Low Sputum Eosinophil Research Articles

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.

Chronic infection with Chlamydia pneumoniae in asthma: a type-2 low infection related phenotype

BackgroundChlamydia pneumoniae and Mycoplasma pneumoniae have been implicated in the pathogenesis of asthma and are responsible for chronic inflammation when host immune system fails to eradicate the bacteria.MethodWe performed a prospective study on 410 patients who underwent a visit at the asthma clinic of CHU of Liege between June 2016 and June 2018 with serology testing for C. pneumoniae and M. pneumoniae.Results65% of our asthmatic population had serum IgA and/or IgG towards C. pneumoniae, while only 12.6% had IgM and/or IgG against M. pneumoniae. Compared to seronegative asthmatics, asthmatics with IgA+ and IgG+ against C. pneumoniae were more often male and older with a higher proportion of patients with smoking history. They received higher doses of inhaled corticosteroids (ICS) and displayed lower FEV1/FVC ratio, higher RV/TLC ratio and lower conductance. They had higher levels of fibrinogen, though in the normal range and had lower sputum eosinophil counts. Patients with IgA− and IgG+ against C. pneumoniae were older and had higher blood monocyte counts and alpha-1-antitrypsin levels as compared to seronegative patients. Patients with IgM and/or IgG towards M. pneumoniae were more often males than seronegative asthmatics. In a subpopulation of 14 neutrophilic asthmatics with Chlamydia pneumoniae IgA + /IgG + treated with macrolides, we found a significant decrease in blood neutrophils and normalization of sputum neutrophil count but no effect on asthma quality of life and exacerbations.ConclusionPositive Chlamydia serologic test is more common than positive Mycoplasma serology. Asthmatics with IgA and IgG against C. pneumoniae have more severe disease with increased airway obstruction, higher doses of ICS, more signs of air trapping and less type-2 inflammation.

The diagnostic utility of the frequency scale for the symptoms of gastroesophageal reflux disease questionnaire (FSSG) for patients with subacute/chronic cough

Background The frequency scale for the symptoms of GERD (FSSG) questionnaire, which originally consists of acid-reflux and dysmotility symptom domains, is a succinct questionnaire to evaluate gastroesophageal reflux disease (GERD) symptoms. Objectives To evaluate the utility of subjective questionnaire of GERD for the diagnosis of GERD-related cough by using FSSG questionnaire. Methods We recruited 256 patients with subacute/chronic cough between April 2012 and March 2018, who were analyzed using FSSG questionnaire and blood eosinophil counts. GERD-related cough was inferred through the presence of classic reflux symptoms including heartburn and/or typical coughing trigger (e.g. phonation, rising, lying, eating, and intake of certain food). The diagnosis was confirmed by response to specific treatments for GERD. Receiver operating characteristic curve analysis was performed to determine the cutoff score for the diagnosis. Results One-hundred ten patients (43%) were diagnosed as having GERD-related cough. FSSG questionnaire was relevant for diagnosing GERD-related cough, with the area under the curve (AUC) of 0.70 (p < 0.0001, cutoff score 7 points, sensitivity 75%, specificity 62%). When limited to patients with blood eosinophils of ≤150/μL or those with sputum eosinophils of ≤3%, sensitivity and specificity of the diagnosis was increased, respectively (sensitivity and specificity; 79% and 65% for blood eosinophils and 82% and 68% for sputum eosinophils. p < 0.0001, AUC 0.74 for both). Conclusions The subjective questionnaire of GERD (FSSG) would be helpful in diagnosing GERD-related cough, particularly in patients with low blood or sputum eosinophil counts.

Mometasone or Tiotropium in Mild Asthma with a Low Sputum Eosinophil Level

BackgroundIn many patients with mild, persistent asthma, the percentage of eosinophils in sputum is less than 2% (low eosinophil level). The appropriate treatment for these patients is unknown.MethodsIn this 42-week, double-blind, crossover trial, we assigned 295 patients who were at least 12 years of age and who had mild, persistent asthma to receive mometasone (an inhaled glucocorticoid), tiotropium (a long-acting muscarinic antagonist), or placebo. The patients were categorized according to the sputum eosinophil level (<2% or ≥2%). The primary outcome was the response to mometasone as compared with placebo and to tiotropium as compared with placebo among patients with a low sputum eosinophil level who had a prespecified differential response to one of the trial agents. The response was determined according to a hierarchical composite outcome that incorporated treatment failure, asthma control days, and the forced expiratory volume in 1 second; a two-sided P value of less than 0.025 denoted statistical significance. A secondary outcome was a comparison of results in patients with a high sputum eosinophil level and those with a low level.ResultsA total of 73% of the patients had a low eosinophil level; of these patients, 59% had a differential response to a trial agent. However, there was no significant difference in the response to mometasone or tiotropium, as compared with placebo. Among the patients with a low eosinophil level who had a differential treatment response, 57% (95% confidence interval [CI], 48 to 66) had a better response to mometasone, and 43% (95% CI, 34 to 52) had a better response to placebo (P=0.14). In contrast 60% (95% CI, 51 to 68) had a better response to tiotropium, whereas 40% (95% CI, 32 to 49) had a better response to placebo (P=0.029). Among patients with a high eosinophil level, the response to mometasone was significantly better than the response to placebo (74% vs. 26%) but the response to tiotropium was not (57% vs. 43%).ConclusionsThe majority of patients with mild, persistent asthma had a low sputum eosinophil level and had no significant difference in their response to either mometasone or tiotropium as compared with placebo. These data provide equipoise for a clinically directive trial to compare an inhaled glucocorticoid with other treatments in patients with a low eosinophil level. (Funded by the National Heart, Lung, and Blood Institute; SIENA ClinicalTrials.gov number, NCT02066298.)

A retrospective study of clinical features of cough variant asthma in Chinese adults

BackgroundClinical features of cough variant asthma (CVA) in Chinese adults are largely uncertain.MethodsA total of 303 patients newly diagnosed as uncontrolled asthma (symptom control and future risk of adverse outcomes), including 175 CVA and 128 classic asthma (CA), were enrolled in this retrospective survey. Clinical features including basic characteristics, pulmonary function, airway hyperresponsiveness (AHR) and cell counts of induced sputum, were compared retrospectively. All patients were classified into four inflammatory subtypes based on the counts of induced sputum eosinophils and neutrophils as eosinophilic (E), neutrophilic (N), mixed granulocytic (M), and paucigranulocytic (P) subtypes. Inflammatory subtype distribution was also compared.ResultsCompared with CA patients, CVA patients were younger (P = 0.009), had a higher prevalence of female patients (P = 0.001), higher parameter values of baseline pulmonary function (P ≤ 0.01 for all), shorter duration of disease (P = 0.002), lower AHR (P = 0.001) and lower sputum eosinophil% (P = 0.009). There was a difference in the AHR distribution as the percentage of moderate and severe AHR in CVA was significantly lower than in CA (41.72% VS 64.70%, P = 0.001). The inflammatory subtype distribution was different as the proportion of E and M subtypes in CVA was lower than in CA (56.0% vs 67.19%, P = 0.049). The proportion of subtype P was the lowest and subtype M was the highest in both CVA and CA patients. There was a similar negative correlation of sputum eosinophil% with AHR in CVA and CA (r = − 0.337, P < 0.0001 and r = − 0.27, P = 0.026, respectively), and a positive correlation between sputum eosinophil% and improvement rate of FEV1 after inhalation of bronchodilator (ΔFEV1%) (r = 0.33, P = 0.01).ConclusionsCVA patients showed a better pulmonary function and lower airway inflammation in contrast to CA patients, which may participate in the pathogenesis of chronic cough in CVA.

Characteristics associated with clinical severity and inflammatory phenotype of naturally occurring virus-induced exacerbations of asthma in adults

BackgroundIn experimental studies viral infections have been shown to induce type 2 inflammation in asthmatics, but whether this is a feature of naturally occurring virus-induced asthma exacerbations is unknown. Thymic stromal lymphopoietin (TSLP) released from the airway epithelium in response to damage, has been suggested as a link between viral infection and type 2 inflammation, but the role of TSLP in asthma exacerbations is unknown. ObjectiveTo assess whether type 2 inflammation, as measured by sputum eosinophils and fractional exhaled nitric oxide (FeNO), is a feature of naturally occurring virus-induced exacerbations of asthma and whether TSLP is associated with this type 2 inflammation. MethodsPatients presenting to hospital with acute asthma were examined during the exacerbation, and after 4 weeks recovery. The assessments included spirometry, FeNO and induced sputum for differential counts and TSLP mRNA levels. Nasal swabs were collected for viral detection. ResultsSputum eosinophils and FeNO were similar between virus-positive (n = 44) and negative patients (n = 44). In virus-positive patients, TSLP expression was lower at exacerbation than follow-up (p = 0.03). High TSLP at exacerbation was associated with lower sputum eosinophils (p = 0.01) and higher FEV1 (p = 0.03). In virus-positive patients, %-predicted FEV1 negatively correlated with both FeNO and sputum eosinophils (p = 0.02 and p = 0.05, respectively). ConclusionOur findings support that type 2 inflammation is present in patients during virus-induced asthma exacerbations, to the same degree as non-viral exacerbations, and correlate negatively with FEV1. However, in virus-positive patients, high TSLP expression during exacerbation was associated with low sputum eosinophils, suggesting that the effect of TSLP in vivo, in the setting of an asthma exacerbation, might be different than the type 2 inducing effects observed in experimental studies.

COPD exacerbation severity and frequency is associated with impaired macrophage efferocytosis of eosinophils.

BackgroundEosinophilic airway inflammation is observed in 10-30% of COPD subjects. Whether increased eosinophils or impairment in their clearance by macrophages is associated with the severity and frequency of exacerbations is unknown.MethodsWe categorised 103 COPD subjects into 4 groups determined by the upper limit of normal for their cytoplasmic macrophage red hue (<6%), an indirect measure of macrophage efferocytosis of eosinophils, and area under the curve sputum eosinophil count (≥3%/year). Eosinophil efferocytosis by monocyte-derived macrophages was studied in 17 COPD subjects and 8 normal controls.ResultsThere were no differences in baseline lung function, health status or exacerbation frequency between the groups: A-low red hue, high sputum eosinophils (n = 10), B-high red hue, high sputum eosinophils (n = 16), C-low red hue, low sputum eosinophils (n = 19) and D- high red hue, low sputum eosinophils (n = 58). Positive bacterial culture was lower in groups A (10%) and B (6%) compared to C (44%) and D (21%) (p = 0.01). The fall in FEV1 from stable to exacerbation was greatest in group A (ΔFEV1 [95 % CI] -0.41 L [-0.65 to -0.17]) versus group B (-0.16 L [-0.32 to -0.011]), C (-0.11 L [-0.23 to -0.002]) and D (-0.16 L [-0.22 to -0.10]; p = 0.02). Macrophage efferocytosis of eosinophils was impaired in COPD versus controls (86 [75 to 92]% versus 93 [88 to 96]%; p = 0.028); was most marked in group A (71 [70 to 84]%; p = 0.0295) and was inversely correlated with exacerbation frequency (r = -0.63; p = 0.006).ConclusionsMacrophage efferocytosis of eosinophils is impaired in COPD and is related to the severity and frequency of COPD exacerbations.

High blood eosinophil count is associated with more frequent asthma attacks in asthma patients

BackgroundThe clinical importance of eosinophils in asthma has been shown by the observation of frequent exacerbation in patients with high sputum eosinophil counts and a corresponding decrease in exacerbations when anti-inflammatory therapy was adjusted to maintain low sputum eosinophil percentages. However, less is known of the relation between blood eosinophilia and asthma exacerbation. ObjectiveTo examine whether patients with asthma and a higher blood eosinophil count have more asthma attacks than those with a lower count. MethodsThe authors analyzed data from the National Health and Nutrition Examination Survey, an annual cross-sectional survey of the US general population. Patients with asthma and asthma attacks were identified based on participants' self-report or parental report. A high blood eosinophil count was defined using 200, 300, or 400 cells/μL as cutoffs. The primary analysis used data from 2001 through 2010 after adjusting for demographic variables, obesity, smoking, neutrophil level, and past treatment for wheezing. A secondary analysis used data from 2007 through 2010 and included recent treatment for asthma and fraction of exhaled nitric oxide level as additional adjustment variables. ResultsIn survey years 2001 through 2010, 3,162 patients with asthma had blood eosinophil data and approximately half (54% of children and 52% of adults) reported an asthma attack in the previous year. In the primary analysis, higher blood eosinophil counts were associated with more asthma attacks in children but not in adults. The secondary analysis suggested an association in both children and adults. ConclusionPatients with asthma with higher blood eosinophil counts experienced more asthma attacks than those with lower eosinophil counts.

Three phenotypes of adult‐onset asthma

Adult-onset asthma differs from childhood-onset asthma in many respects. It is more heterogeneous, often severe and frequently associated with loss of lung function. To identify underlying mechanisms of adult-onset asthma and to capture predictors of disease progression, detailed characterization and phenotyping is necessary. To characterize adult-onset asthma and identify subphenotypes of adult-onset asthma. A cohort of 200 patients with adult-onset (>18year) asthma (age 54(26-75)year) was recruited from one academic and three nonacademic pulmonary outpatient clinics in Amsterdam, the Netherlands. These patients were fully characterized with respect to clinical, functional and inflammatory markers. After data reduction, K-means nonhierarchical cluster analysis was performed to identify clusters of adult-onset asthma. Patients with adult-onset asthma were predominately female (61%) and nonatopic (55%). Within this group of patients were identified three clusters of adult-onset asthma. Cluster 1 (n=69) consisted of patients with severe eosinophilic inflammation-predominant asthma and persistent airflow limitation despite high-intensity anti-inflammatory treatment, with relatively low symptom scores. The second cluster was characterized by obese women with frequent symptoms, high healthcare utilization and low sputum eosinophils. The third cluster consisted of patients with mild-to-moderate, well-controlled asthma with normal lung function and low inflammatory markers. Repeatability accuracy was 98.2%. Amongst patients with adult-onset asthma, three subphenotypes can be identified with distinct clinical and inflammatory characteristics. These subphenotypes help to understand the underlying pathobiology and provide clinicians with directions for personalized management.

Transient sputum eosinophilia may occur over time in non‐eosinophilic asthma and this is not prevented by salmeterol

Symptomatic, steroid-naïve asthmatic patients may have low sputum eosinophil numbers. The aim of the study was to determine whether low sputum eosinophil numbers persisted over time, during treatment with salmeterol monotherapy. Forty steroid-naïve, symptomatic asthmatic patients, with sputum eosinophils <3%, were randomized to receive open-label salmeterol (50 µg twice a day, n = 30) or fluticasone (125 µg twice a day, n = 10) and were then assessed at 1, 3 and 6 months. All patients underwent spirometry, a methacholine challenge test and sputum induction at each visit. Symptom scores and peak expiratory flow were recorded throughout the study. Patients were permitted to withdraw from the study at any time, if they experienced exacerbations or deterioration of symptoms. The average sputum eosinophil percentage remained normal (≤1.9%) in both groups over the study period. The eosinophil percentages were ≤1.9% in 65 of the 80 samples obtained from salmeterol-treated patients throughout the study period. Eight patients had an asthma exacerbation or deterioration, during which one developed sputum eosinophilia. Twelve patients, 11 of whom were randomized to salmeterol and one to fluticasone, developed transient sputum eosinophilia at least once during the study. This was not associated with asthma exacerbation (except for one patient). Sputum neutrophil percentage did not change in either group. Low sputum eosinophil numbers persisted over 6 months in a majority of patients with non-eosinophilic asthma who received salmeterol monotherapy. However, transient sputum eosinophilia occurred in 40% indicating that non-eosinophilic asthma may not be a stable phenotype.

Airway inflammation assessed by invasive and noninvasive means in severe asthma: Eosinophilic and noneosinophilic phenotypes

Airway inflammation assessed by bronchial biopsies demonstrates distinct eosinophilic and noneosinophilic phenotypes in severe asthma, but their relationship to other biomarkers of disease (induced sputum and nitric oxide [NO]) is not clear. We sought to compare airway inflammation using noninvasive (induced sputum, exhaled NO), and invasive (bronchial biopsies) methods in moderate and severe asthma and to assess whether induced sputum and exhaled NO would allow the identification of eosinophilic and noneosinophilic phenotypes in severe asthma. We performed a cross-sectional study of 32 subjects with severe asthma and 35 subjects with moderate asthma, from whom we obtained bronchial biopsies, induced sputum, and exhaled NO measurements. Among subjects with severe asthma, we identified eosinophilic and noneosinophilic phenotypes using both bronchial biopsies and sputum cell counts. However, the vast majority of subjects with high sputum eosinophil counts did not have high mucosal eosinophil counts. Exhaled NO was increased in the eosinophilic phenotype as judged from bronchial biopsy findings, but not on the basis of induced sputum. Subjects with high sputum eosinophil counts experienced more asthma exacerbations than the subjects with low sputum eosinophil counts. In contrast, we did not find any differences in the clinical characteristics between eosinophilic and noneosinophilic phenotypes that were identified by bronchial biopsies. The use of sputum cell counts allowed the identification of a subgroup of subjects with severe asthma who were at risk of more frequent asthma exacerbations. Monitoring sputum eosinophil counts in subjects with severe asthma may allow identifying the subjects with the greatest disease activity.

Low Sputum Eosinophils Predict the Lack of Response to Beclomethasone in Symptomatic Asthmatic Patients

The prognostic role of low sputum eosinophils in steroid-naïve, symptomatic asthmatic patients is controversial. To verify whether low sputum eosinophils predict poor response to treatment with inhaled corticosteroids. Sixty-seven symptomatic asthmatic patients with moderate asthma were examined before and after 2 weeks and 4 weeks of treatment with beclomethasone dipropionate, 500 microg bid. None received corticosteroids in the 3 months preceding the study. At each visit, all patients underwent spirometry, methacholine challenge, and sputum induction. The patients recorded symptom scores and peak expiratory flow (PEF) throughout the study. Seventeen patients had low sputum eosinophils despite being symptomatic. Patients with high (> 3%) sputum eosinophils at baseline showed significant improvement in symptoms, pulmonary function, and bronchial hyperresponsiveness after treatment, whereas patients with low sputum eosinophils showed no significant improvement in most clinical and functional outcomes. Among the baseline indexes examined, sputum eosinophils had the highest negative predictive value but low positive predictive value for the response to treatment. Multiple stepwise regression showed that only baseline FEV(1) and sputum eosinophil percentages significantly correlated with changes in FEV(1) after treatment. We suggest that, among the indexes examined, low sputum eosinophils are the best predictor for poor corticosteroid effects in asthma.

Analysis of Sputum Cell Counts During Spontaneous Moderate Exacerbations of Asthma in Comparison to the Stable Phase

Background. Acute airway inflammation is considered to characterize asthma exacerbations, but its specific cellular pattern has not yet been completely evaluated. Aim. To evaluate the prevalence of sputum eosinophilia during acute asthma exacerbations of moderate severity, compared with a stable phase of the disease, and to assess the concordance between changes in pulmonary function and sputum eosinophilia in the period between exacerbation and post exacerbation. Methods. We compared sputum and blood inflammatory cell counts in 29 asthmatic subjects during a spontaneous moderate exacerbation of asthma (visit 1) with sputum and blood cell counts measured 4 weeks after the resolution of asthma exacerbation (visit 2). At visit 1, all subjects required an appropriate 1 week treatment with oral corticosteroids. Results. At visit 1, all subjects were able to collect spontaneous sputum, whereas at visit 2 sputum was induced by inhalation of hypertonic saline (NaCl 3, 4, and 5%, 10 minutes each) with β2-agonist pretreatment. Asthma exacerbation was accompanied by a significant increase in sputum eosinophil percentages compared with levels after exacerbation [25%(1–78) versus 4%(0–23), p<0.05). Only four subjects showed low sputum eosinophil percentages during exacerbation, and these showed no differences in main clinical findings with respect to subjects with sputum eosinophilia. At visit 2, the stability of asthma was assessed on the basis of PEF, FEV1, symptoms, and use of rescue β2-agonist. Asthma was defined as stable in 21 out of 29 subjects. Sputum eosinophil percentages fell significantly between visit 1 and visit 2 in both stable and unstable patients, but at visit 2 sputum eosinophil percentages were still high in subjects with unstable asthma. In patients who proved to be stable at visit 2, there was a significant correlation between the changes recorded in sputum eosinophil percentages and in FEV1 between the two visits (rho: 0.723, p<0.001). Conclusion. Sputum eosinophil but not neutrophil percentages increase in most asthmatic subjects during moderate exacerbation of asthma. Changes in the degree of airway eosinophilic inflammation are related to changes in the severity of airway obstruction during asthma exacerbation.