Efficacy of Biologics in Patients with Allergic Bronchopulmonary Aspergillosis: A Systematic Review and Meta-Analysis.

BACKGROUND: Treatment of allergic bronchopulmonary aspergillosis (ABPA) is challenging. Biological therapies have been reported as adjunctive treatments for ABPA, primarily in case series or case reports. This study aimed to analyze the efficacy of biologics for managing ABPA both qualitatively and quantitatively. METHODS: All articles on APBA published in October 2023 were searched in PubMed, Web of Science, ClinicalTrials.gov, and Embase databases. The effects of interest were the mean changes from baseline for outcomes, including exacerbation rates, oral corticosteroids usage (OCS), and total immunoglobulin E (IgE) levels. Reported outcomes were quantitatively synthesized by usual or individual patient data (IPD) meta-analyses. PROSPERO registration number: CRD42022373396. RESULTS: A total of 86 studies were included in the systematic review including 346 patients. Sixteen studies on omalizumab were pooled for the usual meta-analysis. Omalizumab therapy significantly reduced exacerbation rates (- 2.29 [95%CI - 3.32, - 1.26]), OCS dosage (- 10.91 mg [95%CI - 18.98, - 2.85]), and total IgE levels (- 273.07 IU/mL [95%CI - 379.30, - 166.84]), meanwhile improving FEV1% predicted (10.09% [95%CI 6.62, 13.55]). Thirty-one studies on dupilumab, mepolizumab, or benralizumab were pooled to perform an IPD meta-analysis, retrospectively. Both dupilumab and mepolizumab significantly reduced exacerbation rates, OCS, and total IgE levels. Benralizumab showed a similar trend, but it was not statistically significant. Tezepelumab showed weak evidence of its effects on ABPA. All five biologics led to milder clinical symptoms (e.g., cough, wheezing) with serious adverse effects that happened once in omalizumab treatment. CONCLUSION: These results indicate the clinical benefit of omalizumab, dupilumab, and mepolizumab in patients with ABPA. Further randomized, controlled studies with a larger sample size and longer follow-up are needed to confirm these findings.

Real-world effectiveness and predictors of super-responders to dupilumab in a Chinese uncontrolled asthma cohort.

Background: Dupilumab has been shown to be effective in clinical trials for moderate-to-severe uncontrolled asthma. However, the efficacy of dupilumab in the real world and the prediction of treatment response have not been well studied in patients with asthma. Objective: To investigate the efficacy of dupilumab and explore predictors of super-responders in a Chinese retrospective cohort. Methods: From January 2021 through December 2022, the patients with uncontrolled asthma who were treated with dupilumab for 4 months were included. Symptom control, type 2 inflammatory biomarkers, and lung function were collected at baseline and follow-up for efficacy assessment. Super-responders were defined as exacerbation-free, off maintenance of oral corticosteroids (mOCS), and with a score of the five-item Asthma Control Questionnaire (ACQ-5) of <0.5. The uni- and multivariable logistic regressions were used to construct predictive models for super-responders based on baseline features. Results: A total of 53 patients were included. After 4 months treatment, the median (interquartile range [IQR]) ACQ-5 score decreased from 1.8 (1.6-2.4) to 0.4 (0.2-0.8) (p < 0.001), the median (IQR) number of exacerbations, from 0.0 (0.0-1.0) to 0.0 (0.0-0.0) (p = 0.005). The median (IQR) dose of mOCS (prednisone equivalent) decreased from 15.0 mg/day (8.8-22.5 mg/day) to 2.5 mg/day (0.0-10.0 mg/day) (p = 0.008) in nine patients who were receiving mOCS. All efficacy assessment parameters, including sputum eosinophil were significantly improved, while blood eosinophil count did not decline (530 cells/mm³ [300-815 cells/mm³] versus 560 cells/mm³ [220-938 cells/mm³], p = 0.710). After taking dupilumab, 25 of 53 patients (47.2%) achieved a super-response. The age of onset < 42 years (odds ratio [OR] 7.471 [95% confidence interval {CI}, 1.286-43.394) and the baseline fractional exhaled nitric oxide (FeNO) of 25-50 ppb (OR 35.038 [95% CI, 3.104-395.553]) predicted super-responders, which showed a C-index of 0.822 (95% CI, 0.697-0.947). Conclusion: Dupilumab significantly improved symptom control, type 2 inflammatory markers, and lung function in Chinese patients with uncontrolled asthma. Airway eosinophils, rather than blood eosinophils, can be a reliable indicator of therapeutic efficacy. The early-onset asthma as well as the medium-high level of baseline FeNO contributed to the prediction of super-responders.

Non-allergic eosinophilic inflammation and airway hyperresponsiveness induced by diesel engine exhaust through activating ILCs.

RATIONALE: Diesel engine exhaust (DEE) is associated with the development and exacerbation of asthma. Studies have shown that DEE can aggravate allergen-induced eosinophilic inflammation in lung. However, it remains not clear that whether DEE alone could initiate non-allergic eosinophilic inflammation and airway hyperresponsiveness (AHR) through innate lymphoid cells (ILCs) pathway. OBJECTIVE: This study aims to investigate the airway inflammation and hyperresponsiveness and its relationship with ILC after DEE exposure. METHOD: Non-sensitized BALB/c mice were exposed in the chamber of diesel exhaust or filtered air for 2, 4, and 6 weeks (4 h/day, 6 days/week). Anti-CD4 mAb or anti-Thy1.2 mAb was administered by intraperitoneal injection to inhibit CD4+T or ILCs respectively. AHR、airway inflammation and ILCs were assessed. RESULT: DEE exposure induced significantly elevated level of neutrophils, eosinophils, collagen content at 4, 6 weeks. Importantly, the airway AHR was only significant in the 4weeks-DEE exposure group. No difference of the functional proportions of Th2 cells was found between exposure group and control group. The proportions of IL-5+ILC2, IL-17+ILC significantly increased in 2, 4weeks-DEE exposure group. After depletion of CD4+T cells, both the proportion of IL-5+ILC2 and IL-17A ILCs was higher in the 4weeks-DEE exposure group which induced AHR, neutrophilic and eosinophilic inflammation accompanied by the IL-5, IL-17A levels. CONCLUSION: Diesel engine exhaust alone can imitate asthmatic characteristics in mice model. Lung-resident ILCs are one of the major effectors cells responsible for a mixed Th2/Th17 response and AHR.

Type 17 mucosal-associated invariant T cells contribute to neutrophilic inflammation in patients with nasal polyps.

BACKGROUND: Immune regulation in chronic rhinosinusitis with nasal polyps (CRSwNP) with a neutrophilic endotype remains unclear. Mucosal-associated invariant T (MAIT) cells are tissue-resident innate T lymphocytes that respond quickly to pathogens and promote chronic mucosal inflammation. OBJECTIVE: We aimed to investigate the roles of MAIT cells in neutrophilic CRSwNP. METHODS: Nasal tissues were obtained from 113 patients with CRSwNP and 29 control subjects. Peripheral and tissue MAIT cells and their subsets were analyzed by flow cytometry. Polyp-derived MAIT cells were analyzed by RNA sequencing to study their effects on neutrophils. RESULTS: Endotypes of CRSwNP were classified as paucigranulocytic (n = 21), eosinophilic (n = 29), neutrophilic (n = 39), and mixed granulocytic (n = 24). Frequencies of MAIT cells were significantly higher in neutrophilic (3.62%) and mixed granulocytic (3.60%) polyps than in control mucosa (1.78%). MAIT cell percentages positively correlated with local neutrophil counts. MAIT cells were more enriched in tissues than in matched PBMCs. The frequencies of MAIT1 subset or IFN-γ+ MAIT cells were comparable among control tissues and CRSwNP subtypes. The proportions of MAIT17 subset or IL-17A+ MAIT cells were significantly increased in neutrophilic or mixed granulocytic polyps compared with controls. RNA sequencing revealed type 17 and pro-neutrophil profiles in neutrophilic polyp-derived MAIT cells. In patients with neutrophilic CRSwNP, the proportions of MAIT and MAIT17 cells were positively correlated with local proinflammatory cytokines and symptom severity. In vitro experiments demonstrated that neutrophilic polyp-derived MAIT cells promoted neutrophil migration, survival, and activation. CONCLUSIONS: MAIT cells from neutrophilic CRSwNP demonstrate type 17 functional properties and promote neutrophil infiltration in nasal mucosa.

Identification of cough-variant asthma phenotypes based on clinical and pathophysiologic data.

BACKGROUND: Cough-variant asthma (CVA) may respond differently to antiasthmatic treatment. There are limited data on the heterogeneity of CVA. OBJECTIVE: We aimed to classify patients with CVA using cluster analysis based on clinicophysiologic parameters and to unveil the underlying molecular pathways of these phenotypes with transcriptomic data of sputum cells. METHODS: We applied k-mean clustering to 342 newly physician-diagnosed patients with CVA from a prospective multicenter observational cohort using 10 prespecified baseline clinical and pathophysiologic variables. The clusters were compared according to clinical features, treatment response, and sputum transcriptomic data. RESULTS: Three stable CVA clusters were identified. Cluster 1 (n = 176) was characterized by female predominance, late onset, normal lung function, and a low proportion of complete resolution of cough (60.8%) after antiasthmatic treatment. Patients in cluster 2 (n = 105) presented with young, nocturnal cough, atopy, high type 2 inflammation, and a high proportion of complete resolution of cough (73.3%) with a highly upregulated coexpression gene network that related to type 2 immunity. Patients in cluster 3 (n = 61) had high body mass index, long disease duration, family history of asthma, low lung function, and low proportion of complete resolution of cough (54.1%). TH17 immunity and type 2 immunity coexpression gene networks were both upregulated in clusters 1 and 3. CONCLUSION: Three clusters of CVA were identified with different clinical, pathophysiologic, and transcriptomic features and responses to antiasthmatics treatment, which may improve our understanding of pathogenesis and help clinicians develop individualized cough treatment in asthma.

Clinical Characteristics of Coronavirus Disease 2019 in China.

BACKGROUND: Since December 2019, when coronavirus disease 2019 (Covid-19) emerged in Wuhan city and rapidly spread throughout China, data have been needed on the clinical characteristics of the affected patients. METHODS: We extracted data regarding 1099 patients with laboratory-confirmed Covid-19 from 552 hospitals in 30 provinces, autonomous regions, and municipalities in mainland China through January 29, 2020. The primary composite end point was admission to an intensive care unit (ICU), the use of mechanical ventilation, or death. RESULTS: The median age of the patients was 47 years; 41.9% of the patients were female. The primary composite end point occurred in 67 patients (6.1%), including 5.0% who were admitted to the ICU, 2.3% who underwent invasive mechanical ventilation, and 1.4% who died. Only 1.9% of the patients had a history of direct contact with wildlife. Among nonresidents of Wuhan, 72.3% had contact with residents of Wuhan, including 31.3% who had visited the city. The most common symptoms were fever (43.8% on admission and 88.7% during hospitalization) and cough (67.8%). Diarrhea was uncommon (3.8%). The median incubation period was 4 days (interquartile range, 2 to 7). On admission, ground-glass opacity was the most common radiologic finding on chest computed tomography (CT) (56.4%). No radiographic or CT abnormality was found in 157 of 877 patients (17.9%) with nonsevere disease and in 5 of 173 patients (2.9%) with severe disease. Lymphocytopenia was present in 83.2% of the patients on admission. CONCLUSIONS: During the first 2 months of the current outbreak, Covid-19 spread rapidly throughout China and caused varying degrees of illness. Patients often presented without fever, and many did not have abnormal radiologic findings. (Funded by the National Health Commission of China and others.).

The Association Between Insulin Use and Asthma: An Epidemiological Observational Analysis and Mendelian Randomization Study.

BACKGROUND: Asthma is a common respiratory disease caused by genetic and environmental factors, but the contribution of insulin use to the risk of asthma remains unclear. This study aimed to investigate the association between insulin use and asthma in a large population-based cohort, and further explore their causal relationship by Mendelian randomization (MR) analysis. METHODS: An epidemiological study including 85,887 participants from the National Health and Nutrition Examination Survey (NHANES) 2001-2018 was performed to evaluate the association between insulin use and asthma. Based on the inverse-variance weighted approach, MR analysis were conducted to estimate the causal effect of insulin use on asthma from the UKB and FinnGen datasets, respectively. RESULTS: In the NHANES cohort, we found that insulin use was associated with an increased risk of asthma [odd ratio (OR) 1.38; 95% CI 1.16-1.64; p < 0.001]. For the MR analysis, we found a causal relationship between insulin use and a higher risk of asthma in both Finn (OR 1.10; p < 0.001) and UK Biobank cohorts (OR 1.18; p < 0.001). Meanwhile, there was no causal association between diabetes and asthma. After multivariable adjustment for diabetes in UKB cohort, the insulin use remained significantly associated with an increased risk of asthma (OR 1.17, p < 0.001). CONCLUSIONS: An association between insulin use and an increased risk of asthma was found via the real-world data from the NHANES. In addition, the current study identified a causal effect and provided a genetic evidence of insulin use and asthma. More studies are needed to elucidate the mechanisms underlying the association between insulin use and asthma.

Longitudinal hematologic and immunologic variations associated with the progression of COVID-19 patients in China.

BACKGROUND: Crucial roles of hematologic and immunologic responses in progression of coronavirus disease 2019 (COVID-19) remain largely unclear. OBJECTIVE: We sought to address the dynamic changes in hematologic and immunologic biomarkers and their associations with severity and outcomes of COVID-19. METHODS: A retrospective study including 548 patients with COVID-19 with clarified outcome (discharged or deceased) from a national cohort in China was performed. Cross-sectional and longitudinal variations were compared and the associations with different severity and outcomes were analyzed. RESULTS: On admission, the counts of lymphocytes, T-cell subsets, eosinophils, and platelets decreased markedly, especially in severe/critical and fatal patients. Increased neutrophil count and neutrophils-to-lymphocytes ratio were predominant in severe/critical cases or nonsurvivors. During hospitalization, eosinophils, lymphocytes, and platelets showed an increasing trend in survivors, but maintained lower levels or dropped significantly afterwards in nonsurvivors. Nonsurvivors kept a high level or showed an upward trend for neutrophils, IL-6, procalcitonin, D-dimer, amyloid A protein, and C-reactive protein, which were kept stable or showed a downward trend in survivors. Positive correlation between CD8+ T-cell and lymphocytes count was found in survivors but not in nonsurvivors. A multivariate Cox regression model suggested that restored levels of lymphocytes, eosinophils, and platelets could serve as predictors for recovery, whereas progressive increases in neutrophils, basophils, and IL-6 were associated with fatal outcome. CONCLUSIONS: Hematologic and immunologic impairment showed a significantly different profile between survivors and nonsurvivors in patients with COVID-19 with different severity. The longitudinal variations in these biomarkers could serve to predict recovery or fatal outcome.

Comorbidity and its impact on 1590 patients with COVID-19 in China: a nationwide analysis.

BACKGROUND: The coronavirus disease 2019 (COVID-19) outbreak is evolving rapidly worldwide. OBJECTIVE: To evaluate the risk of serious adverse outcomes in patients with COVID-19 by stratifying the comorbidity status. METHODS: We analysed data from 1590 laboratory confirmed hospitalised patients from 575 hospitals in 31 provinces/autonomous regions/provincial municipalities across mainland China between 11 December 2019 and 31 January 2020. We analysed the composite end-points, which consisted of admission to an intensive care unit, invasive ventilation or death. The risk of reaching the composite end-points was compared according to the presence and number of comorbidities. RESULTS: The mean age was 48.9 years and 686 (42.7%) patients were female. Severe cases accounted for 16.0% of the study population. 131 (8.2%) patients reached the composite end-points. 399 (25.1%) reported having at least one comorbidity. The most prevalent comorbidity was hypertension (16.9%), followed by diabetes (8.2%). 130 (8.2%) patients reported having two or more comorbidities. After adjusting for age and smoking status, COPD (HR (95% CI) 2.681 (1.424-5.048)), diabetes (1.59 (1.03-2.45)), hypertension (1.58 (1.07-2.32)) and malignancy (3.50 (1.60-7.64)) were risk factors of reaching the composite end-points. The hazard ratio (95% CI) was 1.79 (1.16-2.77) among patients with at least one comorbidity and 2.59 (1.61-4.17) among patients with two or more comorbidities. CONCLUSION: Among laboratory confirmed cases of COVID-19, patients with any comorbidity yielded poorer clinical outcomes than those without. A greater number of comorbidities also correlated with poorer clinical outcomes.

Clinical characteristics and outcomes of hospitalised patients with COVID-19 treated in Hubei (epicentre) and outside Hubei (non-epicentre): a nationwide analysis of China.

BACKGROUND: During the outbreak of coronavirus disease 2019 (COVID-19), consistent and considerable differences in disease severity and mortality rate of patients treated in Hubei province compared to those in other parts of China have been observed. We sought to compare the clinical characteristics and outcomes of patients being treated inside and outside Hubei province, and explore the factors underlying these differences. METHODS: Collaborating with the National Health Commission, we established a retrospective cohort to study hospitalised COVID-19 cases in China. Clinical characteristics, the rate of severe events and deaths, and the time to critical illness (invasive ventilation or intensive care unit admission or death) were compared between patients within and outside Hubei. The impact of Wuhan-related exposure (a presumed key factor that drove the severe situation in Hubei, as Wuhan is the epicentre as well the administrative centre of Hubei province) and the duration between symptom onset and admission on prognosis were also determined. RESULTS: At the data cut-off (31 January 2020), 1590 cases from 575 hospitals in 31 provincial administrative regions were collected (core cohort). The overall rate of severe cases and mortality was 16.0% and 3.2%, respectively. Patients in Hubei (predominantly with Wuhan-related exposure, 597 (92.3%) out of 647) were older (mean age 49.7 versus 44.9 years), had more cases with comorbidity (32.9% versus 19.7%), higher symptomatic burden, abnormal radiologic manifestations and, especially, a longer waiting time between symptom onset and admission (5.7 versus 4.5 days) compared with patients outside Hubei. Patients in Hubei (severe event rate 23.0% versus 11.1%, death rate 7.3% versus 0.3%, HR (95% CI) for critical illness 1.59 (1.05-2.41)) have a poorer prognosis compared with patients outside Hubei after adjusting for age and comorbidity. However, among patients outside Hubei, the duration from symptom onset to hospitalisation (mean 4.4 versus 4.7 days) and prognosis (HR (95%) 0.84 (0.40-1.80)) were similar between patients with or without Wuhan-related exposure. In the overall population, the waiting time, but neither treated in Hubei nor Wuhan-related exposure, remained an independent prognostic factor (HR (95%) 1.05 (1.01-1.08)). CONCLUSION: There were more severe cases and poorer outcomes for COVID-19 patients treated in Hubei, which might be attributed to the prolonged duration of symptom onset to hospitalisation in the epicentre. Future studies to determine the reason for delaying hospitalisation are warranted.

Clinical Features of Coronavirus Disease 2019 Patients With Mechanical Ventilation: A Nationwide Study in China.

OBJECTIVES: The outbreak of coronavirus disease 2019 is becoming a worldwide pandemic. Mechanical ventilation is lifesaving for respiratory distress, this study was designed to delineate the clinical features of the coronavirus disease 2019 patients with mechanical ventilation from a national cohort in China. DESIGN: Prospective observational study. SETTING: The rapid spread of severe acute respiratory syndrome coronavirus 2 has infected more than 7.7 million people and caused more than 423,000 deaths. PATIENTS: Adult hospitalized coronavirus disease 2019 patients with mechanical ventilation from 557 hospitals from China. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: From a nationwide cohort, 141 coronavirus disease 2019 cases with mechanical ventilation were extracted from 1,590 cases. Cigarette smoke, advanced age, coexisting chronic illness, elevated systolic blood pressure, high body temperature, and abnormal laboratory findings are common in these ventilated cases. Multivariate regression analysis showed that higher odds of in-hospital death was associated with invasive mechanical ventilation requirement (hazard ratio: 2.95; 95% CI, 1.40-6.23; p = 0.005), and coexisting chronic obstructive pulmonary disease (hazard ratio, 4.57; 95% CI, 1.65-12.69; p = 0.004) and chronic renal disease (hazard ratio, 5.45; 95% CI, 1.85-16.12; p = 0.002). Compared with patients with noninvasive mechanical ventilation, patients who needs invasive mechanical ventilation showed higher rate of elevated D-dimer (> 1.5 mg/L) at admission (hazard ratio, 3.28, 95% CI, 1.07-10.10; p = 0.039). CONCLUSIONS: The potential risk factors of elevated D-dimer level could help clinicians to identify invasive mechanical ventilation requirement at an early stage, and coexisting chronic obstructive pulmonary disease or chronic renal disease are independent risk factors associated with fatal outcome in coronavirus disease 2019 patients with mechanical ventilation.

Elevated Circulating CD4+CD25+CD127-/low Regulatory T Cells in Patients with Non-asthmatic Eosinophilic Bronchitis.

PURPOSE: Non-asthmatic eosinophilic bronchitis (NAEB) is a common cause of chronic cough. It is characterized by sputum eosinophilia like asthma but lacks airway hyperresponsiveness. Regulatory T cells (Tregs) are recognized as immune suppressors and are involved in the pathogenesis of asthma. However, the relationship between Tregs and NAEB remains unknown. This study aimed to preliminarily explore the role of Tregs in NAEB by comparing circulating Tregs levels to asthma and healthy controls. METHODS: Fractional exhaled nitric oxide (FeNO), spirometry with bronchial provocation test, sputum induction and blood routine test were performed in all subjects. Peripheral blood mononuclear cells were used to detect the Tregs (CD4+CD25+CD127-/low) by flow cytometry. Relationship between the levels of circulating Tregs and clinical indexes was also observed. RESULTS: A total of 15 patients with NAEB, 20 patients with asthma and 11 healthy controls were included. The absolute numbers of circulating Tregs in the NAEB group (49.8 ± 18.9 × 103 cells/ml) and asthma group (53.3 ± 18.7 × 103 cells/ml) were higher than that in healthy control group (32.7 ± 11.6 × 103 cells/ml) (both P < 0.01). In total, the level of circulating Tregs showed positive correlation with FeNO (r = 0.30, P < 0.05). CONCLUSION: Tregs may play a key role not only in asthmatic patients, but also in patients with NAEB, as reflected by the elevated Tregs in peripheral blood.

Clinical utility of ultrahigh fractional exhaled nitric oxide in predicting bronchial hyperresponsiveness in patients with suspected asthma.

BACKGROUND: Fractional exhaled nitric oxide (FeNO) is a non-invasive biomarker for airway eosinophilic inflammation. However, the clinical value of ultrahigh FeNO (≥100 parts per billion (ppb)) in predicting asthma is never explored. We aimed to investigate the value of ultrahigh FeNO as a predictor of bronchial hyperresponsiveness (BHR), an important index for asthma diagnosis. METHODS: A retrospective cohort study was conducted on 259 patients with suspected asthma who received the examination of FeNO, spirometry, bronchial provocation test (BPT) and differential cell count of induced sputum. Patients were stratified by FeNO value: ultrahigh (group A:≥100 ppb), high (group B: 50-99 ppb), intermediate (group C: 26-49 ppb) and normal (group D:≤25 ppb). The positive rates of BPT and sputum eosinophils percentage (Eos%) were compared among four cohorts. The correlations between FeNO and sputum Eos% were measured. RESULTS: A significant higher positive rate of BPT was observed in group A (90.91%) than all others (B: 51.43%, C: 31.43%, D: 28.13%, all p<0.01). Referring to group D, the ORs of positive BPT in groups A, B and C were 26.84, 2.84 and 1.05. Sputum Eos% in group A (19.75 (7.00, 46.25)) is higher than that in others (B: 3.50 (1.00, 12.75), C: 1.13 (0.06,3.50), D: 0.50 (0.00, 2.13)). FeNO correlates with sputum Eos% in groups A and B, but not group C or D. CONCLUSIONS: Ultrahigh FeNO correlates with BHR and could serve as a practical alternative to methacholine challenge to support an asthma diagnosis in patients with suspected asthma in primary care.

Increased Sputum IL-17A Level in Non-asthmatic Eosinophilic Bronchitis.

BACKGROUND: Non-asthmatic eosinophilic bronchitis (NAEB) is one common cause of chronic cough which is characterized as airway eosinophilic inflammation like asthma but lack of airway hyper-responsiveness. Previous studies showed that Th2-pathway plays a role in NAEB, but the role of non-Th2 pathway in mechanism of NAEB remains unknown. Recently, IL-17A, a Th17-pathway cytokine, has been demonstrated to be involved in asthma development. However, the relationship between Th17-pathway and NAEB is unknown. METHODS: We aim to assess the airway level of IL-17A in the subjects with NAEB. Relationships between the IL-17A level and airway function in NAEB or asthma are also observed. We measured IL-17A concentrations in the sputum supernatant from 12 subjects with EB, 16 subjects with asthma [9 eosinophilic asthmatic (EA) and 7 non-eosinophilic asthmatic (NEA) according to the sputum eosinophil ≥ 3%], and 9 healthy control subjects. RESULTS: Increasing IL-17A level was found in NAEB group (29.65 ± 8.13 pg/ml), EA group (32.45 ± 3.22 pg/ml), and NEA group (29.62 ± 6.91 pg/ml) compared with the healthy control group (17.05 ± 10.30 pg/ml) (P < 0.05, P < 0.01, P < 0.05, respectively). The sputum IL-17A level was correlated with FENO (r = 0.44, P < 0.01), FEV1/FVC% (r = - 0.38, P < 0.05), MMEF%pred (r = - 0.34, P < 0.05), and sputum neutrophil% (r = 0.33, P < 0.05) in total. CONCLUSION: Th17-pathway may play a role not only in asthmatics, but also in subjects with NAEB, as reflected by increasing IL-17A concentrations in sputum supernatant.

Allergen-induced Increases in Sputum Levels of Group 2 Innate Lymphoid Cells in Subjects with Asthma.

RATIONALE: Group 2 innate lymphoid cells (ILC2), a major source of type 2 cytokines, initiate eosinophilic inflammatory responses in murine models of asthma. OBJECTIVES: To investigate the role of ILC2 in allergen-induced airway eosinophilic responses in subjects with atopy and asthma. METHODS: Using a diluent-controlled allergen challenge crossover study, where all subjects (n = 10) developed allergen-induced early and late responses, airway eosinophilia, and increased methacholine airway responsiveness, bone marrow, blood, and sputum samples were collected before and after inhalation challenge. MEASUREMENTS AND MAIN RESULTS: ILC2 (lin-FcεRI-CD45+CD127+ST2+) and CD4+T lymphocytes were enumerated by flow cytometry, as well as intracellular IL-5 and IL-13 expression. Steroid sensitivity of ILC2 and CD4+ T cells was investigated in vitro. A significant increase in total, IL-5+, IL-13+, and CRTH2+ ILC2 was found in sputum, 24 hours after allergen, coincident with a significant decrease in blood ILC2. Total, IL-5+, and IL-13+, but not CRTH2+, CD4+ T cells significantly increased at 24 and 48 hours after allergen in sputum. In blood and bone marrow, only CD4+ cells demonstrated increased activation after allergen. Airway eosinophilia correlated with IL-5+ ILC2 at all time points and allergen-induced changes in IL-5+ CD4+ cells at 48 hours after allergen. Dexamethasone significantly attenuated IL-2- and IL-33-stimulated IL-5 and IL-13 production by both cell types. CONCLUSIONS: Innate and adaptive immune cells are increased in the airways associated with allergic asthmatic responses. Total and type 2 cytokine-positive ILC2 are increased only within the airways, whereas CD4+ T lymphocytes demonstrated local and systemic increases. Steroid sensitivity of both cells may explain effectiveness of this therapy in those with mild asthma.

Non-asthmatic eosinophilic bronchitis and its relationship with asthma.

Non-asthmatic eosinophilic bronchitis (NAEB) is an important cause of chronic cough. NAEB shares similar eosinophilic inflammation of airway and response to corticosteroids with asthma. However, in contrast to asthma, NAEB subjects have no airflow obstruction and airway hyperresponsiveness. The pathogenesis of NAEB are involved with many inflammatory cells such as eosinophils, lymphocytes, mast cells, cytokines and inflammatory mediators, includingTh2 cytokines, histamine, leukotrines, prograndins and oxidative stress. The different locations of inflammatory cells and the inflammatory mediators level may explain this difference between EB and asthma. There is no study on dose and duration of treatment. On the prognosis of NAEB, long term follow-up study suggested that NAEB should be a distinct entity rather than an early stage of asthma or COPD. The relapse rate is high after treatment. Assessing sputum eosinophils after treatment is useful to identify those at risk of relapse.

Allergen-induced Changes in Bone Marrow and Airway Dendritic Cells in Subjects with Asthma.

RATIONALE: Dendritic cells (DCs) are antigen-presenting cells essential for the initiation of T-cell responses. Allergen inhalation increases the number of airway DCs and the release of epithelial-derived cytokines, such as IL-33 and thymic stromal lymphopoietin (TSLP), that activate DCs. OBJECTIVES: To examine the effects of inhaled allergen on bone marrow production of DCs and their trafficking into the airways in subjects with allergic asthma, and to examine IL-33 and TSPL receptor expression on DCs. METHODS: Bone marrow, peripheral blood, bronchoalveolar lavage (BAL), and bronchial biopsies were obtained before and after inhalation of diluent and allergen from subjects with asthma that develop allergen-induced dual responses. Classical DCs (cDCs) were cultured from bone marrow CD34(+) cells. cDC1s, cDC2s, and plasmacytoid DCs were measured in bone marrow aspirates, peripheral blood, and BAL by flow cytometry, and cDCs were quantified in bronchial biopsies by immunofluorescence staining. MEASUREMENTS AND MAIN RESULTS: Inhaled allergen increased the number of cDCs grown from bone marrow progenitors, and cDCs and plasmacytoid DCs in bone marrow aspirates 24 hours after allergen. Allergen also increased the expression of the TSLP receptor, but not the IL-33 receptor, on bone marrow DCs. Finally, inhaled allergen increased the percentage of cDC1s and cDC2s in BAL but only cDC2s in bronchial tissues. CONCLUSIONS: Inhaled allergen increases DCs in bone marrow and trafficking of DCs into the airway, which is associated with the development airway inflammation in subjects with allergic asthma. Inhaled allergen challenge also increases expression of TSLP, but not IL-33, receptors on bone marrow DCs.

Increased numbers of activated group 2 innate lymphoid cells in the airways of patients with severe asthma and persistent airway eosinophilia.

BACKGROUND: In patients with severe eosinophilic asthma, local maturation rather than systemic recruitment of mature cells might contribute to persistent airway eosinophilia. Group 2 innate lymphoid cells (ILC2s) are a major source of type 2 cytokines (IL-5 and IL-13) and can facilitate eosinophilic inflammatory responses in mouse models of asthma in the absence of CD4+ lymphocytes. This study investigated the potential role of ILC2s in driving chronic airway eosinophilia in patients with severe asthma, despite regular high-dose oral corticosteroid therapy. METHODS: In a cross-sectional study we enumerated blood and sputum ILC2s (lin(-)CD45(+)127(+)ST2(+)) and levels of intracellular IL-5 and IL-13 in patients with severe asthma (n = 25), patients with steroid-naive mild atopic asthma (n = 19), and nonatopic control subjects (n = 5). Results were compared with numbers of CD4+ lymphocytes, eosinophil lineage-committed progenitors (eosinophilopoietic progenitor cells [EoPs]), and mature eosinophils. RESULTS: Significantly greater numbers of total and type 2 cytokine-producing ILC2s were detected in blood and sputum of patients with severe asthma compared to mild asthmatics. In contrast, intracellular cytokine expression by CD4 cells and EoPs within the airways did not differ between the asthmatic groups. In patients with severe asthma, although sputum CD4+ cells were more abundant than ILC2s and EoPs, proportionally, ILC2s were the predominant source of type 2 cytokines. In addition, there were significantly greater numbers of sputum IL-5(+)IL-13(+) ILC2s in patients with severe asthma whose airway eosinophilia was greater than 3%, despite normal blood eosinophil numbers (<300/µL). CONCLUSIONS: Our findings suggest that ILC2s can promote the persistence of airway eosinophilia in patients with severe asthma through uncontrolled localized production of the type 2 cytokines IL-5 and IL-13, despite high-dose oral corticosteroid therapy.