Trait profiles in difficult-to-treat asthma: Clinical impact and response to systematic assessment.

BACKGROUND: Multidisciplinary systematic assessment improves outcomes in difficult-to-treat asthma, but without clear response predictors. Using a treatable-traits framework, we stratified patients by trait profile, examining clinical impact and treatment responsiveness to systematic assessment. METHODS: We performed latent class analysis using 12 traits on difficult-to-treat asthma patients undergoing systematic assessment at our institution. We examined Asthma Control Questionnaire (ACQ-6) and Asthma Quality of Life Questionnaire (AQLQ) scores, FEV1 , exacerbation frequency, and maintenance oral corticosteroid (mOCS) dose, at baseline and following systematic assessment. RESULTS: Among 241 patients, two airway-centric profiles were characterized by early-onset with allergic rhinitis (n = 46) and adult onset with eosinophilia/chronic rhinosinusitis (n = 60), respectively, with minimal comorbid or psychosocial traits; three non-airway-centric profiles exhibited either comorbid (obesity, vocal cord dysfunction, dysfunctional breathing) dominance (n = 51), psychosocial (anxiety, depression, smoking, unemployment) dominance (n = 72), or multi-domain impairment (n = 12). Compared to airway-centric profiles, non-airway-centric profiles had worse baseline ACQ-6 (2.7 vs. 2.2, p < .001) and AQLQ (3.8 vs. 4.5, p < .001) scores. Following systematic assessment, the cohort showed overall improvements across all outcomes. However, airway-centric profiles had more FEV1 improvement (5.6% vs. 2.2% predicted, p < .05) while non-airway-centric profiles trended to greater exacerbation reduction (1.7 vs. 1.0, p = .07); mOCS dose reduction was similar (3.1 mg vs. 3.5 mg, p = .782). CONCLUSION: Distinct trait profiles in difficult-to-treat asthma are associated with different clinical outcomes and treatment responsiveness to systematic assessment. These findings yield clinical and mechanistic insights into difficult-to-treat asthma, offer a conceptual framework to address disease heterogeneity, and highlight areas responsive to targeted intervention.

Allergen Immunotherapy Enhances Airway Epithelial Antiviral Immunity in Patients with Allergic Asthma (VITAL Study): A Double-Blind Randomized Controlled Trial.

Rationale: Allergic asthma is linked to impaired bronchial epithelial secretion of IFNs, which may be causally linked to the increased risk of viral exacerbations. We have previously shown that allergen immunotherapy (AIT) effectively reduces asthma exacerbations and prevents respiratory infections requiring antibiotics; however, whether AIT alters antiviral immunity is still unknown. Objectives: To investigate the effect of house dust mite sublingual AIT (HDM-SLIT) on bronchial epithelial antiviral and inflammatory responses in patients with allergic asthma. Methods: In this double-blind, randomized controlled trial (VITAL [The Effect of Allergen Immunotherapy on Anti-viral Immunity in Patients with Allergic Asthma]), adult patients with HDM allergic asthma received HDM-SLIT 12-SQ or placebo for 24 weeks. Bronchoscopy was performed at baseline and at Week 24, which included sampling for human bronchial epithelial cells. Human bronchial epithelial cells were cultured at baseline and at Week 24 and stimulated with the viral mimic polyinosinic:polycytidylic acid (poly(I:C)). mRNA expression was quantified using qRT-PCR, and protein concentrations were measured using multiplex ELISA. Measurements and Main Results: Thirty-nine patients were randomized to HDM-SLIT (n = 20) or placebo (n = 19). HDM-SLIT resulted in increased polyinosinic:polycytidylic acid-induced expression of IFN-ß at both the gene (P = 0.009) and protein (P = 0.02) levels. IFN-λ gene expression was also increased (P = 0.03), whereas IL-33 tended to be decreased (P = 0.09). On the other hand, proinflammatory cytokines IL-6 (P = 0.009) and TNF-α (tumor necrosis factor-α) (P = 0.08) increased compared with baseline in the HDM-SLIT group. There were no significant changes in TSLP (thymic stromal lymphopoietin), IL-4, IL-13, and IL-10. Conclusions: HDM-SLIT improves bronchial epithelial antiviral resistance to viral infection. These results potentially explain the efficacy of HDM-SLIT in reducing exacerbations in allergic asthma. Clinical trial registered with www.clinicaltrials.gov (NCT04100902).

Mucosal cryobiopsies: a new method for studying airway pathology in asthma.

Background: In vivo studies of airway pathology in obstructive lung disease are limited by poor quality of specimens obtained with forceps. Obtainment of cryobiopsies has increased diagnostic yield in cancer and interstitial lung disease but has not been used in patients with asthma. In a recent pilot study, we found mucosal cryobiopsies to be larger and more intact than conventional forceps biopsies. The aim of the present study was to compare quality and safety of mucosal cryobiopsies versus conventional forceps biopsies in patients with asthma. Methods: Endobronchial biopsies were obtained with forceps and cryoprobe from patients with asthma not currently treated with inhaled steroids and evaluated histologically. Results: A total of 240 cryobiopsies and 288 forceps biopsies were obtained from 48 patients. Bleeding from the biopsy site was common but self-limiting. No major complications related to the procedure were seen. Cryobiopsy cross areas were four times larger compared with forceps. Stretches of intact epithelium were detected in all cryobiopsies compared to 33% in forceps biopsies. Further, the length of intact epithelium was on average four times longer in the cryobiopsies. Importantly, there was a good preservation of both antigens and mRNA in the cryobiopsies ensuring a suitability and robustness for immunohistochemistry and in situ hybridisation. Conclusion: Obtainment of mucosal cryobiopsies in patients with asthma is safe and yields biopsies that are significantly larger and morphologically better preserved compared with traditional forceps biopsies. The cryotechnique thus seems to be a promising tool for future in vivo studies of airway pathology.

Phenotype and severity of asthma determines bronchial epithelial immune responses to a viral mimic.

BACKGROUND: Asthma is characterised by an aggravated immune response to respiratory viral infections. This phenomenon is a clinically well-recognised driver of acute exacerbations, but how different phenotypes of asthma respond immunologically to viruses is unclear. OBJECTIVES: To describe the association between different phenotypes and severity of asthma and bronchial epithelial immune responses to viral stimulation. METHODS: In the Immunoreact study, healthy subjects (n=10) and 50 patients with asthma were included; 30 (60%) were atopic, and 34 (68%) were eosinophilic; 14 (28%) had severe asthma. All participants underwent bronchoscopy with collection of bronchial brushings. Bronchial epithelial cells (BECs) were expanded and stimulated with the viral replication mimic poly (I:C) (Toll-like receptor (TLR)3 agonist) in vitro. The expression of TLR3-induced pro-inflammatory and antiviral responses of BECs were analysed using reverse transcriptase quantitative PCR and multiplex ELISA and compared across asthma phenotypes and severity of disease. RESULTS: Patients with atopic asthma had increased induction of interleukin (IL)-4, interferon (IFN)-ß, IL-6, tumour necrosis factor-α, and IL-1ß after poly (I:C) stimulation compared to non-atopic patients, whereas in patients with eosinophilic asthma only IL-6 and IL-8 induction was higher than in non-eosinophilic asthma. Patients with severe asthma displayed a decreased antiviral IFN-ß, and increased expression of IL-8, most pronounced in atopic and eosinophilic asthmatics. Furthermore, induction of IL-33 in response to poly (I:C) was increased in severe atopic and in severe eosinophilic asthma, but thymic stromal lymphopoietin only in severe eosinophilic asthma. CONCLUSIONS: The bronchial epithelial immune response to a viral mimic stimulation differs between asthma phenotypes and severities, which may be important to consider when targeting novel asthma treatments.

Mast cell tryptase enhances wound healing by promoting migration in human bronchial epithelial cells.

Epithelial damage and increase of intraepithelial mast cells (MC) are characteristics of asthma. The role of MC mediator tryptase and the protease-activated receptor-2 (PAR2) on epithelial wound healing is not fully investigated. Stimulation of bronchial epithelial cells (BECs) with tryptase promoted gap closure, migration and cellular speed compared to controls. Stimulated BECs had higher expression of migration marker CD151 compared to controls. Proliferation marker KI67 was upregulated in tryptase-stimulated BECs compared to controls. Treatment with PAR2 antagonist I-191 reduced gap closure, migration and cell speed compared to BECs stimulated with tryptase. We found that tryptase enhances epithelial wound healing by increased migration and proliferation, which is in part regulated via PAR2. Our data suggest that tryptase might be beneficial in tissue repair under baseline conditions. However, in a pathological context such as asthma with increased numbers of activated MCs, it might lead to epithelial remodeling and loss of function.

Bronchial provocation testing does not detect exercise-induced laryngeal obstruction.

INTRODUCTION: Exercise-induced laryngeal obstruction (EILO) is a key differential diagnosis for asthma in the presence of exertional respiratory symptoms. Continuous laryngoscopy during exercise (CLE), the current gold standard diagnostic test for EILO, has practical limitations. We aimed to establish if inspiratory flow data obtained during standard bronchoprovocation testing, to establish the presence of extra-thoracic hyper-responsiveness, may prove diagnostic for EILO and thus preclude requirement for CLE testing. METHODS: We consecutively evaluated 37 adult subjects with exertional dyspnea and possible asthma referred over 6 months. All subjects received comprehensive assessment including a detailed clinical evaluation; pulmonary function testing, indirect and direct bronchial provocation testing, and CLE testing. RESULTS: Out of 37 subjects, moderate or severe EILO was diagnosed in 8 subjects (22%, all female) while 5 (14%) had both asthma and EILO. There was no correlation between degree of EILO during CLE and mean decrease in forced inspiratory flow (%FIF50) obtained during neither the Methacholine (r = -0.15; p = 0.38) nor Mannitol (r = 0.04; p = 0.84) provocation tests. CONCLUSION: Inspiratory flow parameters obtained during bronchoprovocation tests did not reliably detect EILO. It remains that CLE is an important and key investigation modality in establishing a secure diagnosis of EILO.

The Danish National Database for Asthma: establishing clinical quality indicators.

Asthma is one of the most common chronic diseases worldwide affecting more than 300 million people. Symptoms are often non-specific and include coughing, wheezing, chest tightness, and shortness of breath. Asthma may be highly variable within the same individual over time. Although asthma results in death only in extreme cases, the disease is associated with significant morbidity, reduced quality of life, increased absenteeism, and large costs for society. Asthma can be diagnosed based on report of characteristic symptoms and/or the use of several different diagnostic tests. However, there is currently no gold standard for making a diagnosis, and some degree of misclassification and inter-observer variation can be expected. This may lead to local and regional differences in the treatment, monitoring, and follow-up of the patients. The Danish National Database for Asthma (DNDA) is slated to be established with the overall aim of collecting data on all patients treated for asthma in Denmark and systematically monitoring the treatment quality and disease management in both primary and secondary care facilities across the country. The DNDA links information from population-based disease registers in Denmark, including the National Patient Register, the National Prescription Registry, and the National Health Insurance Services register, and potentially includes all asthma patients in Denmark. The following quality indicators have been selected to monitor trends: first, conduction of annual asthma control visits, appropriate pharmacological treatment, measurement of lung function, and asthma challenge testing; second, tools used for diagnosis in new cases; and third, annual assessment of smoking status, height, and weight measurements, and the proportion of patients with acute hospital treatment. The DNDA will be launched in 2016 and will initially include patients treated in secondary care facilities in Denmark. In the nearby future, the database aims to include asthma diagnosis codes and clinical data registered by general practitioners and specialised practitioners as well.

FENO and AHR mannitol in patients referred to an out-of-hospital asthma clinic: a real-life study.

OBJECTIVE: Ongoing airway inflammation measured by fractional exhaled nitric oxide (FENO) and airway hyperresponsiveness (AHR) to mannitol are associated in selected asthma patients, but no evidence exists of this association in unselected asthma patients. The aim was to investigate the association between FENO and AHR to mannitol in unselected individuals with possible asthma. METHODS: A real-life study on patients with possible asthma referred to a specialized asthma clinic. Data on asthma history, FEV(1), FENO, atopy, smoking, treatment and AHR to mannitol were collected. RESULTS: In 217 unselected patients with symptoms suggestive of asthma, FENO and response to mannitol were tested. Of the 141 who underwent both tests, 32 (23%) had FENO > 25 ppb, and 58 (41%) had AHR to mannitol. A significant association between high FENO and AHR was found (p < 0.001); 26% responded to mannitol despite a normal NO, and 8% had a high FENO but no AHR. Additionally, a weak association was found between log FENO and log response to mannitol (r = 0.32, p < 0.01). The area under the ROC curve for FENO as a predictor of AHR was 0.66 (95% CI 0.6-0.8) and for mannitol for having high FENO was 0.73 (95%CI 0.6-0.9). CONCLUSION: In a large sample of patients referred to an asthma clinic, an association was found between FENO and AHR to mannitol. However, a significant proportion of asthma patients had a normal FENO despite having AHR, suggesting that in some patients, AHR to mannitol is not driven by eosinophilic airway inflammation.