and BAL fluid of COPD patients. Increased IL-17A levels in severe COPD patients are positively correlated with decreased lung functions and increased severity symptoms and emphysema, supporting an urgency to develop novel therapies modulating IL-17 or RORγ for COPD treatment. We identified a potent RORγ inhibitor, PCCR-1 using hit to lead identification followed by extensive lead optimization by structure–activity relationship. PCCR-1 resulted in RORγ inhibition with a high degree of specificity in a biochemical assay, with > 300-fold selectivity over other isoforms of ROR. Our data suggest promising potency for IL-17A inhibition in human and canine PBMCs and mouse splenocytes with no significant impact on Th1 and Th2 cytokines. In vivo, PCCR-1 exhibited significant efficacy in the acute CS model with dose-dependent inhibition of the PD biomarkers that correlated well with the drug concentration in lung and BAL fluid, demonstrating an acceptable safety profile. This inhibitor effectively inhibited IL-17A release in whole blood and BALf samples from COPD patients. Overall, we identified a selective inhibitor of RORγ to pursue further development of novel scaffolds for COPD treatment.

Biomarkers, Clinical Course, and Individual Needs in COPD Patients in Primary Care: The Study Protocol of the Stockholm COPD Inflammation Cohort (SCOPIC)

Background

To facilitate effective personalized medicine, primary health care needs better methods of assessing and monitoring chronic obstructive pulmonary disease (COPD).

Aim

This cohort study aims to investigate how biomarkers relate to clinical characteristics and COPD patients' subjective needs over time.

Methods

Patients (n=750) in different COPD severity according to the GOLD criteria and age- and sex-matched controls (n=750) will be recruited over a period of 5 years from 15 primary health care centers in Region Stockholm, Sweden, and followed for 10 years in the first instance. Data on patients' subjective needs will be collected via telephone/email, data on clinical/physiological variables (eg, symptoms, exacerbations, comorbidities, medications, smoking habits, lung function) from existing databases that are based on medical records, and data on biomarkers via repeated blood sampling. Quantitative and qualitative methods will be used. Initial results are expected after 2 years (feasibility test), and a larger body of evidence after 5 years.

Discussion

The study is expected to provide definitive and clinically useful scientific evidence about how biomarkers relate to clinical variables and patients' subjective needs. This new evidence will facilitate accurate, and personalized COPD management by the use of valid biomarkers. It will provide useful tools for primary care professionals and may facilitate optimal self-management.

The Role of Innate Lymphoid Cells in Chronic Respiratory Diseases

The lung is a vital mucosal organ that is constantly exposed to the external environment, and as such, its defenses are continuously under threat. The pulmonary immune system has evolved to sense and respond to these danger signals while remaining silent to innocuous aeroantigens. The origin of the defense system is the respiratory epithelium, which responds rapidly to insults by the production of an array of mediators that initiate protection by directly killing microbes, activating tissue-resident immune cells and recruiting leukocytes from the blood. At the steady-state, the lung comprises a large collection of leukocytes, amongst which are specialized cells of lymphoid origin known as innate lymphoid cells (ILCs). ILCs are divided into three major helper-like subsets, ILC1, ILC2 and ILC3, which are considered the innate counterparts of type 1, 2 and 17 T helper cells, respectively, in addition to natural killer cells and lymphoid tissue inducer cells. Although ILCs represent a small fraction of the pulmonary immune system, they play an important role in early responses to pathogens and facilitate the acquisition of adaptive immunity. However, it is now also emerging that these cells are active participants in the development of chronic lung diseases. In this mini-review, we provide an update on our current understanding of the role of ILCs and their regulation in the lung. We summarise how these cells and their mediators initiate, sustain and potentially control pulmonary inflammation, and their contribution to the respiratory diseases chronic obstructive pulmonary disease (COPD) and asthma.

Systemic Galectin-3 in Smokers with Chronic Obstructive Pulmonary Disease and Chronic Bronchitis: The Impact of Exacerbations

PURPOSE

The carbohydrate-binding protein Galectin-3 is increased in several inflammatory diseases and has recently been forwarded as a systemic biomarker in chronic obstructive pulmonary disease (COPD). In this longitudinal study, we characterized the level of systemic Galectin-3 using blood from smokers with a history of COPD and chronic bronchitis (COPD-CB), during stable clinical conditions and exacerbations.

PATIENTS AND METHODS

The study population comprised 56 long-term smokers with COPD-CB, 10 long-term smokers without lung disease (LTS) and 10 clinically healthy never-smokers (HNS). Blood samples were analyzed for levels of Galectin-3, leukocyte populations and C-reactive protein (CRP). In addition, sputum samples from the COPD-CB group were analyzed for bacterial growth.

RESULTS

When comparing stable clinical conditions and exacerbations in the COPD-CB group, we found that the level of Galectin-3, just like that of CRP, leukocytes and neutrophils, respectively, was increased during exacerbations. However, this exacerbation-associated increase of Galectin-3 was modest. During stable clinical conditions of COPD-CB, the level of Galectin-3 was not elevated in comparison with HNS or LTS. Nor did this level of Galectin-3 distinguish patients that remained in a clinically stable condition throughout the study to those that developed an exacerbation. In addition, neither during stable clinical conditions nor during exacerbations, did the presence of bacterial growth in sputum alter Galectin-3 levels. In contrast to Galectin-3, the level of CRP, leukocytes and neutrophils, respectively, were increased during clinical stable conditions in the COPD-CB group compared with the other groups and were further enhanced during exacerbations.

CONCLUSION

Systemic Galectin-3 is increased in a reproducible but modest manner during exacerbations in smokers with COPD-CB. During stable clinical conditions, the level of systemic Galectin-3 does not distinguish patients that remain clinically stable from those that develop exacerbations. This makes it less likely that systemic Galectin-3 may become a clinically useful biomarker in the current setting.

Th1/Th17 Cytokine Profiles are Associated with Disease Severity and Exacerbation Frequency in COPD Patients

Background

T helper (Th) cell cytokine imbalances have been associated with the pathophysiology of chronic obstructive pulmonary disease (COPD), including the Th1/Th2 and Th17/T regulatory cells (Treg) paradigms. Clarifying cytokine profiles during COPD acute exacerbation (AE) and their relationships with clinical manifestations would help in understanding the pathogenesis of disease and improve clinical management.

Materials and Methods

Eighty seven patients admitted to the hospital with AEs of COPD were included in this study, and follow-up was conducted after discharge (every 30 days, for a total of 120 days). Sputum samples of patients at different time points (including at admission, discharge, and follow-up) were collected, and sputum cytokine profiling (12 cytokines in total) was performed using a Luminex assay.

Results

According to the cytokine profiles at admission, patients were divided into three clusters by a k-means clustering algorithm, namely, Th1_high Th17_high (n=26), Th1_lowTh17_low (n=56), and Th1_high Th17_low (n=5), which revealed distinct clinical characteristics. Patients with Th1_high Th17_low profile had a significantly longer length of non-invasive ventilation time and length of hospital stay than patients with Th1_high Th17_high profile (7 vs 0 days, 22 vs 11 days, respectively, p < 0.05), and had the highest AE frequency. Sputum levels of Th17 cytokines (IL-17A, IL-22, and IL-23) during AE were negatively correlated with AE frequency in the last 12 months (r = −0.258, −0.289 and −0.216, respectively, p < 0.05). Moreover, decreased sputum IL-17A levels were independently associated with increased AE frequency, with an OR (95% CI) of 0.975 (0.958–0.993) and p = 0.006.

Conclusion

Th1/Th17 imbalance during AE is associated with the severity of COPD. Decreased Th17 cytokine expression is correlated with increased AE frequency. The Th1/Th17 balance may be a specific target for the therapeutic manipulation of COPD.

Dysregulated alveolar function and complications in smokers following oesophagectomy

Acute respiratory distress syndrome (ARDS) has a significant impact on post-operative morbidity and mortality following oesophagectomy. Smoking is a risk factor for the development of ARDS, although the mechanism is unclear. We examined the effect of smoking on alveolar and systemic inflammation, in addition to alveolar–capillary permeability, leading to ARDS in patients undergoing oesophagectomy.

We compared clinical, biomarker and PiCCO system data between current smokers (n=14) and ex-smokers (n=36) enrolled into a translational substudy of the BALTI-P (Beta Agonist Lung Injury Trial Prevention) trial.

Current smokers compared with ex-smokers had significantly higher numbers of circulating neutrophils, elevated bronchoalveolar lavage (BAL) interleukin (IL)-1 receptor antagonist (IL-1ra), soluble tumour necrosis factor receptor-1 and pre-operative plasma soluble intercellular adhesion molecule-1, and lower BAL vascular endothelial growth factor and post-operative plasma IL-17 (p<0.05). On post-operative day 1, current smokers had higher extravascular lung water index (9.80 versus 7.90; p=0.026) and pulmonary vascular permeability index (2.09 versus 1.70; p=0.013). Current smokers were more likely to develop ARDS (57% versus 25%; p=0.031) and had a significantly reduced post-operative median survival (421 versus 771 days; p=0.023).

Smoking prior to oesophagectomy is associated with dysregulated inflammation, with higher concentrations of inflammatory mediators and lower concentrations of protective mediators. This translates into a higher post-operative inflammatory alveolar oedema, greater risk of ARDS and poorer long-term survival.

Patients who smoke at the time of oesophagectomy have dysregulated immune function, greater post-operative alveolar oedema, higher incidence of ARDS and poorer long-term survivalhttp://ow.ly/EsEh30nbO0R

Distinctive Regulatory T Cells and Altered Cytokine Profile Locally in the Airways of Young Smokers with Normal Lung Function

Smoking influences the immune system in different ways and, hypothetically, effects on pulmonary effector and regulatory T cells emerge as potentially detrimental. Therefore, we characterized the frequencies and characteristics of CD4+ and CD8+ T cell subsets in the blood and lungs of young tobacco smokers. Bronchoalveolar lavage (BAL) and peripheral blood were obtained from healthy moderate smokers (n = 18; 2–24 pack-years) and never-smokers (n = 15), all with normal lung function. Cells were stimulated ex vivo and key intracellular cytokines (IFNγ, IL-17, IL-10 and TNFα) and transcription factors (Foxp3, T-bet and Helios) were analyzed using flow cytometry. Our results indicate that smoking is associated with a decline in lung IL-17+ CD4+ T cells, increased IFNγ+ CD8+ T cells and these alterations relate to the history of daily cigarette consumption. There is an increased fraction of Foxp3+ regulatory T cells being Helios- in the lungs of smokers. Cytokine production is mainly confined to the Helios- T cells, both in regulatory and effector subsets. Moreover, we detected a decline of Helios+Foxp3- postulated regulatory CD8+ T cells in smokers. These alterations in the immune system are likely to increase risk for infection and may have implications for autoimmune processes initiated in the lungs among tobacco smokers.

Exposure to Fine Particulate Air Pollution Is Associated With Endothelial Injury and Systemic Inflammation

RATIONALE

Epidemiological evidence indicates that exposures to fine particulate matter air pollution (PM_2.5) contribute to global burden of disease, primarily as a result of increased risk of cardiovascular morbidity and mortality. However, mechanisms by which PM_2.5 exposure induces cardiovascular injury remain unclear. PM_2.5-induced endothelial dysfunction and systemic inflammation have been implicated, but direct evidence is lacking.

OBJECTIVE

To examine whether acute exposure to PM_2.5 is associated with endothelial injury and systemic inflammation.

METHODS AND RESULTS

Blood was collected from healthy, nonsmoking, young adults during 3 study periods that included episodes of elevated PM_2.5 levels. Microparticles and immune cells in blood were measured by flow cytometry, and plasma cytokine/growth factors were measured using multiplexing laser beads. PM_2.5 exposure was associated with the elevated levels of endothelial microparticles (annexin V⁺/CD41^-/CD31⁺), including subtypes expressing arterial-, venous-, and lung-specific markers, but not microparticles expressing CD62⁺. These changes were accompanied by suppressed circulating levels of proangiogenic growth factors (EGF [epidermal growth factor], sCD40L [soluble CD40 ligand], PDGF [platelet-derived growth factor], RANTES [regulated on activation, normal T-cell-expressed and secreted], GROα [growth-regulated protein α], and VEGF [vascular endothelial growth factor]), and an increase in the levels of antiangiogenic (TNFα [tumor necrosis factor α], IP-10 [interferon γ-induced protein 10]), and proinflammatory cytokines (MCP-1 [monocyte chemoattractant protein 1], MIP-1α/β [macrophage inflammatory protein 1α/β], IL-6 [interleukin 6], and IL-1β [interleukin 1β]), and markers of endothelial adhesion (sICAM-1 [soluble intercellular adhesion molecule 1] and sVCAM-1 [soluble vascular cellular adhesion molecule 1]). PM_2.5 exposure was also associated with an inflammatory response characterized by elevated levels of circulating CD14⁺, CD16⁺, CD4⁺, and CD8⁺, but not CD19⁺ cells.

CONCLUSIONS

Episodic PM_2.5 exposures are associated with increased endothelial cell apoptosis, an antiangiogenic plasma profile, and elevated levels of circulating monocytes and T, but not B, lymphocytes. These changes could contribute to the pathogenic sequelae of atherogenesis and acute coronary events.

Cigarette smoke alters the ability of human dendritic cells to promote anti-Streptococcus pneumoniae Th17 response

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is associated with chronic inflammation and impaired immune response to pathogens leading to bacteria-induced exacerbation of the disease. A defect in Th17 cytokines in response to Streptococcus pneumoniae, a bacteria associated with COPD exacerbations, has been recently reported. Dendritic cells (DC) are professional antigen presenting cells that drive T-cells differentiation and activation. In this study, we hypothesized that exposure to cigarette smoke, the main risk factor of COPD, might altered the pro-Th17 response to S. pneumoniae in COPD patients and human DC.

METHODS

Pro-Th1 and -Th17 cytokine production by peripheral blood mononuclear cells (PBMC) from COPD patients was analyzed and compared to those from smokers and non-smokers healthy subjects. The effect of cigarette smoke extract (CSE) was analyzed on human monocyte-derived DC (MDDC) from controls exposed or not to S. pneumoniae. Bacteria endocytosis, maturation of MDDC and secretion of cytokines were assessed by flow cytometry and ELISA, respectively. Implication of the oxidative stress was analyzed by addition of antioxidants and mitochondria inhibitors. In parallel, MDDC were cocultured with autologous T-cells to analyze the consequence on Th1 and Th17 cytokine production.

RESULTS

PBMC from COPD patients exhibited defective production of IL-1β, IL-6, IL-12 and IL-23 to S. pneumoniae compared to healthy subjects and smokers. CSE significantly reduced S. pneumoniae-induced MDDC maturation, secretion of pro-Th1 and -Th17 cytokines and activation of Th1 and Th17 T-cell responses. CSE exposure was also associated with sustained CXCL8 secretion, bacteria endocytosis and mitochondrial oxidative stress. Antioxidants did not reverse these effects. Inhibitors of mitochondrial electron transport chain partly reproduced inhibition of S. pneumoniae-induced MDDC maturation but had no effect on cytokine secretion and T cell activation.

CONCLUSIONS

We observed a defective pro-Th1 and -Th17 response to bacteria in COPD patients. CSE exposure was associated with an inhibition of DC capacity to activate antigen specific T-cell response, an effect that seems to be not only related to oxidative stress. These results suggest that new therapeutics boosting this response in DC may be helpful to improve treatment of COPD exacerbations.

Effects of thermal water inhalation in chronic upper respiratory tract infections in elderly and young patients

Background

Chronic upper respiratory tract infections (cURTI) are very frequent illnesses which occur at any age of life. In elderly, cURTI are complicated by immunosenescence, with involvement of lung immune responsiveness.

Results

In the present study, 51 elderly (age range: 66–86) and 51 young (age range 24–58) cURTI patients underwent a single cycle (two weeks) of inhalatory therapy with salt-bromide-iodine thermal water in the thermal station “Margherita di Savoia” (Margherita di Savoia, BAT, Italy). Peripheral blood serum cytokines and clinical assessment were performed before therapy (T0) and after six months (T1) and 12 months (T2) from inhalatory treatment. In both elderly and young patients, at baseline an increased release of T helper (h)1-related cytokines [interleukin (IL)-2 and interferon-γ] and of Th2-related cytokine (IL-4) was documented. Inhalatory treatment reduced the excessive secretion of all the above-cited cytokines. IL-10 values were above normality at all times considered in both groups of patients. In addition, an increase in IL-17 and IL-21 serum levels following therapy was observed in both groups of patients. Pro-inflammatory cytokine (IL-1β, IL-6, IL-8 and tumor necrosis factor-α) baseline values were lower than normal values at T0 in both elderly and young cURTI patients. Their levels increased following inhalatory treatment.

Clinically, at T2 a dramatic reduction of frequency of upper respiratory tract infections was recorded in both groups of patients.

Conclusion

Thermal water inhalation is able to modulate systemic immune response in elderly and young cURTI patients, thus reducing excessive production of Th1 and Th2-related cytokines, on the one hand. On the other hand, increased levels of IL-21 (an inducer of Th17 cells) and of IL-17 may be interpreted as a protective mechanism, which likely leads to neutrophil recruitment in cURTI patients. Also restoration of pro-inflammatory cytokine release following inhalatory therapy may result in microbe eradication. Quite importantly, the maintenance of high levels of IL-10 during the follow-up would suggest a consistent regulatory role of this cytokine in attenuating the pro-inflammatory arm of the immune response.

Systemic signs of neutrophil mobilization during clinically stable periods and during exacerbations in smokers with obstructive pulmonary disease

BACKGROUND

It is still unclear whether signs of neutrophil mobilization in the blood of patients with chronic obstructive pulmonary disease represent true systemic events and how these relate to bacterial colonization in the airways. In this study, we evaluated these issues during clinically stable periods and during exacerbations in smokers with obstructive pulmonary disease and chronic bronchitis (OPD-CB).

METHODS

Over a period of 60 weeks for each subject, blood samples were repeatedly collected from 60 smokers with OPD-CB during clinically stable periods, as well as during and after exacerbations. Myeloperoxidase (MPO) and neutrophil elastase (NE) protein and mRNA, growth of bacteria in sputum, and clinical parameters were analyzed. Ten asymptomatic smokers and ten never-smokers were included as controls.

RESULTS

We found that, during clinically stable periods, neutrophil and NE protein concentrations were increased in smokers with OPD-CB and in the asymptomatic smokers when compared with never-smokers. During exacerbations, neutrophil and MPO protein concentrations were further increased in smokers with OPD-CB, without a detectable increase in the corresponding mRNA during exacerbations. However, MPO and NE protein and mRNA displayed positive correlations. During exacerbations, only increased neutrophil concentrations were associated with growth of bacteria in sputum. Among patients with low transcutaneous oxygen saturation during exacerbations, PaO2 (partial oxygen pressure) correlated with concentrations of MPO and NE protein and neutrophils in a negative manner.

CONCLUSION

There are signs of systemic neutrophil mobilization during clinically stable periods and even more so during exacerbations in chronic obstructive pulmonary disease. In this condition, MPO and NE may share a cellular origin, but its location remains uncertain. Factors other than local bacteria, including hypoxemia, may be important for driving systemic signs of neutrophil mobilization.