Sputum Eosinophil Levels Research Articles

Severe Eosinophilic Asthma or Eosinophilic Granulomatosis With Polyangiitis: Potential Biomarkers for Novel Diagnostic Strategies

BackgroundSevere Eosinophilic Asthma (SEA) may be the prodromal phase of Eosinophilic Granulomatosis with Polyangiitis (EGPA). Nevertheless, few studies have tried to recognize EGPA in the early stages of the disease. ObjectivesTo identify a panel of clinical and biological markers to detect which severe asthmatic patient might be considered in a prodromal phase of EGPA and crafting a strategy for diagnostic decision-making. Methods30 patients with EGPA and 49 with SEA were enrolled. A complete pulmonary, ear, nose and Throat (ENT) and rheumatologic assessment were made. Blood (eosinophil count, eosinophilic cationic protein-ECP, IL5, IL4, total-IgE, IgG4, anti-neutrophil cytoplasmic antibody (ANCA), sputum (eosinophils count, periostin, IL8 and GMCSF) and nasal smear (eosinophilia) biomarkers were assessed. Asthma Control Test, Short Form-36, SinoNasalOutcome Test-22, and Asthma Quality of Life Questionnaire were also used. ResultsSEA patients had poorer asthma control (p<0.001) and higher level of sputum eosinophils (p<0.002) while EGPA patients reported higher levels of blood eosinophils in the past. Sputum GMCSF was the only biomarker significantly increased in EGPA patients compared with SEA (p<0.0001). Among SEA patients, those with some suggestive but not diagnostic criteria of EGPA, particularly tissue eosinophilic infiltrates, presented higher levels of sputum GMCSF (p<0.0005), blood and sputum eosinophils (p<0.0006, p<0.011) in comparison with the other patients. ConclusionSputum GMCSF and eosinophils might be useful biomarkers to support early diagnosis and treatment choices in SEA patients, suspected of having EGPA

Proteomic signatures of eosinophilic and neutrophilic asthma from serum and sputum

Eosinophilic and neutrophilic asthma defined by high levels of blood and sputum eosinophils and neutrophils exemplifies the inflammatory heterogeneity of asthma, particularly severe asthma. We analysed the serum and sputum proteome to identify biomarkers jointly associated with these different phenotypes. Proteomic profiles (N=1129 proteins) were assayed in sputum (n=182) and serum (n=574) from two cohorts (U-BIOPRED and ADEPT) of mild-moderate and severe asthma by SOMAscan. Using least absolute shrinkage and selection operator (LASSO)-penalised logistic regression in a stability selection framework, we sought sparse sets of proteins associated with either eosinophilic or neutrophilic asthma with and without adjustment for established clinical factors including oral corticosteroid use and forced expiratory volume. We identified 13 serum proteins associated with eosinophilic asthma, including 7 (PAPP-A, TARC/CCL17, ALT/GPT, IgE, CCL28, CO8A1, and IL5-Rα) that were stably selected while adjusting for clinical factors yielding an AUC of 0.84 (95% CI: 0.83-0.84) compared to 0.62 (95% CI: 0.61-0.63) for clinical factors only. Sputum protein analysis selected only PAPP-A (AUC=0.81 [95% CI: 0.80-0.81]). 12 serum proteins were associated with neutrophilic asthma, of which 5 (MMP-9, EDAR, GIIE/PLA2G2E, IL-1-R4/IL1RL1, and Elafin) complemented clinical factors increasing the AUC from 0.63 (95% CI: 0.58-0.67) for the model with clinical factors only to 0.89 (95% CI: 0.89-0.90). Our model did not select any sputum proteins associated with neutrophilic status. Targeted serum proteomic profiles are a non-invasive and scalable approach for subtyping of neutrophilic and eosinophilic asthma and for future functional understanding of these phenotypes. U-BIOPRED has received funding from the Innovative Medicines Initiative (IMI) Joint Undertaking under grant agreement no. 115010, resources of which are composed of financial contributions from the European Union's Seventh Framework Programme (FP7/2007-2013), and European Federation of Pharmaceutical Industries and Associations (EFPIA) companies' in-kind contributions (www.imi.europa.eu). ADEPT was funded by Johnson & Johnson/Janssen pharmaceutical Company.

An epithelial gene signature of trans-IL-6 signaling defines a subgroup of type 2-low asthma

BackgroundAsthma is stratified into type 2-high and type 2-low inflammatory phenotypes. Limited success has been achieved in developing drugs that target type 2-low inflammation. Previous studies have linked IL-6 signaling to severe asthma. IL-6 cooperates with soluble-IL-6Rα to activate cell signaling in airway epithelium.ObjectiveWe sought to study the role of sIL-6Rα amplified IL-6 signaling in airway epithelium and to develop an IL-6+ sIL-6Rα gene signature that may be used to select asthma patients who potentially respond to anti-IL-6 therapy.MethodsHuman airway epithelial cells were stimulated with combinations of IL-6, sIL-6Rα, and inhibitors, sgp130 (Olamkicept), and anti-IL-6R (Tocilizumab), to assess effects on pathway activation, epithelial barrier integrity, and gene expression. A gene signature was generated to identify IL-6 high patients using bronchial biopsies and nasal brushes.ResultsSoluble-IL-6Rα amplified the activation of the IL-6 pathway, shown by the increase of STAT3 phosphorylation and stronger gene induction in airway epithelial cells compared to IL-6 alone. Olamkicept and Tocilizumab inhibited the effect of IL-6 + sIL-6Rα on gene expression. We developed an IL-6 + sIL-6Rα gene signature and observed enrichment of this signature in bronchial biopsies but not nasal brushes from asthma patients compared to healthy controls. An IL-6 + sIL-6Rα gene signature score was associated with lower levels of sputum eosinophils in asthma.ConclusionsIL-6Rα amplifies IL-6 signaling in bronchial epithelial cells. Higher local airway IL-6 + sIL-6Rα signaling is observed in asthma patients with low sputum eosinophils.

Sputum Neurturin Levels in Adult Asthmatic Subjects.

Neurturin (NRTN) is a neurotrophic factor that was originally identified in the development and maintenance of neural cells. Recent studies involving NRTN knockout mice have reported its anti-inflammatory effects in allergic airway conditions. However, the role of NRTN in human asthma has not yet been identified. The purposes of the present study were to confirm the presence of NRTN in the airways and to investigate the clinical and pathogenetic roles of NRTN in asthma. The NRTN levels in the induced sputum were measured by enzyme-linked immunosorbent assay (ELISA). Relationships between NRTN and clinical characteristics, asthma control status, and airway inflammation were assessed. Sixty-four asthmatic subjects were enrolled in the study. All asthmatic subjects had detectable sputum NRTN levels, with a mean (SD) level of 2.03 (1.29) ng/mL. The sputum NRTN levels had significant positive correlations with sputum eosinophil and exhaled nitric oxide levels and were significantly higher in the atopic subjects than in the non-atopic subjects. No significant difference in sputum NRTN levels were observed for asthma control status and asthma exacerbation. In sputum inflammatory analyses, sputum NRTN level was positively correlated with interleukin (IL)-5 and IL-13 levels, and negatively correlated with matrix metalloproteinase (MMP)-9 level. It is plausible that sputum NRTN could serve as a new marker for Type 2 airway inflammation, implicating its role in the process of airway remodeling in asthma. Future studies should investigate the clinical relevance of sputum NRTN level in prospective analyses.

Biomarkers for predicting type 2-high and uncontrolled asthma in real-world practice

BackgroundBlood eosinophil count (BEC), immunoglobulin (Ig) E, and fractional exhaled nitric oxide (FeNO) are key clinical indicators for identifying type 2 (T2) asthma. ObjectiveTo provide optimal cutoff points of T2 markers for assessing T2-high or uncontrolled asthma in real-world practice. MethodsVarious clinical and laboratory parameters were analyzed according to the result of T2 markers (BEC, serum-free IgE, and FeNO) in adults with asthma who had maintained antiasthmatic medications. The cutoff levels for representing uncontrolled asthma were determined using receiver operating characteristic analysis. Blood levels of periostin and eosinophil-derived neurotoxin were measured by enzyme-linked immunosorbent assay. Activation markers of circulating eosinophils (Siglec8+) and neutrophils (CD66+) were analyzed by flow cytometry. ResultsOf 133 patients with asthma, 23 (17.3%) had 3 T2 markers (BEC ≥ 300 cells/μL, serum-free IgE ≥ 120 ng/mL, and FeNO ≥ 25 parts per billion) and significantly higher levels of sputum eosinophils, blood eosinophil-derived neurotoxin, and Siglec8+ eosinophils but lower 1-second forced expiratory volume percentage, in addition to a higher rate of uncontrolled status (P < .05 for all). Furthermore, patients with uncontrolled asthma had significantly higher levels of FeNO and BEC with lower 1-second forced expiratory volume percentage (P < .05 for all). The optimal cutoff values for predicting uncontrolled asthma were found to be 22 parts per billion of FeNO levels, 161.4 cells/L of BECs, and 85.9 ng/mL of serum-free IgE levels. ConclusionWe suggest the optimal cutoff values of BEC, IgE, and FeNO for classifying T2-high or uncontrolled asthma, which could be applied as candidate biomarkers for targeting patients with asthma who require T2 biologics.

Effect of Benralizumab on Mucus Plugs in Severe Eosinophilic Asthma

Introduction: Mucus plugs are associated with airway obstruction in severe asthma and are involved in the formation of activated eosinophils. Benralizumab, an anti-interleukin-5 receptor antibody, markedly reduces not only peripheral blood eosinophils but also airway eosinophils; however, its effects on mucus plugs have not been clarified. In this study, we examined the efficacy of benralizumab on mucus plugs using computed tomography (CT) imaging. Methods: Twelve patients who were administered benralizumab and underwent CT before and approximately 4 months after the introduction of benralizumab were included in this study, and the number of mucus plugs before and after benralizumab administration was compared. The correlation between the clinical background and treatment effect was also examined. Results: The number of mucus plugs significantly decreased after the introduction of benralizumab. The number of mucus plugs was correlated with sputum eosinophil percentage and eosinophil cationic protein in the sputum supernatants and inversely correlated with forced expiratory volume in 1 s (FEV1). Benralizumab induction resulted in a marked decrease in blood and sputum eosinophil levels and a significant improvement in asthma symptoms, quality of life scores, FEV1, and exacerbation frequency. Furthermore, there was a significant correlation between the reduction in mucus plugs and changes in the symptom score or FEV1. Discussion/Conclusion: These data suggest that benralizumab may have the potential to improve symptoms and respiratory function in patients with severe eosinophilic asthma by reducing mucus plugs.

Sputum inflammatory, neural, and remodeling mediators in eosinophilic and noneosinophilic asthma

BackgroundNeural and remodeling mechanisms may play a role in asthma, particularly noneosinophilic asthma (NEA). ObjectiveTo assess sputum mediators associated with neural, remodeling, and inflammatory mechanisms in eosinophilic asthma (EA), NEA, and participants without asthma. MethodsA total of 111 participants with and 62 without asthma (14-21 years old) underwent sputum induction, exhaled nitric oxide, atopy, and spirometry tests. There were 24 mediators measured in sputum using enzyme-linked immunosorbent assay or bead array. Eosinophilic asthma (n = 52) and NEA (n = 59) were defined using a sputum eosinophil level cut-point of greater than or equal to 2.5%. ResultsElevated levels of nociceptin (median: 39.1 vs 22.4 ng/mL, P = .03), periostin (33.8 vs 9.4 ng/mL, P = .01), and ECP; (220.1 vs 83.7 ng/mL, P = .03) were found in patients with asthma compared with those without asthma. Nociceptin was elevated in EA (54.8 vs 22.4 ng/mL, P = .02) compared with participants without asthma. Eosinophilic asthma had higher levels of inflammatory mediators (ECP: 495.5 vs 100.3 ng/mL, P ≤ .01; interleukin-1β: 285.3 vs 209.3 pg/mL, P = .03; histamine: 5805.0 vs 3172.5 pg/mL, P < .01) and remodeling mediators (VEGF-A); 3.3 vs 2.5 ng/mL, P = .03; periostin: 47.7 vs 22.1 ng/mL, P = .04) than NEA. Whereas macrophages were associated with neural mediators, for example, neurokinin A (r = 0.27, P = .01) and nociceptin (r = 0.30, P = .02), granulocytes were associated with inflammatory and remodeling mediators (eg, ECP and VEGF-A correlated with neutrophils (r = 0.53 and r = 0.33, respectively, P < .01) and eosinophils (r = 0.53 and r = 0.29 respectively, P ≤ .01). ConclusionElevated levels of nociceptin and inflammatory and remodeling markers were found in EA, but no evidence for neural and remodeling pathways was found in NEA. Neural and remodeling mechanisms seem to coexist with inflammation.

IL-4 and IL-13, not eosinophils, drive type 2 airway inflammation, remodeling and lung function decline.

Type 2 (T2) asthma is characterized by airflow limitations and elevated levels of blood and sputum eosinophils, fractional exhaled nitric oxide, IgE, and periostin. While eosinophils are associated with exacerbations, the contribution of eosinophils to lung inflammation, remodeling and function remains largely hypothetical. To determine the effect of T2 cytokines IL-4, IL-13 and IL-5 on eosinophil biology and compare the impact of depleting just eosinophils versus inhibiting all aspects of T2 inflammation on airway inflammation. Human eosinophils or endothelial cells stimulated with IL-4, IL-13 or IL-5 were assessed for gene changes or chemokine release.Mice exposed to house dust mite extract received anti-IL-4Rα (dupilumab), anti-IL-5 or control antibodies and were assessed for changes in lung histological and inflammatory endpoints. IL-4 or IL-13 stimulation of human eosinophils and endothelial cells induced gene expression changes related to granulocyte migration; whereas, IL-5 induced changes reflecting granulocyte differentiation.In a mouse model, blocking IL-4Rα improved lung function by impacting multiple effectors of inflammation and remodeling, except peripheral eosinophil counts, thereby disconnecting blood eosinophils from airway inflammation, remodeling and function. Blocking IL-5 globally reduced eosinophil counts but did not impact inflammatory or functional measures of lung pathology. Whole lung transcriptome analysis revealed that IL-5 or IL-4Rα blockade impacted eosinophil associated genes, whereas IL-4Rα blockade also impacted genes associated with multiple cells, cytokines and chemokines, mucus production, cell:cell adhesion and vascular permeability. Eosinophils are not the sole contributor to asthma pathophysiology or lung function decline and emphasizes the need to block additional mediators to modify lung inflammation and impact lung function.

The ketone body β-hydroxybutyrate mitigates ILC2-driven airway inflammation by regulating mast cell function.

Ketone bodies are increasingly understood to have regulatory effects on immune cell function, with β-hydroxybutyrate (BHB) exerting a predominantly anti-inflammatory response. Dietary strategies to increase endogenous ketone body availability such as the ketogenic diet (KD) have recently been shown to alleviate inflammation of the respiratory tract. However, the role of BHB has not been addressed. Here, we observe that BHB suppresses group 2 innate lymphoid cell (ILC2)-mediated airway inflammation. Central to this are mast cells, which support ILC2 proliferation through interleukin-2 (IL-2). Suppression of the mast cell/IL-2 axis by BHB attenuates ILC2 proliferation and the ensuing type 2 cytokine response and immunopathology. Mechanistically, BHB directly inhibits mast cell function in part through GPR109A activation. Similar effects are achieved with either the KD or 1,3-butanediol. Our data reveal the protective role of BHB in ILC2-driven airway inflammation, which underscores the potential therapeutic value of ketone body supplementation for the management of asthma.

Paucigranulocytic Asthma: Potential Pathogenetic Mechanisms, Clinical Features and Therapeutic Management.

Asthma is a heterogeneous disease usually characterized by chronic airway inflammation, in which several phenotypes have been described, related to the age of onset, symptoms, inflammatory characteristics and treatment response. The identification of the inflammatory phenotype in asthma is very useful, since it allows for both the recognition of the asthmatic triggering factor as well as the optimization of treatment The paucigranulocytic phenotype of asthma (PGA) is characterized by sputum eosinophil levels <1–3% and sputum neutrophil levels < 60%. The precise characteristics and the pathobiology of PGA are not fully understood, and, in some cases, it seems to represent a previous eosinophilic phenotype with a good response to anti-inflammatory treatment. However, many patients with PGA remain uncontrolled and experience asthmatic symptoms and exacerbations, irrespective of the low grade of airway inflammation. This observation leads to the hypothesis that PGA might also be either a special phenotype driven by different kinds of cells, such as macrophages or mast cells, or a non-inflammatory phenotype with a low grade of eosinophilic inflammation. In this review, we aim to describe the special characteristics of PGA and the potential therapeutic interventions that could be offered to these patients.

FeNO in Asthma.

Asthma is a common disease affecting 350 million people worldwide, which is characterized by airways inflammation and hyperreactivity. Historically diagnosis and treatment have been mainly based on symptoms, which have the potential to result in misdiagnosis and inappropriate treatment. Nitric oxide (NO) is exhaled in human breath and is a marker of airways inflammation. Levels of NO are increased in the exhaled breath of patients with type 2 asthma and fractional exhaled nitric oxide (FeNO) provides an objective biomarker of airway inflammation. FeNO testing is an accessible, noninvasive, and easy-to-use test. Cut-off values have been established by the American Thoracic Society (ATS), the Global Initiative for Asthma (GINA), and the National Institute for Health and Care Excellence (NICE) but vary between guidance. FeNO levels have been shown to be predictive of blood and sputum eosinophil levels but should not be used in isolation and current guidance emphasizes the importance of incorporating clinical symptoms and testing when utilizing FeNO results. The inclusion of FeNO testing can increase diagnostic accuracy of asthma, while high levels in asthmatic patients can help predict response to inhaled corticosteroids (ICS) and suppression of levels with ICS to monitor adherence. FeNO levels are also a predictor of asthma risk with increased exacerbation rates and accelerated decline in lung function associated with high levels as well as having an emerging role in predicting response to some biologic therapies in severe asthma. FeNO testing is cost-effective and has been shown, when combined with clinical assessment, to improve asthma management.

Sputum Eosinophil Level among Healthy Individuals Visiting Medicine Outpatient Department of a Tertiary Care Centre: A Descriptive Cross-sectional Study.

Sputum differential is the most comprehensive, and non-invasive investigation for evaluating airway inflammation because of its reliability, reproducibility and responsiveness. The interpretation of the results of induced sputum examination depends on knowledge of normal values from a healthy population. So far, the reference values of sputum differential cells in Nepalese population are not reported. Neutrophil and eosinophil are used to assess the inflammatory response of the airway. The aim of our study was to detect the eosinophil level in the sputum of healthy individuals with normal pulmonary function. A descriptive cross-sectional study was conducted in a tertiary care hospital, from November 1, 2021 to December 31, 2021 after taking ethical clearance from Institutional Review Board (Reference number: 1507202106). Convenience sampling was done. Collected data was entered and analysed using Statistical Package for the Social Sciences version 24.0. Point estimate at 95% was calculated along with mean and standard deviation for continuous data. Among 139 induced sputum samples, 7 (5.03%) had eosinophils present in their sputum (1.40 to 8.67 at 95% Confidence Interval). The age range of the participants was 18 years to 79 years with mean age of 39.5 ± 15.06. Prevalence of eosinophilia (percentage of eosinophil ≥3) was 4 (2.88%). The prevalence of eosinophilia in our study was found to be similar to published literature. The results of the present study show that there is a paucity of eosinophils with predominance of neutrophils, macrophages and lymphocytes in induced sputum samples of healthy non-smoker adults with normal pulmonary function test. eosinophils; healthy volunteers; leukocyte count; reference values; sputum.

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 eosinophilHigh and eosinophilLow patients, as well as neutrophilHigh and neutrophilLow, and could also predict exacerbation history. Conclusion: The 6GS may have applications in clinical practice or for stratifying patients for clinical trials.

Predictors of High Sputum Eosinophils in Chronic Obstructive Pulmonary Disease.

Eosinophils are involved in the development of chronic obstructive pulmonary disease (COPD) and inhaled corticosteroid responsiveness. We evaluated clinical predictors of high sputum eosinophil levels in a COPD cohort in China. We conducted an observational, prospective, population-based, cross-sectional study. Participants were tested for COPD and underwent spirometry, computed tomography scans, and a blood test. Participants also produced induced sputum and responded to an information-gathering questionnaire. High sputum eosinophils were defined as ≥3.0%. Multivariate logistic regression was used to identify predictors of high sputum eosinophil levels. We recruited 895 patients with complete and quality control data. The median percentage of sputum eosinophil abundance was 2.00% (interquartile range: 0.75-5.00) and the prevalence of COPD with high sputum eosinophils was 38.0%. Covariance analysis indicated that the high sputum eosinophil group had lower lung function, more severe emphysema, and air trapping. Multivariate logistic regression indicated that high blood eosinophil levels, severe respiratory symptoms, being a former smoker, and a family history of respiratory diseases were associated with high sputum eosinophil levels. High blood eosinophil levels, severe respiratory symptoms, being a former smoker, and a family history of respiratory diseases may be predictors of high sputum eosinophil levels in Chinese COPD patients. High sputum eosinophils were associated with lower lung function, more emphysema, and gas trapping.

Biomarkers to Predict Response to Inhaled Corticosteroids and Long-Acting Muscarinic Antagonists in Adolescents and Adults with Mild Persistent Asthma.

Rationale: Whether biomarkers can be used to predict response to inhaled corticosteroids (ICS) or long-acting muscarinic antagonists (LAMA) in mild persistent asthma is unclear. Objectives: In a prespecified exploratory analysis of a randomized clinical trial of 295 participants 12 years of age or older with uncontrolled mild persistent asthma, we sought to identify biomarkers of treatment response after 12 weeks of ICS (mometasone, 200 μg or 220 μg twice/d), LAMA (tiotropium, 5 μg/d), or placebo in adults (⩾18 yr) and adolescents (12-17 yr) separately. Methods: The primary outcome was a composite outcome of asthma control (treatment failure, asthma control days, and forced expiratory volume in 1 second [FEV1]). Analyses examined type 2 inflammatory biomarkers and physiologic biomarkers. We assessed the area under the receiver operating characteristic curve (AUC) for response to ICS and LAMA (each versus placebo). An AUC of 0.5 suggests no discrimination, 0.7-0.8 is considered acceptable, more than 0.8-0.9 is considered excellent, and more than 0.9 is considered outstanding. Results: In 237 adults, sputum and blood eosinophil levels and fractional exhaled nitric oxide (FeNO) each predicted ICS response (AUCs: 0.61 [95% confidence interval (CI), 0.53-0.69], 0.64 [95% CI, 0.56-0.72], and 0.62 [95% CI, 0.54-0.70], respectively; all P < 0.01); the AUC for blood eosinophil levels and FeNO together was 0.66 (95% CI, 0.58-0.74; P < 0.001). In 58 adolescents, the number of positive aeroallergens and total serum immunoglobulin E each predicted ICS response (AUCs: 0.69 [95% CI, 0.52-0.85] and 0.73 [95% CI, 0.58-0.87], respectively; both P < 0.03); the AUC for both together was 0.73 (95% CI, 0.58-0.87; P = 0.003). After ipratropium bromide, FEV1 reversibility predicted LAMA response in adults (AUC: 0.61 [95% CI, 0.53-0.69], P = 0.007) but not in adolescents. Conclusions: The AUCs of the type 2 inflammatory biomarkers and physiological biomarkers we examined may not be high enough to confidently identify individuals with asthma who respond to ICS and LAMA. However, our findings indicate that the biomarkers that predict response to ICS or LAMA may differ in adults versus adolescents with uncontrolled mild persistent asthma. Prospective, biomarker-stratified clinical trials are needed to confirm these findings and to identify first-line controllers tailored for each population.

Fractional Exhaled Nitric Oxide (FeNO) Integrating Airway Hyperresponsiveness (AHR) Examination Promotes Etiologic Diagnosis and Treatment for Children with Chronic Cough.

BackgroundChronic cough is the main reason why parents seek medical treatment for their children. This study aimed to evaluate changes in airway function and inflammation levels and associated values in diagnosing and treating chronic cough.Material/MethodsThis study involved 118 children with chronic cough, including 45 cough-variant asthma (CVA) patients, 53 upper-airway cough syndrome (UACS) patients, and 20 post-infection cough (PIC) patients. Chronic cough was diagnosed as described by guidelines of the American College of Chest Physicians for evaluating chronic cough. Pulmonary ventilation function and airway hyperresponsiveness (AHR) were evaluated. Fractional exhaled nitric oxide (FeNO) levels and eosinophilic airway inflammation were measured. Eosinophil (EOS) count in sputum was also examined. CVA patients were treated with inhaled glucocorticoids, which have anti-inflammatory effects.ResultsFeNO and sputum EOS levels were higher in CVA patients compared with UACS and PIC patients (P<0.05). CVA patients demonstrated significantly higher small airway indexes, including 25% forced expiratory flow (FEF), 50% FEF, and 75% FEF, compared with UACS and PIC patients (P<0.05). FeNO level was positively correlated with EOS in sputum (r=0.468, P=0.0001) and cough symptom scores (r=0.402, P<0.05). FeNO, EOS, and cough symptoms were significantly improved in CVA patients after glucocorticoid treatment. AHR was improved in all chronic cough patients after treatment. Cough-relief CVA patients demonstrated significantly higher FeNO levels compared with those without cough relief (P<0.05).ConclusionsFeNO integrating pulmonary function and AHR examination can improve etiologic diagnosis and treatment for chronic cough in children.

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 (eosinophilhigh ≥ 3%; eosinophillow < 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 eosinophilhigh 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 eosinophilhigh 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.

Spontaneous sputum discriminates inflammatory phenotypes in patients with asthma

BackgroundEosinophils in induced sputum are not only a useful biomarker for diagnosing asthma but are also associated with severe asthma. However, little is known about the association between eosinophils in spontaneous sputum and asthma severity. ObjectiveTo investigate whether spontaneous sputum eosinophils are related to severe asthma in adult patients with asthma. MethodsWe conducted a retrospective cross-sectional study on 86 people with asthma whose spontaneous sputa were successfully collected. Patients were classified into 4 phenotypes according to the eosinophil and neutrophil levels in spontaneous sputum. We determined the association between inflammatory phenotypes and severe asthma. Moreover, we also compared asthma severity among the phenotypes classified according to blood eosinophils and spontaneous sputum eosinophils. ResultsAsthma phenotypes were as follows: paucigranulocytic, 30.2%; neutrophilic, 18.6%; eosinophilic, 32.6%; and mixed, 18.6%. People with eosinophilic asthma had the highest blood eosinophils, total immunoglobulin E (IgE), and fractional exhaled nitric oxide among the 4 phenotypes. Significant differences were observed in asthma severity between the phenotypes (P = .019). In particular, 57.2% and 56.2% of patients had severe eosinophilic asthma and mixed asthma, respectively. The logistic regression analysis revealed that spontaneous sputum eosinophilia represented the strongest association with severe asthma among the inflammatory variables. Finally, more patients with severe asthma were included in the phenotype with spontaneous sputum eosinophils greater than 3% and blood eosinophils less than or equal to 300/μL and in the phenotype with spontaneous sputum eosinophils greater than 3% and blood eosinophils greater than 300/μL. ConclusionSpontaneous sputum can provide helpful information on airway inflammatory phenotyping in patients with asthma.

Allergic Endotypes and Phenotypes of Asthma

Allergic asthma is defined as asthma associated with sensitization to aeroallergens, which leads to asthma symptoms and airway inflammation. Allergic asthma is the most common asthma phenotype. The onset of allergic asthma is most often in childhood and is usually accompanied by other comorbidities including atopic dermatitis and allergic rhinitis. It is often persistent although there is a wide variation in disease severity. It is a TH2-driven process. Biomarkers have been identified to distinguish patients with allergic asthma, particularly serum IgE levels, tests to indicate sensitization to aeroallergens such as specific IgE or skin prick test positivity, blood and sputum eosinophil levels, fraction of exhaled nitric oxide, and periostin. Treatments for allergic asthma include environmental control measures, allergen immunotherapy, and glucocorticoids. Biologics, targeting the TH2 pathway, have been shown to be effective in the treatment of allergic asthma.

COPD treatment choices based on blood eosinophils: are we there yet?

Eosinophils are increasingly being recognised as an important characteristic feature of COPD. Patients with COPD and eosinophilic inflammation tend to respond to steroid therapy; however, many questions remain regarding the optimum measurement. Eosinophilic inflammation may be defined based on various sampling techniques, including eosinophil levels in blood, sputum, bronchoalveolar lavage or biopsy, which leads to inconsistencies in its definition. Blood eosinophils may increase in conjunction with sputum eosinophils during COPD exacerbations and therefore may be a good surrogate marker of airway eosinophilic inflammation. However, the timing of the blood eosinophil measurement, the stability of the eosinophil count and the threshold used in different studies are variable. The use of blood eosinophil count to direct biological therapies in COPD has also had variable outcomes. Eosinophilic inflammation has an important role in COPD management; however, its use as the optimum biomarker still needs further investigation.Key pointsEosinophilia may play a significant role in the pathogenesis of COPD.Eosinophilic inflammation in COPD can be steroid responsive; however, eosinophilic inflammation is variable, and caution needs to be taken with measurements and the thresholds used.The long-term effects of reducing eosinophil levels in COPD is unclear.Educational aimsTo explore current knowledge of eosinophils in COPD.To explore the relationship between eosinophilia and corticosteroid use.To understand the limitations of assessing and using eosinophilia in COPD.