[Asthma: a complex disease determined by genetic and environmental factors]

Asthma is a complex disease highly dependent of environmental exposure and genetic background. Through linkage analysis, positional cloning and genome wide association studies, novel asthma genes have come out such as ADAM-33 or ORMLD3. Important environmental factors include allergenic exposure, pollutants and especially particulate matters, tobacco, aerosol exposure, viral infections and level of exposure to endotoxin. The effects of environmental factors are modulated by the genetic sequence and numerous single nucleotide polymorphisms (SNPs). Recently, it has also become clear that environmental factors may alter gene expression by DNA methylation or histone methylation/acetylation without changing the gene sequence and thereby changing asthmatic phenotype.

[COPD: genetics and environmental interactions]

Smoking is the main environmental risk factor of COPD and accounts for 85% to 90% of COPD. However, 10-15% of COPD patients have never smoked and only a fraction of smokers ever develop COPD. Indeed, genetic and environmental (pollution, occupational and infectious) factors, also influence the risk of developing COPD. Finaly COPD must be considered as the clinical consequence of multiple complex interactions between environmental factors and genetic susceptibility. The latter is not clearly understood, with the exception of alpha-1 antitrypsin deficiency. In this article, we present the different aspects of this complex disease which is primarily environmental.

2B4 (CD244) is involved in eosinophil adhesion and chemotaxis, and its surface expression is increased in allergic rhinitis after challenge

A role for the subtypes of CD2 Ig superfamily receptors has been recently demonstrated in eosinophilic inflammation in experimental asthma and atopic asthmatics. We investigated the functions of 2B4 (CD244) molecules in eosinophil adhesion and chemotaxis, and correlated the results to the pathophysiology of allergic rhinitis (AR). Herein, we show that agonistic stimulation of 2B4 by C1.7, the anti-human 2B4 functional grade purified antibody, resulted in significant increase of eosinophils and eosinophil cell line (Eol-1 cells) adhesion to collagen type IV, and random migration. These functions were associated with tyrosine kinase phosphorylation of several protein residues of low molecular weight. Flow cytometry (FACS) experiments demonstrated that Eol-1 cells, normal peripheral blood eosinophils and eosinophils from AR patients, express surface 2B4 molecules. In vitro AR model demonstrated that the CC-chemokine receptor CCR3 stimulation by eotaxin induced significant increase in the expression of surface 2B4 in eosinophils and Eol-1 cells. Immunofluorescence confocal microscopy images showed that eotaxin induces also redistribution of 2B4 molecules towards the pseudopods in eosinophils and Eol-1 cells, changing their shape. Blocking of 2B4 molecules by the corresponding neutralizing antibody inhibited eotaxin induced Eol-1-adhesion, chemotaxis and the cytoskeleton changes. Pretreatment of Eol-1 cells with 1 microM genistein blocked eotaxin-induced Eol-1 adhesion, chemotaxis and 2B4 up-regulated expression. In vivo correlation demonstrated the expression of 2B4 molecules in eosinophils from AR patients to be significantly increased, after nasal provocation challenge. These results identify a novel role for 2B4 molecules in eosinophil functional migratory response and may point to a novel tyrosine kinase-mediated ligation between CCR3 receptor and 2B4 co-receptor in eosinophil chemotaxis. If so, then 2B4 molecules would be a novel target for therapeutic modalities in diseases characterized by eosinophilia such as AR.

Is FENO50 useful diagnostic tool in suspected asthma?

BACKGROUND

Asthma diagnosis is based on the presence of symptoms and the demonstration of airflow variability. Airway inflammation measured by fractional exhaled nitric oxide, measured at a flow rate of 50 ml/s (FE(NO50)) remains a controversial diagnostic tool.

AIM

To assess the ability of FE(NO50) to identify bronchial hyperresponsiveness (BHR) to methacholine (provocative concentration of methacholine causing a 20% fall in FEV(1); PC20M ≤ 16 mg/ml) and to establish whether or not symptoms relate to FE(NO50) and PC20M in patients with no demonstrated reversibility to β(2) -agonist.

METHODS

We conducted a prospective study on 174 steroid naive patients with respiratory symptoms, forced expiratory volume in 1 s (FEV(1) ) ≥ 70% predicted and no demonstrated reversibility to β(2) -agonist. Patients answered to a standardised symptom questionnaire and underwent FE(NO50) and methacholine challenge. Receiver-operating characteristic (ROC) curve and logistic regression analysis assessed the relationship between PC20M and FE(NO50) , taking into account covariates (smoking, atopy, age, gender and FEV(1)).

RESULTS

A total of 82 patients had a PC20M ≤ 16 mg/ml and had significantly higher FE(NO50) (19 ppb vs. 15 ppb; p < 0.05). By constructing ROC curve, we found that FE(NO50) cut-off value of 34 ppb was able to identify not only BHR with high specificity (95%) and positive predictive value (88%) but low sensitivity (35%) and negative predictive value (62%). When combining all variables into the logistic model, FE(NO50) (p = 0.0011) and FEV(1) (p < 0.0001) were independent predictors of BHR whereas age, gender, smoking and atopy had no influence. The presence of diurnal and nocturnal wheezing was associated with raised FE(NO50) (p < 0.001 and p < 0.05, respectively).

CONCLUSION

The value of FE(NO50) > 34 ppb has high predictive value of PC20M < 16 in patients with suspected asthma in whom bronchodilating test failed to demonstrate reversibility or was not indicated. However, FE(NO50) ≤ 34 ppb does not rule out BHR and should prompt the clinician to ask for a methacholine challenge.

Beyond corticosteroids: future prospects in the management of inflammation in COPD

Inflammation plays a central role in the pathophysiology of chronic obstructive pulmonary disease (COPD). Exposure to cigarette smoke induces the recruitment of inflammatory cells in the airways and stimulates innate and adaptive immune mechanisms. Airway inflammation is involved in increased bronchial wall thickness, increased bronchial smooth muscle tone, mucus hypersecretion and loss of parenchymal elastic structures. Oxidative stress impairs tissue integrity, accelerates lung ageing and reduces the efficacy of corticosteroids by decreasing levels of histone deacetylase-2. Protease-antiprotease imbalance impairs tissues and is involved in inflammatory processes. Inflammation is also present in the pulmonary artery wall and at the systemic level in COPD patients, and may be involved in COPD-associated comorbidities. Proximal airways inflammation contributes to symptoms of chronic bronchitis while distal and parenchymal inflammation relates to airflow obstruction, emphysema and hyperinflation. Basal levels of airways and systemic inflammation are increased in frequent exacerbators. Inhaled corticosteroids are much less effective in COPD than in asthma, which relates to the intrinsically poor reversibility of COPD-related airflow obstruction and to molecular mechanisms of resistance relating to oxidative stress. Ongoing research aims at developing new drugs targeting more intimately COPD-specific mechanisms of inflammation, hypersecretion and tissue destruction and repair. Among new anti-inflammatory agents, phosphodiesterase-4 inhibitors have been the first to emerge.

[Targeted asthma therapies: confirmations, hopes, and disappointments]

Asthma is a chronic inflammatory disease of the airways. The inflammatory process is driven by different pathways involving cytokines and other protein mediators. Patients with severe asthma are at high risk of severe exacerbations and death and have few therapeutic options available. Therefore, biological agents have been developed to help patients with refractory asthma by interfering with several compounds of the asthma inflammatory cascade. In addition to decreasing exacerbations, some of those treatments have a steroid sparing role and many beneficial effects in asthmatics.

Disturbed cytokine production at the systemic level in difficult-to-control atopic asthma: evidence for raised interleukin-4 and decreased interferon-γ release following lipopolysaccharide stimulation

BACKGROUND

Disturbed cytokine production is thought to govern inflammation in asthma, which, in its turn, may lead to uncontrolled disease. The aim of this study was to assess the relationship between cytokine production from blood leucocytes and the level of asthma control.

METHODS

We compared the production of interleukin (IL)-4, IL-6, IL-10, interferon (IFN)-γ and tumour necrosis factor-α from peripheral blood leucocytes in non-atopic healthy subjects (n = 22), atopic non-asthmatics (n = 10), well-controlled asthmatics [Juniper asthma control questionnaire (ACQ) score <1.5; n = 20] and patients with uncontrolled asthma despite inhaled or oral corticoids (ACQ score ≥1.5; n = 20). Fifty microlitres of peripheral blood was incubated for 24 h with RPMIc, lipopolysaccharide (LPS; 1 ng/ml) or phytohaemagglutinin (1 μg/ml), and cytokines were measured by immunotrapping (ELISA).

RESULTS

Both controlled and uncontrolled asthmatics as well as atopic non-asthmatics spontaneously produced more IL-4 than non-atopic healthy subjects (p < 0.001). IL-4 production induced by LPS was significantly greater (p < 0.05) in both asthma groups compared to atopic non-asthmatics and non-atopic healthy subjects. By contrast, IFN-γ release induced by LPS was lower in uncontrolled asthmatics than in non-atopic healthy subjects (p < 0.05) and controlled asthmatics (p < 0.05). IL-10 release after LPS was greater in uncontrolled asthmatics than in atopic non-asthmatics (p < 0.05). No difference was observed regarding other cytokines.

CONCLUSION

Blood cells from patients with difficult-to-control atopic asthma display highly skewed Th2 cytokine release following LPS stimulation.

[Medication of the month. Indacaterol (Onbrez Breezhaler) and chronic obstructive pulmonary disease]

Indacaterol is a novel ultra long-acting beta 2-agonist (ultra-LABA), given once-daily, developed for the treatment of Chronic Obstructive Pulmonary Disease (COPD). The clinical studies suggest that indacaterol produces a rapid (within 5 minutes) and sustained bronchodilation (at least 24 hours) in patients with COPD. It improves also several important parameters as lung function, the quality of life, symptoms, exercise capacity, resting and dynamic hyperinflation, and exacerbations, while being well tolerated. These outcomes justify its use in moderate to very severe COPD patients. This review will give a brief summary of recent clinical data on the indacaterol, its comparison with other pharmacological agents used in the treatment of COPD, and also some information about its use in routine.

[Diagnosis of dyspnea]

Dyspnea is an extremely common symptom in medicine and in cardio-pulmonary medicine in particular. In most of the cases dyspnea reflects an unbalance between the ventilatory demand and the possibility of the thoracic and lung mechanics. Through to a simple clinical case describing an early stage of lung fibrosis we review the main causes and the differential diagnoses of dyspnea, and provide means of grading it through validated assessment scales.

Induced sputum in asthma: from bench to bedside

During recent years there has been a growing interest in using non-invasive biomarkers to understand and monitor the airway inflammation in subjects with respiratory tract disorders and mainly asthma and chronic obstructive pulmonary disease (COPD). Sputum induction is generally a well-tolerated and safe procedure and a European Respiratory Society Task Force has published a comprehensive review on sputum methodology. Induced sputum cell count and, to a lesser extent, mediator measurements have been particularly well validated. In asthma, the sputum and the cell culture supernatant can be used for the measurement of a variety of soluble mediators, including eosinophil-derived proteins, nitric oxide (NO) derivatives, cytokines and remodelling-associated proteins. Sputum eosinophilia (> 3%) is a classic feature of asthma although half of the patients seems to be non eosinophilic. Measuring the percentage of sputum eosinophils has proved to be useful in the clinical arena in helping to predict short term response to inhaled corticosteroids (ICS) and tailor the dose of ICS in the severe patients but there is scope for the application of other induced sputum markers potentially useful in clinical practice. The widespread application of induced sputum in asthma across the spectrum of disease severity has given insight into the relationship between airway function and airway inflammation, proposed new disease phenotypes and defined which of these phenotypes respond to current therapy, and perhaps most importantly provided an additional tool to guide the clinical management of asthmatic patients. To date sputum induction is the only non-invasive measure of airway inflammation that has a clearly proven role in asthma management.

[Lung transplantation benefits for terminal lung diseases]

Lung transplantation is an established treatment of pulmonary diseases at an advanced stage. The purpose of our study is to present the benefits, indications and complications of this surgical procedure in the CHU of Liège. The cohort includes 14 patients transplanted between 2005 and 2009, and who were inserted in a pulmonary rehabilitation programme at the university hospital of Liège. The criteria of assessment are the values of respiratory function tests at rest and exercise, and quality of life. Inherent complications related to this type of surgical operation have been collected. We found a dramatic improvement in pulmonary function tests performed at rest both immediately after the transplantation and after 6 months. Likewise exercise capacity was already increased shortly after the transplantation and further improved 6 months later. As for health related quality of life, parameters that improved the most were dyspnoea and global quality of life, and the improvement was already maximal immediately after the transplantation. Our retrospective study confirms the data of the literature, namely an improvement of respiratory function, effort capacity and quality of life after lung transplantation.

Update on the roles of distal airways in asthma

The present review is the summary of an expert workshop that took place in Vence (France) in 2007 on the role of distal airways in asthma. The evidence showing inflammation and remodelling in distal airways, and their possible involvement in asthma control and natural history, was reviewed. The usefulness and limitations of various techniques used for assessing distal airways were also evaluated, including pulmonary function tests and imaging. Finally, the available data studying the benefit of treatment better targeting distal airways in asthma was examined. It was concluded that both proximal and distal airways were involved in asthma and that distal airways were the major determinant of airflow obstruction. Inflammation in distal airways appeared more intense in severe and uncontrolled asthma. Distal airways were poorly attained by conventional aerosol of asthma medications owing to their granulometry, being composed of 3-5&emsp14;μm particles. Both proximal and distal airways might be targeted either by delivering medications systemically or by aerosol of extra-fine particles. Extra-fine aerosols of long-acting β-agonists, inhaled corticosteroids or inhaled corticosteroid/long-acting β-agonist combinations have been shown in short-term studies to be not inferior to non-extra-fine aerosols of comparators. However, available studies have not yet demonstrated that extra-fine inhaled medications offer increased benefit compared with usual aerosols in asthmatic patients.

[COPD and inflammation: statement from a French expert group. Phenotypes related to inflammation]

INTRODUCTION

The objective of the present article is to review available data on possible links between phenotypes and inflammatory profiles in patients with chronic obstructive pulmonary disease (COPD).

BACKGROUND

Chronic bronchitis is associated with proximal bronchial inflammation and small airway inflammation with remodeling at the site of obstruction. CT scanning enables patients to be phenotyped according to the predominantly bronchial or emphysematous nature of the morphological abnormality. Exacerbations, in a context of persistently elevated baseline inflammation, are associated with increased inflammation and a poor prognosis. Long-term studies have correlated inflammatory markers (and anti-inflammatory drug effects) with dynamic hyperinflation, possibly confirming that inflammation promotes hyperinflation. The inflammatory cell count in the pulmonary arterial walls correlates with the severity of endothelial dysfunction. The risk of developing pulmonary hypertension would seem to increase with low-grade systemic inflammation. The role of low-grade systemic inflammation in COPD co-morbidities, and in nutritional and muscular involvement in particular, remains a matter of debate. Regular physical exercise may help reduce this inflammation.

CONCLUSIONS

In COPD, many aspects of the clinical phenotype are related to inflammation. Better knowledge of these relationships could help optimize current and future treatments.

[Analysis of airway inflammation in asthma: clinical academic interest]

While the importance of airway inflammation in severe asthma was known from the pathologists for more than one century, the demonstration of an airway inflammatory process in mild asthma dates back to the early nineties. With the advent of bronchoscopy making it possible to sample biopsies and bronchoalveolar lavage, it has become clear that mild to moderate asthma was characterized by a Th2 driven airway eosinophilic inflammation where cytokine like IL-4, IL-5 and IL-13 play a critical role. Soon after, were developed the technique of induced sputum and the measurement of exhaled nitric oxide as non invasive tools to assess airway inflammation. The application of these techniques on large samples of subjects has been instrumental to the development of the concept of inflammatory phenotype in asthma which proved to be pertinent in the drug management of the disease. Therefore, within a 20 year laps, the monitoring of airway inflammation, also called inflammometry, has gone beyond the academic world to become crucial for the appropriate management of asthmatics by the clinician.

[COPD and inflammation: statement from a French expert group: inflammation and remodelling mechanisms]

The present study reviews the literature on inflammation and remodelling mechanisms in chronic obstructive pulmonary disease (COPD). The development of COPD is associated with chronic pulmonary inflammation. Immunity (innate or adaptive) plays a role in its onset and continuation. Airways inflammation alters bronchial structure/function relations: increased bronchial wall thickness, increased bronchial smooth muscle tone, seromucosal gland hypersecretion and loss of elastic structures. Circulating markers of pulmonary inflammation indicate its systemic dissemination. Oxidative stress plays a major role in the onset and persistence of tissue abnormalities. The determinants of extra- and intra-cellular redox control are only partially known. Susceptibility genes, antioxidant system insufficiency and reduced levels of anti-age molecules and of histone deacetylation are also involved. The molecular and cellular targets of inflammation and remodelling are numerous and complex. Currently, tools exist to limit inflammation in COPD but not to act on structural remodelling.

[Clinical case of the month. The "classic" triad presentation of mucinous bronchiolo-alveolar carcinoma]

The case of a 59-year-old female complaining of cough of recent onset, abundant salty expectoration and lung condensation is presented. This "triad" constitutes a rare but nearly pathognomonic presentation of mucinous bronchioloalveolar carcinoma (BAC) of the lung.

[Organizing pneumonia: three case reports]

Infiltrative lung lesions are not always linked to infectious processes or cancers. An interesting entity, the OP (Organizing Pneumonia) or COP (Cryptogenic Organizing Pneumonia)--formerly BOOP (Bronchiolitis Obliterans Organizing Pneumonia)--is discussed through observations repor. ted in this article. We provide some keys to allow the astute observer to target this often curable disease.

The impact of concomitant rhinitis on asthma-related quality of life and asthma control

BACKGROUND

Characterizing the interactions between the upper and lower airways is important for the management of asthma. This study aimed at assessing the specific impact of concomitant rhinitis on asthma-related quality of life (QOL) and asthma control.

METHODS

A cross-sectional, observational survey was conducted among 1173 patients with asthma (aged 12-45) recruited by general practitioners and chest physicians. AR was defined by self-reported rhinitis symptoms and previously documented sensitization to inhalant allergens. The primary outcomes were (1) asthma control assessed by the Asthma Control Questionnaire (ACQ) and (2) asthma-specific QOL evaluated through the Mini Asthma Quality of Life Questionnaire (mAQLQ).

RESULTS

AR was present in 73.9% of the population with asthma and nonallergic rhinitis (NAR) in 13.6%. AR and NAR were associated with an increased risk of uncontrolled asthma (i.e. ACQ score > 1.5) with adjusted odds ratios (OR) of 2.00 (95% confidence interval [CI]: 1.35-2.97) and 1.77 (95%CI: 1.09-2.89), respectively. Multivariate linear regression analysis showed that AR and NAR had a modest, although significant, negative impact on the global mAQLQ score (beta coefficient: -0.293, standard error [SE]: 0.063 and beta coefficient: -0.221, SE: 0.080, P < 0.001, respectively), even after adjustment for the level of asthma control and demographic characteristics.

CONCLUSION

This survey provides direct evidence that AR and NAR are associated with an incremental adverse impact on the disease-specific QOL of patients with asthma and the level of asthma control. Further investigations are required to determine whether appropriate treatment of rhinitis would efficiently reduce asthma morbidity.