Pulmonary inflammation in patients with chronic obstructive pulmonary disease with higher blood eosinophil counts

The association of blood eosinophil counts and FEV1 decline: a cohort study

BACKGROUND

Accelerated lung function decline is characteristic of COPD. However, the association between blood eosinophil counts and lung function decline, accounting for current smoking status, in young individuals without prevalent lung disease is not fully understood.

METHODS

This is a cohort study of 629 784 Korean adults without COPD or a history of asthma at baseline who participated in health screening examinations including spirometry and differential white blood cell counts. We used a linear mixed-effects model to estimate the annual change in forced expiratory volume in 1 s (FEV1) (mL) by baseline blood eosinophil count, adjusting for covariates including smoking status. In addition, we performed a stratified analysis by baseline and time-varying smoking status.

RESULTS

During a mean follow-up of 6.5 years (maximum 17.8 years), the annual change in FEV1 (95% CI) in participants with eosinophil counts <100, 100-199, 200-299, 300-499 and ≥500 cells·µL-1 in the fully adjusted model were -23.3 (-23.9--22.7) mL, -24.3 (-24.9--23.7) mL, -24.8 (-25.5--24.2) mL, -25.5 (-26.2--24.8) mL and -26.8 (-27.7--25.9) mL, respectively. When stratified by smoking status, participants with higher eosinophil count had a faster decline in FEV1 than those with lower eosinophil count in both never- and ever-smokers, which persisted when time-varying smoking status was used.

CONCLUSIONS

Higher blood eosinophil counts were associated with a faster lung function decline among healthy individuals without lung disease, independent of smoking status. The findings suggest that higher blood eosinophil counts contribute to the risk of faster lung function decline, particularly among younger adults without a history of lung disease.

Protocol for the air purification for eosinophilic COPD study (APECS): a randomised controlled trial of home air filtration by HEPA

INTRODUCTION

Exposure to particulate matter (PM) pollution has been associated with lower lung function in adults with chronic obstructive pulmonary disease (COPD). Patients with eosinophilic COPD have been found to have higher levels of airway inflammation, greater responsiveness to anti-inflammatory steroid inhalers and a greater lung function response to PM pollution exposure compared with those with lower eosinophil levels. This study will evaluate if reducing home PM exposure by high-efficiency particulate air (HEPA) air filtration improves respiratory health in eosinophilic COPD.

METHODS AND ANALYSIS

The Air Purification for Eosinophilic COPD Study (APECS) is a double-blinded randomised placebo-controlled trial that will enrol 160 participants with eosinophilic COPD living in the area of Boston, Massachusetts. Real and sham air purifiers will be placed in the bedroom and living rooms of the participants in the intervention and control group, respectively, for 12 months. The primary trial outcome will be the change in forced expiratory volume in 1 s (FEV1). Lung function will be assessed twice preintervention and three times during the intervention phase (at 7 days, 6 months and 12 months postrandomisation). Secondary trial outcomes include changes in (1) health status by St. George's Respiratory Questionnaire; (2) respiratory symptoms by Breathlessness, Cough and Sputum Scale (BCSS); and (3) 6-Minute Walk Test (6MWT). Inflammatory mediators were measured in the nasal epithelial lining fluid (NELF). Indoor PM will be measured in the home for the week preceding each study visit. The data will be analysed to contrast changes in outcomes in the intervention and control groups using a repeated measures framework.

ETHICS AND DISSEMINATION

Ethical approval was obtained from the Institutional Review Board of Beth Israel Deaconess Medical Centre (protocol #2019P0001129). The results of the APECS trial will be presented at scientific conferences and published in peer-reviewed journals.

TRIAL REGISTRATION

NCT04252235. Version: October 2023.

Hypercapnia and its relationship with respiratory infections

INTRODUCTION

Hypercapnia is developed in patients with acute and/or chronic respiratory conditions. Clinical data concerning hypercapnia and respiratory infections interaction is limited.

AREAS COVERED

Currently, the relationship between hypercapnia and respiratory infections remains unclear. In this review, we summarize studies on the effects of hypercapnia on models of pulmonary infections to clarify the role of elevated CO2 in these pulmonary pathologies. Hypercapnia affects different cell types in the alveoli, leading to changes in the immune response. In vitro studies show that hypercapnia downregulates the NF-κβ pathway, reduces inflammation and impairs epithelial wound healing. While in vivo models show a dual role between short- and long-term effects of hypercapnia on lung infection. However, it is still controversial whether the effects observed under hypercapnia are pH dependent or not.

EXPERT OPINION

The role of hypercapnia is still a controversial debate. Hypercapnia could play a beneficial role in mechanically ventilated models, by lowering the inflammation produced by the stretch condition. But it could be detrimental in infectious scenarios, causing phagocyte dysfunction and lack of infection control. Further data concerning hypercapnia on respiratory infections is needed to elucidate this interaction.

How inhaled corticosteroids target inflammation in COPD

Inhaled corticosteroids (ICS) are the most commonly used anti-inflammatory drugs for the treatment of COPD. COPD has been previously described as a "corticosteroid-resistant" condition, but current clinical trial evidence shows that selected COPD patients, namely those with increased exacerbation risk plus higher blood eosinophil count (BEC), can benefit from ICS treatment. This review describes the components of inflammation modulated by ICS in COPD and the reasons for the variation in response to ICS between individuals. There are corticosteroid-insensitive inflammatory pathways in COPD, such as bacteria-induced macrophage interleukin-8 production and resultant neutrophil recruitment, but also corticosteroid-sensitive pathways including the reduction of type 2 markers and mast cell numbers. The review also describes the mechanisms whereby ICS can skew the lung microbiome, with reduced diversity and increased relative abundance, towards an excess of proteobacteria. BEC is a biomarker used to enable the selective use of ICS in COPD, but the clinical outcome in an individual is decided by a complex interacting network involving the microbiome and airway inflammation.

Association between blood eosinophil count and small airway eosinophils in smokers with and without COPD

Introduction

Airway eosinophilic inflammation is a pathological feature in a subgroup of patients with COPD and in some smokers with a high COPD risk. Although blood eosinophil count is used to define eosinophilic COPD, the association between blood eosinophil count and airway eosinophilic inflammation remains controversial. This cross-sectional study tested this association in smokers with and without COPD while considering potential confounders, such as smoking status and comorbidities.

Methods

Lung specimens were obtained from smokers with and without COPD and non-COPD never-smokers undergoing lung lobectomy. Those with any asthma history were excluded. The infiltration of eosinophils into the small airway wall was quantified on histological sections stained with major basic protein (MBP).

Results

The number of airway MBP-positive cells was greater in smokers (n=60) than in never-smokers (n=14). Smokers with and without COPD (n=30 each) exhibited significant associations between blood eosinophil count and airway MBP-positive cells (ρ=0.45 and 0.71). When smokers were divided into the high and low airway MBP groups based on their median value, blood eosinophil count was higher in the high-MBP group, with no difference in age, smoking status, comorbidities, emphysema or coronary artery calcification on computed tomography, and inhaled corticosteroid (ICS) use. The association between greater blood eosinophil count and the high-MBP group was confirmed in multivariable models adjusted for smoking status, airflow limitation and ICS use.

Conclusion

The blood eosinophil count may reflect eosinophilic inflammation in the small airways in smokers with and without COPD.

Targeting Type 2 Inflammation and Epithelial Alarmins in Chronic Obstructive Pulmonary Disease: A Biologics Outlook

Chronic obstructive pulmonary disease (COPD) is a complex, heterogeneous, progressive inflammatory airway disease associated with a significant impact on patients' lives, including morbidity and mortality, and significant healthcare costs. Current pharmacologic strategies, including first- and second-line therapies such as long-acting β2-agonists, long-acting muscarinic antagonists, inhaled corticosteroids, phosphodiesterase-4 inhibitors, and macrolides, provide relief to patients with COPD. However, many patients remain symptomatic, with persistent symptoms and/or acute exacerbations and progressive lung function loss. Although neutrophilic inflammation is the most common type of inflammation in COPD, 20-40% of patients with COPD exhibit type 2 inflammation, with roles for CD4+ (cluster of differentiation 4) T-helper cell type 1 cells, type 2 innate lymphoid cells, eosinophils, and alternatively activated macrophages. On the basis of the current limitations of available therapies, a significant unmet need exists in COPD management, including the need for targeted therapies to address the underlying pathophysiology leading to disease progression, such as type 2 inflammation, as well as biomarkers to help select the patients who would most benefit from the new therapies. Significant progress is being made, with evolving understanding of the pathobiology of COPD leading to novel therapeutic targets including epithelial alarmins. In this review, we describe the current therapeutic landscape in COPD, discuss unmet treatment needs, review the current knowledge of type 2 inflammation and epithelial alarmins in COPD, explore potential biomarkers of type 2 inflammation in COPD, and finally provide a rationale for incorporating therapies targeting type 2 inflammation and epithelial alarmins in COPD. Video Abstract available online at www.atsjournals.org.

Blood Eosinophil Count as a Predictive Biomarker of Chronic Obstructive Pulmonary Disease Exacerbation in a Real-World Setting

Introduction

Chronic obstructive pulmonary disease (COPD) is the third leading cause of death, and COPD exacerbation worsens the prognosis. Eosinophilic airway inflammation is a COPD phenotype that causes COPD exacerbation and is correlated with peripheral blood eosinophil count. We analyzed real-world data of COPD patients to assess the risk factors of COPD exacerbation focusing on blood eosinophils.

Materials and Methods

Patients with COPD who visited our hospital between January 1, 2018, and December 31, 2018, were recruited, and their background information, spirometry data, laboratory test results, and moderate-to-severe exacerbation events during the one-year follow-up period were collected from the electronic medical records and analyzed. The COPD exacerbation risk factors were assessed using univariate and multivariate logistic regression analyses.

Results

Twenty-two of 271 (8.1%) patients experienced moderate-to-severe exacerbation. Patients with exacerbation showed worse pulmonary function, and we found that a high blood eosinophil count (≥350 cells/μL; p=0.014), low % FEV1 (<50%; p=0.002), increase in white blood cell (≥9000 cells/μL; p=0.039), and use of home oxygen therapy (p=0.005) were risk factors for future exacerbations. We also found a strong correlation between eosinophil count cut-offs and exacerbation risk (r = 0.89, p < 0.001). On the other hand, there was no relation between exacerbation risk and inhalation therapy for COPD.

Conclusion

In a real-world setting, peripheral blood eosinophil count could be a predictor of future COPD exacerbation.

Further evidence of a type 2 inflammatory signature in chronic obstructive pulmonary disease or emphysema

BACKGROUND

There is increasing recognition of a type 2 (T2) inflammatory pattern in a subset of patients with chronic obstructive pulmonary disease (COPD) or emphysema, characterized by blood and airway eosinophilia. The mechanism underlying this is not well established. The recognition that CD125 (interleukin [IL]-5 receptor alpha) is expressed on some lung neutrophils and eosinophils in patients with asthma led us to speculate that CD125 may also be expressed on lung neutrophils in patients with COPD or emphysema.

OBJECTIVE

To interrogate the expression of CD125 on lung neutrophils (and, when present, eosinophils) in patients with COPD/emphysema and identify a meaningful biomarker to predict neutrophil CD125 expression, including other markers of T2 inflammation.

METHODS

We obtained blood and bronchoalveolar lavage (BAL) samples from patients with physician-diagnosed COPD/emphysema undergoing a clinically indicated bronchoscopy.

RESULTS

We found that a highly variable percentage of BAL neutrophils indeed expressed surface CD125 (0%-78.7%), with obvious clustering of CD125high and CD125low patterns. No correlation was found with clinical characteristics, blood or BAL eosinophil or neutrophil counts, BAL cytokines, or BAL eosinophil CD125 expression.

CONCLUSION

We conclude that, similar to asthma, lung neutrophils from patients with COPD display interleukin-5 receptor alpha (CD125) on their surface. This along with the frequent presence of IL-4 and IL-5 in airway fluid further suggests a possible role of the T2 pathway in contributing to COPD severity.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03984799.

Benefits of Budesonide/Glycopyrronium/Formoterol Fumarate Dihydrate on COPD Exacerbations, Lung Function, Symptoms, and Quality of Life Across Blood Eosinophil Ranges: A Post-Hoc Analysis of Data from ETHOS

Purpose

Blood eosinophil (EOS) count can guide treatment decisions for chronic obstructive pulmonary disease (COPD). In the 52-week ETHOS study (NCT02465567), budesonide/glycopyrronium/formoterol fumarate dihydrate (BGF) triple therapy at two inhaled corticosteroid doses reduced moderate/severe exacerbation rates and improved lung function, symptoms, and disease-related quality of life (QoL) versus dual therapy with glycopyrronium/formoterol fumarate dihydrate (GFF) or budesonide/formoterol fumarate dihydrate (BFF) in patients with moderate-to-very severe COPD. This subgroup analysis evaluated treatment benefits in ETHOS by baseline EOS count.

Methods

Patients (40-80 years) with a COPD history were randomly assigned 1:1:1:1 to receive BGF 320/14.4/10 µg, BGF 160/14.4/10 µg, GFF 14.4/10 µg, or BFF 320/10 µg via a metered-dose inhaler. This post-hoc analysis assessed endpoints by baseline EOS count using Global Initiative for Obstructive Lung Disease thresholds (<100, ≥100, ≥100-<300, ≥300 cells/mm³), and investigated continuous relationships between treatment effects and EOS count on exacerbations, symptoms, disease-related QoL, lung function, and safety.

Results

In the modified intention-to-treat population (n=8509), 82.6% had EOS counts ≥100 cells/mm³. BGF 320 reduced moderate/severe exacerbation rates versus GFF in the ≥100, ≥100-<300, and ≥300 subgroups; treatment differences increased with EOS count. BGF 320 improved rescue medication use and lung-function outcomes across all subgroups, and St George's Respiratory Questionnaire total score, Transition Dyspnea Index focal score, and Exacerbations of Chronic Pulmonary Disease Tool total score in all except the <100 subgroup versus GFF. Benefits of BGF 320 versus BFF were generally consistent across subgroups. Safety data were comparable across subgroups.

Conclusion

Benefits of BGF versus GFF were observed across EOS counts, particularly at ≥100 cells/mm³; versus BFF, benefits were largely independent of EOS. These findings confirm that benefits of ICS-containing triple therapy are not restricted to EOS counts ≥300 cells/mm³, supporting recommendations to consider triple therapy in patients with an exacerbation history and EOS counts ≥100 cells/mm³.

The roles of eosinophils and interleukin-5 in the pathophysiology of chronic rhinosinusitis with nasal polyps

Chronic rhinosinusitis with nasal polyps (CRSwNP) is generally associated with eosinophilic tissue infiltration linked to type 2 inflammation and characterized by elevated levels of interleukin (IL)-5 and other type 2 inflammatory mediators. Although distinct and overlapping contributions of eosinophils and IL-5 to CRSwNP pathology are still being explored, they are both known to play an important role in NP inflammation. Eosinophils secrete numerous type 2 inflammatory mediators including granule proteins, enzymes, cytokines, chemokines, growth factors, lipids, and oxidative products. IL-5 is critical for the differentiation, migration, activation, and survival of eosinophils but is also implicated in the biological functions of mast cells, basophils, innate lymphoid cells, B cells, and epithelial cells. Results from clinical trials of therapeutics that target type 2 inflammatory mediators (including but not limited to anti-IL-5, anti-immunoglobulin-E, and anti-IL-4/13) may provide further evidence of how eosinophils and IL-5 contribute to CRSwNP. Finally, the association between eosinophilia/elevated IL-5 and greater rates of NP recurrence after endoscopic sinus surgery (ESS) suggests that these mediators may have utility as biomarkers of NP recurrence in diagnosing and assessing the severity of CRSwNP. This review provides an overview of eosinophil and IL-5 biology and explores the literature regarding the role of these mediators in CRSwNP pathogenesis and NP recurrence following ESS. Based on current published evidence, we suggest that although eosinophils play a key role in CRSwNP pathophysiology, IL-5, a cytokine that activates these cells, also represents a pertinent and effective treatment target in patients with CRSwNP.

Identification of COPD Inflammatory Endotypes Using Repeated Sputum Eosinophil Counts

Higher blood and sputum eosinophil counts are associated with a greater response to corticosteroids in COPD. Low blood eosinophil counts exhibit greater stability over time whereas higher counts demonstrate more variability. Stability of airway eosinophil levels is less well understood. We have studied the stability of sputum eosinophil counts. Differential cell count data for COPD patients (n = 100) were analysed. Subjects with two sputum eosinophil counts, 6 months apart, were included in the analysis. Patients were stratified based on baseline sputum eosinophil count into ‘low’, ‘intermediate’ and ‘high’ groups: eosinophilLOW (<1%), eosinophilINT (1−3%) and eosinophilHIGH (≥3%). Sputum eosinophil counts showed good stability (rho = 0.61, p < 0.0001, ICC of 0.77), with 67.4% of eosinophilLOW patients remaining in the same category on repeat sampling. Bland−Altman analysis of the whole cohort (median difference between measurements = 0.00%, 90th percentile = −1.4 and 4.7%) showed greater variation at higher counts. This was confirmed by the wider 90th centiles in the eosinophilINT (−1.50 to 5.65) and eosinophilHIGH groups (−5.33 to 9.80) compared to the eosinophilLOW group (−0.40 to 1.40). The repeatability of sputum eosinophil counts was related to the baseline eosinophil count; sputum eosinophilLOW COPD patients were relatively stable over time, while the eosinophilHIGH group showed greater variability. These results can facilitate the identification of COPD endotypes with differential responses to treatment.

Increased mast cell activation in eosinophilic chronic obstructive pulmonary disease

Objectives

A subset of chronic obstructive pulmonary disease (COPD) patients have increased numbers of airway eosinophils associated with elevated markers of T2 inflammation. This analysis focussed on mast cell counts and mast cell‐related gene expression in COPD patients with higher vs lower eosinophil counts.

Methods

We investigated gene expression of tryptase (TPSAB1), carboxypeptidase A3 (CPA3), chymase (CMA1) and two mast cell specific gene signatures; a bronchial biopsy signature (MC_bb) and an IgE signature (MC_IgE) using sputum cells and bronchial epithelial brushings. Gene expression analysis was conducted by RNA‐sequencing. We also examined bronchial biopsy mast cell numbers by immunohistochemistry.

Results

There was increased expression of TPSAB1, CPA3 and MC_bb in eosinophil^high than in eosinophil^low COPD patients in sputum cells and bronchial epithelial brushings (fold change differences 1.21 and 1.28, respectively, P < 0.01). Mast cell gene expression was associated with markers of T2 and eosinophilic inflammation (IL13, CLCA1, CST1, CCL26, eosinophil counts in sputum and bronchial mucosa; rho = 0.4–0.8; P < 0.05). There was no difference in MC_IgE gene expression between groups. There was no difference in the total number of bronchial biopsy mast cells between groups.

Conclusion

These results demonstrate that eosinophilic inflammation is associated with altered mast cell characteristics in COPD patients, implicating mast cells as a component of T2 inflammation present in a subset of COPD patients.

New Perspectives on Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is a major cause of morbidity and mortality worldwide; many recent advances have been made in many aspects of the disease. The aim of this article is to illustrate and discuss some of these advances in the management of different types of patients. Large-scale trials have confirmed that long-acting bronchodilator therapy, particularly using the combination of LABA/LAMA, remains the mainstay of COPD treatment, with special attention being paid to careful selection of inhaler devices. The initial choice of pharmacological therapy is based on the GOLD ABCD grouping of patients. It is very important to stress that there is a need to implement a management cycle because COPD is a chronic disease with varying clinical course and a high number of potential comorbidities that may affect morbidity and mortality. Therefore, regular reevaluation of the patient is mandatory. This allows identification of characteristics aimed at maximizing the benefits for a specific patient or a subset of patients. Within this context, the role of the blood eosinophil count as a marker of inhaled corticosteroids response to prevent future exacerbations in patients who, despite appropriate bronchodilator therapy, still suffer from them has been proven to be a useful simple biomarker in medication selection. These advances support the concept of precision medicine, with the goal that patients get the right medicine at the right time for the right reason. Finally, recent studies have shown that early life events may be of critical relevance for the development of COPD. With this as a background, concepts to identify individuals at risk and early identification of cases have become an important objective of current research with the hope of maximizing the effects of therapy and the possibility of impacting disease progression.

Blood Eosinophils and Chronic Obstructive Pulmonary Disease: A GOLD Science Committee 2022 Review

COPD is a heterogeneous condition. Some patients benefit from treatment with inhaled corticosteroids (ICS) but this requires a precision medicine approach, based on clinical characteristics (phenotyping) and biological information (endotyping) in order to select patients most likely to benefit. The GOLD 2019 report recommended using exacerbation history combined with blood eosinophil counts (BEC) to identify such patients. Importantly, the relationship between BEC and ICS effects is continuous; no / small effects are observed at lower BEC, with increasing effects at higher BEC. The GOLD 2022 report has added additional evidence and recommendations concerning the use of BEC in COPD in clinical practice. Notably, associations have been demonstrated in COPD patients between higher BEC and increased levels of type-2 inflammation in the lungs. These differences in type-2 inflammation can explain the differential ICS response according to BEC. Additionally, lower BEC are associated with greater presence of proteobacteria, notably haemophilus, and increased bacterial infections and pneumonia risk. These observations support management strategies that use BEC to help identify subgroups with increased ICS response (higher BEC) or increased risk of bacterial infection (lower BEC). Recent studies in younger individuals without COPD have also shown that higher BEC are associated with increased risk of FEV1 decline and the development of COPD. Here we discuss and summarise the GOLD 2022 recommendations concerning the use of BEC as a biomarker that can facilitate a personalised management approach in COPD.

A sputum 6-gene signature predicts airway inflammation endotypes and exacerbation frequency in chronic obstructive pulmonary disease

Aim: To validate a sputum 6-gene signature (6GS), comprising of CLC, CPA, DNASE1L3, IL-1B, ALPL and CXCR2, for identifying different endotypes in chronic obstructive pulmonary disease. Methodology & results: Sputum cell CLC, CPA3 and DNASE1L3 gene expression correlated with eosinophil percentage, while IL-1B, ALPL and CXCR2 correlated with neutrophil percentage. Hierarchical cluster analyses of IL-1B, ALPL and CXCR2, and CLC, CPA3 and DNASE1L3, identified patient groups that differed in their sputum neutrophil and eosinophil levels, respectively. Multiple logistic regressions demonstrated that the 6GS could distinguish between eosinophil^High and eosinophil^Low patients, as well as neutrophil^High and neutrophil^Low, and could also predict exacerbation history. Conclusion: The 6GS may have applications in clinical practice or for stratifying patients for clinical trials.

Dysregulation of the CD163-Haptoglobin Axis in the Airways of COPD Patients

Pulmonary iron levels are increased in chronic obstructive pulmonary disease (COPD) patients. Iron causes oxidative stress and is a nutrient for pathogenic bacteria. Iron may therefore play an important role in the pathophysiology of COPD. The CD163-haptglobin axis plays a central role in the regulation of iron bioavailability. The aim of this study was to examine dysregulation of the CD163-haptglobin axis in COPD. We measured soluble CD163 (sCD163) and haptoglobin levels in sputum supernatants by enzyme-linked immunosorbent assay (ELISA) and sputum macrophage CD163 and haptoglobin expression by flow cytometry in COPD patients and controls. SCD163 levels were lower in COPD patients compared to controls (p = 0.02), with a significant correlation to forced expiratory volume in 1 s (FEV1)% predicted (rho = 0.5, p = 0.0007). Sputum macrophage CD163 expression was similar between COPD patients and controls. SCD163 levels and macrophage CD163 expression were lower in COPD current smokers compared to COPD ex-smokers. Haptoglobin levels were not altered in COPD patients but were regulated by genotype. Macrophage CD163 and haptolgobin expression were significantly correlated, supporting the role of CD163 in the cellular uptake of haptoglobin. Our data implicates a dysfunctional CD163-haptoglobin axis in COPD, which may contribute to disease pathophysiology, presumably due to reduced clearance of extracellular iron.

Inhaled Phosphodiesterase Inhibitors for the Treatment of Chronic Obstructive Pulmonary Disease

Phosphodiesterase (PDE) 4 inhibitors prevent the metabolism of cyclic adenosine monophosphate, thereby reducing inflammation. Inhaled PDE4 inhibitors aim to restrict systemic drug exposure to enhance the potential for clinical benefits (in the lungs) versus adverse events (systemically). The orally administered PDE4 inhibitor roflumilast reduces exacerbation rates in the subgroup of chronic obstructive pulmonary disease patients with a history of exacerbations and the presence of chronic bronchitis, but can cause PDE4 related adverse effects due to systemic exposure. CHF6001 is an inhaled PDE4 inhibitor, while inhaled ensifentrine is an inhibitor of both PDE3 and PDE4; antagonism of PDE3 facilitates smooth muscle relaxation and hence bronchodilation. These inhaled PDE inhibitors have both reported positive findings from early phase clinical trials, and have been well tolerated. Longer term trials are needed to firmly establish the clinical benefits of these drugs.

Eosinophilic endotype of chronic obstructive pulmonary disease: similarities and differences from asthma

Approximately 25% to 40% of patients with chronic obstructive pulmonary disease (COPD) have the eosinophilic endotype. It is important to identify this group accurately because they are more symptomatic and are at increased risk for exacerbations and accelerated decline in forced expiratory volume in the 1st second. Importantly, this endotype is a marker of treat ment responsiveness to inhaled corticosteroid (ICS), resulting in decreased mortality risk. In this review, we highlight differences in the biology of eosinophils in COPD compared to asthma and the different definitions of the COPD eosinophilic endotype based on sputum and blood eosinophil count (BEC) with the corresponding limitations. Although BEC is useful as a biomarker for eosinophilic COPD endotype, optimal BEC cut-offs can be combined with clinical characteristics to improve its sensitivity and specificity. A targeted approach comprising airway eosinophilia and appropriate clinical and physiological features may improve identification of subgroups of patients who would benefit from biologic therapy or early use of ICS for disease modification.

Air Pollution Exposure and Daily Lung Function in COPD: Effect Modification by Eosinophilia

RATIONALE

Few studies have assessed personal exposure to pollutants and lung function among adults with COPD. Blood eosinophilia may be a biomarker of airway inflammation and pollution susceptibility.

OBJECTIVES

To evaluate if daily pollutant exposures are associated with lung function and if associations are modified by eosinophilia in COPD.

METHODS

We recruited 30 former smokers with moderate-to-severe COPD living in the Boston area and followed them up to 4 non-consecutive months in different seasons. Participants measured morning lung function and carried a portable air quality monitor daily. Previous-day exposure to pollutants (PM2.5, NO2, and ozone) were measured by portable and community monitors. We constructed multi-level linear mixed-effects models with random intercepts for person and observation month, adjusted for temperature, humidity, age, sex, race, height, weight, income, and season, to assess associations of previous-day pollutant exposure with lung function and effect modification by eosinophilia (< vs > 150 cells/µL).

RESULTS

A total of 3,314 observations with exposure and lung function data were collected. Each IQR (5.1 ppb) higher previous-day personal exposure to NO2 was associated with a 11.3 mL (95% CI: -18.7, -4.0) lower FEV1 and a 18.0 mL (95% CI: -32.0, -4.2) lower FVC. Personal and community-level exposure to PM2.5 and community-level NO2 were negatively associated with FEV1 among the 55.2% of participants with eosinophilia (Pinteraction <0.05).

CONCLUSIONS

Our study highlights the need to address air pollution exposure among COPD patients. Future research is needed to verify if eosinophilia is a biomarker for susceptibility to air pollution in COPD.

Airway Bacteria Quantification Using Polymerase Chain Reaction Combined with Neutrophil and Eosinophil Counts Identifies Distinct COPD Endotypes

BACKGROUND

Chronic obstructive pulmonary disease (COPD) inflammatory endotypes are associated with different airway microbiomes. We used quantitative polymerase chain reaction (qPCR) analysis of sputum samples to establish the bacterial load upper limit in healthy controls; these values determined the bacterial colonisation prevalence in a longitudinal COPD cohort. Bacteriology combined with sputum inflammatory cells counts were used to investigate COPD endotypes.

METHODS

Sixty COPD patients and 15 healthy non-smoking controls were recruited. Sputum was analysed by qPCR (for Haemophilus influenzae, Moraxella catarrhalis, Streptococcus pneumoniae and Psuedomonas aeruginosa) and sputum differential cell counts at baseline and 6 months.

RESULTS

At baseline and 6 months, 23.1% and 25.6% of COPD patients were colonised with H. influenzae, while colonisation with other bacterial species was less common, e.g., S. pneumoniae-1.9% and 5.1%, respectively. H. influenzae + ve patients had higher neutrophil counts at baseline (90.1% vs. 67.3%, p < 0.01), with similar results at 6 months. COPD patients with sputum eosinophil counts ≥3% at ≥1 visit rarely showed bacterial colonisation.

CONCLUSIONS

The prevalence of H. influenzae colonisation was approximately 25%, with low colonisation for other bacterial species. H. influenzae colonisation was associated with sputum neutrophilia, while eosinophilic inflammation and H. influenzae colonisation rarely coexisted.

DNA methylation in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD), a complex disease with polygenetic tendency, is one of the most important health problems in the world. Recently, in the study of the pathogenesis of the COPD, epigenetic changes caused by environmental factors, such as DNA methylation, started to attract more attention than genetic factors. In this review, we discuss the main features of DNA methylation, such as DNA methyltransferases and the methylation sites that modulate the DNA methylation level, and their roles in COPD progression. Finally, to promote new ideas for the prevention and treatment of COPD, we focus on the potential of DNA methylation as a COPD therapeutic target.

Mepolizumab for Eosinophil-Associated COPD: Analysis of METREX and METREO

Background

A pre-specified meta-analysis of individual patient data from the 52-week METREX and METREO trials, which investigated mepolizumab for chronic obstructive pulmonary disease (COPD) in patients with blood eosinophil counts ≥150 cells/µL (screening) or ≥300 cells/µL (prior year) and frequent exacerbations, enables more robust characterization of mepolizumab efficacy in COPD and exploration of the relationship between blood eosinophil count and treatment responses.

Methods

In METREX (117106/NCT02105948) and METREO (117113/NCT02105961), randomized patients received mepolizumab or placebo added to existing inhaled corticosteroid (ICS)–based triple maintenance therapy. The annual rate of moderate/severe exacerbations (primary endpoint) was compared between subcutaneous (SC) mepolizumab 100 mg versus placebo (primary comparison of interest) and all doses (100 mg and 300 mg SC) versus placebo in patients with blood eosinophil counts ≥150 cells/µL at screening or ≥300 cells/µL in the prior year. Secondary/other endpoints included time to first moderate/severe exacerbation, exacerbations leading to emergency department visit/hospitalization and health-related quality of life (HRQoL). A predictive model of the relationship between screening blood eosinophil counts and exacerbation rates included data from all randomized patients.

Results

In total, 1510 patients were randomized in METREX and METREO and 1136 patients were included in the pre-specified meta-analysis. From the meta-analysis, mepolizumab 100 mg SC significantly reduced annual moderate/severe exacerbation rates versus placebo by 18% (rate ratio: 0.82; 95% confidence interval: 0.71, 0.95; p=0.006) and delayed time to first moderate/severe exacerbation (hazard ratio: 0.80 [0.68, 0.94]; p=0.006). Mepolizumab 100 mg SC versus placebo numerically reduced exacerbations leading to ED visits/hospitalization and improved HRQoL. A modelling approach demonstrated increasing efficacy for moderate/severe exacerbations with increasing screening blood eosinophil count; this relationship was more pronounced for exacerbations requiring oral corticosteroids (post hoc). The all-doses comparison had similar results.

Conclusion

Mepolizumab reduces exacerbations in patients with eosinophil-associated COPD. Results suggest that blood eosinophil counts (≥150 cells/µL at screening or ≥300 cells/µL in the prior year) allow for identification of patients with COPD who experience exacerbations while treated with maximal ICS-based triple maintenance therapy who are likely to benefit from mepolizumab.

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Pharmacological treatment of stable chronic obstructive pulmonary disease

Pharmacological treatment for chronic obstructive pulmonary disease (COPD) aims to alleviate symptoms and reduce the future risk of events such as exacerbations, disease progression and death. The heterogeneity of COPD results in variable responses to pharmacological interventions. COPD treatment has evolved towards a precision medicine approach, integrating clinical and biomarker information in order to optimize treatment decisions for each individual. The evidence supporting the use of blood eosinophil counts to predict responses to inhaled corticosteroids (ICS) in COPD patients has led to the adoption of this biomarker for use in clinical practice. The development of novel double and triple inhaled combination treatments containing long-acting bronchodilators with or without ICS has involved some landmark randomized controlled trials in COPD patients. These studies have provided valuable evidence to direct the use of different classes of combination treatments. However, there are still some unresolved questions and debates. This review article describes the advances in the pharmacological treatment of COPD, particularly the personalization of treatment. The evidence base for current recommendations is discussed, and controversial issues are dissected.

Multi-omics links IL-6 trans-signalling with neutrophil extracellular trap formation and Haemophilus infection in COPD

BACKGROUND

IL-6 trans-signalling (IL-6TS) is emerging as a pathogenic mechanism in chronic respiratory diseases, however the drivers of IL-6TS in the airways and the phenotypic characteristic of patients with increased IL-6TS pathway activation remain poorly understood.

OBJECTIVE

Our aim was to identify and characterize COPD patients with increased airway IL-6TS and to elucidate the biological drivers of IL-6TS pathway activation.

METHODS

We used an IL-6TS-specific sputum biomarker profile (sIL-6R, IL-6, IL-1β, IL-8, MIP-1β) to stratify sputum data from patients with COPD (n=74; BEAT-COPD) by hierarchical clustering. The IL-6TS signature was related to clinical characteristics and sputum microbiome profiles. The induction of neutrophil extracellular trap formation (NETosis) and IL-6TS by Haemophilus influenzae were studied in human neutrophils.

RESULTS

Hierarchical clustering revealed an IL-6TS-high subset (n=24) of COPD patients, which shared phenotypic traits with an IL-6TS-high subset previously identified in asthma. The subset was characterized by increased sputum cell counts (p=0.0001), persistent sputum neutrophilia (p=0.0004), reduced quality of life (CRQ total score; p=0.008), and increased levels of pro-inflammatory mediators and MMPs in sputum. IL-6TS-high COPD patients showed an increase in Proteobacteria, with Haemophilus as the dominating genus. NETosis induced by H. influenzae was identified as a potential mechanism for increased soluble IL-6 receptor (sIL-6R) levels. This was supported by a significant positive correlation between sIL-6R and NETosis markers in bronchoalveolar lavage fluid from COPD patients.

CONCLUSION

IL-6TS pathway activation due to chronic colonization with Haemophilus may be an important disease driver in a subset of COPD patients.

Blood eosinophil counts and the development of obstructive lung disease: the Kangbuk Samsung Health Study

The impact of blood eosinophil counts on the development of chronic obstructive lung disease (COPD) is unknown. We investigated whether a higher blood eosinophil counts was associated with the risk of developing obstructive lung disease (OLD) in a large cohort of men and women free lung disease at baseline.Cohort study of 359 456 Korean adults without a history of asthma and without OLD at baseline who participated in health screening exams including spirometry. OLD was defined as pre-bronchodilator FEV₁/FVC<0.7 and FEV₁<80% predicted.After a median follow-up of 5.6 years (interquartile range, 2.9-9.2), 5008 participants developed incident OLD (incidence rate, 2.1 per 1000 person-years; 95% CI, 2.1-2.2). In the fully-adjusted model, the HR (95% CI) for incident OLD comparing eosinophil counts of 100-<200, 200-<300, 300-<500 and ≥500 cells·μL^-1 to <100 cells·μL^-1 were 1.07 (1.00-1.15), 1.30 (1.20-1.42), 1.46 (1.33-1.60) and 1.72 (1.51-1.95) (p for trend <0.001). These associations were consistent in clinically relevant subgroups, including never, former, and current smokers.In this large longitudinal cohort study, blood eosinophil counts were positively associated with the risk of developing of OLD. Our findings indicate a potential role of eosinophil count as an independent risk factor for developing COPD.

The relationship between airway immunoglobulin activity and eosinophils in COPD

In chronic obstructive pulmonary disease (COPD), the effects of inhaled corticosteroids are predicted by blood eosinophil counts. We previously briefly reported increased immunoglobulin (Ig)A and IgM levels in bronchoalveolar lavage (BAL) of COPD patients with higher (eosinophil^high) compared to lower (eosinophil^low) blood eosinophils (>250/μL versus < 150/μL), suggesting differences in adaptive immune function. An inverse relationship exists between eosinophil counts and airway pathogenic bacteria levels. The mechanistic reasons for these associations between eosinophils, corticosteroids and pathogenic bacteria are unclear. IgA, IgM and IgG levels were assessed in BAL, bronchial biopsies and epithelium collected from eosinophil^high (n = 20) and eosinophil^low (n = 21) patients. Bronchial B‐cell numbers were measured by immunohistochemistry. B‐cell activity was assessed in bronchial samples and following exposure to BAL from eosinophil^high and eosinophil^low patients. BAL levels of non‐typeable Haemophilus influenza (NTHi)‐specific immunoglobulins were quantified. Results showed airway expression of IgA, IgG1 and IgM were lower in eosinophil^low compared to eosinophil^high patients, with lower levels of NTHi‐specific IgA and IgM. Bronchial B‐cell numbers were similar in both groups, but B‐cell activity was lower in eosinophil^low patients. In conclusion, COPD eosinophil^low patients show differences in adaptive immune function compared to COPD eosinophil^high patients. These differences may cause different microbiomes in these COPD phenotypes.

COPD patients with chronic bronchitis and higher sputum eosinophil counts show increased type-2 and PDE4 gene expression in sputum

Chronic obstructive pulmonary disease (COPD) patients with higher eosinophil counts are associated with increased clinical response to phosphodiesterase‐4‐inhibitors (PDE4i). However, the underlying inflammatory mechanisms associated with this increased response is not yet elucidated. This post hoc analysis focused on sputum gene expression in patients with chronic bronchitis who underwent 32‐day treatment with two doses of the inhaled PDE4i CHF6001 (tanimilast) or placebo on top of triple therapy. Biological characterization and treatment effects were assessed between patients with different sputum eosinophil levels (eosinophil^high ≥ 3%; eosinophil^low < 3%) at baseline (primary samples) or at the end of the treatment of the placebo arm (validation samples). Forty‐one genes were differentially expressed in primary samples (p‐adjusted for false discovery rate < 0.05); all up‐regulated in eosinophil^high patients and functionally enriched for type‐2 and PDE4 inflammatory processes. Eleven out of nineteen genes having immune system biological processes annotations including IL5RA, ALOX15, IL1RL1, CLC, GATA1 and PDE4D were replicated using validation samples. The expression of a number of these inflammatory mediators was reduced by tanimilast treatment, with greater effects observed in eosinophil^high patients. These findings suggest that type‐2 and PDE4 overexpression in COPD patients with higher sputum eosinophil counts contribute to the differential clinical response to PDE4i observed in previous clinical trials.

Clinical Differences between Eosinophilic and Noneosinophilic Acute Exacerbation of Chronic Obstructive Pulmonary Disease: A Multicenter Cross-Sectional Study

METHODS

A total of 643 AECOPD patients were enrolled in this multicenter cross-sectional study. Finally, 455 were included, 214 in the normal-eosinophil AECOPD (NEOS-AECOPD) group, 63 in the mild increased-eosinophil AECOPD (MEOS-AECOPD) group, and 138 in the severe increased-eosinophil AECOPD (SEOS-AECOPD) group. Demographic data, underlying diseases, symptoms, and laboratory findings were collected. Multiple logistic regression analysis was performed to identify the independent factors associated with blood eosinophils (EOS). Correlations between blood EOS and its associated independent factors were evaluated.

RESULTS

The significant differences in 19 factors, including underlying diseases, clinical symptoms, and laboratory parameters, were identified by univariate analysis. Subsequently, multiple logistic regression analysis revealed that lymphocyte%, neutrophil% (NS%), procalcitonin (PCT), and anion gap (AG) were independently associated with blood EOS in AECOPD. Both blood EOS counts and EOS% were significantly correlated with lymphocyte%, NS%, PCT, and AG.

CONCLUSIONS

Collectively, blood EOS was independently associated with lymphocyte%, NS%, PCT, and AG in AECOPD patients. Lymphocyte% was lower, and NS%, PCT, and AG were higher in eosinophilic AECOPD. Our results indicate that viral-dominant infections are the probable major etiologies of eosinophilic AECOPD. Noneosinophilic AECOPD is more likely associated with bacterial-dominant infections. The systemic inflammation in noneosinophilic AECOPD was more severe.

Bacteria and sputum inflammatory cell counts; a COPD cohort analysis

Background

There is evidence that bacterial colonisation in chronic obstructive pulmonary disease (COPD) is associated with increased neutrophilic airway inflammation. This study tested the hypothesis that different bacterial phyla and species cause different inflammatory profiles in COPD patients.

Methods

Sputum was analysed by quantitative polymerase chain reaction (qPCR) to quantify bacterial load and 16S rRNA gene sequencing to identify taxonomic composition. Sputum differential cell counts (DCC) and blood DCC were obtained at baseline and 6 months. Patients were categorised into five groups based on bacterial load defined by genome copies/ml of ≥ 1 × 10⁴, no colonisation and colonisation by Haemophilus influenzae (H. influenzae), Moraxella catarrhalis (M. catarrhalis), Streptococcus pneumoniae (S. pneumoniae), or > 1 potentially pathogenic microorganism (PPM).

Results

We observed an increase in sputum neutrophil (%), blood neutrophil (%) and neutrophil–lymphocyte ratio (NLR) in patients colonised with H. influenzae (82.6, 67.1, and 3.29 respectively) compared to those without PPM colonisation at baseline (69.5, 63.51 and 2.56 respectively) (p < 0.05 for all analyses), with similar findings at 6 months. The bacterial load of H. influenzae and Haemophilus determined by qPCR and 16s rRNA gene sequencing respectively, and sputum neutrophil % were positively correlated between baseline and 6 months visits (p < 0.0001, 0.0150 and 0.0002 with r = 0.53, 0.33 and 0.44 respectively).

Conclusions

These results demonstrate a subgroup of COPD patients with persistent H. influenzae colonisation that is associated with increased airway and systemic neutrophilic airway inflammation, and less eosinophilic airway inflammation.

Increased ACE2 Expression in Bronchial Epithelium of COPD Patients who are Overweight

OBJECTIVE

Mortality from coronavirus disease 2019 (COVID-19) is increased in patients with chronic obstructive pulmonary disease (COPD). Furthermore, higher BMI is related to severe disease. Severe acute respiratory syndrome coronavirus 2 utilizes angiotensin converting enzyme 2 (ACE2) to gain cellular entry.

METHODS

Whether ACE2 bronchial epithelial expression is increased in COPD patients who have overweight compared with those who do not was investigated by RNA sequencing.

RESULTS

Increased ACE2 expression was observed in patients with COPD with overweight (mean BMI, 29 kg/m² ) compared with those without overweight (mean BMI, 21 kg/m² ) (P = 0.004).

CONCLUSIONS

Increased ACE2 expression may cause increased severe acute respiratory syndrome coronavirus 2 infection of the respiratory tract. Overweight COPD patients may be at greater risk for developing severe COVID-19.

Role of Type2 Inflammatory Biomarkers in Chronic Obstructive Pulmonary Disease

Airway inflammation in chronic obstructive pulmonary disease (COPD) is typically thought to be driven by Type1 immune responses, while Type2 inflammation appears to be present in definite proportions in the stable state and during exacerbations. In fact, some COPD patients showed gene expression of Type2 inflammation in the airway, and this subset was associated with the inhaled corticosteroid (ICS) response. Interestingly enough, the relationship between COPD and diseases associated with Type2 inflammation from the perspective of impaired lung development is increasingly highlighted by recent epidemiologic studies on the origin of COPD. Therefore, many researchers have shown an interest in the prevalence and the role of existent Type2 biomarkers such as sputum and blood eosinophils, exhaled nitric oxide fraction, and atopy, not only in asthma but also in COPD. Although the evidence about Type2 biomarkers in COPD is inconsistent and less robust, Type2 biomarkers have shown some potential when analyzing various clinical outcomes or therapeutic response to ICS. In this article, we review the existent and emerging Type2 biomarkers with clinically higher applicability in the management of COPD.

COPD sputum eosinophils: relationship to blood eosinophils and the effect of inhaled PDE4 inhibition

Patients with COPD who have higher eosinophil numbers in the airways and peripheral blood demonstrate a greater clinical response to inhaled corticosteroids (ICS) [1–3]. Furthermore, the effect of the oral phosphodiesterase-4 (PDE4) inhibitor roflumilast on exacerbations in severe COPD patients with chronic bronchitis, who are treated with ICS and long-acting bronchodilators, also appears to be greater at higher blood eosinophil counts [4]. The mechanisms responsible for these differential drug effects remain to be defined, but may relate to increased type-2 inflammation and/or decreased presence of colonising airway bacteria in COPD patients with more eosinophils [5, 6], leading to different responses to anti-inflammatory drugs. An association between blood and sputum eosinophils has been observed in some, but not all studies [7–12]. Accurate sputum eosinophil count measurement requires good quality samples to make cytospins where eosinophils can be clearly counted; variable quality of sputum samples, particularly in multicentre studies, will affect the ability to show a relationship with blood eosinophil counts.

PDE4 inhibition reduces sputum eosinophils in those COPD patients with higher eosinophil counts. This evidence supports an effect of PDE4 inhibitors on eosinophilic inflammation.https://bit.ly/3airXw7

The stability of blood eosinophils in stable chronic obstructive pulmonary disease: a retrospective study in Belgian primary care

Background

Blood eosinophil counts (BEC) were recently included in the 2019 Global Initiative for Obstructive Lung Disease (GOLD) guideline as an easily accessible theragnostic biomarker for Chronic Obstructive Pulmonary Disease (COPD). However, the stability of BEC remains insufficiently studied.

Methods

We conducted a retrospective study in six primary care practices in Belgium on data from Electronic Health Records of stable COPD patients, to characterise the stability of blood eosinophils over time. We report the percentage of patients with BEC persistently below or above the 2019 GOLD guideline thresholds (100 and 300 cells/μL). For each patient the mean, standard deviation (SD) and relative standard deviation (RSD) of the BEC were calculated to determine the intra-patient variability.

Results

Ninety-eight patients were included, yielding 1082 eosinophil measurements (median 8 measurements/patient), with BEC ranging between 0 and 1504 cells/μL. Four (4.1%) patients had BEC persistently below 100 cells/μL, 34 (34.7%) had measurements persistently above this threshold. Approximately half of the patients (51.0%) had BEC persistently below 300 cells/μL and 3 (3.1%) patients had counts persistently above this threshold. 28.6% of patients crossed both threshold values throughout the registration period. The mean BEC per patient ranged between 15 and 846 cells/μL with an intra-patient SD between 5 and 658 cells/μL. The mean intra-patient RSD was 0.46. There was a significant strong positive correlation (Pearson analyses) between the mean BEC and SD (r = 0.765; n = 98). Simple linear regression was used to further describe the influence of the mean eosinophil count on the SD (B = 0.500; 95%CI 0.415–0.586; n = 98; p < 0.001).

Conclusion

BEC can be variable in individual COPD patients. Therefore, the use of a single measurement to guide therapeutic decisions remains debatable. Further prospective research remains necessary to validate the reproducibility of this biomarker.

Eosinophils, basophils and type 2 immune microenvironments in COPD-affected lung tissue

Although elevated blood or sputum eosinophils are present in many patients with COPD, uncertainties remain regarding the anatomical distribution pattern of lung-infiltrating eosinophils. Basophils have remained virtually unexplored in COPD. This study mapped tissue-infiltrating eosinophils, basophils and eosinophil-promoting immune mechanisms in COPD-affected lungs.

Surgical lung tissue and biopsies from major anatomical compartments were obtained from COPD patients with severity grades Global Initiative for Chronic Obstructive Lung Disease stages I–IV; never-smokers/smokers served as controls. Automated immunohistochemistry and in situ hybridisation identified immune cells, the type 2 immunity marker GATA3 and eotaxins (CCL11, CCL24).

Eosinophils and basophils were present in all anatomical compartments of COPD-affected lungs and increased significantly in very severe COPD. The eosinophilia was strikingly patchy, and focal eosinophil-rich microenvironments were spatially linked with GATA3⁺ cells, including type 2 helper T-cell lymphocytes and type 2 innate lymphoid cells. A similarly localised and interleukin-33/ST2-dependent eosinophilia was demonstrated in influenza-infected mice. Both mice and patients displayed spatially confined eotaxin signatures with CCL11⁺ fibroblasts and CCL24⁺ macrophages.

In addition to identifying tissue basophilia as a novel feature of advanced COPD, the identification of spatially confined eosinophil-rich type 2 microenvironments represents a novel type of heterogeneity in the immunopathology of COPD that is likely to have implications for personalised treatment.

Highly localised Th2- and eosinophil-rich pockets were identified in COPD-affected lungs, which increased in number with increasing disease severity and included basophils. This exemplifies a novel type of heterogeneity in the immunopathology of COPD.http://bit.ly/2HexTco

Blood Eosinophil Counts in Chronic Obstructive Pulmonary Disease: A Biomarker of Inhaled Corticosteroid Effects

Blood eosinophil counts have emerged as a chronic obstructive pulmonary disease (COPD) biomarker that predict the effects of inhaled corticosteroids (ICS) in clinical practice. Post-hoc and prospective analysis of randomized control trials have shown that higher blood eosinophil counts at the start of the study predict a greater response to ICS. COPD patients with frequent exacerbations (2 or more moderate exacerbations/yr) or a history of hospitalization have a greater response to ICS. Ex-smokers also appear to have a greater ICS response. Blood eosinophil counts can be combined with clinical information such as exacerbation history and smoking status to enable a precision medicine approach to the use of ICS. Higher blood eosinophil counts are associated with increased eosinophilic lung inflammation, and other biological features that may contribute to the increased ICS response observed. Emerging data indicates that lower blood eosinophil counts are associated with an increased risk of bacterial infection, suggesting complex relationships between eosinophils, ICS response, and the airway microbiome.

Eosinophilic Airway Inflammation in Patients with Stable Biomass Smoke- versus Tobacco Smoke-Associated Chronic Obstructive Pulmonary Disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is an inflammatory disease with predominant involvement of neutrophils, macrophages and CD8+ lymphocytes. Eosinophilic airway inflammations are reported in stable state and during acute exacerbations of tobacco smoke-associated COPD (TS-COPD). Women exposed to biomass fuel smoke are known to have eosinophils in sputum. However, little is known about the sputum cellular inflammatory profile in biomass fuel smoke-associated COPD (BMS-COPD). We therefore aimed to compare the sputum cellular inflammatory profile in tobacco smoke- and biomass smoke-associated COPD.

METHODS

The study was conducted in a tertiary care hospital in Goa, India. A total of 113 patients with stable COPD reporting to the outpatient pulmonary clinic were recruited. All participants were ≥ 40 years of age. Sputum induction studies were performed by the method of Pizzichini et al. after baseline subject characterization. Significant eosinophilia was defined as induced sputum eosinophils ≥ 3%.

RESULTS

There were 85 TS-COPD and 28 BMS-COPD patients. The mean age [standard deviation (SD)] was 64.7 (7.8) and 63.0 years (8.3), p = 0.32 in TS and BMS-COPD, respectively. Eighteen subjects (21.1%) were female smokers. The smoking pack-year median [interquartile range (IQR)] was 36 (20, 58) and hour-years of biomass smoke exposure mean (SD) was 192.4 (61). The TS-COPD and BMS-COPD cases showed a post-bronchodilator forced expiratory volume in one second (FEV1%) mean (SD) of 57.9 (17.1), and 62.6 (19.4), p= 0.22, respectively. Both groups had similar symptoms and severity of disease. Induced sputum total cell count per gram of sputum × 10⁶ mean (SD) was 3.05 (1.53) for TS-COPD, and 2.55(1.37) for BMS-COPD p=0.12. The neutrophils % mean (SD) was 86.4 (16.5) and 87.9 (10.2), p = 0.64; eosinophils % median (IQR) was 2.5 (1, 10) and 8 (2, 12.8), p = 0.07; lymphocytes % median (IQR) was 0 (0, 0.75) and 0 (0, 1) p = 0.13; macrophages % median (IQR) was 2.5 (0.75, 5.7) and 1 (0, 4.7) p = 0.13; and significant eosinophilia (eosinophils ≥3%) was 42 (49.4%) and 20 (71%), p=0.04, for TS-COPD and BMS-COPD, respectively.

CONCLUSIONS

For similar severity of disease and clinical symptoms, significant eosinophilic inflammation was observed in stable BMS-COPD, while both groups had similar neutrophilic inflammation.

PARTICIPANT CONSENT

Obtained.

ETHICS APPROVAL

The study was approved by the Institutional Ethics Committee of the Goa Medical College, Goa, India.

COMPETING INTERESTS

The authors declare no competing financial interests.

Predicting response to benralizumab in chronic obstructive pulmonary disease: analyses of GALATHEA and TERRANOVA studies

BACKGROUND

Benralizumab did not significantly reduce exacerbations compared with placebo in the phase 3 GALATHEA and TERRANOVA trials of benralizumab for patients with chronic obstructive pulmonary disease (COPD). We aimed to identify clinical and physiological characteristics of patients with COPD that could help to identify people who are likely to have the greatest treatment effect with benralizumab.

METHODS

We analysed individual study and pooled results from GALATHEA and TERRANOVA. At study enrolment, patients from GALATHEA and TERRANOVA were aged 40-85 years, had moderate to very severe airflow limitation, had elevated blood eosinophil counts, and at least two exacerbations or one severe exacerbation in the previous year despite dual inhaled therapy (inhaled corticosteroids plus long-acting β₂-agonists or long-acting β₂-agonists plus long-acting muscarinic antagonists) or triple inhaled therapy (inhaled corticosteroids plus long-acting β₂-agonists plus long-acting muscarinic antagonists). We analysed data for 3910 patients who received benralizumab (30 mg or 100 mg subcutaneously every 8 weeks; first three doses every 4 weeks) or placebo with dual or triple therapy to identify factors consistently associated with annual exacerbation rate reduction. We evaluated the annual exacerbation rate for benralizumab versus placebo as the primary endpoint. GALATHEA and TERRANOVA are registered with ClinicalTrials.gov, NCT02138916 and NCT02155660, respectively.

FINDINGS

For 2665 patients with elevated blood eosinophil counts, treatment effect with benralizumab every 8 weeks at 100 mg, but not at 30 mg, occurred for patients with a history of more frequent exacerbations, poorer baseline lung function, or greater baseline lung function improvement with short-acting bronchodilators. Patients with baseline blood eosinophil counts of 220 cells per μL or greater with: three or more exacerbations in the previous year receiving benralizumab every 8 weeks versus placebo, had rate ratios (RRs) of 0·69 (95% CI 0·56-0·83) for 100 mg and 0·86 (0·71-1·04) for 30 mg; postbronchodilator FEV₁ of less than 40% had RRs of 0·76 (0·64-0·91) for 100 mg and 0·90 (0·76-1·06) for 30 mg; and postbronchodilator response of at least 15% had RRs of 0·67 (0·54-0·83) for 100 mg and 0·87 (0·71-1·07) for 30 mg. When combined factors were examined, patients with elevated baseline blood eosinophil counts, with three or more exacerbations in the previous year, and who were receiving triple therapy were identified as likely to benefit from benralizumab 100 mg every 8 weeks versus placebo (RR 0·70 [95% CI 0·56-0·88]). Benralizumab 30 mg every 8 weeks did not benefit patients meeting these criteria compared with placebo (RR 0·99 [95% CI 0·79-1·23]).

INTERPRETATION

Elevated blood eosinophil counts combined with clinical characteristics identified a subpopulation of patients with COPD who had reductions in exacerbations with benralizumab treatment. These hypothesis-generating analyses identified the potential efficacy of benralizumab 100 mg for this subpopulation. These findings require prospective evaluation in clinical trials.

FUNDING

AstraZeneca.

Mepolizumab in the treatment of eosinophilic chronic obstructive pulmonary disease

Despite maximal medical therapy, a subset of patients with chronic obstructive pulmonary disease continue to suffer acute exacerbations. It is also clear that a subset of this population has elevated blood eosinophils. In addition to clearly responding better to inhaled corticosteroids, it is also possible that this subgroup may benefit from biologic treatments targeting eosinophilic inflammation. Mepolizumab, a humanized monoclonal antibody against interleukin-5 (IL-5), may have a therapeutic effect in a subgroup of patients with COPD and eosinophilic airway inflammation. In this review, we discuss the biologic rationale for mepolizumab targeting IL-5 in eosinophilic COPD as well as the results of recently published clinical trials.

Independent factors associate with hospital mortality in patients with acute exacerbation of chronic obstructive pulmonary disease requiring intensive care unit admission: Focusing on the eosinophil-to-neutrophil ratio

Background

Factors associated with hospital mortality are unclear in patients with acute exacerbation of COPD (AECOPD) requiring intensive care unit (ICU) admission. We aimed to characterize these patients and identify factors associated with hospital mortality.

Patients and methods

We used a retrospective observational case-control design and recruited patients between January 2015 and March 2017. Of 146 patients enrolled, 24 (16.4%) died during their hospital stay, while 122 survived.

Results

Multivariate logistic regression analyses revealed factors associated with hospital mortality: age (adjusted odds ratio [AOR] 1.12, 95% CI: 1.03–1.23), C-reactive protein (CRP) level >7.5 mg/dL at the emergency room (AOR 4.52, 95% CI: 1.27–16.04), peak eosinophil-to-neutrophil ratio (ENR)×10² on days 8–14 of treatment (AOR 0.22, 95% CI: 0.08–0.63), and in-hospital complications (AOR 4.23, 95% CI: 1.12–15.98) (all P<0.05). After receiver operating characteristic curve analyses, cutoff level for peak ENR×10² was 0.224. To examine the synergistic effects of CRP level and peak ENR, we divided patients into four groups: (G0, reference group) Peak ENR×10² >0.224 on days 8–14 and initial CRP <7.5 mg/dL; (G1) Peak ENR×10² >0.224 on days 8–14 and initial CRP >7.5 mg/dL; (G2) Peak ENR×10² <0.224 on days 8–14 and initial CRP <7.5 mg/dL; and (G3) Peak ENR×10² <0.224 on days 8–14 and initial CRP >7.5 mg/dL. For G2 and G3 patients, the AOR of mortality was significantly different from that of the reference group (G2: AOR 10.00, P = 0.020; G3: AOR 61.79, P<0.001). The relationship between 28-day mortality and the four groups was statistically significant (log-rank test, P<0.001).

Conclusion

Older age, initial CRP >7.5 mg/dL, peak ENR on days 8–14, and in-hospital complications were associated with hospital mortality in patients with AECOPD requiring ICU admission. Patients with both biomarkers, initial CRP >7.5 mg/dL, and peak ENR×10² <0.224 on days 8–14 of treatment, had an increased risk of hospital mortality.

Do blood eosinophils strictly reflect airway inflammation in COPD? Comparison with asthmatic patients

Introduction

Airway eosinophilic inflammation is a characteristic of asthmatic patients and of a sub group of COPD subjects. Blood eosinophils are deemed as a good surrogate marker of sputum eosinophilic inflammation; however, controversial data have been published particularly in COPD. The aim of our study was to compare blood and sputum eosinophils in COPD and asthmatic patients in “real life”.

Methods

Sputum was induced in stable patients with COPD or asthma with hypertonic saline solution and blood eosinophils were evaluated. Frequency of comorbidities was recorded. Correlations were performed stratifying patients by disease and comorbidities.

Results

146 patients, 57 with COPD and 89 with asthma were evaluated. Blood and sputum eosinophils expressed as percentages were correlated in COPD (rho = 0.40; p = 0.004), but the entity of correlation was lower compared with asthmatic subjects (rho = 0.71; p < 0.0001). When blood eosinophils were expressed as counts the correlation was slightly lower than when expressed as percentages in COPD (rho = 0.35; p = 0.01) and in asthmatic patients (rho = 0.68; p < 0.0001). In COPD patients older than 73 years or with blood eosinophils higher than the median value (210.6 eos/μl), or co-diagnosed with hypertension, ischemic heart disease or atrial fibrillation no correlation between blood and sputum eosinophils was found.

However, the effect of ischemic heart disease and atrial fibrillation could be driven by hypertension since most of these patients have this comorbidity.

Conclusion

Blood eosinophils correlated with sputum eosinophils to a lesser degree in COPD than in asthmatic patients. Older age, high blood eosinophils and hypertension affected the correlation between blood and sputum eosinophils, more studies are needed to evaluate the role of other cardiac comobidities.

Global Strategy for the Diagnosis, Management, and Prevention of Chronic Obstructive Lung Disease: the GOLD science committee report 2019

Precision medicine is a patient-specific approach that integrates all relevant clinical, genetic and biological information in order to optimise the therapeutic benefit relative to the possibility of side-effects for each individual. Recent clinical trials have shown that higher blood eosinophil counts are associated with a greater efficacy of inhaled corticosteroids (ICSs) in chronic obstructive pulmonary disease (COPD) patients. Blood eosinophil counts are a biomarker with potential to be used in clinical practice, to help target ICS treatment with more precision in COPD patients with a history of exacerbations despite appropriate bronchodilator treatment.The Global Initiative for Chronic Obstructive Lung Disease (GOLD) 2017 pharmacological treatment algorithms, based on the ABCD assessment, can be applied relatively easily to treatment-naive individuals at initial presentation. However, their use is more problematic during follow-up in patients who are already on maintenance treatment. There is a need for a different system to guide COPD pharmacological management during follow-up.Recent large randomised controlled trials have provided important new information concerning the therapeutic effects of ICSs and long-acting bronchodilators on exacerbations. The new evidence regarding blood eosinophils and inhaled treatments, and the need to distinguish between initial and follow-up pharmacological management, led to changes in the GOLD pharmacological treatment recommendations. This article explains the evidence and rationale for the GOLD 2019 pharmacological treatment recommendations.

Exacerbations and health care resource use among patients with COPD in relation to blood eosinophil counts

Purpose

Current understanding of the relationship between COPD phenotype and health care resource utilization (HCRU) is limited. This real-world study evaluated disease burden and HCRU for COPD subgroups prone to exacerbation as defined by blood eosinophil (EOS) count and multiple inhaler triple therapy (MITT) use.

Methods

This was a large-scale, retrospective, longitudinal, observational cohort study using data from the US IBM Watson Explorys real-world database (GSK Study HO-17-18395). The population of interest comprised patients with COPD ≥40 years of age with ≥2 moderate or ≥1 severe exacerbations (prior year) while on inhaled maintenance therapy, with ≥1 blood EOS count. Data were analyzed during the year prior to index date (last COPD encounter between January 1, 2011 and December 31, 2016). Four subgroups were analyzed based on a combination of EOS counts (<150 and ≥150 cells/μL) and MITT use (receiving or not receiving). Among these groups, clinical characteristics, exacerbations, and HCRU were described. A sensitivity analysis that further stratified EOS into four categories (<150, ≥150–<300, ≥300–<500, and ≥500 cells/μL) was also performed.

Results

The COPD population of interest comprised 34,268 patients. Subgroups with EOS ≥150 cells/μL vs <150 cells/μL had more comorbidities and experienced significantly higher mean numbers of moderate exacerbations (not receiving MITT, ≥150 cells/μL vs <150 cells/μL: 1.93 vs 1.82, P<0.0001; receiving MITT 2.26 vs 2.16, P=0.0062) and COPD-related emergency visits (not receiving MITT, ≥150 cells/μL vs <150 cells/μL: 3.0 vs 2.5, P<0.001; receiving MITT 3.4 vs 3.1, P=0.0011). Increasing EOS category was associated with higher HCRU.

Conclusion

Blood EOS ≥150/μL cells were associated with increased HCRU and higher exacerbation rates compared with EOS <150 cells/μL, irrespective of MITT use. COPD phenotyping using blood EOS could help identify candidates for additional therapies that target eosinophilic inflammatory pathways.