Sputum Eosinophils Research Articles

Relationship between inflammatory status and microbial composition in severe asthma and during exacerbation.

In T2-mediated severe asthma, biologic therapies, such as mepolizumab, are increasingly used to control disease. Current biomarkers can indicate adequate suppression of T2 inflammation, but it is unclear whether they provide information about airway microbial composition. We investigated the relationships between current T2 biomarkers and microbial profiles, characteristics associated with a ProteobacteriaHIGH microbial profile and the effects of mepolizumab on airway ecology. Microbiota sequencing was performed on sputum samples obtained at stable and exacerbation state from 140 subjects with severe asthma participating in two clinical trials. Inflammatory subgroups were compared on the basis of biomarkers, including FeNO and sputum and blood eosinophils. ProteobacteriaHIGH subjects were identified by Proteobacteria to Firmicutes ratio ≥0.485. Where paired sputum from stable visits was available, we compared microbial composition at baseline and following ≥12 weeks of mepolizumab. Microbial composition was not related to inflammatory subgroup based on sputum or blood eosinophils. FeNO ≥50 ppb when stable and at exacerbation indicated a group with less dispersed microbial profiles characterised by high alpha-diversity and low Proteobacteria. ProteobacteriaHIGH subjects were neutrophilic and had a longer time from asthma diagnosis than ProteobacteriaLOW subjects. In those studied, mepolizumab did not alter airway bacterial load or lead to increased Proteobacteria. High FeNO could indicate a subgroup of severe asthma less likely to benefit from antimicrobial strategies at exacerbation or in the context of poor control. Where FeNO is <50 ppb, biomarkers of microbial composition are required to identify those likely to respond to microbiome-directed strategies. We found no evidence that mepolizumab alters airway microbial composition.

Rheology predicts sputum eosinophilia in patients with muco-obstructive lung diseases

BackgroundMucus is known to play a pathogenic role in muco-obstructive lung diseases, but little is known about the determinants of mucus rheology. The purpose of this study is to determine which sputum components influence sputum rheology in patients with muco-obstructive lung diseases. MethodsWe performed a cross sectional prospective cohort study. Spontaneous sputum was collected from consecutive patients with muco-obstructive lung diseases. Sputum rheology was assessed using the Rheomuco® rheometer (Rheonova, Grenoble); the elastic modulus G′, viscous modulus G″, and the critical stress threshold σc were recorded. Key quantitative and qualitative biological sputum components were determined by cytology, nucleic acid amplification tests and mass spectrometry. Results48 patients were included from January to August 2019. Among them, 10 had asthma, 14 COPD and 24 non-CF bronchiectasis (NCFB). The critical stress threshold σc predicted a sputum eosinophilia superior to 1.25% with 89.19% accuracy (AUC = 0.8762). G′ and G″ are positively correlated with MUC5AC protein concentration ((rho = 0.361; P = .013) and (rho = 0.335; P = .021), respectively). σc was positively correlated with sputum eosinophilia (rho = 0.394; P = .012), MUC5B (rho = 0.552; P < .001) and total protein (rho = 0.490; P < .001) concentrations. G′ and G″ were significantly higher in asthma patients (G’ = 14.49[7.18–25.26]Pa, G’‘ = 3.0[2.16–5.38]Pa) compared to COPD (G’ = 5.01[2.94–6.48]Pa, P = .010; G’‘ = 1.45[1.16–1.94]Pa, P = .006) and to NCFB (G’ = 4.99[1.49–10.49]Pa, P = .003; G’’ = 1.46[0.71–2.47]Pa, P = .002). ConclusionIn muco-obstructive lung diseases, rheology predicts sputum eosinophilia and is correlated with mucin concentrations, regardless of the underlying disease. Clinical trial registration(registrar, website, and registration number), where applicable NCT04081740.

Local IL-10 replacement therapy was effective for steroid-insensitive asthma in mice

Subgroups of patients with severe asthma showing marked increases in sputum eosinophils and/or neutrophils are insensitive to corticosteroids. Previous reports have shown that exogenous administration of an anti-inflammatory cytokine, interleukin (IL)-10 negatively regulated both eosinophilic and neutrophilic migration into tissues. The objective of this study was to elucidate whether intratracheal IL-10 administration suppresses asthmatic responses in a steroid-insensitive model of mice. Ovalbumin (OVA)-sensitized BALB/c mice were intratracheally challenged with OVA at 500 µg/animal four times. Dexamethasone (1 mg/kg, intraperitoneal) or IL-10 (25 ng/mouse, intratracheal) was administered during the multiple challenges. The number of leukocytes, expression of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and IL-10 receptor in the lung, and the development of airway remodeling and hyperresponsiveness were evaluated after the fourth challenge. Consistent with our previous study, dexamethasone hardly suppressed the development of airway remodeling and hyperresponsiveness. Although intratracheal IL-10 administration did not affect the development of airway remodeling, the infiltration of eosinophils and neutrophils, and the development of airway hyperresponsiveness were significantly inhibited. Moreover, IL-10 administration significantly decreased the numbers of ICAM-1+ and VCAM-1+ pulmonary vascular endothelial cells, which express IL-10 receptor 1, even though neither production of eosinophilic nor neutrophilic cytokines in the lung was inhibited. Therefore, IL-10 can suppress eosinophil and neutrophil infiltration by inhibiting the proliferation of ICAM-1+ and VCAM-1+ pulmonary vascular endothelial cells, resulting in inhibition of airway hyperresponsiveness in steroid-insensitive asthmatic mice. IL-10 replacement therapy may be clinically useful for the treatment of steroid-insensitive asthma.

Application of a Cold Dry Air Provocation Test in Pediatric Patients with Asthma.

Asthma is a chronic inflammatory airway disease characterized by reversible airway obstruction and airway hyperreactivity. We proposed a cold dry air (CDA) provocation test and investigated its application in pediatric patients with asthma. We enrolled 72 children and adolescents older than 5 years who presented to our hospital with chronic cough, shortness of breath, and wheezing. We analyzed the results of allergy, pulmonary function, methacholine provocation, and CDA provocation tests. The FEV1 change 5 min after the provocation was recorded as CDA5 dFEV1; that after 15 min was recorded as CDA15 dFEV1. PT10 was the provocation time causing a 10% decrease in FEV1; a decrease of >10% in dFEV1 was considered a positive CDA test. Among the 72 subjects, 51 were diagnosed with asthma. A positive CDA test in patients with asthma correlated with non-eosinophilic asthma. In patients with asthma, sputum eosinophils and eosinophil cationic protein (ECP) levels of the patients with a positive CDA test were significantly lower than those of patients with a negative test. CDA5 dFEV1 correlated with PC20 and total immunoglobulin E. CDA15 dFEV1 correlated with PC20, sputum eosinophils, and ECP. PT10 became shorter as the peripheral blood eosinophil, FVC, FEV1, FEV1/FVC, and FEF25-75 decreased. The CDA provocation test showed airway hyperreactivity to non-specific stimuli, a high correlation with non-eosinophilic asthma, and the possibility of assessing asthma severity via PT10.

Diagnostic Accuracy of Liquid Biomarkers in Airway Diseases: Toward Point-of-Care Applications.

BackgroundLiquid biomarkers have shown increasing utility in the clinical management of airway diseases. Salivary and blood samples are particularly amenable to point-of-care (POC) testing due to simple specimen collection and processing. However, very few POC tests have successfully progressed to clinical application due to the uncertainty and unpredictability surrounding their diagnostic accuracy.ObjectiveTo review liquid biomarkers of airway diseases with well-established diagnostic accuracies and discuss their prospects for future POC applications.MethodologyA literature review of publications indexed in Medline or Embase was performed to evaluate the diagnostic accuracy of liquid biomarkers for chronic obstructive pulmonary disease (COPD), asthma, laryngopharyngeal reflux (LPR), and COVID-19.ResultsOf 3,628 studies, 71 fulfilled the inclusion criteria. Sputum and blood eosinophils were the most frequently investigated biomarkers for the management of asthma and COPD. Salivary pepsin was the only biomarker with a well-documented accuracy for the diagnosis of LPR. Inflammatory blood biomarkers (e.g., CRP, D-dimers, ferritin) were found to be useful to predict the severity, complications, and mortality related to COVID-19 infection.ConclusionMultiple liquid biomarkers have well-established diagnostic accuracies and are thus amenable to POC testing in clinical settings.

Circadian molecular clock disruption in chronic pulmonary diseases.

The circadian clock is the biochemical oscillator with a near 24-h period that is responsible for generating the circadian rhythms in peripheral organs including the lung. Mounting evidence suggests that circadian clock disruption during chronic lung diseases plays an essential role in augmented oxidative stress, inflammatory response, metabolic imbalances, hypoxia/hyperoxia, mucus secretion, dysregulated autophagy, and alters pulmonary function. Here, we review circadian clock disruption and discuss candidate clock genes that are altered at the transcriptional or translational level in chronic pulmonary diseases. This review aims to provide the current knowledge and understanding of the circadian molecular clock disruption in chronic pulmonary diseases which will further advance the development of novel clock-based therapeutics in the future.

Effect of inhaled corticosteroids on microbiome and microbial correlations in asthma over a 9‐month period

The effect of inhaled corticosteroids (ICS) on the airway microbiome requires longitudinal research for corroboration. Asthma patients, not undergoing ICS treatment (baseline), were enrolled and prescribed ICS; all these patients were followed up with regular visits at 3 months (visit 1) and 9 months (visit 2). Induced sputum was collected, and fungal microbiota (mycobiome) and bacterial microbiota (bacteriome) were estimated using 16S rRNA and internal transcribed spacer (ITS) sequencing. Bacterial α diversity indices were not significantly different between baseline, visit 1, and visit 2. Visit 1 showed lower fungal evenness than the baseline, and visit 2 showed lower fungal diversity and evenness than the baseline. Fungal, but not bacterial, community compositions differed significantly between the baseline, visit 1, and visit 2. The most abundant bacterial phyla and genera did not differ significantly between the baseline, visit 1, and visit 2. Compared with the baseline, visit 1 showed significantly increased frequency of the fungal phylum Ascomycota and lower frequency of Basidiomycota. We found sharply decreased fungal genera Wallemia, Cladosporium, Penicillium, and Alternaria at visit 1 and visit 2 compared with the baseline, although the differences were not statistically significant. We also found the proportion of Basidiomycota was positively correlated with percentages of sputum eosinophils and neutrophils. The proportions of Saccharomyces, Wallemia, and Aplosporella were positively correlated with percentage of sputum eosinophils. Moreover, we identified distinct inter‐ and intra‐kingdom interactions in baseline, visit 1, and visit 2. Therefore, ICS use altered the airway microbial diversity, evenness, community composition, and microbial connections.

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.

Heart rate variability as a marker of autonomic nervous system activity in young people with eosinophilic and non-eosinophilic asthma

Objective An imbalance in autonomic nervous system (ANS) activity may play a role in asthma, but it is unclear whether this is associated with specific pathophysiology. This study assessed ANS activity by measuring heart rate variability (HRV) in eosinophilic (EA) and non-eosinophilic asthma (NEA) and people without asthma. Methods HRV, combined hypertonic saline challenge/sputum induction, exhaled nitric oxide (FeNO), skin prick tests to measure atopy, and spirometry tests were conducted in teenagers and young adults (14–21 years) with (n = 96) and without (n = 72) generally well-controlled asthma. HRV parameters associated with sympathetic and parasympathetic ANS branches were analyzed. EA and NEA were defined using a 2.5% sputum eosinophil cut-point. Airway hyperreactivity (AHR) was defined as ≥15% reduction in FEV1 following saline challenge. Results HRV parameters did not differ between asthmatics and non-asthmatics or EA and NEA. They were also not associated with markers of inflammation, lung function or atopy. However, increased absolute low frequency (LFµs2; representing increased sympathetic nervous system (SNS) activity) was found in asthmatics who used β-agonist medication compared to those who did not (median: 1611, IQR 892–3036 vs 754, 565–1592; p < 0.05) and increased normalized low frequency (LF nu) was found in those with AHR compared to without AHR (64, 48–71 vs 53, 43–66; p < 0.05). Conclusion ANS activity (as measured using HRV analysis) is not associated with pathophysiology or inflammatory phenotype in young asthmatics with generally well-controlled asthma. However, enhanced SNS activity can be detected in asthmatics with AHR or who use β-agonist medication.

Interleukin 8 and bronchial eosinophils in patients with asthma and cold airway hyperresponsiveness

Introduction. Cold airway hyperresponsiveness (CAHR) is common in patients with asthma. The effect of inhaled corticosteroid/long-acting β2-agonist therapy (ICS / LABA) on its severity, and the role of IL-8, and the eosino-philic profile of bronchial inflammation have not been studied. Aim. To study the dynamic relationship between the level of IL-8 and eosinophilic inflammation in the bronchi of asthma patients with CAHR using anti-inflammatory combined therapy with ICS / LABA. Materials and methods. Patients with asthma (n=59) received ICS / LABA for 24 weeks. The level of disease control (ACT, points), cellular composition of induced sputum (IS), bronchial response (ΔFEV1IHCA, %) to 3-minute isocapnic hyperventilation with cold (-20ºС) air (IHCA) was assessed. Exhaled breath condensate (EBC) was collected before and after the IHCA, in which the concentration of IL-8 (pg/mL) was determined. Results. Group 1 included 28 patients with CAHR (ΔFEV1IHCA = -14.1 ± 1.7%), group 2 included 31 patients with no response to cold bronchoprovocation (ΔFEV1IHCA = - 3.0 ± 2.4 %, p &lt; 0.0001). Initially, patients of groups 1 and 2 had no differences in ACT (16.8±0.6 and 15.7 ± 0.8 points), FEV1 (92.5 ± 3.6 and 87.8 ± 2.2%), the number of eosinophils in sputum (8.0 ± 2.4 and 4.7 ± 1.3%, respectively, p &gt; 0.05). The concentration of IL-8 before and after the IHCA test in group 1 was 131.2 ± 18.0 and 146.3 ± 23.5 pg/mL, respectively (p &gt; 0.05), in group 2 it was 130.5 ± 8.8 and 149.9 ± 18.4 pg/mL, respectively (p&gt;0.05). After treatment, the airway response to the IHCA significantly decreased in group 1 (ΔFEV1IHCA = - 8.8 ± 1.5 %, p &lt; 0.01), in group 2 it remained unchanged (- 3.6 ± 1.3 %, p &gt; 0.05). The level of asthma control in group 1 increased to 20.7 ± 1.6 ACT points (p &lt; 0.01), in group 2 – up to 19.7 ± 1.7 (p &lt; 0.05). The lung function did not change. After treatment, the level of IL-8 before and after the IHCA in group 1 did not change (89.8 ± 11.7 and 85.5 ± 7.8 pg/mL, p &gt; 0.05), as did the number of eosinophils (8.0 ± 2.4 and 6.2 ± 3.1 %, p &gt; 0.05). In group 2, the level of IL-8 before and after IHCA decreased from 89.2 ± 7.7 to 73.9 ± 10.3 pg/mL (p &lt; 0.01), the concentration of eosinophils decreased from 4.7 ± 1.3 up to 1.5 ± 0.57 % (p &lt; 0.05). Conclusion. 24-week therapy with ICS/LABA in patients with CAHR leads to improved asthma control, a decrease in the severity of cold bronchospasm, without being accompanied by changes in the level of IL-8, which affects the dynamics of the concentration of eosinophils in the bronchi.

Treatment Resistance in Severe Asthma Patients With a Combination of High Fraction of Exhaled Nitric Oxide and Low Blood Eosinophil Counts.

Background: Combining a fraction of exhaled nitric oxide (FeNO) and blood eosinophil count (B-EOS) may be a useful strategy for administration of biologics such as anti-IgE or anti-IL-5 to patients with type 2 inflammatory-predominant severe asthma and is important to be elucidated considering the increasing use of biologics. Methods: This cross-sectional study analyzed the clinical data from 114 adult patients with severe asthma, who were treated at Saitama Medical University Hospital. The eligible patients were stratified into four subgroups defined by thresholds of FeNO and blood eosinophil (B-EOS) counts to detect sputum eosinophilia, using the receiver operating characteristic curve analysis. A total of 75 patients with optimal samples were stratified into four subtypes defined by thresholds of sputum eosinophilia and neutrophilia. Clinical characteristics, pattern of biologics, and distribution of sputum subtypes were analyzed in the stratified subclasses according to the FeNO and B-EOS thresholds. The asthma exacerbation (AE)-free time of the FeNO/B-EOS subgroups and any biologics treatment including anti-IgE or anti-IL-5 use were examined using the Kaplan–Meier method. The hazard ratios (HRs) for AE-free time were examined using the Cox proportional hazard model. Results: The optimal cutoff values for prediction of sputum eosinophilia were defined as ≥2.7% wherein for FeNO as ≥27 ppb and B-EOS as ≥265/µL were considered. The high-FeNO subgroups showed significant high total IgE, compared with the low FeNO. The high-FeNO/high-B-EOS and the high-FeNO/low-B-EOS subgroups showed the largest prevalence of mepolizumab and benralizumab use among the other FeNO/B-EOS, respectively. The high-FeNO/low-B-EOS showed the largest frequency of AEs, high HR, and the shortest AE-free time, among the other FeNO/B-EOS. The sputum eosinophil-predominant subtype was the great majority in the high FeNO/high B-EOS. A diverse distribution of sputum leukocyte-predominant subtype was observed in the other FeNO/B-EOS. The subsequent AE-free time and its HR were comparable among the biologics use groups. Conclusion: The strategy of classifying severe asthma based on the combination of FeNO and B-EOS proposes particular refractory type 2 severe asthma and underlying airway inflammation as a feasible trait for optimal biologics use.

Bronchiectasis enters the inflammation era.

Bronchiectasis enters the inflammation era.

Astegolimab, an anti-ST2, in chronic obstructive pulmonary disease (COPD-ST2OP): a phase 2a, placebo-controlled trial

Chronic obstructive pulmonary disease (COPD) is a heterogeneous inflammatory airway disease. The epithelial-derived IL-33 and its receptor ST2 have been implicated in airway inflammation and infection. We aimed to determine whether astegolimab, a selective ST2 IgG2 monoclonal antibody, reduces exacerbations in COPD. COPD-ST2OP was a single-centre, randomised, double-blinded, placebo-controlled phase 2a trial in moderate-to-very severe COPD. Participants were randomly assigned (1:1) with a web-based system to received 490 mg subcutaneous astegolimab or subcutaneous placebo, every 4 weeks for 44 weeks. The primary endpoint was exacerbation rate assessed for 48 weeks assessed with a negative binomial count model in the intention-to-treat population, with prespecified subgroup analysis by baseline blood eosinophil count. The model was the number of exacerbations over the 48-week treatment period, with treatment group as a covariate. Safety was assessed in the whole study population until week 60. Secondary endpoints included Saint George's Respiratory Questionnaire for COPD (SGRQ-C), FEV1, and blood and sputum cell counts. The trial was registered with ClinicalTrials.gov, NCT03615040. The exacerbation rate at 48 weeks in the intention-to-treat analysis was not significantly different between the astegolimab group (2·18 [95% CI 1·59 to 2·78]) and the placebo group (2·81 [2·05 to 3·58]; rate ratio 0·78 [95% CI 0·53 to 1·14]; p=0·19]). In the prespecified analysis stratifying patients by blood eosinophil count, patients with 170 or fewer cells per μL had 0·69 exacerbations (0·39 to 1·21), whereas those with more than 170 cells per μL had 0·83 exacerbations (0·49 to 1·40). For the secondary outcomes, the mean difference between the SGRQ-C in the astegolimab group versus placebo group was -3·3 (95% CI -6·4 to -0·2; p=0·039), and mean difference in FEV1 between the two groups was 40 mL (-10 to 90; p=0·094). The difference in geometric mean ratios between the two groups for blood eosinophil counts was 0·59 (95% CI 0·51 to 0·69; p<0·001) and 0·25 (0·19 to 0·33; p<0·001) for sputum eosinophil counts. Incidence of treatment-emergent adverse events was similar between groups. In patients with moderate-to-very severe COPD, astegolimab did not significantly reduce exacerbation rate, but did improve health status compared with placebo. Funded by Genentech and National Institute for Health Research Biomedical Research Centres.

Assessment of airway inflammation and disease burden in moderate to severe asthmatic smokers

BACKGROUND: Conflicting results have been found among studies assessing the effect of smoking on airway inflammation among asthmatic subjects. OBJECTIVE: We sought to compare the inflammatory and clinical characteristics of active smokers and nonsmokers with uncontrolled moderate-to-severe asthma. Methods: We conducted a cross-sectional study comparing active-smoker and nonsmoker subjects with uncontrolled moderate-to-severe asthma. Sociodemographic and clinical data were collected. FeNO levels and spirometry were measured. We obtained sputum and blood cell counts and measured the cotinine level. The clinical data were linked to 3 Québec administrative databases. RESULTS: A total of 40 active smokers and 39 nonsmokers were included. Uncontrolled asthmatic smokers and nonsmokers had the same clinical characteristics. Although, blood eosinophil counts were similar between groups, the number of subjects with a high sputum eosinophil count (> 10%) was higher in nonsmokers. Asthmatic smokers had lower levels of FeNO than nonsmoker asthmatics. The nonsmoker group showed a higher number of total asthma exacerbations (1.9 ± 0.7) than the smoker group (1.0 ± 1.2) (p < 0.01) in the year preceding their assessment. The annual costs related to asthma care tended to be higher in uncontrolled asthmatic nonsmokers (352.05 ± 813.45CAD) than in smokers (263.38 ± 684.00CAD), whereas the annual cost for health care of all causes tended to be lower in nonsmokers (1617.57 ± 1736.53 CAD) than in smokers (2575.07 ± 3453.30 CAD). INTERPRETATION: The clinical characteristics of uncontrolled moderate-to-severe active asthmatic smokers and nonsmokers were similar. Although the FeNO levels were profoundly affected by smoking, the impact of smoking on airway eosinophilic inflammation appeared marginal. CLINICAL TRIAL REGISTRATION: NCT02833727

Longitudinal Impact of Sputum Inflammatory Phenotypes on Small Airway Dysfunction and Disease Outcomes in Asthma

Little is known about the relationship between airway inflammatory phenotypes and some important asthma features such as small airway dysfunction (SAD). To describe the longitudinal impact of airway inflammatory phenotypes on SAD and asthma outcomes. We measured eosinophil and neutrophil counts in induced sputum at baseline and 1 year later to stratify 197 adult patients with asthma into 4 inflammatory phenotypes. We conducted a comprehensive assessment of lung function using spirometry, body plethysmography, impulse oscillometry, and inert gas single and multiple breath washouts. We compared lung function, asthma severity, exacerbation frequency, and symptom control between the phenotypes. We studied the longitudinal impact of persistent sputum inflammatory phenotypes and the change of sputum cell counts on lung function. Patients were stratified into eosinophilic (23%, n=45), neutrophilic (33%, n= 62), mixed granulocytic (22%, n= 43), and paucigranulocytic (24%, n= 47) phenotypes. Patients with eosinophilic and mixed granulocytic asthma had higher rates of airflow obstruction and severe exacerbation as well as poorer symptom control than patients with paucigranulocytic asthma. All SAD measures were worse in patients with eosinophilic and mixed asthma than in those with paucigranulocytic asthma (all P values <.05). Eosinophilic asthma also indicated worse distal airflow obstruction, increased ventilation inhomogeneity (all P values <.05), and higher tendency for severe exacerbation (P= .07) than neutrophilic asthma. Longitudinally, persistent mixed granulocytic asthma was associated with the worst follow-up measures of SAD compared with persistent neutrophilic, persistent paucigranulocytic, or nonpersistent asthma phenotypes. In patients with stable forced expiratory volume in 1 second (FEV1), the mean increase in small airway resistance (R5-20) was greater in patients with persistent mixed granulocytic asthma (+103%) than in patients with persistent neutrophilic (+26%), P= .040, or persistent paucigranulocytic asthma (-41%), P= .028. Multivariate models adjusted for confounders and treatment with inhaled or oral corticosteroids or antieosinophilic biologics indicated that the change of sputum eosinophil rather than neutrophil counts is an independent predictor for the longitudinal change in FEV1, forced expiratory flow at 25% to 75% of forced vital capacity, specific effective airway resistance, residual lung volume, and lung clearance index. In asthma, airway eosinophilic inflammation is the main driver of lung function impairment and poor disease outcomes, which might also be aggravated by the coexistence of airway neutrophilia to confer a severe mixed granulocytic asthma phenotype. Persistent airway eosinophilia might be associated with dynamic SAD even in patients with stable FEV1.

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.

Impact of former smoking exposure on airway eosinophilic activation and autoimmunity in patients with severe asthma.

Severe eosinophilic asthma is characterised by frequent exacerbations and a relative insensitivity to steroids. Experimentally, smoking may induce eosinophilic airway inflammation, but the impact in patients with severe asthma is not clear. To investigate the association between smoking exposure in patients with severe asthma, and eosinophilic inflammation and activation, as well as airway autoimmunity and steroid responsiveness. Patients with severe asthma according to European Respiratory Society/American Thoracic Society criteria were assessed with sputum samples, analysed by cell differential count, and for the presence of free eosinophil granules (FEGs), autoantibodies against eosinophil peroxidase (EPX) and macrophage receptor with collagenous structure (MARCO). A subgroup of patients with eosinophilic airway inflammation was re-assessed after a 2-week course of prednisolone. 132 severe asthmatics were included in the study. 39 (29.5%) patients had ≥10 pack-years of smoking history: 36 (27.3%) were former smokers and three (2.3%) current smokers; and 93 (70.5%) had <10 pack-years exposure. Eosinophilic airway inflammation was more prevalent among patients with ≥10 pack-years (66.7%), compared to patients with <10 pack-years (38.7%, p=0.03), as was the level of FEGs (p=0.001) and both anti-EPX and anti-MARCO (p<0.05 and p<0.0001, respectively). Omitting current smokers did not affect these associations. Furthermore, prednisolone reduced, but did not normalise, sputum eosinophils in patients with a ≥10 pack-year smoking history. In patients with severe asthma, a former smoking history is associated with eosinophilic airway inflammation and activation and relative insensitivity to steroids, as well as airway autoimmunity.

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.

Club cell 10-kDa protein (CC10) as a surrogate for identifying type 2 asthma phenotypes

Objective: Club cell 10-kDa protein (CC10) is a documented biomarker for airway obstructive diseases. Primarily produced by nonciliated club cells in the distal airway and in nasal epithelial cells, CC10 suppresses Th2 cell differentiation and Th2 cytokine production. In this study, we aimed to determine whether CC10 can also be used as an alternative biomarker for identifying Type 2 (T2) asthma. Methods: 74 patients with asthma, and 24 healthy controls were enrolled in the study. T2-high asthma was defined as elevation in two or more biomarkers, such as sputum eosinophilia ≥ 3%, high blood eosinophils ≥ 300/µL, or high FeNO ≥ 30 ppb. T2-low asthma was defined as no elevation in biomarkers. Enzyme-linked immunosorbent assay (ELISA) was used to assess the CC10 levels in plasma. Results: The plasma CC10 level in patients with T2-high asthma was lower than that of patients with T2-low asthma and healthy controls (P < 0.05). To distinguish between T2-high and T2-low phenotype in patients with asthma, a receiver-operating characteristic (ROC) analysis was performed. It showed a sensitivity of 58.1% and specificity of 78.0% when using 22.74 ng/ml of plasma CC10. Correlation analysis indicated that the plasma CC10 level was inversely correlated with sputum eosinophil, blood eosinophil, and FeNO, and positively correlated with log PD20. However, no correlation with sputum neutrophil percentages, macrophage percentages, IgE, or lung function was found. Conclusions: Plasma CC10 is potentially useful in predicting T2-high and T2-low asthma. Lower plasma CC10 was associated with enhanced airway hyperresponsiveness, and Type 2 inflammation.