TLR/WNT: A Novel Relationship in Immunomodulation of Lung Cancer.

The most frequent cause of death by cancer worldwide is lung cancer, and the 5-year survival rate is still very poor for patients with advanced stage. Understanding the crosstalk between the signaling pathways that are involved in disease, especially in metastasis, is crucial to developing new targeted therapies. Toll-like receptors (TLRs) are master regulators of the immune responses, and their dysregulation in lung cancer is linked to immune escape and promotes tumor malignancy by facilitating angiogenesis and proliferation. On the other hand, over-activation of the WNT signaling pathway has been reported in lung cancer and is also associated with tumor metastasis via induction of Epithelial-to-mesenchymal-transition (EMT)-like processes. An interaction between both TLRs and the WNT pathway was discovered recently as it was found that the TLR pathway can be activated by WNT ligands in the tumor microenvironment; however, the implications of such interactions in the context of lung cancer have not been discussed yet. Here, we offer an overview of the interaction of TLR-WNT in the lung and its potential implications and role in the oncogenic process.

Hsa-Mir-320c, Hsa-Mir-200c-3p, and Hsa-Mir-449c-5p as Potential Specific miRNA Biomarkers of COPD: A Pilot Study.

Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory disease commonly induced by cigarette smoke. The expression of miRNAs can be altered in patients with COPD and could be used as a biomarker. We aimed to identify a panel of miRNAs in bronchoalveolar lavage (BAL) to differentiate COPD patients from smokers and non-smokers with normal lung function. Accordingly, forty-five subjects classified as COPD, smokers, and non-smokers (n = 15 per group) underwent clinical, functional characterization and bronchoscopy with BAL. The mean age of the studied population was 61.61 ± 12.95 years, BMI 25.72 ± 3.82 Kg/m2, FEV1/FVC 68.37 ± 12.00%, and FEV1 80.07 ± 23.63% predicted. According to microarray analysis, three miRNAs of the most upregulated were chosen: miR-320c, miR-200c-3p, and miR-449c-5p. These miRNAs were validated by qPCR and were shown to be differently expressed in COPD patients. ROC analysis showed that these three miRNAs together had an area under the curve of 0.89 in differentiating COPD from controls. Moreover, in silico analysis of candidate miRNAs by DIANA-miRPath showed potential involvement in the EGFR and Hippo pathways. These results suggest a specific 3-miRNA signature that could be potentially used as a biomarker to distinguish COPD patients from smokers and non-smoker subjects.

Usefulness of Bronchoscopic Probe-Based Confocal Laser Endomicroscopy in the Diagnosis of Pneumocystis jirovecii Pneumonia.

BACKGROUND: Probe-based confocal laser endomicroscopy (pCLE) is a novel technique that provides in vivo microscopic imaging of the distal lung. We hypothesized that the intra-alveolar exudates characterizing Pneumocystis jirovecii pneumonia (PJP) can be identified by pCLE in vivo and help in its diagnosis. OBJECTIVES: We aimed to assess the usefulness of pCLE for the in vivo diagnosis of PJP. METHODS: Thirty-two human immunodeficiency virus (HIV)-positive patients with new pulmonary infiltrates and fever were studied using pCLE. Real-time alveolar images were recorded during the bronchoscopy for off-line analysis by two independent observers. Bronchoalveolar lavage samples were also obtained and processed for microbiology and cytological evaluation, including Grocott stain for P. jirovecii. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of pCLE for the diagnosis of PJP in these patients were calculated. RESULTS: Fourteen patients (44%) were confirmed to have PJP by cultures/staining. pCLE was well tolerated in all patients. It identified intra-alveolar exudates in 13 of them (41%), where 11 of them (85%) had positive Grocott stain for P. jirovecci, with 93% concordance between observers. Sensitivity, specificity, PPV and NPV of pCLE for the diagnosis of PJP were 79, 89, 85 and 84%, respectively. In smokers, these figures improved to be 92, 88, 85 and 94%. CONCLUSIONS: pCLE is a quick and safe procedure for on-site diagnosis of PJP in HIV+ patients with excellent specificity and sensitivity mainly in smokers.

Risk of postoperative complications in chronic obstructive lung diseases patients considered fit for lung cancer surgery: beyond oxygen consumption.

OBJECTIVES: Patients with poor lung function usually undergo cardiopulmonary exercise testing (CPET) and those with a predicted postoperative maximal oxygen consumption (VO2 max) of >10 ml/kg/min undergo lung resection surgery and still some complications are observed. We aimed to determine other parameters beyond VO2 able to predict postoperative complications in patients undergoing lung resection surgery. METHODS: This is an observational study with longitudinal follow-up. Patients with forced expiratory volume in 1 second (FEV1) or diffusing capacity for carbon monoxide of <40% underwent CPET and those with VO2 max of >10 ml/kg/min were considered fit for surgery. Patients were followed up prospectively for 12 months and postoperative complications and survival were recorded. Physiological parameters obtained during CPET and pulmonary function tests were analysed. RESULTS: Eighty-three chronic obstructive pulmonary disease (COPD) patients were evaluated for surgery between 2010 and 2015. Twenty-four patients were considered unfit for surgery and received an alternative therapy. Fifty-five patients had a VO2 max of >10 ml/kg/min and underwent lung surgery. Among them, 4% died and 41% developed complications postoperatively. Baseline minute ventilation to carbon dioxide output (VE/VCO2) slope was significantly higher among those who developed postoperative complications or died (P = 0.047). Furthermore, VE/VCO2 slope of >35 (at maximal exercise) was the single parameter most strongly associated with the probability of mortality and postoperative complications (hazard ratio 5.14) with a survival probability of 40% after 1 year of follow-up. In a multivariable model, VO2, VE/VCO2 slope of >35 and work load were independently associated with the probability of having an event. CONCLUSIONS: VO2 is not the unique parameter to consider when CPET is performed to evaluate the postoperative risk of lung cancer surgery in COPD patients. The signs of ventilatory inefficiency such as VE/VCO2 slope predict complications better than VO2 does.

Lack of Correlation Between Pulmonary and Systemic Inflammation Markers in Patients with Chronic Obstructive Pulmonary Disease: A Simultaneous, Two-Compartmental Analysis. / Ausencia de correlación entre marcadores de inflamación pulmonar y sistémica en pacientes con enfermedad pulmonar obstructiva crónica: un análisis bi-compartimental simultáneo.

INTRODUCTION: The origin of systemic inflammation in chronic obstructive pulmonary disease (COPD) patients remains to be defined, but one of the most widely accepted hypothesis is the 'spill over' of inflammatory mediators from the lung to the circulation. OBJECTIVE: To evaluate the relationship between pulmonary and systemic inflammation in COPD quantifying several inflammatory markers in sputum and serum determined simultaneously. METHODOLOGY: Correlations between various inflammatory variables (TNF-α, IL6, IL8) in sputum and serum were evaluated in 133 patients from the PAC-COPD cohort study. A secondary objective was the evaluation of relationships between inflammatory variables and lung function. RESULTS: Inflammatory markers were clearly higher in sputum than in serum. No significant correlation was found (absolute value, r=0.03-0.24) between inflammatory markers in blood and in sputum. There were no significant associations identified between those markers and lung function variables, such as FEV1, DLCO and PaO2 neither. CONCLUSIONS: We found no correlation between pulmonary and systemic inflammation in patients with stable COPD, suggesting different pathogenic mechanisms.

Prevalence and Perception of 24-Hour Symptom Patterns in Patients With Stable Chronic Obstructive Pulmonary Disease in Spain. / Prevalencia y percepción de la variabilidad diaria de los síntomas en pacientes con enfermedad pulmonar obstructiva crónica estable en España.

INTRODUCTION: Few studies have examined the 24-hour symptom profile in patients with chronic obstructive pulmonary disease (COPD). The main objective of this study was to determine daily variations in the symptoms of patients with stable COPD in Spain, compared with other European countries. METHODS: Observational study conducted in 8 European countries. The results from the Spanish cohort (n=122) are compared with the other European subjects (n=605). We included patients with COPD whose treatment had been unchanged in the previous 3months. Patients completed questionnaires on morning, day-time, and night-time symptoms of COPD, the COPD assessment test (CAT), the hospital anxiety and depression scale (HADS), and the COPD and asthma sleep impact scale (CASIS). RESULTS: Mean age: 69 (standard deviation [SD]=9) years; mean post-bronchodilator FEV1: 50.5 (SD=19.4)% (similar in Spanish and European cohorts). The proportion of men among the Spanish cohort was greater (91.0% versus 60.7%, P<.0001). A total of 52.5% patients experienced some type of symptom throughout the day, compared to 57.5% of the other Europeans, P<.001). Patients with symptoms throughout the day had poorer health-related quality of life (HRQoL) and higher levels of anxiety/depression than patients without symptoms. Patients with night-time symptoms had a poorer quality of sleep. Spanish patients with symptoms throughout the day had higher CAT scores (16.9 versus 20.5 in the other Europeans, P<.05). CONCLUSIONS: Despite receiving treatment, more than half of patients report symptoms throughout the day. These patients have poorer HRQoL and higher levels of anxiety/depression. Among patients with similar lung function, the Spanish cohort was less symptomatic and reported better HRQoL than other Europeans.

Myeloid-Derived Suppressor Cells: Possible Link Between Chronic Obstrucive Pulmonary Disease and Lung Cancer.

Chronic obstructive pulmonary disease (COPD) and lung cancer (LC) are prevalent diseases and are a leading cause of morbidity and mortality worldwide. There is strong evidence to show that COPD is an independent risk factor for LC. Chronic inflammation plays a significant pathogenic role in COPD comorbidities, particularly in LC. On the one hand, cellular and molecular inflammatory mediators promote carcinogenesis and, on the other, chronic inflammation impairs the capacity of the immune system to identify and destroy pre-malignant and malignant cells, a process known as tumor immune surveillance. This altered antitumor immunity is due in part to the expansion of myeloid-derived suppressor cells (MDSC), which are characterized by an ability to suppress the antitumor activity of T-cells by down-regulation of the T-cell receptor ζ chain (TCRζ) through the catabolism of L-arginine. COPD and LC patients share a common pattern of expansion and activation of circulating MDSC associated with TCRζ downregulation and impaired peripheral T-cell function. The objectives of this study were to review the evidence on the association between COPD and LC and to analyze how MDSC accumulation may alter tumor immune surveillance in COPD, and therefore, promote LC development.

Expansion of myeloid-derived suppressor cells in chronic obstructive pulmonary disease and lung cancer: potential link between inflammation and cancer.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is a risk factor for lung cancer (LC). Myeloid-derived suppressor cells (MDSCs) down-regulate the T cell receptor ζ chain (TCR ζ) through L-arginine deprivation and lead to T cell dysfunction and deficient antitumor immunity. We hypothesized that abnormally high levels of MDSCs in COPD patients may alter tumor immunosurveillance. METHODS: We compared the proportion of circulating MDSCs (Lin-HLA-DR-/CD33+/CD11b+) (by flow cytometry), arginase I (ARG I) serum levels (by ELISA), and expression levels of TCR ζ on circulating lymphocytes (by flow cytometry) in 28 patients with LC, 62 subjects with COPD, 41 patients with both LC and COPD, 40 smokers with normal spirometry and 33 non-smoking controls. T cell proliferation assays were performed in a subgroup of participants (CFSE dilution protocol). RESULTS: We found that: (1) circulating MDSCs were up-regulated in COPD and LC patients (with and without COPD); (2) MDSCs expansion was associated with TCR ζ down-regulation in the three groups; (3) in LC patients, these findings were independent of COPD and tobacco smoking exposure; (4) TCR ζ down-regulation correlates with T cell hyporesponsiveness in COPD and LC patients. CONCLUSIONS: These results suggest that tumor immunosurveillance might be impaired in COPD and may contribute to the increased risk of LC reported in these patients.

B Cell-Activating Factor. An Orchestrator of Lymphoid Follicles in Severe Chronic Obstructive Pulmonary Disease.

RATIONALE: Patients with chronic obstructive pulmonary disease (COPD) have increased pulmonary lymphoid follicle (LF) counts. B cell-activating factor of tumor necrosis factor family (BAFF) regulates B cells in health, but its role in COPD pathogenesis is unclear. OBJECTIVES: To determine whether BAFF expression in pulmonary LFs correlates with COPD severity, LF size or number, and/or readouts of B-cell function in LFs. METHODS: We correlated BAFF immunostaining in LFs in lung explants or biopsies from nonsmoking control subjects (NSC), smokers without COPD (SC), and patients with COPD with the number and size of LFs, and LF B-cell apoptosis, activation, and proliferation. We analyzed serum BAFF levels and BAFF expression in B cells in blood and bronchoalveolar lavage samples from the same subject groups. We assessed whether: (1) cigarette smoke extract (CSE) increases B-cell BAFF expression and (2) recombinant BAFF (rBAFF) rescues B cells from CSE-induced apoptosis by inhibiting activation of nuclear factor-κB (NF-κB). MEASUREMENTS AND MAIN RESULTS: Patients with Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage IV COPD had increased numbers and larger pulmonary LFs than patients with GOLD stages I-II COPD and SC. We identified two main types of pulmonary LFs: (1) type A, the predominant type in GOLD stages I-II COPD and SC, characterized by abundant apoptotic but few BAFF-positive cells (mostly B cells); and (2) type B, the main type in GOLD stage IV COPD, characterized by abundant BAFF-positive cells but few apoptotic cells (mostly B cells). BAFF levels were also higher in blood and bronchoalveolar lavage B cells in patients with COPD versus NSC and SC. Surprisingly, rBAFF blocked CSE-induced B-cell apoptosis by inhibiting CSE-induced NF-κB activation. CONCLUSIONS: Our data support the hypothesis that B-cell BAFF expression creates a self-perpetuating loop contributing to COPD progression by promoting pulmonary B-cell survival and LF expansion.

Constrictive Pericarditis: Etiologic Spectrum, Patterns of Clinical Presentation, Prognostic Factors, and Long-term Follow-up.

INTRODUCTION AND OBJECTIVES: Some reports have described a change in the etiologic spectrum of constrictive pericarditis. In addition, data on the relationship between its clinical presentation and etiology are lacking. We sought to describe the etiologies of the disease, their relationship with its clinical presentation and surgical findings, and to identify predictors of poor outcome. METHODS: We analyzed 140 consecutive patients who underwent surgery for constrictive pericarditis over a 34-year period in a single center. RESULTS: The etiology was idiopathic in 76 patients (54%), acute idiopathic pericarditis in 24 patients (17%), tuberculous pericarditis in 15 patients (11%), purulent pericarditis in 10 patients (7%), and cardiac surgery, radiation and uremia in 5, 3 and 2 patients respectively (4%, 2% and 1%). Mean duration of symptoms before pericardiectomy was 19 months (standard deviation, 44 months), the most acute presentation being for purulent pericarditis (26 days [range, 7-60 days]) and the most chronic for idiopathic cases (29 months [range, 4 days-360 months]). Perioperative mortality was 11%. There was no difference in mortality between etiologies. Median follow-up was 12 years (range, 0.1-33.0 years) in which 50 patients died. In a Cox-regression analysis, age at surgery, advanced New York Heart Association functional class (III to IV) and previous acute idiopathic pericarditis were associated with increased mortality during follow-up. CONCLUSIONS: Most cases of constrictive pericarditis are idiopathic. Cardiac surgery and radiation accounted for a minority of cases. Etiologic investigations are warranted only in acute or subacute presentations. Age, advanced functional class, and previous acute idiopathic pericarditis are associated with increased mortality.

Characterisation and prognosis of undiagnosed chronic obstructive pulmonary disease patients at their first hospitalisation.

BACKGROUND: Under-diagnosis of COPD is an important unmet medical need. We investigated the characteristics and prognosis of hospitalised patients with undiagnosed COPD. METHODS: The PAC-COPD cohort included 342 COPD patients hospitalised for the first time for an exacerbation of COPD (2004-2006). Patients were extensively characterised using sociodemographic, clinical and functional variables, and the cohort was followed-up through 2008. We defined "undiagnosed COPD" by the absence of any self-reported respiratory disease and regular use of any pharmacological respiratory treatment. RESULTS: Undiagnosed COPD was present in 34% of patients. They were younger (mean age 66 vs. 68 years, p = 0.03), reported fewer symptoms (mMRC dyspnoea score, 2.1 vs. 2.6, p < 0.01), and had a better health status (SGRQ total score, 29 vs. 40, p < 0.01), milder airflow limitation (FEV1% ref., 59% vs. 49%, p < 0.01), and fewer comorbidities (two or more, 40% vs. 56%, p < 0.01) when compared with patients with an established COPD diagnosis. Three months after hospital discharge, 16% of the undiagnosed COPD patients had stopped smoking (vs. 5%, p = 0.019). During follow-up, annual hospitalisation rates were lower in undiagnosed COPD patients (0.14 vs. 0.25, p < 0.01); however, this difference disappeared after adjustment for severity. Mortality was similar in both groups. CONCLUSIONS: Undiagnosed COPD patients have less severe disease and lower risk of re-hospitalisation when compared with hospitalised patients with known COPD.

Determinants of false-negative results in non-small-cell lung cancer staging by endobronchial ultrasound-guided needle aspiration.

OBJECTIVES: False-negative results of endobronchial ultrasound-guided transbronchial needle aspiration in non-small-cell lung cancer staging have shown significant variability in previous studies. The aim of this study was to identify procedure- and tumour-related determinants of endobronchial ultrasound-guided transbronchial needle aspiration false-negative results. METHODS: We conducted a prospective study that included non-small-cell lung cancer patients staged as N0/N1 by endobronchial ultrasound-guided transbronchial needle aspiration and undergoing therapeutic surgery. The frequency of false-negative results in the mediastinum was calculated. Procedure-related, first, and tumour-related, second, determinants of false-negative results in stations reachable and non-reachable by endobronchial ultrasound were determined by multivariate logistic regression. RESULTS: False-negative endobronchial ultrasound-guided transbronchial needle aspiration results were identified in 23 of 165 enrolled patients (13.9%), mainly in stations reachable by endobronchial ultrasound (17 cases, 10.3%). False-negative results were related to the extensiveness of endobronchial ultrasound sampling: their prevalence was low (2.4%) when sampling of three mediastinal stations was satisfactory, but rose above 10% when this requirement was not fulfilled (P = 0.043). In the multivariate analysis, abnormal mediastinum on computer tomography/positron emission tomography [odds ratio (OR) 7.77, 95% confidence interval (CI) 2.19-27.51, P = 0.001] and extensiveness of satisfactory sampling of mediastinal stations (OR 0.37, 95% CI 0.16-0.89, P = 0.026) were statistically significant risk factors for false-negative results in stations reachable by endobronchial ultrasound. False-negative results in non-reachable nodes were associated with a left-sided location of the tumour (OR 10.11, 95% CI 1.17-87.52, P = 0.036). CONCLUSIONS: The presence of false-negative ultrasound-guided transbronchial needle aspiration results were observed in nearly 15% of non-small-cell lung cancer patients but in only 3% when satisfactory samples were obtained from three mediastinal stations. False-negative results in stations reachable by endobronchial ultrasound were associated with the extensiveness of sampling, and in stations out of reach of endobronchial ultrasound with left-sided tumours. These results suggest that satisfactory sampling of at least three mediastinal stations by EBUS-TBNA may be a quality criterion to be recommended for EBUS-TBNA staging.

Probe-based confocal laser endomicroscopy imaging of endobronchial hamartomas.

Probe-based confocal laser endomicroscopy (pCLE) is a new technique that can microscopically image the airways in vivo during ordinary flexible bronchoscope procedures. pCLE can visualize the basement membrane of the bronchial epithelium, allowing the study of the different changes in benign or malignant/premalignant bronchial lesions. We present 2 cases of pathology-proven endobronchial hamartoma diagnosed by biopsy which show characteristic images under pCLE examination. The tumor was removed in both cases by rigid bronchoscopy using a diathermy loop and a cryoprobe.

Air pollution and biomarkers of systemic inflammation and tissue repair in COPD patients.

The origin(s) of systemic inflammation in patients with chronic obstructive pulmonary disease (COPD) is unclear. We investigated the impact of exposure to ambient air pollution on systemic biomarkers of inflammation (C-reactive protein (CRP), tumour necrosis factor-α, interleukin (IL)-6, IL-8 and fibrinogen) and tissue repair (hepatocyte growth factor (HGF)) in 242 clinically stable COPD patients (mean age 67.8 years and forced expiratory volume in 1 s 71.3% predicted) in Barcelona, Spain, in 2004-2006. A spatiotemporal exposure assessment framework was applied to predict ambient nitrogen dioxide (NO2) and levels of particles with a 50% cut-off aerodynamic diameter of 2.5 µm (PM2.5) at each participant's home address during 10 periods of 24 h (lags 1-10) and 1 year prior to the blood sampling date. We used linear regression models to estimate associations between biomarkers and exposure levels. An interquartile range (IQR) increase in NO2 exposure in lag 5 was associated with 51%, 10% and 9% increases in CRP, fibrinogen and HGF levels respectively. We also observed 12% and 8% increases in IL-8 associated with an IQR increase in NO2 exposure in lag 3 and over the year before sampling, respectively. These increases were larger in former smokers. The results for PM2.5 were not conclusive. These results show that exposure to ambient NO2 increases systemic inflammation in COPD patients, especially in former smokers.

Real-time prediction of mediastinal lymph node malignancy by endobronchial ultrasound.

OBJECTIVE: To evaluate the utility of different ultrasonographic (US) features in differentiating benign and malignant lymph node (LN) by endobronchial ultrasound (EBUS) and validate a score for real-time clinical application. METHODS: 208 mediastinal LN acquired from 141 patients were analyzed. Six different US criteria were evaluated (short axis ≥10 mm, shape, margin, echogenicity, and central hilar structure [CHS], and presence of hyperechoic density) by two observers independently. A simplified score was generated where the presence of margin distinction, round shape and short axis ≥10 mm were scored as 1 and heterogeneous echogenicity and absence of CHS were scored as 1.5. The score was evaluated prospectively for real-time clinical application in 65 LN during EBUS procedure in 39 patients undertaken by two experienced operators. These criteria were correlated with the histopathological results and the sensitivity, specificity, positive and negative predictive values (PPV and NPV) were calculated. RESULTS: Both heterogenicity and absence of CHS had the highest sensitivity and NPV (≥90%) for predicting LN malignancy with acceptable inter-observer agreement (92% and 87% respectively). On real-time application, the sensitivity and specificity of the score >5 were 78% and 86% respectively; only the absence of CHS, round shape and size of LN were significantly associated with malignant LN. CONCLUSIONS: Combination of different US criteria can be useful for prediction of mediastinal LN malignancy and valid for real-time clinical application.

Structure-function relationship in COPD revisited: an in vivo microscopy view.

BACKGROUND: Fibred confocal fluorescence microscopy (FCFM) is a novel technology that allows the in vivo assessment and quantification during bronchoscopy of the bronchial wall elastic fibre pattern, alveolar and vessel diameters and thickness of the elastic fibre in the alveolar wall. AIMS: To relate these structural characteristics with lung function parameters in healthy subjects, smokers with normal spirometry and patients with chronic obstructive pulmonary disease (COPD). METHODS: We performed FCFM in 20 never smokers, 20 smokers with normal spirometry and 23 patients with COPD who required bronchoscopy for clinical reasons. The bronchial wall elastic fibre pattern was classified as lamellar, loose and mixed pattern, and later confirmed pathologically. Airspace dimensions and extra-alveolar vessel diameters were measured. Lung function measurements and pulmonary CT scans were obtained in all participants. RESULTS: Patients with COPD were characterised by a significantly higher prevalence of loose fibre bronchial deposition pattern and larger alveolar diameter which correlated inversely with several lung function parameters (forced expiratory volume in 1 s (FEV1) , FEV1/forced vital capacity ratio, maximum expiratory flow, carbon monoxide transfer factor and carbon monoxide transfer coefficient; p<0.05). Increased alveolar macrophages were demonstrated in active smokers with or without COPD. CONCLUSIONS: This is the first FCFM study to describe in vivo microscopic changes in the airways and alveoli of patients with COPD that are related to lung function impairment. These findings open the possibility of assessing the in vivo effects of therapeutic interventions for COPD in future studies.

Differential effects of smoking and COPD upon circulating myeloid derived suppressor cells.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is characterized by an enhanced and persistent innate and acquired immune response to tobacco smoking. Myeloid-derived suppressor cells (MDSCs) modulate T-cell responses by down-modulating the T cell receptor ζ chain (TCR ζ) through the catabolism of l-arginine. The effects of smoking on MDSCs and their potential participation in COPD immunopathogenesis have not been explored so far. METHODS: To investigate it, we compared the level of circulating Lineage-/HLA-DR-/CD33+/CD11b+ MDSCs, the serum concentration of arginase I (ARG I) and the expression of peripheral T-cell receptor ζ chain (TCR ζ) in never smokers, smokers with normal spirometry and COPD patients. Flow cytometry was used to quantify circulating MDSCs and TCR ζ expression. Serum ARG I levels were determined by ELISA. RESULTS: The main findings of this study were that: (1) current smoking upregulates and activates circulating MDSCs both in smoker controls and COPD patients; and, (2) at variance with the smokers with normal spirometry, in patients with COPD this effect persists after quitting smoking and is accompanied by a significant and specific down-regulation of the TCR ζ chain expression in circulating T lymphocytes. CONCLUSION: Smoking modulates circulating MDSCs. Their regulation appears altered in patients with COPD.

Effect of bronchial colonisation on airway and systemic inflammation in stable COPD.

The recovery of potentially pathogenic microorganisms (PPMs) from bronchial secretions is associated with a local inflammatory response in COPD patients. The objective of this study was to determine the relationships between bronchial colonisation and both bronchial and systemic inflammation in stable COPD. In COPD patients recruited on first admission for an exacerbation, bacterial sputum cultures, interleukin (IL)-1ß, IL-6 and IL-8 levels, and blood C-reactive protein (CRP) were measured in stable condition. Bronchial colonisation was found in 39 of the 133 (29%) patients and was significantly related to higher sputum IL-1ß (median [percentile 25-75]; 462 [121-993] vs. 154 [41-477] pg/ml, p = 0.002), IL-6 (147 [71-424] vs. 109 [50-197] pg/ml, p = 0.047) and IL-8 values (15 [9-19] vs. 8 [3-15] (×10³) pg/ml, p = 0.002). Patients with positive cultures also showed significantly elevated levels of serum CRP (6.5 [2.5-8.5] vs. 3.5 [1.7-5.4] mg/l, p = 0.016). Bronchial colonisation by Haemophilus influenzae was associated with higher levels of IL-1ß and IL-8 and clinically significant worse scores on the activity and impact domains of the St. George's Respiratory Questionnaire. In conclusion, bronchial colonisation is associated with bronchial inflammation and high blood CRP levels in stable COPD patients, being Haemophilus influenzae related to a more severe inflammatory response and impairment in health-related quality of life.