Macrolides for chronic asthma

Macrolides versus placebo for chronic asthma

BACKGROUND

Asthma is a chronic disease in which inflammation of the airways causes symptomatic wheezing, coughing and difficult breathing. Macrolides are antibiotics with antimicrobial and anti-inflammatory activities that have been explored for the long-term control of asthma symptoms.

OBJECTIVES

To assess the effects of macrolides compared with placebo for managing chronic asthma.

SEARCH METHODS

We searched the Cochrane Airways Group Specialised Register up to March 2021. We also manually searched bibliographies of previously published reviews and conference proceedings and contacted study authors. We included records published in any language in the search.

SELECTION CRITERIA

We included randomised controlled clinical trials (RCTs) involving both children and adults with asthma treated with macrolides versus placebo for four or more weeks. Primary outcomes were exacerbation requiring hospitalisation, severe exacerbations (exacerbations requiring emergency department (ED) visits or systemic steroids, or both), symptom scales, asthma control questionnaire (ACQ, score from 0 totally controlled, to 6 severely uncontrolled), Asthma Quality of Life Questionnaire (AQLQ, with score from 1 to 7 with higher scores indicating better QoL), rescue medication puffs per day, morning and evening peak expiratory flow (PEF; litres per minutes), forced expiratory volume in one second (FEV1; litres), bronchial hyperresponsiveness, and oral corticosteroid dose. Secondary outcomes were adverse events (including mortality), withdrawal, blood eosinophils, sputum eosinophils, eosinophil cationic protein (ECP) in serum, and ECP in sputum.

DATA COLLECTION AND ANALYSIS

Two review authors independently examined all records identified in the searches then reviewed the full text of all potentially relevant articles before extracting data in duplicate from all included studies. As per protocol, we used a fixed-effect model. We conducted a sensitivity analysis for analyses with high heterogeneity (I2 greater than 30%). GRADE was used to assess the certainty of the body of evidence.

MAIN RESULTS

Twenty-five studies met the inclusion criteria, randomising 1973 participants to receive macrolide or placebo for at least four weeks. Most of the included studies reported data from adults (mean age 21 to 61 years) with persistent or severe asthma, while four studies included children. All participants were recruited in outpatient settings. Inclusion criteria, interventions and outcomes were highly variable. The evidence suggests macrolides probably deliver a moderately sized reduction in exacerbations requiring hospitalisations compared to placebo (odds ratio (OR) 0.47, 95% confidence interval (CI) 0.20 to 1.12; studies = 2, participants = 529; moderate-certainty evidence). Macrolides probably reduce exacerbations requiring ED visits and/or treatment with systemic steroids (rate ratio (RaR) 0.65, 95% CI 0.53 to 0.80; studies = 4, participants = 640; moderate-certainty evidence). Macrolides may reduce symptoms (as measured on symptom scales) (standardised mean difference (SMD) -0.46, 95% CI -0.81 to -0.11; studies = 4, participants = 136 ; very low-certainty evidence). Macrolides may result in a little improvement in ACQ (SMD -0.17, 95% CI -0.31 to -0.03; studies = 5, participants = 773; low-certainty evidence). Macrolides may have little to no effect on AQLQ (mean difference (MD) 0.24, 95% CI 0.12 to 0.35; studies = 6, participants = 802; very low-certainty evidence). For both the ACQ and the AQLQ the suggested effect of macrolides versus placebo did not reach a minimal clinically important difference (MCID, 0.5 for ACQ and AQLQ) (ACQ: low-certainty evidence; AQLQ: very low-certainty evidence). Due to high heterogeneity (I2 > 30%), we conducted sensitivity analyses on the above results, which reduced the size of the suggested effects by reducing the weighting on the large, high quality studies.  Macrolides may result in a small effect compared to placebo in reducing need for rescue medication (MD -0.43 puffs/day, 95% CI -0.81 to -0.04; studies = 4, participants = 314; low-certainty evidence). Macrolides may increase FEV1, but the effect is almost certainly below a level discernible to patients (MD 0.04 L, 95% CI 0 to 0.08; studies = 10, participants = 1046; low-certainty evidence). It was not possible to pool outcomes for non-specific bronchial hyperresponsiveness or lowest tolerated oral corticosteroid dose (in people requiring oral corticosteroids at baseline). There was no evidence of a difference in severe adverse events (including mortality), although less than half of the studies reported the outcome (OR 0.80, 95% CI 0.49 to 1.31; studies = 8, participants = 854; low-certainty evidence). Reporting of specific adverse effects was too inconsistent across studies for a meaningful analysis.

AUTHORS' CONCLUSIONS

Existing evidence suggests an effect of macrolides compared with placebo on the rate of exacerbations requiring hospitalisation. Macrolides probably reduce severe exacerbations (requiring ED visit and/or treatment with systemic steroids) and may reduce symptoms. However, we cannot rule out the possibility of other benefits or harms because the evidence is of very low quality due to heterogeneity among patients and interventions, imprecision and reporting biases. The results were mostly driven by a well-designed, well powered RCT, indicating that azithromycin may reduce exacerbation rate and improve symptom scores in severe asthma. The review highlights the need for researchers to report outcomes accurately and according to standard definitions. Macrolides can reduce exacerbation rate in people with severe asthma. Future trials could evaluate if this effect is sustained across all the severe asthma phenotypes, the comparison with newer biological drugs, whether effects persist or wane after treatment cessation and whether effects are associated with infection biomarkers.

Severe acute asthma at the pediatric intensive care unit: can we link the clinical phenotypes to immunological endotypes?

INTRODUCTION

The clinical phenotype of severe acute asthma at the pediatric intensive care unit (PICU) is highly heterogeneous. However, current treatment is still based on a 'one-size-fits-all approach'.

AREAS COVERED

We aim to give a comprehensive description of the clinical characteristics of pediatric patients with severe acute asthma admitted to the PICU and available immunological biomarkers, providing the first steps toward precision medicine for this patient population. A literature search was performed using PubMed for relevant studies on severe acute (pediatric) asthma.

EXPERT OPINION

Omics technologies should be used to investigate the relationship between cellular molecules and pathways, and their clinical phenotypes. Inflammatory phenotypes might guide bedside decisions regarding the use of corticosteroids, neutrophil modifiers and/or type of beta-agonist. A next step toward precision medicine should be inclusion of these patients in clinical trials on biologics.

Neutrophilic Inflammation in Asthma and Association with Disease Severity

Asthma is a chronic inflammatory disorder of the airways. While the local infiltration of eosinophils and mast cells, and their role in the disease have long been recognized, neutrophil infiltration has also been assessed in many clinical studies. In these studies, airway neutrophilia was associated with asthma severity. Importantly, neutrophilia also correlates with asthma that is refractory to corticosteroids, the mainstay of asthma treatment. However, it is now increasingly recognized that neutrophils are a heterogeneous population, and a more precise phenotyping of these cells may help delineate different subtypes of asthma. Here, we review current knowledge of the role of neutrophils in asthma and highlight future avenues of research in this field.

Effect of azithromycin on asthma exacerbations and quality of life in adults with persistent uncontrolled asthma (AMAZES): a randomised, double-blind, placebo-controlled trial

BACKGROUND

Exacerbations of asthma cause a substantial global illness burden. Adults with uncontrolled persistent asthma despite maintenance treatment require additional therapy. Since macrolide antibiotics can be used to treat persistent asthma, we aimed to assess the efficacy and safety of oral azithromycin as add-on therapy in patients with uncontrolled persistent asthma on medium-to-high dose inhaled corticosteroids plus a long-acting bronchodilator.

METHODS

We did a randomised, double-blind, placebo controlled parallel group trial to determine whether oral azithromycin decreases the frequency of asthma exacerbations in adults (≥18 years) with symptomatic asthma despite current use of inhaled corticosteroid and long-acting bronchodilator, and who had no hearing impairment or abnormal prolongation of the corrected QT interval. Patients were randomly assigned (1:1) to receive azithromycin 500 mg or placebo three times per week for 48 weeks. Patients were centrally allocated using concealed random allocation from a computer-generated random numbers table with permuted blocks of 4 or 6 and stratification for centre and past smoking. Primary efficacy endpoints were the rate of total (severe and moderate) asthma exacerbations over 48 weeks and asthma quality of life. Data were analysed on an intention-to-treat basis. The trial is registered at the Australian and New Zealand Clinical Trials Registry (ANZCTR), number 12609000197235.

FINDINGS

Between June 12, 2009, and Jan 31, 2015, 420 patients were randomly assigned (213 in the azithromycin group and 207 in the placebo group). Azithromycin reduced asthma exacerbations (1·07 per patient-year [95% CI 0·85-1·29]) compared with placebo (1·86 per patient-year [1·54-2·18]; incidence rate ratio [IRR] 0·59 [95% CI 0·47-0·74]; p<0·0001). The proportion of patients experiencing at least one asthma exacerbation was reduced by azithromycin treatment (127 [61%] patients in the placebo group vs 94 [44%] patients in the azithromycin group, p<0·0001). Azithromycin significantly improved asthma-related quality of life (adjusted mean difference, 0·36 [95% CI 0·21-0·52]; p=0·001). Diarrhoea was more common in azithromycin-treated patients (72 [34%] vs 39 [19%]; p=0·001).

INTERPRETATION

Adults with persistent symptomatic asthma experience fewer asthma exacerbations and improved quality of life when treated with oral azithromycin for 48 weeks. Azithromycin might be a useful add-on therapy in persistent asthma.

FUNDING

National Health and Medical Research Council of Australia, John Hunter Hospital Charitable Trust.

The differential effects of azithromycin on the airway epithelium in vitro and in vivo

Macrolides including azithromycin (AZM) can improve clinical symptoms in asthma regardless of infection status. The mechanisms underlying these beneficial effects are yet to be elucidated. The aim of this study was to determine the effect of AZM on the airway epithelial barrier both in an in vitro model and in patients with asthma. Primary human bronchial epithelial cells (HBEC) were grown at air liquid interface (ALI) and challenged using lipopolysaccharides from Pseudomonas aeruginosa AZM was added at various stages and barrier integrity assessed using transepithelial electrical resistance (TEER) and permeability to FITC-dextran. MMP-9 levels were measured using ELISA AZM enhanced barrier integrity (TEER/FITC-dextran), increased thickness, suppressed mucin production, and MMP-9 release during the formation of a normal epithelial barrier in vitro. MMP-9 levels inversely correlated with TEER AZM also enhanced maintenance of the barrier and facilitated repair post-LPS challenge. To provide translation of our findings, 10 patients with moderate-severe asthma were recruited and received 250 mg AZM o.d for 6 weeks. Bronchial biopsies taken pre- and post-AZM treatment did not show evidence of increased epithelial barrier thickness or decreased mucin production. Similarly, bronchial wash samples did not show reduced MMP-9 levels. Overall, our data show that AZM can significantly improve the development of a normal bronchial epithelial barrier in vitro, mimicking reepithelization postinjury. AZM also suppressed MMP-9 release which correlated with barrier integrity, suggesting a putative mechanism. However, these effects were not observed in biopsy samples from asthma patients treated with AZM, possibly due to small sample size.

Respiratory drugs and macrolides prevent asthma exacerbations: A real-world investigation

OBJECTIVE

We investigated the real-world effectiveness of several drugs (including short- and long-acting beta-agonists [SABAs and LABAs], inhaled corticosteroids [ICS], and antibiotics) in preventing severe asthma exacerbations by carrying-out a large observational study based on the healthcare utilization databases of the Italian Lombardy Region.

METHODS

We identified all patients aged 6-40 years who performed an Emergency Department visit for asthma during 2010-2012 as cases. To address bias due to unmeasured confounders, we implemented a case-crossover (CC) design. Addressing other specific sources of systematic errors (e.g. protopathic bias) was of particular concern in this study.

RESULTS

A total of 7300 cases were included in the study. The CC odds ratios (95% confidence intervals) for current vs. past use were 0.81 (0.71, 0.92) for SABAs, 0.83 (0.72, 0.96) for ICS, 0.78 (0.66, 0.91) for LABA/ICS fixed combinations, 0.79 (0.65, 0.97) for other respiratory drugs, and 0.79 (0.69, 0.92) for macrolides antibiotics. Sensitivity analyses showed that our results were robust with respect to several sources of bias.

CONCLUSIONS

Our study provides evidence from the real-world clinical practice on the effectiveness of several respiratory drugs and macrolides in reducing the risk of severe asthma exacerbations.

Macrolides for chronic asthma

BACKGROUND

Asthma is a chronic disease in which inflammation of the airways causes symptomatic coughing, wheezing, and difficult breathing. The inflammation may have different underlying causes, including a reaction to infection in the lungs. Macrolides are antibiotics with antimicrobial and antiinflammatory activities that have been used long-term to control asthma symptoms.

OBJECTIVES

To assess the effects of macrolides for managing chronic asthma.

SEARCH METHODS

We searched the Cochrane Airways Group Specialised Register up to April 2015. We also manually searched bibliographies of previously published reviews and conference proceedings and contacted study authors. We included records published in any language in the search.

SELECTION CRITERIA

Randomised controlled clinical trials involving both children and adults with chronic asthma treated with macrolides versus placebo for more than four weeks .

DATA COLLECTION AND ANALYSIS

Two reviewers independently examined all records identified in the searches then reviewed the full text of all potentially relevant articles before extracting data in duplicate from all included studies.

MAIN RESULTS

Twenty-three studies met the inclusion criteria, randomising a total of 1513 participants to receive macrolide or placebo. The quality of evidence was generally very low due to incomplete reporting of study methodology and clinical data, suspected publication bias, indirectness of study populations, risk of bias and imprecision (because of small numbers of patients and events). Most of the included studies reported data from patients with persistent or severe asthma, but inclusion criteria, interventions and outcomes were highly variable.Macrolides were not found to be better than placebo for the majority of clinical outcomes including exacerbations requiring hospital admission (odds ratio (OR) 0.98, 95% confidence interval (CI) 0.13 to 7.23; participants = 143; studies = 2; I(2) = 0%) or at least treatment with oral steroids (OR 0.82, 95% CI 0.43 to 1.57; participants = 290; studies = 5; I(2) = 0%). The evidence on symptom scales (standard mean difference (SMD) -0.04, 95% CI -0.36 to 0.28), asthma control (SMD -0.05, 95% CI -0.26 to 0.15), quality of life (mean difference (MD) 0.06, 95% CI -0.12 to 0.24) and rescue medication use (MD -0.26, 95% CI -0.65 to 0.12) was all of very low quality and did not show a benefit of macrolide treatment. There was some evidence that macrolides led to some improvement in lung function (forced expiratory volume in one second (FEV1): MD 0.08, 95% CI 0.02 to 0.14), although not on all the measures we assessed. Measures of bronchial hyperresponsiveness were too varied to pool, but most studies showed no clear benefit of macrolide over placebo. Two studies recruiting people taking regular oral corticosteroids suggested macrolides may have a steroid-sparing effect in this population. Macrolides were well tolerated with respect to severe adverse events, although less than half of the studies reported the outcome (OR 0.80, 95% CI 0.24 to 2.68; participants = 434; studies = 7; I(2) = 0%). Reporting of specific side effects was too patchy across studies to analyse meaningfully. As already reported in the previous versions of the systematic review, biomarkers of asthma activity, such as sputum and serum level of eosinophil cationic protein (ECP) or sputum and serum eosinophils, were lower in patients treated with macrolides, but this was not associated with clinical benefits.Two within-study subgroup analyses showed a possible benefit of macrolides for non-eosinophilic asthma, but it was not possible to investigate this further using the data available for this review.

AUTHORS' CONCLUSIONS

Existing evidence does not show macrolides to be better than placebo for the majority of clinical outcomes. However, they may have a benefit on some measures of lung function, and we cannot rule out the possibility of other benefits or harms because the evidence is of very low quality due to heterogeneity among patients and interventions, imprecision and reporting biases.The review highlights the need for researchers to report clinically relevant outcomes accurately and completely using guideline definitions of exacerbations and validated scales. The possible benefit of macrolides in patients with non-eosinophilic asthma based on subgroup analyses in two of the included studies may require further investigation.

Potentially pathogenic airway bacteria and neutrophilic inflammation in treatment resistant severe asthma

BACKGROUND

Molecular microbiological analysis of airway samples in asthma has demonstrated an altered microbiome in comparison to healthy controls. Such changes may have relevance to treatment-resistant severe asthma, particularly those with neutrophilic airway inflammation, as bacteria might be anticipated to activate the innate immune response, a process that is poorly steroid responsive. An understanding of the relationship between airway bacterial presence and dominance in severe asthma may help direct alternative treatment approaches.

OBJECTIVE

We aimed to use a culture independent analysis strategy to describe the presence, dominance and abundance of bacterial taxa in induced sputum from treatment resistant severe asthmatics and correlate findings with clinical characteristics and airway inflammatory markers.

METHODS

Induced sputum was obtained from 28 stable treatment-resistant severe asthmatics. The samples were divided for supernatant IL-8 measurement, cytospin preparation for differential cell count and Terminal Restriction Fragment Length Polymorphism (T-RFLP) profiling for bacterial community analysis.

RESULTS

In 17/28 patients, the dominant species within the airway bacterial community was Moraxella catarrhalis or a member of the Haemophilus or Streptococcus genera. Colonisation with these species was associated with longer asthma disease duration (mean (SD) 31.8 years (16.7) vs 15.6 years (8.0), p = 0.008), worse post-bronchodilator percent predicted FEV1 (68.0% (24.0) vs 85.5% (19.7), p = 0.025) and higher sputum neutrophil differential cell counts (median (IQR) 80% (67-83) vs 43% (29-67), p = 0.001). Total abundance of these organisms significantly and positively correlated with sputum IL-8 concentration and neutrophil count.

CONCLUSIONS

Airway colonisation with potentially pathogenic micro-organisms in asthma is associated with more severe airways obstruction and neutrophilic airway inflammation. This altered colonisation may have a role in the development of an asthma phenotype that responds less well to current asthma therapies.

The role of macrolides in asthma: current evidence and future directions

Macrolides, such as clarithromycin and azithromycin, possess antimicrobial, immunomodulatory, and potential antiviral properties. They represent a potential therapeutic option for asthma, a chronic inflammatory disorder characterised by airway hyper-responsiveness that leads to recurrent episodes of wheezing, breathlessness, chest tightness, and coughing. Results from clinical trials, however, have been contentious. The findings could be confounded by many factors, including the heterogeneity of asthma, treatment duration, dose, and differing outcome measures. Recent evidence suggests improved effectiveness of macrolides in patients with sub-optimally controlled severe neutrophilic asthma and in asthma exacerbations. We examine the evidence from clinical trials and discuss macrolide properties and their relevance to the pathophysiology of asthma. At present, the use of macrolides in chronic asthma or acute exacerbations is not justified. Further work, including proteomic, genomic, and microbiome studies, will advance our knowledge of asthma phenotypes, and help to identify a macrolide-responsive subgroup. Future clinical trials should target this subgroup and place emphasis on clinically relevant outcomes such as asthma exacerbations.

[Long-term macrolide treatment in adult chronic bronchial diseases: benefits and limits]

Decreased frequency of pulmonary exacerbations, mainly related to immunomodulatory effects of macrolide antibiotics, has been demonstrated in bronchiectasis and chronic obstructive pulmonary diseases (COPD). Due to its tolerance, azithromycin is the antibiotic of choice for maintenance therapy at the dose of 250 mg per day or 500 mg × 3 per week (for body weight >55 kg). Maintenance therapy with macrolide could be proposed in selected patients with bronchiectasis or COPD with more than 3 acute exacerbations in the previous year or decreased lung function despite compliance with optimum treatment. The risk of sudden cardiac death with azithromycin is rare and controversial. It should be avoided in patients with a high baseline risk of cardiovascular disease, QT>450 msec, pulse rate>100 bpm and potential drug interactions, particularly those known to cause QT prolongation. It is recommended to search for hearing deficit (audiometry) and sputum culture positive for mycobacteria. Patients must also be aware that it can rapidly lead to macrolide resistance in commensal or pathogenic flora. Follow-up evaluation every 3 month can be proposed with medical history (hearing deficit) and electrocardiography. After one year, the treatment should be stopped in the absence of reduction in the frequency of exacerbations.

Macrolides: from in vitro anti-inflammatory and immunomodulatory properties to clinical practice in respiratory diseases

BACKGROUND

Macrolides have long been recognised to exert immunomodulary and anti-inflammatory actions. They are able to suppress the "cytokine storm" of inflammation and to confer an additional clinical benefit through their immunomodulatory properties.

METHODS

A search of electronic journal articles was performed using combinations of the following keywords: macrolides, COPD, asthma, bronchitis, bronchiolitis obliterans, cystic fibrosis, immunomodulation, anti-inflammatory effect, diabetes, side effects and systemic diseases.

RESULTS

Macrolide effects are time- and dose-dependent, and the mechanisms underlying these effects remain incompletely understood. Both in vitro and in vivo studies have provided ample evidence of their immunomodulary and anti-inflammatory actions. Importantly, this class of antibiotics is efficacious with respect to controlling exacerbations of underlying respiratory problems, such as cystic fibrosis, asthma, bronchiectasis, panbrochiolitis and cryptogenic organising pneumonia. Macrolides have also been reported to reduce airway hyper-responsiveness and improve pulmonary function.

CONCLUSION

This review provides an overview on the properties of macrolides (erythromycin, clarithromycin, roxithromycin, azithromycin), their efficacy in various respiratory diseases and their adverse effects.

Neomacrolides in the treatment of patients with severe asthma and/or bronchiectasis: a retrospective observational study

RATIONALE

Previous studies have demonstrated that long-term low-dose macrolides are efficacious in cystic fibrosis (CF) and diffuse panbronchiolitis, two chronic neutrophilic airway diseases.

AIMS

The aims of this study were to evaluate the efficacy and safety of low-dose neomacrolides as add-on therapy in patients with severe asthma and/or bronchiectasis and to identify predictors for therapeutic response.

METHODS

In a retrospective observational cohort study, we examined 131 adult, non-CF patients with severe asthma and/or bronchiectasis, receiving low-dose neomacrolides as add-on treatment. Pulmonary function tests and symptom scores were assessed at baseline and after 3 to 8 weeks of therapy.

RESULTS

After 3-8 weeks of treatment with low-dose neomacrolides, 108 patients were available for evaluation. In asthma patients (n = 47), pulmonary function tests and symptom scores improved significantly. Responders (≥7% forced expiratory volume in one second predicted [FEV(1)%] improvement) were older (55 vs. 47 years; p = 0.042) and had a longer duration of asthma (29 vs. 9 years; p = 0.052). In patients with bronchiectasis only (n = 61), symptom scores improved significantly. Responders (≥60% symptom score improvement) were older (61 vs. 53 years; p = 0.004), more frequently male (53% vs. 27%; p = 0.043), and there was a nonsignificant trend towards higher high-resolution CT (HRCT) score for bronchiectasis in responders (6.4 vs. 4.6; p = 0.053). In multivariate logistic regression analysis, age and male gender were independent predictors for improvement in this group.

CONCLUSION

The results of this retrospective study suggest that neomacrolides may be useful as an add-on therapy in patients with severe asthma and/or bronchiectasis. Older age may predict good response in patients with severe asthma, whereas older age, male gender and a higher HRCT score for bronchiectasis may predict therapeutic response in patients with bronchiectasis only. Prospective controlled trials of neomacrolides in patients with severe asthma are needed to confirm these observations.

Bacterial infections and pediatric asthma

Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis seem to have no role in asthma in children. Mycoplasma pneumoniae and Chlamydophila pneumoniae can induce wheezing and cause asthma exacerbations in children, and chronic Chlamydophila infections may even participate in asthma pathogenesis. However, studies have failed to show any benefits from antibiotics for incipient or stable pediatric asthma, as well as for asthma exacerbations in children. Exposure to antibiotics in infancy has been an independent risk factor of later asthma in many studies. A recent study applying molecular biology methods to lower airway samples provided preliminary evidence that lower airways are not sterile but have their own protective microbiota, which can be disturbed in lung diseases like asthma.

Chronic macrolide therapy in inflammatory airways diseases

Long-term therapy with the macrolide antibiotic erythromycin was shown to alter the clinical course of diffuse panbronchiolitis in the late 1980s. Since that time, macrolides have been found to have a large number of antiinflammatory properties in addition to being antimicrobials. These observations provided the rationale for many studies performed over the last decade to assess the usefulness of macrolides in other inflammatory airways diseases, such as cystic fibrosis, asthma, COPD, and bronchiolitis obliterans syndrome. This review summarizes the immunomodulatory properties of macrolides and the results of these recent studies demonstrating their potential for being disease-modifying agents.

An integrative review of systematic reviews related to the management of breathlessness in respiratory illnesses

BACKGROUND

Breathlessness is a debilitating and distressing symptom in a wide variety of diseases and still a difficult symptom to manage. An integrative review of systematic reviews of non-pharmacological and pharmacological interventions for breathlessness in non-malignant disease was undertaken to identify the current state of clinical understanding of the management of breathlessness and highlight promising interventions that merit further investigation.

METHODS

Systematic reviews were identified via electronic databases between July 2007 and September 2009. Reviews were included within the study if they reported research on adult participants using either a measure of breathlessness or some other measure of respiratory symptoms.

RESULTS

In total 219 systematic reviews were identified and 153 included within the final review, of these 59 addressed non-pharmacological interventions and 94 addressed pharmacological interventions. The reviews covered in excess of 2000 trials. The majority of systematic reviews were conducted on interventions for asthma and COPD, and mainly focussed upon a small number of pharmacological interventions such as corticosteroids and bronchodilators, including beta-agonists. In contrast, other conditions involving breathlessness have received little or no attention and studies continue to focus upon pharmacological approaches. Moreover, although there are a number of non-pharmacological studies that have shown some promise, particularly for COPD, their conclusions are limited by a lack of good quality evidence from RCTs, small sample sizes and limited replication.

CONCLUSIONS

More research should focus in the future on the management of breathlessness in respiratory diseases other than asthma and COPD. In addition, pharmacological treatments do not completely manage breathlessness and have an added burden of side effects. It is therefore important to focus more research on promising non-pharmacological interventions.

Effects of atypical infections with Mycoplasma and Chlamydia on asthma

Mycoplasma pneumoniae and Chlamydophila pneumoniae are atypical bacteria that are frequently found in patients with asthma. A definitive diagnosis of infection is often difficult to obtain because of limitations with sampling and detection. Numerous animal studies have outlined mechanisms by which these infections may promote allergic lung inflammation and airway remodeling. In addition, there is mounting evidence from human studies suggesting that atypical bacterial infections contribute to asthma exacerbations, chronic asthma, and disease severity. The role of antimicrobials directed against atypical bacteria in asthma is still under investigation.

Mechanisms of action and clinical application of macrolides as immunomodulatory medications

Macrolides have diverse biological activities and an ability to modulate inflammation and immunity in eukaryotes without affecting homeostatic immunity. These properties have led to their long-term use in treating neutrophil-dominated inflammation in diffuse panbronchiolitis, bronchiectasis, rhinosinusitis, and cystic fibrosis. These immunomodulatory activities appear to be polymodal, but evidence suggests that many of these effects are due to inhibition of extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation and nuclear factor kappa B (NF-kappaB) activation. Macrolides accumulate within cells, suggesting that they may associate with receptors or carriers responsible for the regulation of cell cycle and immunity. A concern is that long-term use of macrolides increases the emergence of antimicrobial resistance. Nonantimicrobial macrolides are now in development as potential immunomodulatory therapies.

A trial of clarithromycin for the treatment of suboptimally controlled asthma

BACKGROUND

PCR studies have demonstrated evidence of Mycoplasma pneumoniae and Chlamydophila pneumoniae in the lower airways of patients with asthma.

OBJECTIVE

To test the hypothesis that clarithromycin would improve asthma control in individuals with mild-to-moderate persistent asthma that was not well controlled despite treatment with low-dose inhaled corticosteroids.

METHODS

Adults with an Asthma Control Questionnaire score ≥1.5 after a 4-week period of treatment with fluticasone propionate were entered into a PCR-stratified randomized, controlled trial to evaluate the effect of 16 weeks of either clarithromycin or placebo, added to fluticasone, on asthma control in individuals with or without lower airway PCR evidence of M pneumoniae or C pneumoniae.

RESULTS

A total of 92 participants were randomized. Twelve (13%) subjects demonstrated PCR evidence of M pneumoniae or C pneumoniae in endobronchial biopsies; 80 were PCR-negative for both organisms. In PCR-positive participants, clarithromycin yielded a 0.4 ± 0.4 unit improvement in the Asthma Control Questionnaire score, with a 0.1 ± 0.3 unit improvement in those allocated to placebo. This between-group difference of 0.3 ± 0.5 (P = .6) was neither clinically nor statistically significant. In PCR-negative participants, a nonsignificant between-group difference of 0.2 ± 0.2 units (P = .3) was observed. Clarithromycin did not improve lung function or airway inflammation but did improve airway hyperresponsiveness, increasing the methacholine PC(20) by 1.2 ± 0.5 doubling doses (P = .02) in the study population.

CONCLUSION

Adding clarithromycin to fluticasone in adults with mild-to-moderate persistent asthma that was suboptimally controlled by low-dose inhaled corticosteroids alone did not further improve asthma control. Although there was an improvement in airway hyperresponsiveness with clarithromycin, this benefit was not accompanied by improvements in other secondary outcomes.

Ectopic lymphoid tissue formation in the lungs of mice infected with Chlamydia pneumoniae is associated with epithelial macrophage inflammatory protein-2/CXCL2 expression

Infection with Chlamydia pneumoniae (Cp) accounts for around 10% of community acquired bacterial pneumonia and has been associated with other chronic inflammatory conditions. We describe a C57/Bl6 murine model of Cp lung infection characterized by a dose-dependent, resolving neutrophilia followed by lymphocytic infiltration of the lungs. By 21 days post-infection, mice exhibit a T helper type 1 (Th1) polarized serum antibody response with local mucosal antibody secretion and organization of ectopic lymphoid tissue which persisted in the absence of detectable Cp DNA. Macrophage inflammatory protein (MIP)-2/CXCL2, which recruits neutrophils and lymphocytes and is associated with ectopic lymphoid tissue formation, was secreted in the lungs post-infection. In vitro, lung epithelial cells up-regulated MIP-2/CXCL2 in response to both rough lipopolysaccharide (reLPS) and Cp infection. We conclude that Cp infection can have long-term inflammatory effects on tissue that persist after clearance of active infection.

Pharmacotherapy of severe asthma

Severe asthma is a complex and heterogeneous phenotype where management can be challenging. While many patients with severe asthma respond to high-dose inhaled corticosteroids in combination with a long-acting beta-agonist, there remains a significant subset of patients that require oral corticosteroids to control symptoms. Alternative therapies are needed to help reduce the need for continuous oral corticosteroids; however, there are currently very few effective options. Several new alternatives to oral corticosteroids have been evaluated in severe asthma as add-on to conventional therapy. These include macrolide antibiotics, omalizumab, tumor necrosis factor-alpha inhibitors, cytokine receptor antagonists, and bronchial thermoplasty. The challenge with these entities is determining the appropriate phenotype of severe asthma where effectiveness is demonstrated, given the significant heterogeneity of the disease. Therefore, there is a crucial need to better understand the mechanisms and pathophysiology of severe asthma so more effective immunomodulators and biologic therapies can emerge.

[Recurrent wheezing in three year-olds: facts and opportunities]

The 3 year-old group of children has an increased incidence and prevalence of recurrent wheezing episodes. There are different subgroups, who give different inflammatory responses to different triggering agents, and subgroups that differ in aetiopathology and immunopathology. Current diagnostic methods (exhaled nitric oxide in multiple breaths, nitric oxide in exhaled air condensate, induced sputum, broncho-alveolar lavage and endo-bronchial biopsy), enable the inflammatory pattern to be identified and to give the most effective and safe treatment. The various therapeutic options for treatment are reviewed, such as inhaled glucocorticoids when the inflammatory phenotype is eosinophilic, and leukotriene receptor antagonists, when the inflammatory phenotype is predominantly neutrophilic. In accordance with the current recommendations, for the diagnosis as well as for the therapy initiated in children of this age, they must be regularly reviewed, so that if the benefit is not clear, the treatment must be stopped and an alternative diagnosis and treatment considered. The start of treatment should be determined depending on the intensity and frequency of the symptoms, with the aim of decreasing morbidity and increasing the quality of life of the patient.

Diagnosis and treatment of asthma in childhood: a PRACTALL consensus report

Asthma is the leading chronic disease among children in most industrialized countries. However, the evidence base on specific aspects of pediatric asthma, including therapeutic strategies, is limited and no recent international guidelines have focused exclusively on pediatric asthma. As a result, the European Academy of Allergy and Clinical Immunology and the American Academy of Allergy, Asthma and Immunology nominated expert teams to find a consensus to serve as a guideline for clinical practice in Europe as well as in North America. This consensus report recommends strategies that include pharmacological treatment, allergen and trigger avoidance and asthma education. The report is part of the PRACTALL initiative, which is endorsed by both academies.

Macrolide antibiotics as immunomodulatory medications: proposed mechanisms of action

Macrolide antibiotics administered in sub-antimicrobial doses improve pulmonary function and decrease exacerbation frequency for persons with diffuse panbronchiolitis or cystic fibrosis. Data also suggest a beneficial effect of macrolide antibiotics in the treatment of steroid dependent asthma. Many potential immunomodulatory effects of macrolide antibiotics have been reported including the ability to down-regulate prolonged inflammation, decreasing airway mucus secretion, inhibiting bacterial biofilm, decreasing the production of reactive oxygen species, inhibiting neutrophil activation and mobilization, accelerating neutrophil apoptosis, and blocking the activation of nuclear transcription factors. Macrolides initially decrease, then increase, and have finally a sustained suppression of cytokine secretions from normal human bronchial epithelial cells through inhibition and activation of extracellular signal-regulated kinases (ERK) and then reversibly retard cell proliferation probably through ERK. Consistent with this, macrolide antibiotics possibly reduce mucin production as well as neutrophil migration by interfering with ERK signal transduction.

Antimicrobial strategies: an option to treat allergy?

Respiratory infections by bacteria and viruses often trigger symptoms of asthma in both adults and children. This observation and subsequent mechanistic studies have demonstrated important interactions among allergens, microbes and the atopic host. The mechanisms responsible for microbe-induced asthma exacerbations are only incompletely understood. A focal point of current research is the inflammatory response of the host following an encounter with a pathogenic microbe, including variations in chemokine and cytokine production and resulting in changes in bronchial hyper-responsiveness and lung function. Direct bronchial infection, exposure of nerves with resulting neurogenic inflammation and a deviated host immune response are among the mechanisms underlying these functional disorders. Lately, suboptimal innate immune responses, expressed as defective interferon production, have gained attention as they might be amenable to intervention. This review describes the suggested mechanisms involved in the complex interactions between 'asthmagenic' microbes, the immune system and atopy, based on in-vitro and in-vivo experimental models and epidemiological evidence. In addition, it provides a synopsis of potential therapeutic strategies either directly against the microorganisms or in respect to the associated inflammation.

Effect of clarithromycin on cytokines and chemokines in children with an acute exacerbation of recurrent wheezing: a double-blind, randomized, placebo-controlled trial

BACKGROUND

Clarithromycin is postulated to possess immunomodulatory properties in addition to its antimicrobial activity.

OBJECTIVE

To evaluate the effect of clarithromycin on serum and nasopharyngeal cytokine and chemokine concentrations in children with an acute exacerbation of recurrent wheezing.

METHODS

Children with a history of recurrent wheezing or asthma and who presented with an acute exacerbation of wheezing were enrolled in a double-blind, randomized trial of clarithromycin vs placebo. Concentrations of tumor necrosis factor alpha (TNF-alpha), interferon-gamma (IFN-gamma), interleukin-1beta (IL-1beta), IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, granulocyte-macrophage colony-stimulating factor, RANTES, eotaxin, macrophage inflammatory protein 1alpha, macrophage inflammatory protein 1beta, and monocyte chemoattractant protein 1 were measured in serum and/or nasopharyngeal aspirates before, during, and after therapy. Mycoplasma pneumoniae and Chlamydophila pneumoniae infection were evaluated for by polymerase chain reaction and serologic testing.

RESULTS

Nasopharyngeal concentrations of TNF-alpha, IL-1beta, and IL-10 were significantly and persistently lower in children treated with clarithromycin compared with placebo. There tended to be a greater effect of clarithromycin on nasopharyngeal cytokine concentrations in patients with evidence of M. pneumoniae or C. pneumoniae infection. No significant differences were detected in serum cytokines for children treated with clarithromycin compared with placebo.

CONCLUSION

Clarithromycin therapy reduces mucosal TNF-alpha, IL-1beta, and IL-10 concentrations in children with an acute exacerbation of recurrent wheezing.

The mechanisms, diagnosis, and management of severe asthma in adults

There has been a recent increase in the prevalence of asthma worldwide; however, the 5-10% of patients with severe disease account for a substantial proportion of the health costs. Although most asthma cases can be satisfactorily managed with a combination of anti-inflammatory drugs and bronchodilators, patients who remain symptomatic despite maximum combination treatment represent a heterogeneous group consisting of those who are under-treated or non-adherent with their prescribed medication. After excluding under-treatment and poor compliance, corticosteroid refractory asthma can be identified as a subphenotype characterised by a heightened neutrophilic airway inflammatory response in the presence or absence of eosinophils, with evidence of increased tissue injury and remodelling. Although a wide range of environmental factors such as allergens, smoking, air pollution, infection, hormones, and specific drugs can contribute to this phenotype, other features associated with changes in the airway inflammatory response should be taken into account. Aberrant communication between an injured airway epithelium and underlying mesenchyme contributes to disease chronicity and refractoriness to corticosteroids. The importance of identifying underlying causative factors and the recent introduction of novel therapeutic approaches, including the targeting of immunoglobulin E and tumour necrosis factor alpha with biological agents, emphasise the need for careful phenotyping of patients with severe disease to target improved management of the individual patient's needs.

Secondary outcomes of a pilot randomized trial of azithromycin treatment for asthma

OBJECTIVES

The respiratory pathogen Chlamydia pneumoniae (C. pneumoniae) produces acute and chronic lung infections and is associated with asthma. Evidence for effectiveness of antichlamydial antibiotics in asthma is limited. The primary objective of this pilot study was to investigate the feasibility of performing an asthma clinical trial in practice settings where most asthma is encountered and managed. The secondary objectives were to investigate (1) whether azithromycin treatment would affect any asthma outcomes and (2) whether C. pneumoniae serology would be related to outcomes. This report presents the secondary results.

DESIGN

Randomized, placebo-controlled, blinded (participants, physicians, study personnel, data analysts), allocation-concealed parallel group clinical trial.

SETTING

Community-based health-care settings located in four states and one Canadian province.

PARTICIPANTS

Adults with stable, persistent asthma.

INTERVENTIONS

Azithromycin (six weekly doses) or identical matching placebo, plus usual community care.

OUTCOME MEASURES

Juniper Asthma Quality of Life Questionnaire (Juniper AQLQ), symptom, and medication changes from baseline (pretreatment) to 3 mo posttreatment (follow-up); C. pneumoniae IgG and IgA antibodies at baseline and follow-up.

RESULTS

Juniper AQLQ improved by 0.25 (95% confidence interval; -0.3, 0.8) units, overall asthma symptoms improved by 0.68 (0.1, 1.3) units, and rescue inhaler use decreased by 0.59 (-0.5, 1.6) daily administrations in azithromycin-treated compared to placebo-treated participants. Baseline IgA antibodies were positively associated with worsening overall asthma symptoms at follow-up (p = 0.04), but IgG was not (p = 0.63). Overall asthma symptom improvement attributable to azithromycin was 28% in high IgA participants versus 12% in low IgA participants (p for interaction = 0.27).

CONCLUSIONS

Azithromycin did not improve Juniper AQLQ but appeared to improve overall asthma symptoms. Larger community-based trials of antichlamydial antibiotics for asthma are warranted.