Induction of IL-10-producing type 2 innate lymphoid cells by allergen immunotherapy is associated with clinical response.

The role of innate immune cells in allergen immunotherapy that confers immune tolerance to the sensitizing allergen is unclear. Here, we report a role of interleukin-10-producing type 2 innate lymphoid cells (IL-10+ ILC2s) in modulating grass-pollen allergy. We demonstrate that KLRG1+ but not KLRG1- ILC2 produced IL-10 upon activation with IL-33 and retinoic acid. These cells attenuated Th responses and maintained epithelial cell integrity. IL-10+ KLRG1+ ILC2s were lower in patients with grass-pollen allergy when compared to healthy subjects. In a prospective, double-blind, placebo-controlled trial, we demonstrated that the competence of ILC2 to produce IL-10 was restored in patients who received grass-pollen sublingual immunotherapy. The underpinning mechanisms were associated with the modification of retinol metabolic pathway, cytokine-cytokine receptor interaction, and JAK-STAT signaling pathways in the ILCs. Altogether, our findings underscore the contribution of IL-10+ ILC2s in the disease-modifying effect by allergen immunotherapy.

Persistence of parental-reported asthma at early ages: A longitudinal twin study.

BACKGROUND: Currently, we cannot predict whether a pre-school child with asthma-like symptoms will have asthma at school age. Whether genetic information can help in this prediction depends on the role of genetic factors in persistence of pre-school to school-age asthma. We examined to what extent genetic and environmental factors contribute to persistence of asthma-like symptoms at ages 3 to asthma at age 7 using a bivariate genetic model for longitudinal twin data. METHODS: We performed a cohort study in monozygotic and dizygotic twins from the Netherlands Twin Register (NTR, n = 21,541 twin pairs). Bivariate genetic models were fitted to longitudinal data on asthma-like symptoms reported by parents at age 3 and 7 years to estimate the contribution of genetic and environmental factors. RESULTS: Bivariate genetic modeling showed a correlation on the liability scale between asthma-like symptoms at age 3 and asthma at age 7 of 0.746 and the contribution of genetics was estimated to be 0.917. The genetic analyses indicated a substantial influence of genetic factors on asthma-like symptoms at ages 3 and 7 (heritability 80% and 90%, respectively); hence, contribution of environmental factors was low. Persistence was explained by a high (rg = 0.807) genetic correlation. CONCLUSION: Parental-reported asthma-like symptoms at age 3 and asthma at age 7 are highly heritably. The phenotype of asthma-like symptoms at age 3 and 7 was highly correlated and mainly due to heritable factors, indicating high persistence of asthma development over ages 3 and 7.

Exhaled breath analysis by use of eNose technology: a novel diagnostic tool for interstitial lung disease.

INTRODUCTION: Early and accurate diagnosis of interstitial lung diseases (ILDs) remains a major challenge. Better noninvasive diagnostic tools are much needed. We aimed to assess the accuracy of exhaled breath analysis using eNose technology to discriminate between ILD patients and healthy controls, and to distinguish ILD subgroups. METHODS: In this cross-sectional study, exhaled breath of consecutive ILD patients and healthy controls was analysed using eNose technology (SpiroNose). Statistical analyses were done using partial least square discriminant analysis and receiver operating characteristic analysis. Independent training and validation sets (2:1) were used in larger subgroups. RESULTS: A total of 322 ILD patients and 48 healthy controls were included: sarcoidosis (n=141), idiopathic pulmonary fibrosis (IPF) (n=85), connective tissue disease-associated ILD (n=33), chronic hypersensitivity pneumonitis (n=25), idiopathic nonspecific interstitial pneumonia (n=10), interstitial pneumonia with autoimmune features (n=11) and other ILDs (n=17). eNose sensors discriminated between ILD and healthy controls, with an area under the curve (AUC) of 1.00 in the training and validation sets. Comparison of patients with IPF and patients with other ILDs yielded an AUC of 0.91 (95% CI 0.85-0.96) in the training set and an AUC of 0.87 (95% CI 0.77-0.96) in the validation set. The eNose reliably distinguished between individual diseases, with AUC values ranging from 0.85 to 0.99. CONCLUSIONS: eNose technology can completely distinguish ILD patients from healthy controls and can accurately discriminate between different ILD subgroups. Hence, exhaled breath analysis using eNose technology could be a novel biomarker in ILD, enabling timely diagnosis in the future.

Quantitative Method for the Analysis of Ivacaftor, Hydroxymethyl Ivacaftor, Ivacaftor Carboxylate, Lumacaftor, and Tezacaftor in Plasma and Sputum Using Liquid Chromatography With Tandem Mass Spectrometry and Its Clinical Applicability.

BACKGROUND: The novel cystic fibrosis transmembrane conductance regulator (CFTR) modulators, ivacaftor, lumacaftor, and tezacaftor, are the first drugs directly targeting the underlying pathophysiological mechanism in cystic fibrosis (CF); however, independent studies describing their pharmacokinetics are lacking. The aim of this study was to develop a quantification method for ivacaftor and its 2 main metabolites, lumacaftor and tezacaftor, in plasma and sputum using liquid chromatography with tandem mass spectrometry. METHODS: The developed method used a small sample volume (20 µL) and simple pretreatment method; protein precipitation solution and internal standard were added in one step to each sample. Liquid chromatography with tandem mass spectrometry was performed for a total run time of 6 minutes. The method was validated by assessing selectivity, carryover, linearity, accuracy and precision, dilution, matrix effects, and stability. RESULTS: The selectivity was good as no interference from matrices was observed. In the concentration range from 0.01 to 10.0 mg/L, calibration curves were linear with a correlation coefficient >0.9997 for all compounds. The within-run and between-run accuracy were between 99.7% and 116% at the lower limit of quantitation (LLOQ) and between 95.8% and 112.9% for all concentrations above LLOQ for all analytes in plasma and sputum. Within-run and between-run precisions were <12.7% for LLOQ and <6.7% for the higher limit of quantitation. Samples were stable, with no significant degradation at examined temperatures and time points. Clinical applicability was revealed by analyzing samples from 2 patients with CF. CONCLUSIONS: The presented method enables simultaneous quantification of ivacaftor, lumacaftor, and tezacaftor in plasma and sputum and is an improvement over previous methods because it uses smaller sample volumes, a simple pretreatment protocol, and includes tezacaftor. In future studies, it can be applied for examining pharmacokinetics characteristics of new CF transmembrane conductance regulator modulators.

Risk of major bleeding among users of direct oral anticoagulants combined with interacting drugs: A population-based nested case-control study.

AIMS: To assess the association between concurrent use of potential pharmacokinetic or pharmacodynamic interacting drugs and major bleeding among direct oral anticoagulant (DOAC) users. METHODS: We performed a case-control study nested in a cohort of new users of DOACs (dabigatran etexilate, apixaban or rivaroxaban). Data were obtained from the UK Clinical Practice Research Datalink linked to Hospital Episode Statistics (2008-2015). Cases were patients hospitalized having a primary diagnosis of major bleeding. Up to 4 controls were matched on age, sex, index date and region. Odds ratios (ORs) for the risk of major bleeding were assessed by conditional logistic regression analysis and adjusted for well-known covariates for the risk of bleeding. RESULTS: We identified 393 patients with a major bleeding from a total of 23 492 new users of DOACs and 1494 matched controls. Most subjects were users of rivaroxaban (58.8%) on the index date. The concurrent use of pharmacodynamic interacting drugs was associated with an increased risk of major bleeding (21.6% of cases vs 13.5% of controls, adjusted odds ratio [aOR] 1.92; 95% confidence interval [CI], 1.40-2.66). For the antiplatelet drugs the aOR was 2.01 (95% CI, 1.29-3.11) and for the selective serotonin reuptake inhibitors the aOR was 1.68 (95% CI, 1.10-2.59). We found no increased risk of major bleeding for concurrent use of pharmacokinetic interacting drugs vs DOACs alone (45.0 vs 51.2%; aOR: 0.77; 95% CI: 0.53-1.10). CONCLUSION: Among patients taking DOACs the concurrent use of antiplatelet drugs or selective serotonin reuptake inhibitors was associated with increased risk of major bleeding, while pharmacokinetic interacting drugs do not increase this risk.

Bronchiectasis in Severe Asthma: Does It Make a Difference?

BACKGROUND: Asthma and bronchiectasis are 2 heterogeneous diseases that frequently coexist, particularly in severe asthma. Recognition of this co-diagnosis may importantly affect treatment decisions and outcome. Previous studies in asthma with bronchiectasis show inconsistent outcomes, probably due to the heterogeneity of the included asthma cohorts. OBJECTIVES: We hypothesized that bronchiectasis contributes to asthma severity and that patients with severe asthma and bronchiectasis present with distinct characteristics resulting in different treatable traits. In addition, we explored whether bronchiectasis in severe asthma is more common in a specific phenotype. METHODS: This is a single-center study consecutively including patients with severe asthma from a tertiary referral center. Severe asthma was diagnosed according to the ATS/ERS guidelines. Asthma and infectious exacerbations were defined by the attending specialist as respiratory symptoms requiring treatment with systemic steroids or antibiotics, respectively. Two independent blinded radiologists evaluated each CT. RESULTS: 19% of patients with severe asthma showed bronchiectasis on CT. Patients with bronchiectasis had a lower FEV1% predicted (p = 0.02) and FEV1/FVC (p = 0.004) and more infectious exacerbations (p = 0.003) compared to patients without bronchiectasis. Bronchiectasis is more common in patients with a longer duration of asthma, sensitization to A. fumigatus or a positive sputum culture. Sputum cultures of patients with severe asthma and bronchiectasis revealed more P. aeruginosa, S. maltophilia, H. parainfluenzae, and A. fumigates compared to the non-bronchiectasis group. The adult-onset, eosinophilic asthma phenotype showed the highest prevalence of bronchiectasis (29.4%). CONCLUSIONS: Patients with severe asthma and coexisting bronchiectasis were found to represent a distinct group, in terms of disease severity, microbiology, and asthma phenotype. Performing (HR)CT and sputum cultures can help to identify these patients. These results can possibly contribute to early recognition and targeted treatment of this patient group.

Identification and prospective stability of electronic nose (eNose)-derived inflammatory phenotypes in patients with severe asthma.

BACKGROUND: Severe asthma is a heterogeneous condition, as shown by independent cluster analyses based on demographic, clinical, and inflammatory characteristics. A next step is to identify molecularly driven phenotypes using "omics" technologies. Molecular fingerprints of exhaled breath are associated with inflammation and can qualify as noninvasive assessment of severe asthma phenotypes. OBJECTIVES: We aimed (1) to identify severe asthma phenotypes using exhaled metabolomic fingerprints obtained from a composite of electronic noses (eNoses) and (2) to assess the stability of eNose-derived phenotypes in relation to within-patient clinical and inflammatory changes. METHODS: In this longitudinal multicenter study exhaled breath samples were taken from an unselected subset of adults with severe asthma from the U-BIOPRED cohort. Exhaled metabolites were analyzed centrally by using an assembly of eNoses. Unsupervised Ward clustering enhanced by similarity profile analysis together with K-means clustering was performed. For internal validation, partitioning around medoids and topological data analysis were applied. Samples at 12 to 18 months of prospective follow-up were used to assess longitudinal within-patient stability. RESULTS: Data were available for 78 subjects (age, 55 years [interquartile range, 45-64 years]; 41% male). Three eNose-driven clusters (n = 26/33/19) were revealed, showing differences in circulating eosinophil (P = .045) and neutrophil (P = .017) percentages and ratios of patients using oral corticosteroids (P = .035). Longitudinal within-patient cluster stability was associated with changes in sputum eosinophil percentages (P = .045). CONCLUSIONS: We have identified and followed up exhaled molecular phenotypes of severe asthma, which were associated with changing inflammatory profile and oral steroid use. This suggests that breath analysis can contribute to the management of severe asthma.

Clinical and inflammatory phenotyping by breathomics in chronic airway diseases irrespective of the diagnostic label.

Asthma and chronic obstructive pulmonary disease (COPD) are complex and overlapping diseases that include inflammatory phenotypes. Novel anti-eosinophilic/anti-neutrophilic strategies demand rapid inflammatory phenotyping, which might be accessible from exhaled breath.Our objective was to capture clinical/inflammatory phenotypes in patients with chronic airway disease using an electronic nose (eNose) in a training and validation set.This was a multicentre cross-sectional study in which exhaled breath from asthma and COPD patients (n=435; training n=321 and validation n=114) was analysed using eNose technology. Data analysis involved signal processing and statistics based on principal component analysis followed by unsupervised cluster analysis and supervised linear regression.Clustering based on eNose resulted in five significant combined asthma and COPD clusters that differed regarding ethnicity (p=0.01), systemic eosinophilia (p=0.02) and neutrophilia (p=0.03), body mass index (p=0.04), exhaled nitric oxide fraction (p<0.01), atopy (p<0.01) and exacerbation rate (p<0.01). Significant regression models were found for the prediction of eosinophilic (R2=0.581) and neutrophilic (R2=0.409) blood counts based on eNose. Similar clusters and regression results were obtained in the validation set.Phenotyping a combined sample of asthma and COPD patients using eNose provides validated clusters that are not determined by diagnosis, but rather by clinical/inflammatory characteristics. eNose identified systemic neutrophilia and/or eosinophilia in a dose-dependent manner.

The association between a genetic risk score for allergy and the risk of developing allergies in childhood-Results of the WHISTLER cohort.

BACKGROUND: Several genetic variants have been associated with the susceptibility to allergic disease in adults, but it remains unclear whether these genetic variants are also associated with the onset of allergic disease early in life. The aim of this study was to develop a genetic risk score (GRS) for allergy based on findings in adults and study its predictive capacity for allergy in children. METHODS: A GRS was constructed based on 10 SNPs previously associated with allergies in adults. The GRS was tested in children who participated in a population-based newborn cohort (WHISTLER) and were followed from birth to school age. Logistic regression analysis was used to study the association between the GRS and the parental-reported allergies at age 5 (based on a reported allergy to ≥1 of the following allergens: pollen, house dust mites, or pets). A Cox regression model was used to study the association between GRS and a physician-diagnosed allergy during follow-up (allergic conjunctivitis, allergic rhinitis, and eczema/dermatitis). Cohen's kappa coefficient was calculated to study the agreement between physician-diagnosed allergy and parental-reported allergy at age 5. RESULTS: The GRS was significantly associated with parental-reported allergy (odds ratio: 15.9, 95% confidence interval (CI): 1.07-233.73) at age 5, as well as with a physician-diagnosed allergy during follow-up (hazard ratio: 1.89, 95% CI: 1.05-3.41). The overall agreement between physician-diagnosed and parental-reported allergies was 70.5% (kappa: 0.10, 95% CI: 0.03-0.18). CONCLUSIONS: An adult-derived GRS for allergy predicts the risk of developing allergies in childhood.

Blood eosinophilia, use of inhaled corticosteroids, and risk of COPD exacerbations and mortality.

PURPOSE: It remains unclear whether eosinophilia is useful for in guiding inhaled corticosteroid (ICS) therapy in chronic obstructive pulmonary disease (COPD) patients. The goal of this study is to evaluate the risk of acute exacerbations, COPD-related hospitalisations/accident and emergency visits, and all-cause mortality with various levels of eosinophil counts among COPD patients using ICS. METHODS: A cohort study was conducted using the UK Clinical Practice Research Datalink. Patients were aged 40+ and had COPD (n = 32 693). Current users of ICS were stratified by relative and absolute eosinophil counts to determine the risk of outcomes with blood eosiniphilia using Cox regression analysis. RESULTS: Among COPD patients, current use of ICS was not associated with a reduced risk of acute COPD exacerbations, COPD-related hospitalisations/accident and emergency visits, and all-cause mortality. Stratification of ICS use by absolute or relative eosinophil counts did not result in significant differences in risk of COPD exacerbations or hospitalisations/accident and emergency visits. However, all-cause mortality was reduced by 12% to 24% among patients with eosinophilia. CONCLUSIONS: COPD-related acute exacerbations or hospitalisations/accident and emergency visits were not reduced with eosinophilia among users of ICS with COPD. However, all-cause mortality was reduced by 12% to 24%. These findings are potentially important and require further evaluation in prospective studies.

A common missense variant of LILRB5 is associated with statin intolerance and myalgia.

Aims: A genetic variant in LILRB5 (leukocyte immunoglobulin-like receptor subfamily-B) (rs12975366: T > C: Asp247Gly) has been reported to be associated with lower creatine phosphokinase (CK) and lactate dehydrogenase (LDH) levels. Both biomarkers are released from injured muscle tissue, making this variant a potential candidate for susceptibility to muscle-related symptoms. We examined the association of this variant with statin intolerance ascertained from electronic medical records in the GoDARTS study. Methods and results: In the GoDARTS cohort, the LILRB5 Asp247 variant was associated with statin intolerance (SI) phenotypes; one defined as having raised CK and being non-adherent to therapy [odds ratio (OR) 1.81; 95% confidence interval (CI): 1.34-2.45] and the other as being intolerant to the lowest approved dose of a statin before being switched to two or more other statins (OR 1.36; 95% CI: 1.07-1.73). Those homozygous for Asp247 had increased odds of developing both definitions of intolerance. Importantly the second definition did not rely on CK elevations. These results were replicated in adjudicated cases of statin-induced myopathy in the PREDICTION-ADR consortium (OR1.48; 95% CI: 1.05-2.10) and for the development of myalgia in the JUPITER randomized clinical trial of rosuvastatin (OR1.35, 95% CI: 1.10-1.68). A meta-analysis across the studies showed a consistent association between Asp247Gly and outcomes associated with SI (OR1.34; 95% CI: 1.16-1.54). Conclusion: This study presents a novel immunogenetic factor associated with statin intolerance, an important risk factor for cardiovascular outcomes. The results suggest that true statin-induced myalgia and non-specific myalgia are distinct, with a potential role for the immune system in their development. We identify a genetic group that is more likely to be intolerant to their statins.

Determinants of angiotensin-converting enzyme inhibitor (ACEI) intolerance and angioedema in the UK Clinical Practice Research Datalink.

AIM: The aim of the present study was to describe the occurrence and determinants of angiotensin-converting enzyme (ACE) inhibitor (ACEI) intolerance and angioedema (AE) among patients initiating ACEI therapy in a real-world primary care population. METHODS: Two nested case-control studies were conducted in a cohort of 276 977 patients aged ≥45 years initiating ACEIs from 2007 to 2014 in the UK Clinical Practice Research Datalink (CPRD). Cases of AE occurring for the first time during ACEI therapy (n = 416) were matched with AE-free controls (n = 4335) on the duration of ACEI treatment. Documented switches to angiotensin-II receptor blockers in the prescription records were used to identify ACEI-intolerance cases (n = 24 709), and these were matched with continuous ACEI users (n = 84 238) on the duration of ACEI therapy. Conditional logistic regression was used to assess the associations of demographic factors, comorbidities and comedication with AE and ACEI intolerance. RESULTS: AE during ACEI therapy was associated with age over 65 years [odds ratio (OR) 1.36, 95% confidence interval (CI) 1.07, 1.73], history of allergy (OR 1.53, 95% CI 1.19, 1.96), use of calcium channel blockers (OR 1.57, 95% CI 1.23; 2.01), use of antihistamines (OR 21.25, 95% CI 16.44, 27.46) and use of systemic corticosteroids (OR 4.52, 95% CI 3.26, 6.27). ACEI intolerance was significantly associated with more comorbidities and comedication compared with AE, including allergy (OR 2.02, 95% CI 1.96, 2.09), use of antiasthmatic drugs (OR 1.51, 95% CI 1.42, 1.61) and use of antihistamines (OR 1.53, 95% CI 1.43, 1.63). CONCLUSIONS: Among ACEI users developing AE or ACEI intolerance, several comorbidities and comedication classes were significantly more prevalent compared with ACEI users not developing these adverse reactions.

The SLCO1B1 c.521T>C polymorphism is associated with dose decrease or switching during statin therapy in the Rotterdam Study.

OBJECTIVE: The SLCO1B1 c.521T>C polymorphism is associated with statin plasma levels and simvastatin-induced adverse drug reactions. We studied whether the c.521T>C polymorphism is associated with dose decreases or switches to other cholesterol-lowering drugs during simvastatin and atorvastatin therapy, because these events are indicators of adverse drug reactions. MATERIALS AND METHODS: We identified 1939 incident simvastatin and atorvastatin users in the Rotterdam Study, a population-based cohort study. Associations were studied using Cox proportional hazards analysis. Meta-analysis was performed with data from the Utrecht Cardiovascular Pharmacogenetics study. RESULTS: Simvastatin users with the c.521 CC genotype had a significantly higher risk of a dose decrease or switch than users with the TT genotype [hazard ratio (HR) 1.74, 95% confidence interval (CI) 1.05-2.88]. Female sex, age below 70 years, and low starting dose were risk factors. In atorvastatin users with starting dose of more than 20 mg, the risk of a dose decrease or switch was higher in users carrying a C allele than in users with the TT genotype (HR 3.26, 95% CI 1.47-7.25). In the meta-analysis the association in simvastatin users remained, with a significantly higher risk of a dose decrease or switch in simvastatin users with two minor alleles (HR 1.69, 95% CI 1.05-2.73). For atorvastatin users no significant association was found. CONCLUSION: In simvastatin users in the Rotterdam Study, we demonstrated an association between the c.521T>C polymorphism and dose decrease or switching, as indicators of adverse drug reactions, and provided risk factors for this association. For atorvastatin, an association was found in users with a starting dose of more than 20 mg.

Pharmacogenetic-guided dosing of coumarin anticoagulants: algorithms for warfarin, acenocoumarol and phenprocoumon.

Coumarin derivatives, such as warfarin, acenocoumarol and phenprocoumon are frequently prescribed oral anticoagulants to treat and prevent thromboembolism. Because there is a large inter-individual and intra-individual variability in dose-response and a small therapeutic window, treatment with coumarin derivatives is challenging. Certain polymorphisms in CYP2C9 and VKORC1 are associated with lower dose requirements and a higher risk of bleeding. In this review we describe the use of different coumarin derivatives, pharmacokinetic characteristics of these drugs and differences amongst the coumarins. We also describe the current clinical challenges and the role of pharmacogenetic factors. These genetic factors are used to develop dosing algorithms and can be used to predict the right coumarin dose. The effectiveness of this new dosing strategy is currently being investigated in clinical trials.

Beliefs about medicines in Dutch acenocoumarol and phenprocoumon users.

AIMS: Adherence to the generally complex regimen of coumarin derivatives is vital in order to keep patients in the adequate International Normalized Ratio range. Patients' beliefs about medicines are associated with the level of therapy adherence. Our first aim was to assess beliefs about coumarins. Secondly, we compared the beliefs about coumarins with the beliefs about other cardiovascular drugs. METHODS: The Beliefs about Medicines Questionnaire was used to assess medication beliefs. The questionnaire was completed by new users of coumarins indicated for venous thromboembolism or atrial fibrillation. A necessity score and a concerns score were calculated for all patients. The analyses were repeated for users of antihypertensive drugs or statins (not using coumarins). RESULTS: Three hundred and twenty patients were included in the analysis of the beliefs about coumarins. The mean necessity score was 15.3, the concerns score 12.3 and the necessity-concerns differential 3.0. Patients with venous thromboembolism (n = 71) had higher necessity scores than patients with atrial fibrillation (n = 249; 16.8 vs. 14.9, P < 0.001). The mean necessity score in 493 users of other cardiovascular drugs was 16.1, the concerns score 13.5 and the necessity-concerns differential 2.6. The necessity score was higher in chronic cardiovascular drug users (n = 192) than in new users (n = 301; 17.9 vs. 14.9, P < 0.001). CONCLUSIONS: Coumarin users score higher on the necessity scale than on the concerns scale, which is also the case in users of other cardiovascular drugs. Patients with atrial fibrillation have a less positive attitude towards these drugs than patients with venous thromboembolism, and could therefore benefit more from specific attention.

The Non-Invasive Detection of Pulmonary Exacerbations in Disorders of Mucociliary Clearance with Breath Analysis: A Systematic Review.

Background: Disorders of mucociliary clearance, such as cystic fibrosis (CF), primary ciliary dyskinesia (PCD) and bronchiectasis of unknown origin, are characterised by periods with increased respiratory symptoms, referred to as pulmonary exacerbations. These exacerbations are hard to predict and associated with lung function decline and the loss of quality of life. To optimise treatment and preserve lung function, there is a need for non-invasive and reliable methods of detection. Breath analysis might be such a method. Methods: We systematically reviewed the existing literature on breath analysis to detect pulmonary exacerbations in mucociliary clearance disorders. Extracted data included the study design, technique of measurement, definition of an exacerbation, identified compounds and diagnostic accuracy. Results: Out of 244 identified articles, 18 were included in the review. All studies included patients with CF and two also with PCD. Age and the definition of exacerbation differed between the studies. There were five that measured volatile organic compounds (VOCs) in exhaled breath using gas chromatography with mass spectrometry, two using an electronic nose and eleven measured organic compounds in exhaled breath condensate. Most studies showed a significant correlation between pulmonary exacerbations and one or multiple compounds, mainly hydrocarbons and cytokines, but the validation of these results in other studies was lacking. Conclusions: The detection of pulmonary exacerbations by the analysis of compounds in exhaled breath seems possible but is not near clinical application due to major differences in results, study design and the definition of an exacerbation. There is a need for larger studies, with a longitudinal design, international accepted definition of an exacerbation and validation of the results in independent cohorts.

Inflammatory phenotypes underlying uncontrolled childhood asthma despite inhaled corticosteroid treatment: rationale and design of the PACMAN2 study.

BACKGROUND: The diagnosis of childhood asthma covers a broad spectrum of pathological mechanisms that can lead to similarly presenting clinical symptoms, but may nonetheless require different treatment approaches. Distinct underlying inflammatory patterns are thought to influence responsiveness to standard asthma medication. METHODS/DESIGN: The purpose of the PACMAN2 study is to identify inflammatory phenotypes that can discriminate uncontrolled childhood asthma from controlled childhood asthma by measures in peripheral blood and exhaled air. PACMAN2 is a nested, case-control follow-up study to the ongoing pharmacy-based "Pharmacogenetics of Asthma medication in Children: Medication with Anti-inflammatory effects" (PACMAN) study. The original PACMAN cohort consists of children aged 4-12 years with reported use of asthma medication. The PACMAN2 study will be conducted within the larger PACMAN cohort, and will focus on detailed phenotyping of a subset of the PACMAN children. The selected participants will be invited to a follow-up visit in a clinical setting at least six months after their baseline visit based on their adherence to usage of inhaled corticosteroids, their asthma symptoms in the past year, and their age (≥ 8 years). During the follow-up visit, current and long-term asthma symptoms, medication use, environmental factors, medication adherence and levels of exhaled nitric oxide will be reassessed. The following measures will also be examined: pulmonary function, exhaled volatile organic compounds, as well as inflammatory markers in peripheral blood and blood plasma. Comparative analysis and cluster-analyses will be used to identify markers that differentiate children with uncontrolled asthma despite their use of inhaled corticosteroids (ICS) (cases) from children whose asthma is controlled by the use of ICS (controls). DISCUSSION: Asthmatic children with distinct inflammatory phenotypes may respond differently to anti-inflammatory therapy. Therefore, by identifying inflammatory phenotypes in children with the PACMAN2 study, we may greatly impact future personalised treatment strategies, uncover new leads for therapeutic targets and improve the design of future clinical studies in the assessment of the efficacy of novel therapeutics.

Developments in the Management of Severe Asthma in Children and Adolescents: Focus on Dupilumab and Tezepelumab.

Severe asthma in children and adolescents exerts a substantial health, financial, and societal burden. Severe asthma is a heterogeneous condition with multiple clinical phenotypes and underlying inflammatory patterns that might be different in individual patients. Various add-on treatments have been developed to treat severe asthma, including monoclonal antibodies (biologics) targeting inflammatory mediators. Biologics that are currently approved to treat children (≥ 6 years of age) or adolescents (≥ 12 years of age) with severe asthma include: anti-immunoglobulin E (omalizumab), anti-interleukin (IL)-5 (mepolizumab), anti-IL5 receptor (benralizumab), anti-IL4/IL13 receptor (dupilumab), and antithymic stromal lymphopoietin (TSLP) (tezepelumab). However, access to these targeted treatments varies across countries and relies on few and crude indicators. There is a need for better treatment stratification to guide which children might benefit from these treatments. In this narrative review we will assess the most recent developments in the treatment of severe pediatric asthma, as well as potential biomarkers to assess treatment efficacy for this patient population.