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Objectives: Longitudinal data are common in asthma studies, to assess asthma progression in patients and identify predictors of future outcomes, including asthma exacerbations and asthma control. Different methods can quantify temporal behaviour in prospective patient-collected diary variables to obtain predictive biomarkers of asthma outcomes. The aims of this systematic review were to evaluate methods for extracting biomarkers from longitudinally collected diary data in asthma and investigate associations between them and patient-reported outcomes (PROs) of patients with asthma., Design: Systematic review and narrative synthesis., Data Sources: MEDLINE, EMBASE, CINAHL and the Cochrane Library were searched for studies published between January 2000 and July 2023., Eligibility Criteria: Included studies generated biomarkers from prospective patient-collected peak expiratory flow, symptom scores, reliever use and nocturnal awakenings, and evaluated their associations with asthma PROs, namely asthma exacerbations, asthma control, asthma-related quality of life and asthma severity., Data Extraction and Synthesis: Two independent reviewers used standardised methods to screen and extract data from included studies. Study quality and risk of bias were assessed using the Transparent Reporting of a multivariable prediction model for Individual Prognosis Or Diagnosis (TRIPOD) and the Prediction model Risk Of Bias ASessment Tool (PROBAST), respectively., Results: 24 full-text articles met the inclusion criteria and were included in the review. Generally, higher levels of variability in the diary variables were associated with poorer outcomes, especially increased asthma exacerbation risk, and poor asthma control. There was increasing interest in non-parametric methods to quantify complex behaviour of diary variables (6/24). TRIPOD and PROBAST highlighted a lack of consistent reporting of model performance measures and potential for model bias., Conclusion: Prospectively patient-collected diary variables aid in generating asthma assessment tools, including surrogate endpoints, for clinical trials and predictive biomarkers of adverse outcomes, warranting remote monitoring. Studies consistently lacked robust reporting of model performance. Future research should use diary variable-derived biomarkers., Competing Interests: Competing interests: FAAC, EQ and MR do not report any conflicts of interest. SS reports grants from the UK Medical Research Council and the Engineering and Physical Sciences Research Council, and personal fees from GSK, AstraZeneca, Roche, Novartis, Chiesi, CSL Behring, Areteia Therapeutics and Owlstone Medical, outside of the submitted work., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY. Published by BMJ.)

Background: Component-resolved diagnosis allows detection of IgE sensitization having the advantage of reproducibility and standardization compared to crude extracts. The main disadvantage of the traditional allergen identification methods, 1- or 2-dimensional western blotting and screening of expression cDNA libraries with patients' IgEs, is that the native structure of the protein is not necessarily maintained., Methods: We used a novel immunoprecipitation technique in combination with mass spectrometry to identify new allergens of Aspergillus fumigatus. Magnetic Dynabeads coupled with anti-human IgE antibodies were used to purify human serum IgE and subsequently allergens from A. fumigatus protein extract., Results: Of the 184 proteins detected by subsequent mass peptide fingerprinting, a subset of 13 were recombinantly expressed and purified. In a panel of 52 A. fumigatus-sensitized people with asthma, 23 non-fungal-sensitized asthmatics and 18 healthy individuals, only the former showed an IgE reaction by immunoblotting and/or ELISA. We discovered 11 proteins not yet described as A. fumigatus allergens, with fructose-bisphosphate aldolase class II (FBA2) (33%), NAD-dependent malate dehydrogenase (31%) and Cu/Zn superoxide dismutase (27%) being the most prevalent. With respect to these three allergens, native versus denatured protein assays indicated a better recognition of the native proteins. Seven of 11 allergens fulfilled the WHO/IUIS criteria and were accepted as new A. fumigatus allergens., Conclusion: In conclusion, we introduce a straightforward method of allergen identification from complex allergenic sources such as A. fumigatus by immunoprecipitation combined with mass spectrometry, which has the advantage over traditional methods of identifying allergens by maintaining the structure of the proteins., (© 2024 The Authors. Allergy published by European Academy of Allergy and Clinical Immunology and John Wiley & Sons Ltd.)

Acute cardiorespiratory breathlessness accounts for one in eight of all emergency hospitalizations. Early, noninvasive diagnostic testing is a clinical priority that allows rapid triage and treatment. Here, we sought to find and replicate diagnostic breath volatile organic compound (VOC) biomarkers of acute cardiorespiratory disease and understand breath metabolite network enrichment in acute disease, with a view to gaining mechanistic insight of breath biochemical derangements. We collected and analyzed exhaled breath samples from 277 participants presenting acute cardiorespiratory exacerbations and aged-matched healthy volunteers. Topological data analysis phenotypes differentiated acute disease from health and acute cardiorespiratory exacerbation subtypes (acute heart failure, acute asthma, acute chronic obstructive pulmonary disease, and community-acquired pneumonia). A multibiomarker score (101 breath biomarkers) demonstrated good diagnostic sensitivity and specificity (≥80%) in both discovery and replication sets and was associated with all-cause mortality at 2 years. In addition, VOC biomarker scores differentiated metabolic subgroups of cardiorespiratory exacerbation. Louvain clustering of VOCs coupled with metabolite enrichment and similarity assessment revealed highly specific enrichment patterns in all acute disease subgroups, for example, selective enrichment of correlated C5-7 hydrocarbons and C3-5 carbonyls in heart failure and selective depletion of correlated aldehydes in acute asthma. This study identified breath VOCs that differentiate acute cardiorespiratory exacerbations and associated subtypes and metabolic clusters of disease-associated VOCs.

Background: Although small airway disease is a feature of asthma, its association with relevant asthma outcomes remains unclear. The ATLANTIS study was designed to identify the combination of physiological and imaging variables that best measure the presence and extent of small airway disease in asthma, both cross-sectionally and longitudinally. In this longitudinal analysis, we evaluated which small airway parameters studied were most strongly associated with asthma control, exacerbations, and quality of life., Methods: In this observational cohort study, participants with mild, moderate, or severe stable asthma were recruited between June 30, 2014, and March 3, 2017, via medical databases and advertisements in nine countries worldwide. Eligible participants were aged 18-65 years with a clinical asthma diagnosis for at least 6 months. Participants were followed up for 1 year, with visits at baseline, 6 months, and 12 months. Physiological tests included spirometry, lung volumes, impulse oscillometry, multiple breath nitrogen washout (MBNW), and percentage decrease in forced vital capacity during methacholine challenge. CT densitometry was performed to evaluate small airway disease. We examined the associations between these measurements and asthma exacerbations, asthma control, and quality of life using univariate and multivariate analyses. A composite ordinal score comprising percent predicted R5-20 (resistance of small-to-mid-sized airways), AX (area of reactance), and X5 (reactance of more central, conducting small airways at 5 Hz) was constructed., Findings: 773 participants (median age 46 years [IQR 34-54]; 450 [58%] female) were included in this longitudinal study. Univariate analyses showed that components of impulse oscillometry, lung volumes, MBNW, and forced expiratory flow at 25-75% of FVC were significantly correlated with asthma control and exacerbations (Spearman correlations 0·20-0·25, p<0·0001 after Bonferroni correction). As a composite of impulse oscillometry, the ordinal score independently predicted asthma control and exacerbations in a multivariate analysis with known exacerbation predictors. CT parameters were not significantly correlated with asthma control, exacerbation, or quality of life., Interpretation: Small airway disease, as measured by physiological tests, is longitudinally associated with clinically important asthma outcomes, such as asthma control and exacerbations., Funding: Chiesi Farmaceutici., Competing Interests: Declaration of interests MK reports grants paid to their institution for their research from the National Institutes of Health, American Lung Association, Chiesi Farmaceutici (for support of this study), AstraZeneca and Sanofi-Regeneron; personal fees for consultancies from Chiesi Farmaceutici, Genentech (Roche), GSK, Sanofi Regeneron, and AstraZeneca; speaker fees from Chiesi Farmaceutici; personal fees from participation in a data safety and monitoring board for AstraZeneca and ALung; and leadership in the American Thoracic Society. MVdB receives grants paid to their institution from Chiesi Farmaceutici (for this study), Sanofi, Genentech, GSK, and Roche. LMF reports personal fees for consultancies from Chiesi Farmaceutici; speaker fees from participation in advisory boards for Chiesi Farmaceutici, AstraZeneca, GSK, Alfasigma, Novartis, and Verona Pharma; travel expense reimbursement from Chiesi Farmaceutici, Novartis, and Menarini; and personal fees from participation in a data safety and monitoring board for Novartis. TVdM reports part-time employment with GSK and personal fees for consultancies from Chiesi Farmaceutici. GN reports being employed by Chiesi Farmaceutici. AP reports funding by Chiesi Farmaceutici (for this and other studies), AstraZeneca, GSK, Boehringer Ingelheim, Pfizer, Teva, and Sanofi paid to their institution; personal fees for consulting from Chiesi Farmaceutici, AstraZeneca, GSK, Novartis, Sanofi, Iqvia, Avillion, Elpen Pharmaceutic, and ALS; personal fees for lectures and presentations from Chiesi Farmaceutici, AstraZeneca, GSK, Boehringer Ingelheim, Menarini, Novartis, Zambon, Mundipharma, Teva, Sanofi, Edmond Pharma, Iqvia, MSD, Avillion, Elpen Pharmaceutic, ALS. KFR reports support from Chiesi Farmaceutici paid to their institution for this study; speaker fees from AstraZeneca, Boehringer Ingelheim, Chiesi Farmaceutici, Novartis, Sanofi/Regeneron, GlaxoSmithKline, Berlin Chemie, and Roche Pharma; personal fees from participation in a data safety and monitoring board for AstraZeneca, Boehringer Ingelheim, and Sanofi/Regeneron; and a leadership or fiduciary role for the German Center for Lung Research, the German Chest Society, and the American Thoracic Society. DS reports personal fees for consulting from Aerogen, AstraZeneca, Boehringer Ingelheim, Chiesi Farmaceutici, Cipla, CSL Behring, Epiendo, Genentech, GlaxoSmithKline, Glenmark, Gossamerbio, Kinaset, Menarini, Novartis, Pulmatrix, Sanofi, Teva, Theravance, and Verona. CB reports support paid to their institution from Chiesi Farmaceutici for this study; grants paid to their institution from GSK, AstraZeneca, Boehringer Ingelheim, Novartis, Chiesi Farmaceutici, Sanofi, Genetech, Merck, Mologic, 4DPharma, and Gossamer; and personal fees for consulting from GSK, AstraZeneca, Boehringer Ingelheim, Novartis, Chiesi Farmaceutici, Sanofi, Genentech, Merck, Mologic, 4DPharma, Gossamer, TEVA, Regeneron, Roche, and CSL Behring. SS reports funding paid to their institution from Chiesi Farmaceutici for support of this study; personal fees from GSK, Novartis, ERT Medical, AstraZeneca, Knopp Biotech, Owlstone Medical, Mundipharma, CSL Behring, and Boehringer Ingelheim; and personal fees for lectures from Chiesi Farmaceutici. All other authors declare no competing interests., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Objectives: Implementation of guidelines into clinical practice is challenging and complex. This study aims to (1) identify the training needs and capacity requirements, and (2) explore the impact on healthcare utilisation and asthma-related quality of life of implementing both spirometry and fraction of exhaled nitric oxide in diagnosis of asthma among children in the UK primary care., Methods: Ten UK general practitioner practices and a total of 612 children (5-16 years) with diagnosed or suspected asthma were invited to participate in this prospective observational study. The total times that the trainer and trainee clinical staff spent on developing the training package, providing and receiving, and performing and interpreting the two tests as part of routine child asthma review were collected, and costs were calculated. We compared healthcare utilisation and asthma-related and general health-related quality of life data between the 6 months before and after the asthma review guided by objective tests., Results: The average training cost for the 27 primary care clinical members was £1395. The average cost to implement and deliver the test-guided asthma review among the 612 included children was £22. In the 6 months following the tests-guided asthma review, both unplanned primary care attendance, and hospital admissions were reduced, and the asthma-related health status increased significantly., Conclusion: This study provides robust cost estimates of the resources needed to implement the National Institute for Health and Care Excellence asthma guideline. It also demonstrates the potential to save healthcare costs and improve health status among asthmatic children by implementing this guideline., Competing Interests: Competing interests: EAG: consultancy work for Boehringer ingelheim in November 2016 and for Anaxsys in July 2018 with money paid to the institution (University of leicester), investigator-led research grant from Circassia and Gilead, research collaboration with Medimmune and travel grants from Vertex., (© Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Objective: To identify risk factors for asthma attacks and poor asthma control in children aged 5-16 years., Methods: Prospective observational cohort study of 460 children with asthma or suspected asthma from 10 UK general practices.Gender, age, ethnicity, body mass index, practice deprivation decile, spirometry and fraction of exhaled nitric oxide (FeNO) were recorded at baseline. Asthma control scores, asthma medication ratio (AMR) and the number of asthma attacks were recorded at baseline and at 6 months.The above independent variables were included in binary multiple logistic regression analyses for the dependent variables of: (1) poor symptom control and (2) asthma attacks during follow-up., Results: Poor symptom control at baseline predicted poor symptom control at 6 months (OR 4.4, p=0.001), while an increase in deprivation decile (less deprived) was negatively associated with poor symptom control at 6 months (OR 0.79, p=0.003). Higher FeNO levels (OR 1.02, p<0.001) and a recent history of asthma attacks (OR 2.03, p=0.02) predicted asthma attacks during follow-up. Asian ethnicity was associated with a lower OR for a future attack (OR 0.32, p=0.02).A decrease in AMR was also associated with an increased OR for future asthma attacks (OR 2.99, p=0.003) when included as an independent variable., Conclusions: We identified risk factors for poor symptom control and asthma attacks in children. Routine assessment of these factors should form part of the asthma review to identify children at an increased risk of adverse asthma-related events., Competing Interests: Competing interests: EAG: consultancy work for Boehringer Ingelheim in November 2016 and Anaxsys in July 2018 with money paid to the institution (University of Leicester), investigator led research grant from Circassia and Gilead. Research collaboration with Medimmune. Travel grants from Vertex., (© Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Fungal involvement in asthma is associated with severe disease. The full spectrum of fungal species in asthma is not well described and is derived largely from insensitive culture techniques., Objectives: To use high-throughput sequencing to describe the airway mycobiota in asthmatics with and without fungal sensitization and healthy controls; to compare samples representing different airway compartments; to determine whether the mycobiota was influenced by the fungal composition of outdoor air; and to compare findings with clinically relevant outcomes., Methods: We amplified the internal transcribed spacer region 2 of the nuclear ribosomal operon to identify the fungal species present. Ninety-seven subjects were recruited and provided sputum (83 asthmatics; 14 healthy subjects), with 29 also undergoing a bronchoscopy. A subset of airway samples were compared with matched outdoor air and mouthwash samples., Results: Two hundred and six taxa at the species level were identified in sputum, most at low relative abundance. Aspergillus fumigatus, Candida albicans and Mycosphaerella tassiana had the highest relative abundances and were the most prevalent species across all subjects. The airway mycobiota consisted of a complex community with high diversity between individuals. Notable shifts in the balance of fungi detected in the lung were associated with asthma status, asthma duration and biomarkers of inflammation. Aspergillus tubingensis, a member of the Aspergillus niger species complex, was most prevalent from bronchoscopic protected brush samples and significantly associated with a low sputum neutrophilia. Cryptococcus pseudolongus, from the Cryptococcus humicola species complex, was more abundant from bronchoscopy samples than sputum, and differentially more abundant in asthma than health., Conclusions and Clinical Relevance: The airway mycobiota was dominated by a relatively small number of species, but was distinct from the oropharyngeal mycobiota and air samples. Members of the A. niger and C. humicola species complexes may play unexpected roles in the pathogenesis of asthma., (© 2020 The Authors. Clinical & Experimental Allergy published by John Wiley & Sons Ltd.)

Background: The National Institute for Health and Care Excellence recommends the use of spirometry and measuring the fraction of exhaled nitric oxide (FeNO) as part of the diagnostic work-up for children with suspected asthma, and spirometry for asthma monitoring, across all care settings. However, the feasibility and acceptability of these tests within primary care are not known., Aim: To investigate the feasibility, acceptability, training, and capacity requirements of performing spirometry and FeNO testing in children managed for asthma in UK primary care., Design and Setting: Prospective observational study involving 10 general practices in the East Midlands, UK, and 612 children between 2016 and 2017., Method: Training and support to perform spirometry and FeNO in children aged 5 to 16 years were provided to participating practices. Children on the practice's asthma registers, and those with suspected asthma, were invited for a routine asthma review. Time for general practice staff to achieve competencies in performing and/or interpreting both tests, time to perform the tests, number of children able to perform the tests, and feedback on acceptability were recorded., Results: A total of 27 general practice staff were trained in a mean time of 10.3 (standard deviation 2.7) hours. Usable spirometry and FeNO results were obtained in 575 (94%) and 472 (77%) children respectively. Spirometry is achievable in the majority of children aged ≥5 years, and FeNO in children aged ≥7 years. All of the staff and 97% of families surveyed provided positive feedback for the tests., Conclusion: After training, general practice staff obtained quality spirometry and FeNO data from most children tested. Testing was acceptable to staff and families. The majority of general practice staff reported that spirometry helped them to manage children's asthma better., (© British Journal of General Practice 2020.)

Background: Whether the clinical or pathophysiologic significance of the "treatable trait" high blood eosinophil count in COPD is the same as for asthma remains controversial. We sought to determine the relationship between the blood eosinophil count, clinical characteristics and gene expression from bronchial brushings in COPD and asthma., Methods: Subjects were recruited into a COPD (emphysema versus airway disease [EvA]) or asthma cohort (Unbiased BIOmarkers in PREDiction of respiratory disease outcomes, U-BIOPRED). We determined gene expression using RNAseq in EvA (n = 283) and Affymetrix microarrays in U-BIOPRED (n = 85). We ran linear regression analysis of the bronchial brushings transcriptional signal versus blood eosinophil counts as well as differential expression using a blood eosinophil > 200 cells/μL as a cut-off. The false discovery rate was controlled at 1% (with continuous values) and 5% (with dichotomized values)., Results: There were no differences in age, gender, lung function, exercise capacity and quantitative computed tomography between eosinophilic versus noneosinophilic COPD cases. Total serum IgE was increased in eosinophilic asthma and COPD. In EvA, there were 12 genes with a statistically significant positive association with the linear blood eosinophil count, whereas in U-BIOPRED, 1197 genes showed significant associations (266 positive and 931 negative). The transcriptome showed little overlap between genes and pathways associated with blood eosinophil counts in asthma versus COPD. Only CST1 was common to eosinophilic asthma and COPD and was replicated in independent cohorts., Conclusion: Despite shared "treatable traits" between asthma and COPD, the molecular mechanisms underlying these clinical entities are predominately different., (© 2019 The Authors. Allergy published by John Wiley & Sons Ltd.)

Rationale: Asthma is characterized by disease within the small airways. Several studies have suggested that forced oscillation technique-derived resistance at 5 Hz (R5) - resistance at 20 Hz (R20) is a measure of small airway disease; however, there has been limited validation of this measurement to date. Objectives: To validate the use of forced oscillation R5 - R20 as a measure of small airway narrowing in asthma, and to investigate the role that small airway narrowing plays in asthma. Methods: Patient-based complete conducting airway models were generated from computed tomography scans to simulate the impact of different degrees of airway narrowing at different levels of the airway tree on forced oscillation R5 - R20 ( n  = 31). The computational models were coupled with regression models in an asthmatic cohort ( n  = 177) to simulate the impact of small airway narrowing on asthma control and quality of life. The computational models were used to predict the impact on small airway narrowing of type-2 targeting biologics using pooled data from two similarly design randomized, placebo-controlled biologic trials ( n  = 137). Measurements and Main Results: Simulations demonstrated that narrowing of the small airways had a greater impact on R5 - R20 than narrowing of the larger airways and was associated (above a threshold of approximately 40% narrowing) with marked deterioration in both asthma control and asthma quality of life, above the minimal clinical important difference. The observed treatment effect on R5 - R20 in the pooled trials equated to a predicted small airway narrowing reversal of approximately 40%. Conclusions: We have demonstrated, using computational modeling, that forced oscillation R5 - R20 is a direct measure of anatomical narrowing in the small airways and that small airway narrowing has a marked impact on both asthma control and quality of life and may be modified by biologics.

Asthma exacerbations are a common reason for hospital admission. We sought to identify whether patterns of inhaler prescribing are significantly associated with regional asthma admission rates. Asthma admission rates were obtained for English Clinical Commissioning Group (CCG) regions from 2013/2014 to 2016/2017. Raw prescribing data were obtained from OpenPrescribing.net, based on monthly general practice-level data published by the National Health Service Business Services Authority. Data were analysed using a linear mixed effects model. The ratio of salbutamol to inhaled corticosteroid prescriptions within a CCG was positively associated with asthma admission rates, independently of median age, asthma prevalence and socioeconomic deprivation., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2019. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Asthma is a disease characterized by ventilation heterogeneity (VH). A number of studies have demonstrated that VH markers derived by using impulse oscillometry (IOS) or multiple-breath washout (MBW) are associated with key asthmatic patient-related outcome measures and airways hyperresponsiveness. However, the topographical mechanisms of VH in the lung remain poorly understood., Objectives: We hypothesized that specific regionalization of topographical small-airway disease would best account for IOS- and MBW-measured indices in patients., Methods: We evaluated the results of paired expiratory/inspiratory computed tomography in a cohort of asthmatic (n = 41) and healthy (n = 11) volunteers to understand the determinants of clinical VH indices commonly reported by using IOS and MBW. Parametric response mapping (PRM) was used to calculate the functional small-airways disease marker PRM fSAD and Hounsfield unit (HU)-based density changes from total lung capacity to functional residual capacity (ΔHU); gradients of ΔHU in gravitationally perpendicular (parallel) inferior-superior (anterior-posterior) axes were quantified., Results: The ΔHU gradient in the inferior-superior axis provided the highest level of discrimination of both acinar VH (measured by using phase 3 slope analysis of multiple-breath washout data) and resistance at 5 Hz minus resistance at 20 Hz measured by using impulse oscillometry (R5-R20) values. Patients with a high inferior-superior ΔHU gradient demonstrated evidence of reduced specific ventilation in the lower lobes of the lungs and high levels of PRM fSAD . A computational small-airway tree model confirmed that constriction of gravitationally dependent, lower-zone, small-airway branches would promote the largest increases in R5-R20 values. Ventilation gradients correlated with asthma control and quality of life but not with exacerbation frequency., Conclusions: Lower lobe-predominant small-airways disease is a major driver of clinically measured VH in adults with asthma., (Copyright © 2019 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.)

The use of commercialised forced oscillation (FOT) devices to assess impedance in obstructive diseases such as asthma has gained popularity. However, it has yet to be fully established whether resistance and reactance measurements are comparable across different FOT devices, particularly in disease. We compared two commercially available FOT devices: Impulse Oscillometry (IOS) and TremoFlo FOT (Thorasys) in a) clinical adult population of healthy controls (n = 14), asymptomatic smokers (n = 17) and individuals with asthma (n = 73) and b) a 3D printed CT-derived airway tree model resistance, as well as a 3 L standardised volume reactance. Bland-Altman Plots and linear regressions were used to evaluate bias between the devices. Resistance measurements at both 5 and 20 Hz were numerically higher with IOS compared to FOT, with evidence of small and statistically significant proportional systematic bias and a positive Bland-Altman regression slope at both 5 and 20 Hz. In contrast, the IOS device recorded reactances that were less negative at both 5 Hz and 20 Hz and significantly smaller reactance areas when compared to TremoFlo. Larger statistically significant proportional systematic biases were demonstrated with both reactance at 5 Hz and reactance area (AX) between the devices with a negative Bland-Altman regression slope. The printed airway resistance and standardised volume reactance confirmed the observations seen in patients. We have demonstrated that the impulse oscillation system and TremoFlo FOT demonstrate comparative bias, particularly when comparing airway reactance in patients. Our results highlight the need for further standardisation across FOT measurement devices, specifically using variable test loads for reactance standardisation.

Background: Asthma is a complex chronic disease underpinned by pathological changes within the airway wall. How variations in structural airway pathology and cellular inflammation contribute to the expression and severity of asthma are poorly understood., Objectives: Therefore we evaluated pathological heterogeneity using topological data analysis (TDA) with the aim of visualizing disease clusters and microclusters., Methods: A discovery population of 202 adult patients (142 asthmatic patients and 60 healthy subjects) and an external replication population (59 patients with severe asthma) were evaluated. Pathology and gene expression were examined in bronchial biopsy samples. TDA was applied by using pathological variables alone to create pathology-driven visual networks., Results: In the discovery cohort TDA identified 4 groups/networks with multiple microclusters/regions of interest that were masked by group-level statistics. Specifically, TDA group 1 consisted of a high proportion of healthy subjects, with a microcluster representing a topological continuum connecting healthy subjects to patients with mild-to-moderate asthma. Three additional TDA groups with moderate-to-severe asthma (Airway Smooth Muscle High , Reticular Basement Membrane High , and Remodeling Low groups) were identified and contained numerous microclusters with varying pathological and clinical features. Mutually exclusive T H 2 and T H 17 tissue gene expression signatures were identified in all pathological groups. Discovery and external replication applied to the severe asthma subgroup identified only highly similar "pathological data shapes" through analyses of persistent homology., Conclusions: We have identified and replicated novel pathological phenotypes of asthma using TDA. Our methodology is applicable to other complex chronic diseases., (Crown Copyright © 2018. Published by Elsevier Inc. All rights reserved.)

The Royal College of Physicians three questions (RCP3Q) is widely used for assessing asthma control within primary care in the UK, despite limited evidence in children. This study compared the RCP3Q as a tool for assessing asthma control in children (5-16 years) against the validated Asthma Control Test (ACT), Childhood Asthma Control Test (C-ACT), and Mini-Paediatric Quality of Life Questionnaire (MiniPAQLQ). We conducted a prospective observational cohort study involving children from eight primary care practices in Leicestershire. Children with doctor diagnosed asthma, or receiving regular asthma medication, were invited to participate. A total of 319 participants completed the MiniPAQLQ and the C-ACT/ACT questionnaires, before RCP3Q responses were collected as part of their routine asthma review conducted immediately afterwards. RCP3Q sensitivity for detecting uncontrolled asthma ranged from 43-60% and specificity from 80-82%. Using an RCP3Q score ≥2 to predict uncontrolled asthma and an RCP3Q score of zero to predict well-controlled asthma resulted in 10% of participants misclassified as uncontrolled and 8% as well-controlled, respectively. Using an RCP3Q threshold score of ≥1 resulted in 25% of participants being misclassified as uncontrolled. Our data suggests limited utility of the RCP3Q to assess asthma control in children. Alternative indicators of asthma control, such as the validated Asthma Control Test and the Children's Asthma Control Test should be considered instead.

Rationale: Asthma is often characterised by inflammation, damage and dysfunction of the small airways, but no standardised biomarkers are available., Objectives: Using a novel approach-particles in exhaled air (PExA)-we sought to (a) sample and analyse abundant protein biomarkers: surfactant protein A (SPA) and albumin in adult asthmatic and healthy patients and (b) relate protein concentrations with physiological markers using phenotyping., Methods: 83 adult asthmatics and 21 healthy volunteers were recruited from a discovery cohort in Leicester, UK, and 32 adult asthmatics as replication cohort from Sweden. Markers of airways closure/small airways dysfunction were evaluated using forced vital capacity, impulse oscillometry and multiple breath washout. SPA/albumin from PEx (PExA sample) were analysed using ELISA and corrected for acquired particle mass. Topological data analysis (TDA) was applied to small airway physiology and PExA protein data to identify phenotypes., Results: PExA manoeuvres were feasible, including severe asthmatic subjects. TDA identified a clinically important phenotype of asthmatic patients with multiple physiological markers of peripheral airway dysfunction, and significantly lower levels of both SPA and albumin., Conclusion: We report that the PExA method is feasible across the spectrum of asthma severity and could be used to identify small airway disease phenotypes.

Patients with asthma and chronic obstructive pulmonary disease (COPD) are susceptible to exacerbations, often caused by microbial pathogens. We hypothesised that intracellular Toll-like receptor (TLR) function in blood mononuclear cells (PBMCs) from these subjects would be impaired and that this impairment is related to exacerbation frequency. PBMCs stimulated with a TLR-9 agonist (but not TLR-3 or 7/8) produced significantly less IFN-α in asthma (26 [3-696]pg/ml) compared to control (943 [164-1651]) and COPD (597 [127-1186]) subjects (p = 0.0019) but this was not related to the number of exacerbations per year in asthma or COPD. In COPD, IFN-α levels were related to KCO (% predicted) in COPD (r = -0.41, p = 0.01). IFN-α was derived from plasmacytoid dendritic cells (pDCs) and their frequency was lower in asthma compared to control subjects (control 0.48% [0.33-0.64] versus asthma 0.29% [0.13-0.34], p = 0.019) whereas pDC function per se was not significantly impaired between groups. The mechanism underlying reduced IFN-α production and the clinical consequences in severe asthma remains to be established., (Copyright © 2015 Elsevier GmbH. All rights reserved.)

Background: The effects of inhaled corticosteroids (ICS) on healthy airways are poorly defined. Objectives: To delineate the effects of ICS on gene expression in healthy airways, without confounding caused by changes in disease‐related genes and disease‐related alterations in ICS responsiveness. Methods: Randomized open‐label bronchoscopy study of high‐dose ICS therapy in 30 healthy adult volunteers randomized 2:1 to (i) fluticasone propionate 500 mcg bd daily or (ii) no treatment, for 4 weeks. Laboratory staff were blinded to allocation. Biopsies and brushings were analysed by immunohistochemistry, bulk RNA sequencing, DNA methylation array and metagenomics. Results: ICS induced small between‐group differences in blood and lamina propria eosinophil numbers, but not in other immunopathological features, blood neutrophils, FeNO, FEV1, microbiome or DNA methylation. ICS treatment upregulated 72 genes in brushings and 53 genes in biopsies, and downregulated 82 genes in brushings and 416 genes in biopsies. The most downregulated genes in both tissues were canonical markers of type‐2 inflammation (FCER1A, CPA3, IL33, CLEC10A, SERPINB10 and CCR5), T cell‐mediated adaptive immunity (TARP, TRBC1, TRBC2, PTPN22, TRAC, CD2, CD8A, HLA‐DQB2, CD96, PTPN7), B‐cell immunity (CD20, immunoglobulin heavy and light chains) and innate immunity, including CD48, Hobit, RANTES, Langerin and GFI1. An IL‐17‐dependent gene signature was not upregulated by ICS. Conclusions: In healthy airways, 4‐week ICS exposure reduces gene expression related to both innate and adaptive immunity, and reduces markers of type‐2 inflammation. This implies that homeostasis in health involves tonic type‐2 signalling in the airway mucosa, which is exquisitely sensitive to ICS. [ABSTRACT FROM AUTHOR]