Relationship between airway neutrophilia and ageing in asthmatics and non-asthmatics

Clinical Subtypes of Neutrophilic Asthma: A Cluster Analysis From Australasian Severe Asthma Network

BACKGROUND

Clinical heterogeneity may exist within asthma subtypes defined by inflammatory markers. However, the heterogeneity of neutrophilic asthma (NA) remains largely unexplored.

OBJECTIVE

To explore potential clusters and the stability of NA.

METHODS

Participants with NA from the Australasian Severe Asthma Network underwent a multidimensional assessment. They were then asked to participate in a 12-month longitudinal cohort study. We explored potential clusters using a hierarchical cluster analysis and validated the differential future risk of asthma exacerbations in the identified clusters. A decision tree analysis was developed to predict cluster assignments. Finally, the stability of prespecified clusters was examined within 1 month.

RESULTS

Three clusters were identified in 149 patients with NA. Cluster 1 (n = 99; 66.4%) was characterized by female-predominant nonsmokers with well-controlled NA, cluster 2 (n = 16; 10.7%) by individuals with comorbid anxiety/depressive symptoms with poorly controlled NA, and cluster 3 by older male smokers with late-onset NA. Cluster 2 had a greater proportion of participants with severe exacerbations (P = .005), hospitalization (P = .010), and unscheduled visits (P = .013) and a higher number of emergency room visits (P = .039) than that of the other two clusters. The decision tree assigned 92.6% of participants correctly. Most participants (87.5%; n = 7) in cluster 2 had a stable NA phenotype, whereas participants of clusters 1 and 3 had variable phenotypes.

CONCLUSIONS

We identified three clinical clusters of NA, in which cluster 2 represents an uncontrolled and stable NA subtype with an elevated risk of exacerbations. These findings have clinical implications for the management of NA.

Management of Elderly Asthma: Key Questions and Tentative Answers

The aging lung undergoes structural changes, immunosenescence, and inflammation, rendering the elderly more susceptible to developing obstructive airway disease. Thus, asthma in those of chronological age ≥ 65 years is not rare. Elderly asthma (EA) imposes considerable burdens in terms of mortality and morbidity, and expenditure. However, clinicians lack knowledge of EA and thus often prescribe inappropriate management. In this review, we ask 3 key questions frequently encountered during EA diagnosis and treatment: 1) Is EA different?; 2) How can we appropriately diagnose EA?; 3) Are there management strategies specific to EA? Based on recent studies, we provide tentative answers as follows: 1) late-onset EA differs in clinical features and pathogenetic mechanisms from non-EA, and thus further phenotypic and endotypic characterization of EA is needed; 2) both over- and under-diagnosis of asthma in the elderly can be reduced if the objective diagnostic tests are appropriately performed; 3) cautious prescription of ICS to selected EA patients should be encouraged, and a multifaceted approach which involves increasing medical awareness and inhaler use proficiency and adherence, seeking the assistance of caregivers, and correcting micronutrient deficiencies is required to reduce acute exacerbations in EA patients.

Biomarkers in severe asthma: Identifying the treatable trait

Asthma is a chronic condition of bronchial hyper-reactivity associated with inflammation ranges from mild to severe form. It affects 1 - 18% of the population globally and it is estimated that > 300million people in the world have asthma. Of this 5 - 10% have severe asthma. while the proportion of patients suffering from severe are smaller, the morbidity and mortality are higher in this group. With the advances in our understanding of the pathophysiology of asthma there is a need to understand the role of various biomarkers. We live in an era of precision medicine and today there is a clear unmet need to understand targeted therapies. This review aims to raise awareness to the available biomarkers used in clinical practice in India and their role in predicting response to targeted therapies.

Immunosenescence, Inflammaging, and Lung Senescence in Asthma in the Elderly

Prevalence of asthma in older adults is growing along with increasing global life expectancy. Due to poor clinical consequences such as high mortality, advancement in understanding the pathophysiology of asthma in older patients has been sought to provide prompt treatment for them. Age-related alterations of functions in the immune system and lung parenchyma occur throughout life. Alterations with advancing age are promoted by various stimuli, including pathobionts, fungi, viruses, pollutants, and damage-associated molecular patterns derived from impaired cells, abandoned cell debris, and senescent cells. Age-related changes in the innate and adaptive immune response, termed immunosenescence, includes impairment of phagocytosis and antigen presentation, enhancement of proinflammatory mediator generation, and production of senescence-associated secretory phenotype. Immnunosenescence could promote inflammaging (chronic low-grade inflammation) and contribute to late-onset adult asthma and asthma in the elderly, along with age-related pulmonary disease, such as chronic obstructive pulmonary disease and pulmonary fibrosis, due to lung parenchyma senescence. Aged patients with asthma exhibit local and systemic type 2 and non-type 2 inflammation, associated with clinical manifestations. Here, we discuss immunosenescence’s contribution to the immune response and the combination of type 2 inflammation and inflammaging in asthma in the elderly and present an overview of age-related features in the immune system and lung structure.

Recent insights in the role of biomarkers in severe asthma management

Contemporary asthma management requires a proactive and individualized approach, combining precision diagnosis and personalized treatment. The introduction of biologic therapies for severe asthma to everyday clinical practice, increases the need for specific patient selection, prediction of outcomes and monitoring of these costly and long-lasting therapies. Several biomarkers have been used in asthma in disease identification, prediction of asthma severity and prognosis, and response to treatment. Novel advances in the area of personalized medicine regarding disease phenotyping and endotyping, encompass the development and application of reliable biomarkers, accurately quantified using robust and reproducible methods. The availability of powerful omics technologies, together with integrated and network-based genome data analysis, and microbiota changes quantified in serum, body fluids and exhaled air, will lead to a better classification of distinct phenotypes or endotypes. Herein, in this review we discuss on currently used and novel biomarkers for the diagnosis and treatment of asthma.

Microbiota Associations with Inflammatory Pathways in Asthma

BACKGROUND

The airway microbiota plays an important role in asthma pathophysiology. However, the relationship between the airway microbiota and asthma phenotypes is still poorly understood.

OBJECTIVE

We aimed to characterize the airway microbiota in asthma patients and determine its correlation with airway inflammatory phenotypes and other phenotypic characteristics.

METHODS

The microbial composition of induced sputum specimens collected from asthma patients was determined using 16S rDNA gene sequencing.

RESULTS

Patients with asthma had a higher abundance of bacterial taxa associated with Bacteroidetes, Fusobacteria, and Proteobacteria and a reduced abundance of Firmicutes and Actinobacteria compared to healthy controls. This study classified the asthma-associated lung microbiota into three community types based on DMM models, which were defined as three pulmotypes (P1, P2, and P3). The lungs of patients with pulmotype 3 (P3) were dominated by Faecalibacterium and Bacteroides, while patients with pulmotype 1 (P1) had a greater abundance of Pasteurellaceae, Streptococcus, and Rothia. P1 patients were older (p = 0.045) and had lower blood TGF levels (P=0.028). P3 patients had fewer eosinophils (P=0.016) and more neutrophils (P=0.039) in induced sputa than P1 patients.

CONCLUSIONS

Differences in asthma-associated airway microbiota pulmotypes are associated with and might influence asthma, particularly inflammatory phenotypes.

Effects of obesity on pulmonary function considering the transition from obstructive to restrictive pattern from childhood to young adulthood

Adults with obesity exhibit a restrictive pattern, whereas children with obesity exhibit an obstructive pattern. However, the transition process remains unclear. We performed a systematic search for studies reporting on body mass index and pulmonary function in children. The main outcomes were forced expiratory volume in 1 s (FEV₁ ), forced vital capacity (FVC), and their ratio (FEV₁ /FVC). We compared individuals with overweight or with obesity with individuals with normal weight. Random-effects models were used to calculate pooled estimates. A total of 17 studies were included. Individuals with obesity had a lower FEV₁ /FVC ratio (mean difference [MD] = -3.61%; 95% confidence interval [CI] = -4.58%, -2.64%) and a higher percent-predicted FVC (MD = 3.33%; 95% CI = 0.79%, 5.88%) than those with normal weight. Obesity impaired pulmonary function in the obstructive pattern during childhood to young adulthood, and the maximum obstruction was observed at the age of 16 years in boys and 20 years in girls. The effects attenuated at approximately 30 years and then shifted to the restrictive pattern after 35 years of age in men and 40 years in women. The effects of obesity on pulmonary function change from the obstructive pattern in childhood to the restrictive pattern in adulthood.

Distribution of inflammatory phenotypes among patients with asthma in Jilin Province, China: a cross-sectional study

Background

The inflammatory phenotypes of asthma predict the treatment response and prognosis. The phenotype distributions differ depending on the geographical region. This study aimed to assess the distribution of different inflammatory phenotypes among asthma patients in Jilin Province, China.

Methods

A total of 255 patients with asthma were recruited from Jilin Province, China for this cross-sectional study. Each patient underwent sputum induction following clinical assessment and peripheral blood collection. Inflammatory phenotypes were classified according to the inflammatory cell counts in the sputum.

Results

Paucigranulocytic asthma (PGA) was the most common inflammatory phenotype (52.2%), followed by eosinophilic asthma (EA, 38.3%), mixed granulocytic asthma (MGA, 5.2%), and neutrophilic asthma (NA, 4.3%). NA was more common among patients over 45 years old and those who were treated with higher doses of inhaled corticosteroids (ICS), but was less common following antibiotics treatment (p < 0.05). The proportion of patients with EA decreased as the ICS treatment dose and time increased (p = 0.038). Patients with uncontrolled asthma had higher numbers of sputum eosinophils and neutrophils (p < 0.05). Patients with severe asthma had a higher percentage of sputum neutrophils (p < 0.05). A greater proportion of patients with NA had severe asthma (60%) compared to those with EA (18.2%) (p = 0.016).

Conclusions

The most common asthma inflammatory cell phenotype in Jilin Province, China is PGA, followed by EA, MGA, and NA. The low prevalence of NA in Jilin Province compared to other countries and also other regions in China might be due to excessive antibiotic use and irregular ICS treatment in this region.

Treatment Response Biomarkers in Asthma and COPD

Chronic obstructive pulmonary disease (COPD) and asthma are two of the most common chronic diseases worldwide. Both diseases are heterogenous and complex, and despite their similarities, they differ in terms of pathophysiological and immunological mechanisms. Mounting evidence supports the presence of several phenotypes with various responses to treatment. A systematic and thorough assessment concerning the diagnosis of both asthma and COPD is crucial to the clinical management of the disease. The identification of different biomarkers can facilitate targeted treatment and monitoring. Thanks to the presence of numerous immunological studies, our understanding of asthma phenotypes and mechanisms of disease has increased markedly in the last decade, and several treatments with monoclonal antibodies are available. There are compelling data that link eosinophilia with an increased risk of COPD exacerbations but a greater treatment response and lower all-cause mortality. Eosinophilia can be considered as a treatable trait, and the initiation of inhaled corticosteroid in COPD patients with eosinophilia is supported in many studies. In spite of advances in our understanding of both asthma and COPD in terms pathophysiology, disease mechanisms, biomarkers, and response to treatment, many uncertainties in the management of obstructive airways exist.

Asthma Across the Ages: Adults

Asthma is a common disease affecting approximately 300 million people worldwide, across all age ranges. Despite advances in asthma outcomes of the last few decades, there remains room for improvement in asthma management and for patient outcomes, particularly in older patients. The heterogeneity of asthma is now well recognized, and is known to complicate response to treatment and patient behavior and impact health outcomes. Asthma and its heterogeneity change according to age. Asthma affects people differently across the life span. In adults, prevalence is highest among those in middle age; however, mortality is greater in the older age group. In this clinical commentary, we describe how age impacts asthma prevalence and incidence, outcomes, disease expression, and approach to management in adulthood and in older patients.

Characteristics of inflammatory phenotypes among patients with asthma: relationships of blood count parameters with sputum cellular phenotypes

BACKGROUND

There is a need to identify the asthma inflammatory phenotypes of patients to facilitate personalized asthma treatment. Sputum induction is time-consuming and requires expert clinical technique. This study aimed to assess the distribution and characteristics of asthma inflammatory phenotypes in Jilin Province, China; it also aimed to identify an easier method for characterization of an asthma phenotype, rather than sputum cellular analysis.

METHODS

In this study, 232 asthma patients underwent sputum induction following clinical assessment and blood collection. Inflammatory cell counts in sputum were used to classify asthma inflammatory phenotypes. Receiver operating characteristic curve and Spearman correlation coefficient analyses were used to identify correlations between clinical parameters.

RESULTS

Among the included patients, there had 52.1% paucigranulocytic, 38.4% eosinophilic, 4.3% neutrophilic, and 5.2% mixed granulocytic asthma phenotypes, respectively. In total, 129 (55.6%) patients had asthma-chronic obstructive pulmonary disease (COPD) overlap (ACO); these patients had higher proportion of smokers, higher sputum neutrophil count, worse lung function, and worse asthma control, compared with patients who had asthma alone (p < 0.05). Sputum eosinophil/neutrophil counts were positively correlated with blood eosinophil/neutrophil counts (p < 0.01). To identify the presence of sputum eosinophil proportion ≥ 3%, optimal cut-off values for blood eosinophil count and fractional exhaled nitric oxide (FeNO) were 0.2 × 10⁹/L and 30.25 ppd (area under the curve (AUC) = 0.744; AUC = 0.653, p < 0.001). AUCs did not significantly differ between FeNO and blood eosinophil count (p = 0.162), but both exhibited poor specificity (57% and 49%, respectively). To identify the presence of sputum neutrophil proportion ≥ 61%, the optimal cut-off value for blood neutrophil proportion was 69.3% (AUC = 0.691, p = 0.0003); however, this exhibited poor sensitivity (50%).

CONCLUSIONS

Paucigranulocytic asthma was the most common phenotype, followed by eosinophilic asthma. Higher proportion of smokers, poor patient compliance, insufficient treatment, and poor asthma control may have been the main causes of high ACO proportion among patients in this study. Blood eosinophil/neutrophil counts exhibited poor specificity and sensitivity for prediction of airway eosinophilic/neutrophilic inflammation.

Neutrophils in asthma: the good, the bad and the bacteria

Airway inflammation plays a key role in asthma pathogenesis but is heterogeneous in nature. There has been significant scientific discovery with regard to type 2-driven, eosinophil-dominated asthma, with effective therapies ranging from inhaled corticosteroids to novel biologics. However, studies suggest that approximately 1 in 5 adults with asthma have an increased proportion of neutrophils in their airways. These patients tend to be older, have potentially pathogenic airway bacteria and do not respond well to classical therapies. Currently, there are no specific therapeutic options for these patients, such as neutrophil-targeting biologics.Neutrophils comprise 70% of the total circulatory white cells and play a critical defence role during inflammatory and infective challenges. This makes them a problematic target for therapeutics. Furthermore, neutrophil functions change with age, with reduced microbial killing, increased reactive oxygen species release and reduced production of extracellular traps with advancing age. Therefore, different therapeutic strategies may be required for different age groups of patients.The pathogenesis of neutrophil-dominated airway inflammation in adults with asthma may reflect a counterproductive response to the defective neutrophil microbial killing seen with age, resulting in bystander damage to host airway cells and subsequent mucus hypersecretion and airway remodelling. However, in children with asthma, neutrophils are less associated with adverse features of disease, and it is possible that in children, neutrophils are less pathogenic.In this review, we explore the mechanisms of neutrophil recruitment, changes in cellular function across the life course and the implications this may have for asthma management now and in the future. We also describe the prevalence of neutrophilic asthma globally, with a focus on First Nations people of Australia, New Zealand and North America.

Asthma phenotypes and endotypes in childhood

Asthma is a very heterogeneous disease and since early childhood many classifications have been proposed according to phenotype and endotype. The phenotype includes the clinical features of asthma such as age of onset, triggers, comorbidities, response to treatment and evolution over time. The endotype is more difficult to define, includes the underlying immunopathological mechanisms of the disease and requires reliable biomarkers. A deep knowledge of phenotype and endotype of the patient may guide a tailored therapeutic approach. In this review the main phenotypes and endotypes of asthma acknowledged in children will be discussed.

Comparative analysis of clinical, physiological, temperamental and personality characteristics of elderly subjects and young subjects with asthma

BACKGROUND

Asthma is a heterogeneous disease of a complex etiology in which genetic, environmental and personality variables are important factors determining the development of complicated strategies related to coping with stress and temperament traits. Our thesis is that coping styles in asthmatic patients are modified by the environment (chronic inflammation and stress) which affects individual temperament traits in the course of time. Thus, patient age is one of factors which determine the clinical image of asthma and its natural history.

AIM

The aim of the study was to evaluate the variables describing stress coping styles and temperament in young (18 to 35 years old) and elderly asthmatics (aged ≥60 years).

MATERIAL AND METHODS

A total of 200 patients, 104 elderly and 96 young asthmatics were enrolled in the study. Apart from medical examination, the following tests were performed in all subjects: the Formal Characteristics of Behavior- Temperament Inventory (FCB-TI), Coping Inventory for Stressful Situations (CISS), Beck Depression Inventory, State-Trait Anxiety Inventory, and Borg Rating of Perceived Exertion (RPE) Scale.

RESULTS

Elderly patients with asthma exhibited higher intensity of anxiety as a trait, a higher level of depression and experienced dyspnea, as well as higher levels of stress coping strategies such as Avoidance-Oriented Coping (AOC), Distraction Seeking (DS) and Social Diversion (SD) compared to young asthmatics. In elderly patients, Perseverance and Sensory Sensitivity traits have been observed to decline with the duration and development of asthma at later life stages as opposed to young asthmatics, in whom these temperament characteristics are elevated.

CONCLUSIONS

Asthma is a heterogeneous disease of a complex etiopathogenesis that has a complex interplay with mental health. The present study confirms a relationship between age and stress coping strategies as well as temperament traits.

Targeting neutrophils in asthma: A therapeutic opportunity?

Suppression of airway inflammation with inhaled corticosteroids has been the key therapeutic approach for asthma for many years. Identification of inflammatory phenotypes in asthma has moreover led to important breakthroughs, e.g. with specific targeting of the IL-5 pathway as add-on treatment in difficult-to-treat eosinophilic asthma. However, the impact of interfering with the neutrophilic component in asthma is less documented and understood. This review provides an overview of established and recent insights with regard to the role of neutrophils in asthma, focusing on research in humans. We will describe the main drivers of neutrophilic responses in asthma, the heterogeneity in neutrophils and how they could contribute to asthma pathogenesis. Moreover we will describe findings from clinical trials, in which neutrophilic inflammation was targeted. It is clear that neutrophils are important actors in asthma development and play a role in exacerbations. However, more research is required to fully understand how modulation of neutrophil activity could lead to a significant benefit in asthma patients with airway neutrophilia.

Serum potential biomarkers according to sputum inflammatory cell profiles in adult asthmatics

BACKGROUND/AIMS

Asthma is not a single disease but, rather, a heterogeneous inf lammatory disorder with various pathogenic mechanisms. We analyzed the associations between the cellular profile of sputum and the serum levels of inflammatory mediators/cytokines in a cohort of adult asthmatics.

METHODS

We recruited 421 adult asthmatic patients. All subjects were classified into four groups according to their sputum cellular profiles: G1, eosinophilic; G2, mixed granulocytic; G3, neutrophilic; and G4, paucigranulocytic. Serum levels of cytokines and mediators including periostin, eosinophil-derived neurotoxin (EDN), S100A9, and folliculin were quantified.

RESULTS

Among 421 patients, G1 accounted for 149 (35.4%), G2 for 71 (16.9%), G3 for 155 (36.8%), and G4 for 46 (10.9%). Serum periostin and EDN levels were significantly higher in G1 (p = 0.004, and p = 0.031) than in the others. Serum S100A9 levels were elevated in G2 and G3 (p = 0.008). Serum folliculin levels differed significantly among the four groups, with the highest level in G4 (p = 0.042). To identify G1 from G1 plus G2 groups, the optimal serum cut-off levels were 1.71 ng/mL for periostin, and 1.61 ng/mL for EDN. When these two parameters were combined, the sensitivity was 76.0% and the specificity was 64.3% (area under the curve, 0.701; p = 0.004).

CONCLUSION

The serum periostin and EDN levels may be used as predictors to discriminate the eosinophilic asthma group from patients having eosinophilic or mixed granulocytic asthma, and the serum folliculin level is significantly elevated in patients with paucigranulocytic asthma compared to those with different inflammatory cell profile.

Relationship between airway inflammation and airflow limitation in elderly asthmatics

Background

The prevalence of asthma in elderly population has been increasing. Previous studies have demonstrated clinical characteristics of elderly asthmatics (EA). However, little is known regarding the influence of immunological change on the physiological status of EA.

Objective

We investigated the relationship between inflammatory mediators and the pulmonary function (PF) of EA.

Methods

Eligible adult asthmatics recruited from the Allergy Center of Saitama Medical University Hospital were classified into a non-EA group (<40 years old, n = 15) and an EA group (≥60 years old, n = 43). Sputum induction and PF tests were performed. Concentrations of an eosinophil-derived neurotoxin (EDN) and neutrophil elastase (NE) in sputum supernatants were measured by enzyme-linked immunosorbent assay and a fluorometric assay using a commercial assay kit, respectively. Cell counts and EDN and NE concentrations in sputum were compared between the 2 groups. The association among those parameters and PF were analyzed in each group.

Results

The EA group had a significantly higher severe asthmatics proportion (p = 0.01), a lower current smokers proportion (p = 0.002), lower sensitization rate to aeroallergens (p = 0.012), several PFs deterioration (p < 0.0001) and lower total IgE levels (p = 0.001) than the non-EA group. Sputum neutrophil counts and NE concentrations were significantly higher in the EA group than those in the non-EA group (median neutrophil: 4.11 vs. 2.74 ×10⁵/mL, p = 0.03; NE: 2.0 vs.1.6 µg/mL, p < 0.05, respectively), whereas sputum eosinophil counts and EDN concentrations were not. Sputum EDN concentrations were significantly positively correlated with sputum neutrophil counts (r = 0.39, p = 0.031) and NE concentrations (r = 0.57, p < 0.0001) only in the EA group. Eosinophil-related parameters were negatively correlated with several PFs in the 2 groups. Neutrophil-related parameters were negatively correlated with PFs only in the non-EA group.

Conclusion

This study determines that in EA, persistent active eosinophilic airway inflammation is accompanied by advanced neutrophilic inflammation, which may contribute to deteriorated PF. This distinct airway inflammation may increase the severity of asthma in EA.

New insights in neutrophilic asthma

PURPOSE OF REVIEW

Recent advances in both murine models and clinical research of neutrophilic asthma are improving our understanding on the etiology and pathophysiology of this enigmatic endotype of asthma. We here aim at providing an overview of our current and latest insights on the pathophysiology and treatment of neutrophilic asthma.

RECENT FINDINGS

Activation of the NLRP3 inflammasome pathway with increased IL-1β has been demonstrated in various studies involving patients with asthma. It has been suggested that type 3 innate lymphoid cells are implicated in the inflammatory cascade leading to neutrophilic inflammation. The role of neutrophil extracellular traps is only at the start of being understood and might be an attractive novel therapeutic target. A diverse panel of nonallergic stimuli, such as cigarette smoke, intensive exercise, cold air or saturated fatty acids, have been linked with neutrophilic airway inflammation. Azithromycin treatment could reduce asthma exacerbations and quality of life in patients with persistent asthma.

SUMMARY

Research of the last few years has accelerated our insights in mechanisms underlying neutrophilic asthma. This is in stark contrast with the lack of efficacy of different therapies targeting neutrophil chemotaxis and/or signalling cascade, such as IL-17A or CXCR2. Macrolide therapy might be a useful add-on therapy for patients with persistent asthma.

Severe asthma phenotypes and endotypes

Current management of severe asthma relying either on guidelines (bulk approach) or on disease phenotypes (stratified approach) did not improve the burden of the disease. Several severe phenotypes are described: clinical, functional, morphological, inflammatory, molecular and microbiome-related. However, phenotypes do not necessarily relate to or give insights into the underlying pathogenetic mechanisms which are described by the disease endotypes. Based on the major immune-inflammatory pathway involved type-2 high, type-2 low and mixed endotypes are described for severe asthma, with several shared pathogenetic pathways such as genetic and epigenetic, metabolic, neurogenic and remodelling subtypes. The concept of multidimensional endotyping as un unbiased approach to severe asthma is discussed, together with new tools and targets facilitating the shift from the stratified to the precision medicine approach.

Chronic rhinosinusitis in elderly patients is associated with an exaggerated neutrophilic proinflammatory response to pathogenic bacteria

BACKGROUND

Potential effects of aging on chronic rhinosinusitis (CRS) pathophysiology have not been well defined but might have important ramifications given a rapidly aging US and world population.

OBJECTIVE

The goal of the current study was to determine whether advanced age is associated with specific inflammatory CRS endotypes or immune signatures.

METHODS

Levels of 17 mucus cytokines and inflammatory mediators were measured in 147 patients with CRS. Hierarchical cluster analysis was used to identify and characterize inflammatory CRS endotypes, as well as to determine whether age was associated with specific immune signatures.

RESULTS

A CRS endotype with a proinflammatory neutrophilic immune signature was enriched in older patients. In the overall cohort patients 60 years and older had increased mucus levels of IL-1β, IL-6, IL-8, and TNF-α when compared with their younger counterparts. Increases in levels of proinflammatory cytokines were associated with both tissue neutrophilia and symptomatic bacterial infection/colonization in aged patients.

CONCLUSIONS

Aged patients with CRS have a unique inflammatory signature that corresponds to a neutrophilic proinflammatory response. Neutrophil-driven inflammation in aged patients with CRS might be less likely to respond to corticosteroids and might be closely linked to chronic microbial infection or colonization.

Factors reducing omalizumab response in severe asthma

BACKGROUND

Despite adding Omalizumab to conventional therapy, several severe asthmatics still show poor disease control. We investigated the factors that may affect a reduced Omalizumab response in a large population of severe asthmatics.

METHODS

340 patients were retrospectively evaluated. FEV₁%, FVC%, Asthma Control Test (ACT), fractional exhaled nitric oxide (FENO), possible step-downs/step-ups of concomitant therapies, exacerbations, disease control levels, ICS doses and SABA use, observed at the end of treatment, were considered as a response to Omalizumab.

RESULTS

Age was an independent risk factor for a reduced response concerning FEV₁%, FVC%, ACT and for a lower asthma control. Obesity (vs normal weight) was a determinant condition for exacerbations (OR:3.114[1.509-6.424], p = 0.002), for a disease partial/no control (OR:2.665[1.064-6.680], p = 0.036), for excessive SABA use (OR:4.448[1.837-10.768], p = 0.002) and for an unchanged/increased level of concomitant asthma medications. Furthermore, obesity also reduced the response in FEV₁ (β = -6.981,p = 0.04), FVC (β = -11.689,p = 0.014) and ACT (β = -2.585, p = 0.027) and was associated with a higher FENO level (β = 49.045,p = 0.040). Having at least one comorbidity was a risk factor for exacerbations (OR:1.383[1.128-1.697], p = 0.008) and for an ACT <20 (OR:2.410[1.071-3.690], p = 0.008). Specifically, chronic heart disease was associated with both a lower ACT and FVC% whereas gastroesophageal reflux with a partial/no asthma control. Nasal polyps were a predisposing factor leading both to exacerbations and to the use of higher inhaled corticosteroids doses. Moreover, smoking habits, pollen or dog/cat dander co-sensitizations may negatively influence Omalizumab response.

CONCLUSION

Age, obesity, comorbidities, smoking habits, nasal polyps, allergic poly-sensitization might reduce Omalizumab effectiveness independently to other asthma-influencing factors.

Role of sputum biomarkers in the management of asthma

PURPOSE OF REVIEW

Airway inflammation is considered to be a cardinal feature of asthma. However, the type of airway inflammation is heterogeneous and airway inflammation may even be absent. Biomarkers may help to identify the inflammatory phenotype or endotype, especially now the time has come that targeted therapies enter daily practice.

RECENT FINDINGS

Sputum biomarkers have increased our insights into the different inflammatory asthma phenotypes, their response to treatment and their association with progression of disease. New endotypes of type 2 driven inflammation were identified using a multidimensional approach. A specific mast cell subtype has been linked with type 2 driven inflammation and response to inhaled corticosteroids. Advances have been made with regard to sputum cytokine analysis and might also help to guide future treatment of severe asthma.

SUMMARY

Identifying the target population for biological therapies will not be possible without the use of biomarkers. Optimized, easy-to-apply, automated methods for sputum analysis (cellular content or soluble markers) need to be developed for implementation of sputum biomarkers in daily clinical practice.

An Official American Thoracic Society Workshop Report: Evaluation and Management of Asthma in the Elderly

Asthma in the elderly (>65 yr old) is common and associated with higher morbidity and mortality than asthma in younger patients. The poor outcomes in this group are due, in part, to underdiagnosis and undertreatment. There are a variety of factors related to aging itself that affect the presentation of asthma in the elderly and influence diagnosis and management. Structural changes in the aging lung superimposed on structural changes due to asthma itself can worsen the disease and physiologic function. Changes in the aging immune system influence the cellular composition and function in asthmatic airways. These processes and differences from younger individuals with asthma are not well understood. Phenotypes of asthma in the elderly have not been clearly delineated, but it is likely that age of onset and overlap with chronic obstructive pulmonary disease impact disease characteristics. Physiologic tests and biomarkers used to diagnose and follow asthma in the elderly are generally similar to testing in younger individuals; however, whether they should be modified in aging has not been established. Confounding influences, such as comorbidities (increasing the risk of polypharmacy), impaired cognition and motor skills, psychosocial effects of aging, and age-related adverse effects of medications, impact both diagnosis and treatment of asthma in the elderly. Future efforts to understand asthma in the elderly must include geriatric-specific methodology to diagnose, characterize, monitor, and treat their disease.

Methodology for Sputum Induction and Laboratory Processing

The technique of sputum induction and processing is a recognized non-invasive method allowing the collection and analysis of cells from the airways, which is interesting in various respiratory diseases like asthma, chronic obstructive pulmonary disease (COPD), chronic cough, or idiopathic pulmonary fibrosis. This technique is well tolerated, safe and non-invasive, but is currently limited to research services and specialized centers in clinical practice because it is technically demanding, time-consuming, and requires trained staff. The success rate of sputum induction and analysis is about 80%. Here, we describe the induction and laboratory processing of sputum samples. Sputum is induced by inhalation of hypertonic or isotonic saline with salbutamol. For the processing, we use the whole sputum technique. Dithiothreitol (DTT) is used to allow mucolysis of sputum samples. The primary aim of sputum processing is to obtain a differential cell count to study the cell types present in the airway lumen. Additional analyses may also be performed on sputum supernatant and sputum cells, which may allow further investigation into inflammatory processes and immune mechanisms. Examples include studying mediators in sputum supernatant and performing a large spectrum of analysis on sputum cells such as flow cytometry, genomics, or proteomics. Finally, representative results of sputum analysis in healthy controls, asthmatics, and COPD patients are presented.

Effects of treatment changes on asthma phenotype prevalence and airway neutrophil function

Background

Asthma inflammatory phenotypes are often defined by relative cell counts of airway eosinophils/neutrophils. However, the importance of neutrophilia remains unclear, as does the effect of ICS treatment on asthma phenotypes and airway neutrophil function. The purpose of this study was to assess asthma phenotype prevalence/characteristics in a community setting, and, in a nested preliminary study, determine how treatment changes affect phenotype stability and inflammation, with particular focus on airway neutrophils.

Methods

Fifty adult asthmatics and 39 non-asthmatics were assessed using questionnaires, skin prick tests, spirometry, exhaled nitric oxide (FENO) measurement, and sputum induction. Twenty-one asthmatics underwent further assessment following treatment optimisation (n = 11) or sub-optimisation (n = 10).

Results

Forty percent (20/50) had eosinophilic asthma (EA) and 8% had neutrophilic asthma. EA was associated with increased FENO, bronchodilator reversibility (BDR) and reduced lung function (p < 0.05). Following optimisation/sub-optimisation, the EA/NEA (non-eosinophilic asthma) phenotype changed in 11/21 (52%) asthmatics. In particular, fewer subjects had EA post treatment optimisation, but this was not statistically significant. However, a significant (p < 0.05) reduction in FENO, ACQ7 score, and BDR was observed after treatment optimisation, as well as an increase in FEV₁-% predicted (p < 0.05). It was also associated with reduced eosinophils (p < 0.05) and enhanced neutrophil phagocytosis (p < 0.05) in EA only, and enhanced neutrophil oxidative burst in both EA and NEA (p < 0.05).

Conclusions

In this community based population, non-eosinophilic asthma was common, less severe than EA, and at baseline most asthmatics showed no evidence of inflammation. In the nested change in treatment study, treatment optimisation was associated with reduced sputum eosinophils, improved symptoms and lung function, and enhanced neutrophil function, but a significant reduction in EA could not be demonstrated.

Trial registration

The nested change in treatment component of this study is registered at the Australia and New Zealand Clinical Trial Registry (www.ANZCTR.org.au) ACTRN12617001356358. Registration date 27/09/2017. Retrospectively registered.

Electronic supplementary material

The online version of this article (10.1186/s12890-017-0511-6) contains supplementary material, which is available to authorized users.

Sputum colour can identify patients with neutrophilic inflammation in asthma

Introduction

Sputum colour is associated with neutrophilic inflammation in chronic bronchitis and chronic obstructive pulmonary disease (COPD). Neutrophilia and sputum expectoration is notable in asthma, but whether sputum colour is associated with and predicts the presence of neutrophilic inflammation in asthma is unknown. The objective of the study is to assess the ability of sputum colour in distinguishing asthma inflammatory phenotypes.

Methods

Induced sputum samples collected from 271 adults with stable asthma were retrospectively assessed. Sputum colour was determined using the BronkoTest sputum colour chart and correlated to differential cell counts and CXCL-8 concentration. Neutrophilic inflammation was defined as an age-corrected sputum neutrophil proportion (≥61.6% for age 20–40 years; ≥63.2% for age 40–60 and ≥67.2% for age >60 years), whereas neutrophilic bronchitis (NB) was defined as high total cell count (≥5.1×10⁶ cells/mL) plus an increased age-corrected neutrophil proportion. The optimal cut-off for sputum colour to predict neutrophilic inflammation and NB was determined using receiver operator characteristic curve analysis.

Results

A sputum colour score of ≥3 represented and predicted neutrophilic inflammation with modest accuracy (area under the curve (AUC)=0.64; p<0.001, specificity=78.4%, sensitivity=49.2%). Participants with a sputum colour score of ≥3 had significantly (p<0.05) higher CXCL-8, total cells and neutrophil number and proportion. Sputum colour score was also positively correlated with these factors. Sputum colour score ≥3 predicted NB with reasonably good accuracy (AUC=0.79, p<0.001, specificity=79.3%, sensitivity=70.7%).

Conclusions

Visual gradation of sputum colour in asthma relates to high total cell count and neutrophilic inflammation. Assessment of sputum colour can identify adults with asthma who are likely to have NB without the need for sputum processing and differential cell count, which may facilitate asthma management.

Comparative Clinical, Physiological, and Inflammatory Characteristics of Elderly Subjects With or Without Asthma and Young Subjects With Asthma

BACKGROUND

Asthma seems to present in the elderly as a specific phenotype that remains to be further described. In this prospective observational study, we aimed to assess the multidimensional aspects of asthma in the elderly.

METHODS

In young (18 to 35 years old) subjects with mild to moderate asthma and elderly subjects (aged ≥60 years) either with or without mild to moderate asthma, we compared asthma control, health care and medication use, lung function, markers of airway and systemic inflammation, and adherence to therapy.

RESULTS

Fifty subjects were recruited in each group. Elderly people with asthma showed more marked airway obstruction compared with young people with asthma and elderly people without asthma. They also had poorer asthma control, mainly associated with a lower FEV₁, compared with young people with asthma, although airway responsiveness, health care use, prescribed doses of inhaled corticosteroids, and adherence to treatment were similar in both groups. Elderly subjects had an increase in some markers of systemic inflammation and bronchial epithelial dysfunction compared with young people with asthma. Blood eosinophils were higher in both asthma groups, particularly in elderly people with asthma. Sputum neutrophils were increased in both groups of elderly subjects and sputum eosinophils were increased in elderly people with asthma compared with the other two groups.

CONCLUSIONS

Asthma in the elderly presents as a specific phenotype associated with increased airway obstruction and mixed airway inflammation in addition to signs of systemic inflammation.

Severe therapy resistant asthma in children: translational approaches to uncover sub-phenotypes

INTRODUCTION

Paediatric severe therapy resistant asthma (STRA) affects a very small proportion of all children with asthma, but results in significant morbidity, has a high risk of mortality and utilises approximately half of all healthcare resources for childhood asthma. children with STRA need add-on 'beyond guidelines' therapies because of poor control despite maximal conventional treatments and optimisation of basic asthma management. however, STRA is heterogeneous with marked phenotypic variation between patients and mechanisms from adult severe asthma cannot be extrapolated to children. Areas covered: This review will cover our current knowledge of paediatric STRA pathophysiology, with examples of translational approaches that have been used to define sub-phenotypes including; 1. pre-clinical age-appropriate models using clinically relevant allergens, 2. in vitro techniques incorporating complex co-cultures of structural and inflammatory cells, and 3. techniques that allow detailed cellular immunophenotyping of small airway samples will be discussed. Studies using these approaches that have demonstrated the importance of the innate mediator IL-33 and vitamin D deficiency in severe steroid resistant disease will also be discussed. Expert commentary: These experimental approaches allow investigation of age and disease specific molecular pathways and the development of personalised therapies that can be stratified and targeted to sub-phenotypes of paediatric STRA.

Reference value of induced sputum cell counts and its relationship with age in healthy adults in Guangzhou, Southern China

PURPOSE

To establish the reference value of total and differential cell counts in induced sputum in healthy adults in Guangzhou, and to explore the relationship of age and gender with sputum cell counts.

METHODS

A total of 185 healthy, nonatopic, never-smokers between 19 and 74 years old underwent induced sputum test with hypertonic saline (3%) inhalation. Sputum samples were collected for total and differential cell counts.

RESULTS

Qualified sputum samples were obtained from 153 subjects (mean age: 43 ± 17) with a success rate of 82.7% (153/185). The mean Standard Deviation (STDEV) and 2.5% to 97.5% percentile total cell counts were 2.1 × 106/g (1.0), (.7-4.5 × 106/g). The mean STDEV and 2.5% to 97.5% percentile differential cell counts were as follows: neutrophil 38.3% (17.7), (8.9%-72.9%); macrophage 58.9% (17.7), (24.7%-90.0%); eosinophils: median, .3%; interquartile range (IQR), 1.1%; and .0% to 95.0% percentile, .0% to 2.0%; and lymphocytes: median, 1.0%; IQR, 1.8%; and .0% to 95.0% percentile, .0% to 4.5%. There was positive correlation of age with the percentage of neutrophil and eosinophil (r = .659, r = .402; P < .001). The percentage of neutrophil, macrophage and eosinophil were significantly different among different age groups. The total cell counts and sputum cell counts were comparable between males and females.

CONCLUSIONS

This study initially establishes reference value of induced sputum cell counts in healthy adults in Guangzhou, Southern China, and it verifies that neutrophilic and eosinophilic counts increase by age.

Characteristics of non-smoking adult asthma patients with chronic airflow limitation

OBJECTIVE

Chronic airflow limitation (CAL) can develop in a subgroup of patients with asthma. Characterising these patients is important because reduced lung function is a risk factor for adverse asthma outcomes. We hypothesised that heterogeneity in patients with CAL may be influenced by age at asthma onset. We first compared never-smoking asthma patients with and without CAL, and subsequently examined the differences between patients with late and early-onset asthma within the CAL cohort.

METHODS

Patients seen in our hospital's respiratory clinic between 1 Jan 2015 and 31 December 2015 were recruited to the study. CAL was defined as post-bronchodilator forced expiratory volume in 1 second (FEV1)<80% predicted, in the presence of post-bronchodilator ratio <70%. Variables independently associated with CAL were determined using a multivariate logistic regression model. Comparisons between patients with late-onset asthma (age ≥18 years) and early-onset asthma were made within the CAL cohort.

RESULTS

247 patients were included in the study. Age was the only variable independently associated with CAL after regression analysis, with an increase in odds of 3.8% (95% CI 0.4-7.3%) for every 1 year increase in age, p = 0.027. 63.2% of patients with CAL had late-onset asthma. Compared to patients with early-onset asthma, those with late-onset asthma had higher fractional exhaled nitric oxide levels (43 ± 32 ppb vs 20 ± 8 pb, p = 0.008).

CONCLUSIONS

An increase in age is associated with CAL in never-smoking asthma patients. In addition, age at asthma onset appears to influence airway inflammation in patients with CAL.

Airway and serum biochemical correlates of refractory neutrophilic asthma

Background

Despite progress in the diagnosis and management of asthma, many patients have poorly controlled or refractory asthma (RA). The mechanism of this RA is not well understood.

Objective

We sought to explore the relationship between neutrophils and other biomarkers of RA.

Method

Sixty patients with RA, 30 patients with nonrefractory asthma (NRA), and 20 healthy subjects were enrolled. We performed a comprehensive characterization of these study subjects, which included laboratory and pulmonary function studies, chest computed tomography, and bronchoscopy with bronchoalveolar lavage (BAL). We analyzed BAL fluid and serum for a total of 244 biomolecules using a multiplex assay and correlated them with clinical and other laboratory parameters.

Results

RA was significantly different from NRA with regard to pulmonary function indices, bronchial basement membrane thickness, and BAL fluid neutrophil and lymphocyte counts but not eosinophil counts. BAL fluid neutrophil counts negatively and positively correlated with forced vital capacity and age, respectively. Of the 244 biomolecules studied, 52 and 14 biomolecules from BAL fluid and serum, respectively, were significantly different among the study groups. Thirteen of these 52 molecules correlated with BAL fluid neutrophil counts. BAL fluid from 40% of patients with RA was positive for a pathogenic microbe. Infection-negative neutrophilic RA was associated with an increase in levels of select biomarkers of inflammation in the serum, suggesting the presence of systemic inflammation.

Conclusions

RA was associated with increased numbers of neutrophils and proneutrophilic biomolecules in the airways. Subclinical infection was present in 40% of patients with RA, which likely contributed to neutrophilic inflammation. A subgroup of patients with noninfected neutrophilic RA was associated with systemic inflammation.

Effect of aging on sputum inflammation and asthma control

BACKGROUND

Aged asthmatic patients experience increased morbidity and mortality. Knowledge of the aging effect on airway inflammation and asthma control is limited.

OBJECTIVE

We sought to compare airway inflammation and its relationship to asthma control in aged versus younger patients and determine whether differences are asthma specific or caused by "inflamm-aging."

METHODS

We performed a prospective study of aged (>60 years) and younger (21-40 years) inner-city patients with asthma. After a run-in period to control for inhaled corticosteroid use, induced sputum was collected. Age-matched nonasthmatic control subjects were included to measure age-related inflammatory changes.

RESULTS

Aged (mean age, 67.9 ± 5.1 years; n = 35) compared with younger (mean age, 30.8 ± 5.9 years; n = 37) asthmatic patients had significantly worse asthma control and lower FEV₁. Aged asthmatic patients had higher sputum neutrophil (30.5 × 10⁴/mL and 23.1%) and eosinophil (7.0 × 10⁴/mL and 3.8%) numbers and percentages compared with younger patients (neutrophils, 13.0 × 10⁴/mL [P < .01] and 6.9% [P < .01]; eosinophils, 2.0 × 10⁴/mL [P < .01] and 1.2% [P < .01]). Aged asthmatic patients had higher sputum IL-6 (P < .01) and IL-8 (P = .01) levels. No significant inflammatory differences between aged and younger control subjects were observed. In aged asthmatic patients increased sputum IL-6 and macrophage inflammatory protein 3α/CCL20 levels were significantly associated with decreased asthma control and increased sputum neutrophil numbers and IL-1β, IL-6, and macrophage inflammatory protein 3α/CCL20 levels were associated with hospitalization.

CONCLUSIONS

The inflammatory patterns of aged versus younger asthmatic patients are associated with increased sputum neutrophil and eosinophil values and cytokine levels related to neutrophil recruitment. Differences in airway inflammation can contribute to diminished asthma control in the aged. Further understanding of asthma pathophysiology in aged patients is needed to improve management of this vulnerable population.

Effects of older age and age of asthma onset on clinical and inflammatory variables in severe refractory asthma

BACKGROUND

Asthma in the elderly as well as asthma of adult-onset has been associated with increased morbidity, but little is known specifically about the effects of age on clinical and inflammatory outcomes in severe refractory asthma. The aims of the study were to examine the effects of age [<65 versus ≥65 years] and age of onset of asthma [childhood-onset, <18 versus adult-onset, ≥18 years] on clinical and inflammatory variables in patients with severe asthma.

METHODS

In 1042 subjects with refractory asthma recruited to the British Thoracic Society Severe Asthma Registry, we compared patient demographics, disease characteristics and biomarkers of inflammation in patients aged <65 years (n = 896) versus ≥65 years (n = 146) and onset at age <18 years (n = 430) versus ≥18 years (n = 526).

RESULTS

Severe asthma patients aged ≥65 years had improved symptom control, better asthma quality of life and in the last year, less emergency visits and rescue oral steroid courses [3 (1-6) versus 5 (2-7), p < 0.001] than severe asthmatics aged <65 years. Blood eosinophils were lower in the elderly group. Patients with severe adult-onset asthma had similar symptom control, lung function and health-care utilization compared to severe childhood-onset asthma. Adult-onset asthmatics had higher blood eosinophils and were less atopic.

CONCLUSIONS

Patients with severe refractory asthma aged ≥65 years exhibit better clinical and health care outcomes and have lower blood eosinophils compared to those aged <65 years. Severe refractory adult-onset asthma is associated with similar levels of asthma control, higher blood eosinophils and less atopy than severe refractory childhood-onset asthma.

Novel approaches to the management of noneosinophilic asthma

Noneosinophilic airway inflammation occurs in approximately 50% of patients with asthma. It is subdivided into neutrophilic or paucigranulocytic inflammation, although the proportion of each subtype is uncertain because of variable cut-off points used to define neutrophilia. This article reviews the evidence for noneosinophilic inflammation being a target for therapy in asthma and assesses clinical trials of licensed drugs, novel small molecules and biologics agents in noneosinophilic inflammation. Current symptoms, rate of exacerbations and decline in lung function are generally less in noneosinophilic asthma than eosinophilic asthma. Noneosinophilic inflammation is associated with corticosteroid insensitivity. Neutrophil activation in the airways and systemic inflammation is reported in neutrophilic asthma. Neutrophilia in asthma may be due to corticosteroids, associated chronic pulmonary infection, altered airway microbiome or delayed neutrophil apoptosis. The cause of poorly controlled noneosinophilic asthma may differ between patients and involve several mechanism including neutrophilic inflammation, T helper 2 (Th2)-low or other subtypes of airway inflammation or corticosteroid insensitivity as well as noninflammatory pathways such as airway hyperreactivity and remodelling. Smoking cessation in asthmatic smokers and removal from exposure to some occupational agents reduces neutrophilic inflammation. Preliminary studies of 'off-label' use of licensed drugs suggest that macrolides show efficacy in nonsmokers with noneosinophilic severe asthma and statins, low-dose theophylline and peroxisome proliferator-activated receptor gamma (PPARγ) agonists may benefit asthmatic smokers with noneosinophilic inflammation. Novel small molecules targeting neutrophilic inflammation, such as chemokine (CXC) receptor 2 (CXCR2) antagonists reduce neutrophils, but do not improve clinical outcomes in studies to date. Inhaled phosphodiesterase (PDE)4 inhibitors, dual PDE3 and PDE4 inhibitors, p38MAPK (mitogen-activated protein kinase) inhibitors, tyrosine kinase inhibitors and PI (phosphoinositide) 3kinase inhibitors are under development and these compounds may be of benefit in noneosinophilic inflammation. The results of clinical trials of biological agents targeting mediators associated with noneosinophilic inflammation, such as interleukin (IL)-17 and tumor necrosis factor (TNF)-α are disappointing. Greater understanding of the mechanisms of noneosinophilic inflammation in asthma should lead to improved therapies.

Asthma in the elderly patient

Asthma affects a significant proportion of elderly patients, but unfortunately, it is responsible for a high asthma-related morbidity and mortality in this population. This may be related not only to the development of a more severe asthma phenotype compared to younger patients, with more marked airway obstruction and a more neutrophilic type of airway inflammation, but also to the presence of many co-morbid conditions. Furthermore, in older patients, asthma is often under-diagnosed, undertreated and poorly managed. Unfortunately, elderly patients have usually been excluded of clinical trials on asthma and there is an urgent need to perform more research on the optimal management of asthma in this population.

Paradoxical changes in innate immunity in aging: recent progress and new directions

Immunosenescence, describing alterations, including decline of immune responses with age, is comprised of inappropriate elevations, decreases, and dysregulated immune responses, leading to more severe consequences of bacterial and viral infections and reduced responses to vaccination. In adaptive immunity, these changes include increased proportions of antigen-experienced B and T cells at the cost of naïve cell populations. Innate immune changes in aging are complex in spanning multiple cell types, activation states, and tissue context. Innate immune responses are dampened in aging, yet there is also a paradoxical increase in certain signaling pathways and cytokine levels. Here, we review recent progress and highlight novel directions for expected advances that can lead the aging field to a new era of discovery that will embrace the complexity of aging in human populations.

Full blood count parameters for the detection of asthma inflammatory phenotypes

BACKGROUND

In asthma, the airway inflammatory phenotype influences clinical characteristics and treatment response. Although induced sputum is the gold standard test for phenotyping asthma, a more accessible method is needed for clinical practice.

OBJECTIVE

To investigate whether white blood cell counts and/or their derived ratios can predict sputum eosinophils or neutrophils in uncontrolled asthma.

METHODS

This cross-sectional study evaluated 164 treated but uncontrolled asthmatic patients with sputum induction and blood collection. Receiver-operating characteristic (ROC) curves were used to assess the relationship between blood and sputum parameters.

RESULTS

There was a significant positive relationship between blood eosinophil parameters and the percentage of sputum eosinophil count. A weak but significant correlation was found between sputum neutrophil percentage and blood neutrophil percentage (r = 0.219, P = 0.005). ROC curve analysis identified that blood eosinophil percentage count was the best predictor for eosinophilic asthma, with an area under the curve (AUC) of 0.907 (P < 0.001). The optimum cut-point for blood eosinophil percentage was 2.7%, and this yielded a sensitivity of 92.2% and a specificity of 75.8%. The absolute blood eosinophil count was also highly predictive with an AUC of 0.898 (P < 0.0001) at a blood eosinophil cut-off of 0.26 × 10(9) /L. The blood eosinophil/lymphocyte ratio (ELR) and eosinophil/neutrophil ratio (ENR) were increased in eosinophilic asthma, and the neutrophil/lymphocyte ratio (NLR) was increased in neutrophilic asthma. Neutrophilic asthma could also be detected by blood neutrophil percentages and NLR, but with less accuracy.

CONCLUSIONS AND CLINICAL RELEVANCE

Blood eosinophil counts and derived ratios (ELR and ENR) can accurately predict eosinophilic asthma in patients with persistent uncontrolled asthma despite treatment. Blood neutrophil parameters are poor surrogates for the proportion of sputum neutrophils. Blood counts may be a useful aid in the monitoring of uncontrolled asthma.

Occupational exposures, smoking and airway inflammation in refractory asthma

Background

The influence of occupation and ex/passive smoking on inflammatory phenotype is not well understood. The aim of this study was to examine the relationship between occupation, past smoking and current passive smoking and airway inflammation in a population of adults with refractory asthma.

Methods

Sixty-six participants with refractory asthma were characterised. Occupational exposure to asthma causing or worsening agents were identified with an asthma-specific job exposure matrix. Exposure to passive cigarette smoke was determined by questionnaire and exhaled carbon monoxide assessment. The carbon content of macrophages was assessed in a sub-group of participants.

Results

Nineteen participants had smoked previously with low smoking pack years (median 1.7 years). Ex-smokers more commonly lived with a current smoker (26% vs. 9%, p = 0.11) and were more likely to allow smoking inside their home (26% vs. 4%, p = 0.02) compared to never smokers. Twenty participants had occupations with an identified exposure risk to an asthmagen; thirteen had exposures to irritants such as motor vehicle exhaust and environmental tobacco smoke. Sputum neutrophils were elevated in participants with asthma who had occupational exposures, particularly those who were diagnosed with asthma at a more than 30 years of age.

Conclusions

Sputum neutrophils are elevated in refractory asthma with exposure to occupational asthmagens. In addition to older age, exposure to both environmental and occupational particulate matter may contribute to the presence of neutrophilic asthma. This may help explain asthma heterogeneity and geographical variations in airway inflammatory phenotypes in asthma.

Sputum ADAM8 expression is increased in severe asthma and COPD

BACKGROUND

Severe asthma and chronic obstructive pulmonary disease (COPD) are chronic inflammatory airway diseases in which the mechanisms are not fully understood. A disintegrin and metalloproteinase domain 8 (ADAM8) is an enzyme expressed on most leucocytes and may be important for facilitating leucocyte migration in respiratory disease.

OBJECTIVE

To investigate ADAM8 mRNA and protein expression in asthma and COPD and its relationship between asthma severity and inflammatory phenotypes.

METHODS

Induced sputum was collected from 113 subjects with asthma (severe n = 31, uncontrolled n = 39 and controlled n = 35), 20 subjects with COPD and 21 healthy controls. Sputum ADAM8 mRNA expression was measured by qPCR, and soluble ADAM8 (sADAM8) protein was measured in the sputum supernatant by validated ELISA.

RESULTS

ADAM8 mRNA correlated with ADAM8 protein levels (r = 0.27, P < 0.01). ADAM8 mRNA (P = 0.004) and sADAM8 protein (P = 0.014) levels were significantly higher in both asthma and COPD compared with healthy controls. ADAM8 mRNA (P = 0.035) and sADAM8 protein (P = 0.002) levels were significantly higher in severe asthma compared with controlled asthma. Total inflammatory cell count (P < 0.01) and neutrophils (P < 0.01) were also elevated in severe asthmatic sputum. Although ADAM8 mRNA was significantly higher in eosinophilic and neutrophilic asthma (P < 0.001), sADAM8 did not differ between asthma inflammatory phenotypes. ADAM8 expression positively correlated with sputum total cell count and sputum neutrophils.

CONCLUSIONS AND CLINICAL RELEVANCE

ADAM8 expression is increased in both severe asthma and COPD and associated with sputum total cell count and neutrophils. ADAM8 may facilitate neutrophil migration to the airways in severe asthma and COPD.

Developing and emerging clinical asthma phenotypes

For more than a century, clinicians have attempted to subdivide asthma into different phenotypes based on triggers that cause asthma attacks, the course of the disease, or the prognosis. The first phenotypes that were described included allergic asthma, intrinsic or nonallergic asthma, infectious asthma, and aspirin-exacerbated asthma. These phenotypes are being reviewed elsewhere in this issue of the journal. The present article focuses on developing and emerging clinical asthma phenotypes. First, asthma phenotypes that are associated with environmental exposures (occupational agents, cigarette smoke, air pollution, cold dry air); second, asthma phenotypes that are associated with specific symptoms or clinical characteristics (cough, obesity, adult onset of disease); and third, asthma phenotypes that are based on biomarkers. This latter approach is the most promising because it attempts to identify asthma phenotypes with different underlying mechanisms so that therapies can be better targeted toward disease-specific features and disease outcomes can be improved.

[Asthma in the elderly]

Asthma is a common condition in the elderly although often confounded with chronic obstructive pulmonary disease (COPD) in this population. Asthma in the elderly seems to represent a specific phenotype characterized by more severe, but often less perceived, airway obstruction, a neutrophilic or mixed-type of airway inflammation and frequent comorbidities. Patients aged 65 years and over have an increased asthma-related morbidity and mortality compared to younger patients, probably due to difficulties in regard to diagnosis, assessment of the disease severity and treatment. Research is urgently needed to determine the optimal treatment of the aged patient. In this document we will review the state of knowledge on this topic and discuss the challenges of multidisciplinary asthma management in the elderly.

Supplementation with γ-tocopherol attenuates endotoxin-induced airway neutrophil and mucous cell responses in rats

Neutrophil-mediated tissue injury is a shared pathogenesis of both chronic pulmonary diseases and acute responses to pathogens, allergens, and airborne pollutants. Interventions to minimize toxic effects of neutrophil-derived oxidants and proteases are usually limited to corticosteroids, which can have adverse side effects. We used a rodent model of endotoxin-induced lung injury to test the hypothesis that the dietary supplement γ-tocopherol (γT), a natural form of vitamin E with antioxidant and novel anti-inflammatory properties, will protect from adverse nasal and pulmonary inflammatory responses induced by endotoxin (lipopolysaccharide; LPS). Male Fisher F344 rats were intranasally (i.n.) instilled with LPS for 2 consecutive days. Beginning 2 days before i.n. LPS, the rats were gavaged daily with 30mg/kg γT. Twenty-four hours after the last i.n. LPS, bronchoalveolar lavage fluid (BALF) was collected, and pulmonary and nasal tissues were analyzed for gene expression and morphometric analyses of neutrophils and intraepithelial mucosubstances (IM). LPS caused increased BALF total cells (70% increase), neutrophils (300%), protein (35%), PGE2 (500%), and secreted mucins (75%). Robust increases in neutrophils and IM were detected in conducting airways. Pulmonary expression of MUC5AC, MIP-2, CINC-1, and MCP-1 was elevated three- to eightfold by LPS. Treatment with γT inhibited LPS-induced increases in BALF total cells, neutrophils, protein, PGE2, and secreted mucins, as well as IM and tissue neutrophil influx. Furthermore γT induced the expression of the regulatory cytokines IL-10 and IFN-γ while decreasing MUC5AC, MIP-2, CINC-1, and MCP-1. These data demonstrate novel therapeutic effects of the dietary vitamin E γT promoting anti-inflammatory pathways to protect from neutrophil-mediated lung injury.

Chronic traffic pollution exposure is associated with eosinophilic, but not neutrophilic inflammation in older adult asthmatics

OBJECTIVE

Airway inflammatory patterns in older asthmatics are poorly understood despite high asthma-related morbidity and mortality. In this study, we sought to define the relationship between exposure to traffic pollutants, biomarkers in induced sputum, and asthma control in older adults.

METHODS

Induced sputum was collected from 35 non-smoking adults ≥65 years with a physician's diagnosis of asthma and reversibility with a bronchodilator or a positive methacholine challenge. Patients completed the Asthma Control Questionnaire (ACQ), and Elemental Carbon Attributable to Traffic (ECAT), a surrogate for chronic diesel particulate exposure, was determined. Equal numbers of subjects with high (≥0.39 µg/m(3)) versus low (<0.39 µg/m(3)) ECAT were included. Differential cell counts were performed on induced sputum, and myeloperoxidase (MPO) and eosinophil peroxidase (EPO) were measured in supernatants. Regression analyses were used to evaluate the relationship between sputum findings, ACQ scores, and ECAT.

RESULTS

After adjustment for potential confounders, subjects with poorly controlled asthma based on ACQ ≥ 1.5 (n = 7) had significantly higher sputum eosinophils (median = 4.4%) than those with ACQ < 1.5 (n = 28; eosinophils = 2.6%; β = 10.1 [95% CI = 0.1-21.0]; p = 0.05). Subjects with ACQ ≥ 1.5 also had significantly higher sputum neutrophils (84.2% versus 65.2%; β = 7.1 [0.2-14.6]; p = 0.05). Poorly controlled asthma was associated with higher sputum EPO (β = 2.4 [0.2-4.5], p = 0.04), but not MPO (p = 0.9). High ECAT was associated with higher eosinophils (β = 10.1 [1.8-18.4], p = 0.02) but not higher neutrophils (p = 0.6).

CONCLUSIONS

Poorly controlled asthma in older adults is associated with eosinophilic and neutrophilic inflammation. Chronic residential traffic pollution exposure may be associated with eosinophilic, but not neutrophilic inflammation in older asthmatics.