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Breath tests cover the fraction of nitric oxide in expired gas (), volatile organic compounds (VOCs), variables in exhaled breath condensate (EBC) and other measurements. For EBC and for , official recommendations for standardised procedures are more than 10 years old and there is none for exhaled VOCs and particles. The aim of this document is to provide technical standards and recommendations for sample collection and analytic approaches and to highlight future research priorities in the field. For EBC and, new developments and advances in technology have been evaluated in the current document. This report is not intended to provide clinical guidance on disease diagnosis and management.Clinicians and researchers with expertise in exhaled biomarkers were invited to participate. Published studies regarding methodology of breath tests were selected, discussed and evaluated in a consensus-based manner by the Task Force members.Recommendations for standardisation of sampling, analysing and reporting of data and suggestions for research to cover gaps in the evidence have been created and summarised.Application of breath biomarker measurement in a standardised manner will provide comparable results, thereby facilitating the potential use of these biomarkers in clinical practice.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) disease (COVID-19) pandemic has attracted interest because of its global rapid spread, clinical severity, high mortality rate and capacity to overwhelm healthcare systems [1, 2]. SARS-CoV-2 transmission occurs mainly through droplets, although surface contamination contributes and debate continues on aerosol transmission [3-5]. The disease is usually characterised by initial signs and symptoms [4-9] similar to those of related viral infections (e.g. influenza, SARS, Middle East respiratory syndrome) and tuberculosis (TB), although prognosis and complications sometimes differ. Experience with concomitant TB and COVID-19 is extremely limited. One case-control study of COVID-19 patients with interferon-γ release assay-confirmed TB infection [10] and a single case of TB with COVID-19 have been submitted to, but not yet published in, peer-reviewed journals [11]. In a recent analysis of 1217 consecutive respiratory specimens collected from COVID-19 patients (Mycobacterium tuberculosis was not tested), the authors concluded that higher rates of co-infection between SARS-CoV-2 and other respiratory pathogens can be expected [12]. The present study describes the first-ever global cohort of current or former TB patients (post-TB treatment sequelae) with COVID-19, recruited by the Global Tuberculosis Network (GTN) in eight countries and three continents. No analysis for determinants of outcome was attempted. The study is nested within the GTN project monitoring adverse drug reactions [13, 14] for which the coordinating centre has an ethics committee approval, alongside ethics clearance from participating centres according to respective national regulation [13, 14]. A specific nested database was created in collaboration with the eight countries reporting patients with TB and COVID-19; the remaining countries had not yet observed COVID-19 in their patients at the time this manuscript was written. Continuous variables, if not otherwise specified, are presented as medians with interquartile ranges. Overall, 49 consecutive patients with current or former TB and COVID-19 from 26 centres in Belgium (n=1), Brazil (Porto Alegre, Rio Grande do Sul State; n=1), France (n=12), Italy (n=17), Russia (Moscow Region; n=6), Singapore (n=1), Spain (n=10) and Switzerland (Vaud Canton; n=1) were recruited (dataset updated as of

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In asthma, the acute increment of airway responsiveness caused by exposure to allergen is associated with influx of eosinophils into the airways. The relationship between chronic airway hyperresponsiveness and airway inflammation is unclear, as they do not change consistently following long-term anti-inflammatory treatments. We studied 71 patients with chronic asthma and allergic sensitization to perennial allergens. Airway responsiveness was determined by inhalation of methacholine, and airway inflammation was quantified by induced sputum (n = 28) or bronchoalveolar lavage (n = 43) and bronchial biopsy (n = 20). The relationships between airway responsiveness and the numbers of different inflammatory cells were assessed by multiple regression analysis. No significant correlations were found between the degree of airway responsiveness and the numbers of inflammatory cells in sputum or bronchoalveolar lavage or bronchial biopsy. By contrast, baseline lung function was inversely related to the numbers of eosinophils and directly related to the numbers of macrophages. The eosinophil cationic protein contents of either sputum or bronchoalveolar lavage were significantly correlated with the percentages of eosinophils but not with airway responsiveness. We suggest that other factors (e.g., airway wall remodeling or autonomic dysfunction) may be responsible for most of the interindividual variability of airway responsiveness in asthma.

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Linezolid is used off-label to treat multidrug-resistant tuberculosis (MDR-TB) in absence of systematic evidence. We performed a systematic review and meta-analysis on efficacy, safety and tolerability of linezolid-containing regimes based on individual data analysis.12 studies (11 countries from three continents) reporting complete information on safety, tolerability, efficacy of linezolid-containing regimes in treating MDR-TB cases were identified based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Metaanalysis was performed using the individual data of 121 patients with a definite treatment outcome (cure, completion, death or failure).Most MDR-TB cases achieved sputum smear (86 (92.5%) out of 93) and culture (100 (93.5%) out of 107) conversion after treatment with individualised regimens containing linezolid (median (inter-quartile range) times for smear and culture conversions were 43.5 (21-90) and 61 (29-119) days, respectively) and 99 (81.8%) out of 121 patients were successfully treated. No significant differences were detected in the subgroup efficacy analysis (daily linezolid dosage f600 mg versus .600 mg). Adverse events were observed in 63 (58.9%) out of 107 patients, of which 54 (68.4%) out of 79 were major adverse events that included anaemia (38.1%), peripheral neuropathy (47.1%), gastro-intestinal disorders (16.7%), optic neuritis (13.2%) and thrombocytopenia (11.8%). The proportion of adverse events was significantly higher when the linezolid daily dosage exceeded 600 mg.The study results suggest an excellent efficacy but also the necessity of caution in the prescription of linezolid.

Chronic respiratory patients requiring oxygen or home mechanical ventilation experience frequent exacerbations and hospitalisations with related costs. Strict monitoring and care have been recommended. The aim of the present study was to primarily evaluate reduction in hospitalisations and, secondly, exacerbations, general practitioner (GP) calls and related costeffectiveness of tele-assistance (TA) for these patients.A total of 240 patients (101 with chronic obstructive pulmonary disease (COPD)) were randomised to two groups: an intervention group entered a 1-yr TA programme while controls received traditional care.No anthropometric and clinical differences were found between groups both in baseline and in mortality (18% for TA, 23% for controls). Compared with controls, the TA group experienced significantly fewer hospitalisations (-36%), urgent GP calls (-65%) and acute exacerbations (-71%). Only COPD patients, as a separate group, had fewer hospitalisations, emergency room admissions, urgent GP calls or exacerbations. Each patient referred to staff a mean¡SD 36¡25 times. After deduction of TA costs, the average overall cost for each patient was 33% less than that for usual care.In chronic respiratory failure patients on oxygen or home mechanical ventilation, a nursecentred tele-assistance prevents hospitalisations while it is cost-effective. The chronic obstructive pulmonary disease group seems to have a greater advantage from tele-assistance.