Treatable Mechanisms in Asthma

Asthma is a heterogeneous condition, but firm identification of heterogeneity-focused treatments is still lacking. Dividing patients into subgroups of asthma pheno-/endotypes based on combined clinical and cellular biological characteristics and linking them to targeted treatments could be a potentially useful approach to personalize therapy for better outcomes. Nonetheless, there are still many problems related to the identification and validation of asthma phenotypes and endotypes. Alternatively, a precision-medicine strategy for the management of patients with airways disease that is free from the traditional diagnostic labels and based on identifying "treatable traits" in each patient might be preferable. However, it would represent a quite unsophisticated approach because the definition of a treatable trait is too imprecise. In fact, there is still no understanding of the mechanisms underlying treatable traits that allow directing any targeted therapies against any particular treatable trait. Fortunately, in-depth identification of underlying molecular pathways to guide targeted treatment in individual patients is in progress thanks to the improvement in big data management obtained from '-omic' sciences that is greatly increasing knowledge concerning asthma.

Molecular mechanism of asthma and its novel molecular target therapeutic agent

Asthma is a chronic disease with major public health ramifications owing to its high morbidity and mortality rates, especially in severe and recurrent cases. Conventional therapeutic options could partially alleviate the burden of asthma, yet a novel approach is needed to completely control this condition. To do so, a comprehensive understanding of the molecular mechanism underlying asthma is essential to recognize and treat the major pathways that drive its pathophysiology. In this review, we will discuss the molecular mechanism of asthma, in particular focusing on the type of inflammatory responses it elicits, namely type 2 and non-type 2 asthma. Furthermore, we will discuss the novel therapeutic options that target the aberrant molecules found in asthma pathophysiology. We will specifically focus on the role of novel monoclonal antibody therapies recently developed, such as the anti-IgE, IL-5, IL-5Rα, and IL-4Rα antibodies, drugs that have been extensively studied preclinically and clinically.

Choice of biologics in asthma endotypes

PURPOSE OF REVIEW

The aim of this study was to highlight the phenotypes and endotypes of asthma as a tool for selection of the Food and Drug Administration approved biologic therapies.

RECENT FINDINGS

An evolving concept of asthma has led to the identification of distinct phenotypes and endotypes in this disease. Asthma endotypes are defined as the biological mechanism and are often categorized as T2-high and T2-low based on the influence of T helper type 2 (T2) cells and type 2 cytokines, including interleukin (IL)-4, IL-5, IL-9 and IL-13. Biomarkers such as peripheral blood absolute eosinophil count, total IgE, specific IgE and fractional exhaled nitric oxide may be used as indicators of asthma endotypes and help predict response to biologic therapies. There are currently five biologic therapies approved as a treatment option for T2-high asthma: omalizumab, benralizumab, mepolizumab, reslizumab and dupilumab.

SUMMARY

Here, we explore the current understandings of asthma endotypes and review their associated phenotypes. We provide practical and evidence-based guidance for clinicians considering a biologic for asthma add-on maintenance therapy.

Asthma: New Integrative Treatment Strategies for the Next Decades

Asthma is a chronic disease whose main anatomical-functional alterations are grouped into obstruction, nonspecific bronchial hyperreactivity, inflammation and airway remodeling. Currently, the Global Initiative of Asthma 2020 (GINA 2020) suggests classifying it into intermittent cases, slightly persistent, moderately persistent and severely persistent, thus determining the correct guidelines for its therapy. In general, the drugs used for its management are divided into two groups, those with a potential bronchodilator and the controlling agents of inflammation. However, asthmatic treatments continue to evolve, and notable advances have been made possible in biological therapy with monoclonal antibodies and in the relationship between this disease and oxidative stress. This opens a new path to dietary and herbal strategies and the use of antioxidants as a possible therapy that supports conventional pharmacological treatments and reduces their doses and/or adverse effects. This review compiles information from different published research on risk factors, pathophysiology, classification, diagnosis and the main treatments; likewise, it synthesizes the current evidence of herbal medicine for its control. Studies on integrative medicine (IM) therapies for asthmatic control are critically reviewed. An integrative approach to the prevention and management of asthma warrants consideration in clinical practice. The intention is to encourage health professionals and scientists to expand the horizons of basic and clinical research (preclinical, clinical and integrative medicine) on asthma control.

Expression of SARS-CoV-2 receptor ACE2 and coincident host response signature varies by asthma inflammatory phenotype

BACKGROUND

More than 300 million people carry a diagnosis of asthma, with data to suggest that they are at a higher risk for infection or adverse outcomes from severe acute respiratory syndrome coronavirus 2. Asthma is remarkably heterogeneous, and it is currently unclear how patient-intrinsic factors may relate to coronavirus disease 2019.

OBJECTIVE

We sought to identify and characterize subsets of patients with asthma at increased risk for severe acute respiratory syndrome coronavirus 2 infection.

METHODS

Participants from 2 large asthma cohorts were stratified using clinically relevant parameters to identify factors related to angiotensin-converting enzyme-2 (ACE2) expression within bronchial epithelium. ACE-2-correlated gene signatures were used to interrogate publicly available databases to identify upstream signaling events and novel therapeutic targets.

RESULTS

Stratifying by type 2 inflammatory biomarkers, we identified subjects who demonstrated low peripheral blood eosinophils accompanied by increased expression of the severe acute respiratory syndrome coronavirus 2 receptor ACE2 in bronchial epithelium. Genes highly correlated with ACE2 overlapped with type 1 and 2 IFN signatures, normally induced by viral infections. T-cell recruitment and activation within bronchoalveolar lavage cells of ACE2-high subjects was reciprocally increased. These patients demonstrated characteristics corresponding to risk factors for severe coronavirus disease 2019, including male sex, history of hypertension, low peripheral blood, and elevated bronchoalveolar lavage lymphocytes.

CONCLUSIONS

ACE2 expression is linked to upregulation of viral response genes in a subset of type 2-low patients with asthma with characteristics resembling known risk factors for severe coronavirus disease 2019. Therapies targeting the IFN family and T-cell-activating factors may therefore be of benefit in a subset of patients.

Data-driven questionnaire-based cluster analysis of asthma in Swedish adults

The aim of this study was to identify asthma phenotypes through cluster analysis. Cluster analysis was performed using self-reported characteristics from a cohort of 1291 Swedish asthma patients. Disease burden was measured using the Asthma Control Test (ACT), the mini Asthma Quality of Life Questionnaire (mini-AQLQ), exacerbation frequency and asthma severity. Validation was performed in 748 individuals from the same geographical region. Three clusters; early onset predominantly female, adult onset predominantly female and adult onset predominantly male, were identified. Early onset predominantly female asthma had a higher burden of disease, the highest exacerbation frequency and use of inhaled corticosteroids. Adult onset predominantly male asthma had the highest mean score of ACT and mini-AQLQ, the lowest exacerbation frequency and higher proportion of subjects with mild asthma. These clusters, based on information from clinical questionnaire data, might be useful in primary care settings where the access to spirometry and biomarkers is limited.

Role of Impulse Oscillometry in Assessing Asthma Control in Children

BACKGROUND

Impulse oscillometry is an effort-independent technique of assessment of airway resistance and reactance, and can be performed in children unable to complete spirometry.

OBJECTIVE

To evaluate the utility of impulse oscillometry and spirometry for assessing asthma control in children.

STUDY DESIGN

Prospective cohort study.

PARTICIPANTS

Children aged 5-15 years, with mild to severe persistent asthma.

INTERVENTION

On each 3-monthly follow-up visit, clinical assessment, classification of control of asthma, impulse oscillometry and spirometry were performed.

OUTCOME

Utility of impulse oscillometry parameters [impedance (Z5), resistance (R5), reactance (X5) at 5 Hz, and R5-20 (resistance at 20Hz -5Hz) (% predicted), and area of reactance (AX, actual values)] and FEV1 (% predicted) to discriminate between controlled and uncontrolled asthma was assessed by receiver operating characteristic (ROC) curve. Association of FEV1 and impulse oscillometry parameters over time with controlled asthma was evaluated by generalized estimating equation model.

RESULTS

Number of visits in 256 children [mean (SD) age, 100 (41.6) mo; boys: 198 (77.3%)], where both impulse oscillometry and spirometry were performed was 2616; symptoms were controlled in 48.9% visits. Area under the curve for discrimination between controlled and uncontrolled asthma by FEV1, AX, R5-20, Z5, R5, and X5 were 0.58, 0.55, 0.55, 0.52, 0.52 and 0.52, respectively. FEV1 [OR (95% CI): 1.02 (1.01-1.03)] and AX [OR (95% CI): 0.88 (0.81-0.97)] measured over the duration of follow-up were significantly associated with controlled asthma.

CONCLUSIONS

Spirometry and impulse oscillometry parameters are comparable in ascertaining controlled asthma. Impulse oscillometry being less effort-dependent may be performed for monitoring control of childhood asthma, especially in younger children.

Classification of asthma

Asthma is a chronic inflammatory disorder of the airways that results, physiologically, in hyperreactivity and, clinically, in recurrent episodes of wheezing, chest tightness, or coughing. Airway inflammation, smooth-muscle contraction, epithelial sloughing, mucous hypersecretion, bronchial hyperresponsiveness, and mucosal edema contribute to the underlying pathophysiology of asthma. Diagnostic tests such as methacholine or mannitol challenges or spirometry (pre- and postbronchodilator responses) help to identify such underlying pathophysiology via assessments of bronchial hyperreactivity and lung mechanics but are imperfect and, ultimately, must be viewed in the context of a patient's clinical presentation, including response to pharmacotherapy. Asthma can be classified into either intermittent or persistent, and the latter is either mild, moderate, or severe. Some patients change, in either direction, from intermittent to persistent asthma. In addition, patients with asthma may be classified as allergic (immunoglobulin E mediated), nonallergic (often triggered by viral upper respiratory tract infections or no apparent cause), occupational, aspirin-exacerbated respiratory disease, potentially fatal, exercise-induced, and cough variant asthma. In the latter, the patients have a nonproductive cough that responds to treatment for asthma but not with antibiotics, expectorants, mucolytics, antitussives, or beta₂-adrenergic agonists, and to treatment for acid reflux and rhinosinusitis. Thus, cough variant asthma is in the differential diagnosis of chronic cough.

Recent Advances in Severe Asthma: From Phenotypes to Personalized Medicine

This review focuses on recent clinical and translational discoveries in severe and uncontrolled asthma that now enable phenotyping and personalized therapies in these patients. Although asthma is common in both children and adults and typically responds to standard therapies, a subset of individuals with asthma experience severe and/or persistent symptoms despite appropriate therapies. Airflow obstruction leading to frequent symptoms requiring higher levels of controller therapy is the cardinal feature of severe asthma, but the underlying molecular mechanisms, or endotypes, are diverse and variable between individuals. Two major risk factors that contribute to severe asthma are genetics and environmental exposures that modulate immune responses, and although these often interact in complex manners that are not fully understood, certain endotypes converge in severe asthma. A number of studies have evaluated various features of patients with severe asthma and classified patients into phenotypes with clinical relevance. This phenotyping is now incorporated into clinical practice and can be used to guide advanced biological therapies that target specific molecules and inflammatory pathways that contribute to asthma pathogenesis.

Obese- and allergic-related asthma phenotypes among children across the United States

OBJECTIVES

Pediatric asthma is heterogeneous with phenotypes that reflect differing underlying inflammation and pathophysiology. Little is known about the national prevalence of certain obesity- and allergy-related asthma phenotypes or associated characteristics. We therefore assessed the national prevalence, risk factors, and caregiver-reported severity of four asthma phenotypes: not-allergic-not-obese, allergic-not-obese, obese-not-allergic, and allergic-and-obese.

METHODS

We analyzed data from the 2007-2008 National Survey of Children's Health (NSCH) of 10-17 year-olds with caregiver-reported asthma. We described sociodemographic and health risk factors of each phenotype and then applied logistic and ordinal regression models to identify associated risk factors and level of severity of the phenotypes.

RESULTS

Among 4427 children with asthma in this NSCH cohort, the association between race and phenotype was statistically significant (p < 0.0001); white children with asthma were most likely to have allergic-not-obese asthma while black and Hispanic children with asthma were most likely to have the obese-nonallergic phenotype (p < 0.001). Attention-deficit disorder/attention-deficit hyperactivity disorder was more likely to be present in allergic-not-obese children (odds ratio (OR) 1.50, confidence interval (CI) 1.14-1.98, p = 0.004). The phenotype with the highest risk for more severe compared to mild asthma was the obese-and-allergic asthma phenotype (OR 3.34, CI 2.23-5.01, p < 0.001).

CONCLUSIONS

Allergic-not-obese asthma comprised half of our studied asthma phenotypes, while obesity-related asthma (with or without allergic components) comprised one-fifth of asthma phenotypes in this cohort representative of the US population. Children with both obese and allergic asthma are most likely to have severe asthma. Future management of childhood asthma might consider more tailoring of treatment and management plans based upon different childhood asthma phenotypes.

Scoring systems for allergies and asthma in clinical research and practice

Background: Scoring systems are increasingly being developed for various diseases, including asthma and allergic disorders, with the objective of improving the classification of disease severity and the assessment of efficacy of therapeutic modalities. Objective: This review provided concise summaries of published scoring systems used for allergic rhinitis, asthma, atopic dermatitis, urticaria, Stevens-Johnson syndrome/toxic epidermal necrolysis, eosinophilic esophagitis, and systemic allergic reactions (anaphylaxis). Methods: We searched the medical literature between 1985 and 2018 for published scoring systems that have been developed and used in clinical trials or in practice for assessment of asthma and a variety of allergic disorders. Results: The scoring systems for each of these diseases were briefly presented in the text in chronological order of publication, and selected information was presented in the tables for easy comparisons. For more details, the reader should refer to the original relevant publications. Conclusion: Such assessment methods are useful for sound designing of clinical trials, fair comparisons of findings of studies, and objective measurements of patients' progress in clinical practice. The choice of using one scoring system over another would depend on its proven degree of validity, the purpose, and applicability.

Comparing Asthma Control Test with Global Initiative for Asthma Defined Control in Nigerian Adult Asthmatics: A Prospective Cross-sectional study

BACKGROUND

Assessment of control is central to asthma management. The Asthma Control Test (ACT) and Global Initiative for Asthma (GINA) defined control are commonly used measures of asthma control. This study examined the agreement between the ACT and GINA defined control and determined the best cut-off point of ACT to predict GINA level of control.

METHODS

It was a cross-sectional study of 82 consecutive [72% females, age 44 (IQR) 29-60 years] asthmatic patients in a tertiary teaching hospital. We compared ACT with GINA defined control using Cohen's kappa and receiver operating characteristics curve was computed to determine sensitivity and specificity.

RESULTS

There was fair to moderate level of agreement between ACT and GINA defined control (kappa 0.34 to 0.46). To detect GINA-defined controlled asthma, the ACT cut-off point of =20 had a sensitivity of 81%, specificity of 74%, a positive predictive value of 52% and negative predictive value of 92%, with an area under the receiver operating characteristics curve(AUC) value of 0.82 [95% confidence interval (CI): 0.72-0.90]. ACT scores of = 19 predicted GINA-defined uncontrolled asthma with sensitivity of 87%, specificity of 51%, positive predictive value of 41%, negative predictive value of 91% with AUC values of 0.75 (95% CI: 0.75-0.84).

CONCLUSION

In Nigerian asthmatics, ACT scores of =20 and =19 are useful for identifying patients with controlled and uncontrolled asthma respectively, as defined by GINA 2014 criteria. However, the former is more predictive than the latter.

Diagnosis and Treatment of Asthma in Nonpregnant Women

Asthma is a common condition affecting 8.3% of the adult population in the United States. The disease is characterized by chronic airway inflammation that leads to airway hyperresponsiveness and obstruction that results in coughing, wheezing, shortness of breath, and a feeling of chest tightness. The diagnosis and classification of asthma is based on reported symptoms, physical examination findings, and spirometry. Pharmacologic therapy is prescribed using a stepwise approach that begins with inhaled short-acting beta₂ -agonists for intermittent asthma with the addition of daily inhaled corticosteroids for more persistent cases. Individuals with asthma are reevaluated on a regular basis to monitor symptoms, and pharmacologic treatments are adjusted as needed. Familiarity with the stepwise approach for asthma management and confidence in the efficacy and safety profiles of inhaled medications will assist clinicians in successful management of asthma in the primary care setting.

Changes in the Burden of Comorbidities in Patients with COPD and Asthma-COPD Overlap According to the GOLD 2017 Recommendations

PURPOSE

Comorbidities associated with chronic obstructive pulmonary disease (COPD) affect quality of life and increase mortality. Asthma-COPD overlap (ACO) may express a different profile of comorbidities compared to COPD alone. It is unclear how recent changes in GOLD recommendations affect the profile of comorbidities in COPD and ACO.

METHODS

Eight hundred and thirty-four patients with COPD were recruited from 67 Hungarian secondary care outpatient clinics, 469 of them had ACO. Comorbidities were defined by respiratory specialists based on medical history, patient report, and medications. COPD grades were defined according to the old 2016 and the new 2017 GOLD document. Comorbidities were compared along COPD ABCD groups determined by the old and new GOLD.

RESULTS

66 and 72% of the COPD patients in groups C and D (GOLD 2016) were recategorized to groups A and B (GOLD 2017), respectively. There was no difference in the prevalence of disorders along the 2016 GOLD categories except for osteoporosis in ACO (p = 0.01). When the patients were categorized according to the 2017 GOLD criteria, the prevalence of osteoporosis (p = 0.01) was different among the four groups in all COPD patients. Subgroup analysis of non-ACO COPD patients revealed inter-group differences for cardiac arrhythmia (p < 0.01). No alteration was seen in the prevalence of coronary artery disease, hypertension, diabetes, or the total number of comorbidities.

CONCLUSION

A significant number of patients are recategorized according to the GOLD 2017 criteria. This change only marginally affects the profile of comorbidities; still this needs to be considered when assessing the patients in daily practice.

Modeling asynchronous event sequences with RNNs

Sequences of events have often been modeled with computational techniques, but typical preprocessing steps and problem settings do not explicitly address the ramifications of timestamped events. Clinical data, such as is found in electronic health records (EHRs), typically comes with timestamp information. In this work, we define event sequences and their properties: synchronicity, evenness, and co-cardinality; we then show how asynchronous, uneven, and multi-cardinal problem settings can support explicit accountings of relative time. Our evaluation uses the temporally sensitive clinical use case of pediatric asthma, which is a chronic disease with symptoms (and lack thereof) evolving over time. We show several approaches to explicitly incorporating relative time into a recurrent neural network (RNN) model that improve the overall classification of patients into those with no asthma, those with persistent asthma, those in long-term remission, and those who have experienced relapse. We also compare and contrast these results with those in an inpatient intensive care setting.

Efficacy and Safety of Dupilumab in Glucocorticoid-Dependent Severe Asthma

BACKGROUND

Dupilumab is a fully human anti-interleukin-4 receptor α monoclonal antibody that blocks both interleukin-4 and interleukin-13 signaling. Its effectiveness in reducing oral glucocorticoid use in patients with severe asthma while maintaining asthma control is unknown.

METHODS

We randomly assigned 210 patients with oral glucocorticoid-treated asthma to receive add-on dupilumab (at a dose of 300 mg) or placebo every 2 weeks for 24 weeks. After a glucocorticoid dose-adjustment period before randomization, glucocorticoid doses were adjusted in a downward trend from week 4 to week 20 and then maintained at a stable dose for 4 weeks. The primary end point was the percentage reduction in the glucocorticoid dose at week 24. Key secondary end points were the proportion of patients at week 24 with a reduction of at least 50% in the glucocorticoid dose and the proportion of patients with a reduction to a glucocorticoid dose of less than 5 mg per day. Severe exacerbation rates and the forced expiratory volume in 1 second (FEV₁) before bronchodilator use were also assessed.

RESULTS

The percentage change in the glucocorticoid dose was -70.1% in the dupilumab group, as compared with -41.9% in the placebo group (P<0.001); 80% versus 50% of the patients had a dose reduction of at least 50%, 69% versus 33% had a dose reduction to less than 5 mg per day, and 48% versus 25% completely discontinued oral glucocorticoid use. Despite reductions in the glucocorticoid dose, in the overall population, dupilumab treatment resulted in a severe exacerbation rate that was 59% (95% confidence interval [CI], 37 to 74) lower than that in the placebo group and resulted in an FEV₁ that was 0.22 liters (95% CI, 0.09 to 0.34) higher. Injection-site reactions were more common with dupilumab than with placebo (9% vs. 4%). Transient blood eosinophilia was observed in more patients in the dupilumab group than in the placebo group (14% vs. 1%).

CONCLUSIONS

In patients with glucocorticoid-dependent severe asthma, dupilumab treatment reduced oral glucocorticoid use while decreasing the rate of severe exacerbations and increasing the FEV₁. Transient eosinophilia was observed in approximately 1 in 7 dupilumab-treated patients. (Funded by Sanofi and Regeneron Pharmaceuticals; LIBERTY ASTHMA VENTURE ClinicalTrials.gov number, NCT02528214 .).

Dupilumab Efficacy and Safety in Moderate-to-Severe Uncontrolled Asthma

BACKGROUND

Dupilumab is a fully human anti-interleukin-4 receptor α monoclonal antibody that blocks both interleukin-4 and interleukin-13 signaling. We assessed its efficacy and safety in patients with uncontrolled asthma.

METHODS

We randomly assigned 1902 patients 12 years of age or older with uncontrolled asthma in a 2:2:1:1 ratio to receive add-on subcutaneous dupilumab at a dose of 200 or 300 mg every 2 weeks or matched-volume placebos for 52 weeks. The primary end points were the annualized rate of severe asthma exacerbations and the absolute change from baseline to week 12 in the forced expiratory volume in 1 second (FEV₁) before bronchodilator use in the overall trial population. Secondary end points included the exacerbation rate and FEV₁ in patients with a blood eosinophil count of 300 or more per cubic millimeter. Asthma control and dupilumab safety were also assessed.

RESULTS

The annualized rate of severe asthma exacerbations was 0.46 (95% confidence interval [CI], 0.39 to 0.53) among patients assigned to 200 mg of dupilumab every 2 weeks and 0.87 (95% CI, 0.72 to 1.05) among those assigned to a matched placebo, for a 47.7% lower rate with dupilumab than with placebo (P<0.001); similar results were seen with the dupilumab dose of 300 mg every 2 weeks. At week 12, the FEV₁ had increased by 0.32 liters in patients assigned to the lower dose of dupilumab (difference vs. matched placebo, 0.14 liters; P<0.001); similar results were seen with the higher dose. Among patients with a blood eosinophil count of 300 or more per cubic millimeter, the annualized rate of severe asthma exacerbations was 0.37 (95% CI, 0.29 to 0.48) among those receiving lower-dose dupilumab and 1.08 (95% CI, 0.85 to 1.38) among those receiving a matched placebo (65.8% lower rate with dupilumab than with placebo; 95% CI, 52.0 to 75.6); similar results were observed with the higher dose. Blood eosinophilia occurred after the start of the intervention in 52 patients (4.1%) who received dupilumab as compared with 4 patients (0.6%) who received placebo.

CONCLUSIONS

In this trial, patients who received dupilumab had significantly lower rates of severe asthma exacerbation than those who received placebo, as well as better lung function and asthma control. Greater benefits were seen in patients with higher baseline levels of eosinophils. Hypereosinophilia was observed in some patients. (Funded by Sanofi and Regeneron Pharmaceuticals; LIBERTY ASTHMA QUEST ClinicalTrials.gov number, NCT02414854 .).

Diagnosis and treatment of severe asthma: a phenotype-based approach

Severe asthma is a heterogeneous and often difficult to treat condition that results in a disproportionate cost to healthcare systems. Appropriate diagnosis and management of severe asthma is critical, as most asthma deaths have been retrospectively identified as having poorly recognised severe asthma. With multiple biologic agents becoming available, it is crucial to correctly phenotype patients in order to identify those that will respond to these high-cost treatments. We provide an overview of the assessment, phenotyping and management of severe asthma in primary and secondary care.

[CME: Mepolizumab, an Additional Therapeutic Agent for Severe Asthma]

CME: Mepolizumab, an Additional Therapeutic Agent for Severe Asthma Abstract. The challenging therapy of severe uncontrollable bronchial asthma aims primarily at sufficient symptom control and the minimization of the exacerbation rate. If, despite extended drug therapy, symptom control is very difficult to achieve, biologics should preferably be used instead of corticosteroid therapy. The aim of this article is to point out these different asthma therapy pathways and to describe diagnostic criteria as well as practical experiences through application in patients.

A genome-by-environment interaction classifier for precision medicine: personal transcriptome response to rhinovirus identifies children prone to asthma exacerbations

OBJECTIVE

To introduce a disease prognosis framework enabled by a robust classification scheme derived from patient-specific transcriptomic response to stimulation.

MATERIALS AND METHODS

Within an illustrative case study to predict asthma exacerbation, we designed a stimulation assay that reveals individualized transcriptomic response to human rhinovirus. Gene expression from peripheral blood mononuclear cells was quantified from 23 pediatric asthmatic patients and stimulated in vitro with human rhinovirus. Responses were obtained via the single-subject gene set testing methodology "N-of-1-pathways." The classifier was trained on a related independent training dataset (n = 19). Novel visualizations of personal transcriptomic responses are provided.

RESULTS

Of the 23 pediatric asthmatic patients, 12 experienced recurrent exacerbations. Our classifier, using individualized responses and trained on an independent dataset, obtained 74% accuracy (area under the receiver operating curve of 71%; 2-sided P = .039). Conventional classifiers using messenger RNA (mRNA) expression within the viral-exposed samples were unsuccessful (all patients predicted to have recurrent exacerbations; accuracy of 52%).

DISCUSSION

Prognosis based on single time point, static mRNA expression alone neglects the importance of dynamic genome-by-environment interplay in phenotypic presentation. Individualized transcriptomic response quantified at the pathway (gene sets) level reveals interpretable signals related to clinical outcomes.

CONCLUSION

The proposed framework provides an innovative approach to precision medicine. We show that quantifying personal pathway-level transcriptomic response to a disease-relevant environmental challenge predicts disease progression. This genome-by-environment interaction assay offers a noninvasive opportunity to translate omics data to clinical practice by improving the ability to predict disease exacerbation and increasing the potential to produce more effective treatment decisions.

The Differences in Spirometry Predictive Equations in Classifying Presence and Degree of Lung Function Impairment: Which Suit Fits the Best?

PURPOSE

The aim of this study was to compare the differences between three most commonly used predictive equations (PE): ECCS (European Community of Coal and Steel), the third National Health and Nutrition Examination Survey (NHANES III), and GLI (Global Lung Initiative) in healthy individuals and when grading severity of lung function impairment in patients with obstructive lung diseases.

METHODS

The study included 200 healthy volunteers and 200 patients with obstructive lung diseases at the Institute for Pulmonary Diseases of Vojvodina. In all subjects, we calculated the absolute and relative (percent) predicted values using ECCS, NHANES III, and GLI reference equations.

RESULTS

The mean differences between ECCS and NHANES III predicted values were 5.63% (95% CI  5.29-5.98%, p < 0.001) for FEV1 and 10% (95% CI 9.52-10.79%, p < 0.001) for FVC. Similar differences were observed between ECCS and GLI predicted values. There were minimal differences between NHANES III and GLI predictive values. In healthy subjects, the mean absolute difference between measured FEV1 and FEV1 ECCS predicted was 0.36l (95% CI 0.32l, 0.40l, p < 0.001), FEV1 NHANES predicted was 0.30 l (95% CI 0.27-0.35l, p < 0.001), and FEV1 GLI predicted was 0.31l (95% CI 0.27- 0.35l, p < 0.001). The use of three different PE leads to significant differences in classification of obstruction severity in both asthma and COPD patients.

CONCLUSIONS

There were significant differences between FEV1 and FVC predicted when using different PE. The absolute difference between actual and predicted FEV1 in healthy individuals was highest when using ECCS. The use of different PE may change the interpretation of severity of airway obstruction.

Asthma management

The UK is considered to have the highest rates of morbidity and mortality among children and adults with asthma in Europe. According to the National Review of Asthma Deaths (NRAD), 28 children died in the UK between February 2012 and January 2013 because of asthma. Most of these deaths would be considered preventable by respiratory specialists.

[Comparison of functional parameters of small airways between patients with typical asthma and cough-variant asthma]

OBJECTIVE

To compare the functional parameters of the small airways and clinical characteristics between patients with typical asthma (TA) and cough-variant asthma (CVA).

METHODS

Forty-three newly diagnosed asthmatic patients were enrolled, including 15 with TA and positive bronchial provocation test [TA BPT(+)], 12 with TA and positive bronchial dilation test [TA BDT(+)] and 16 with CVA, and 27 healthy subjects served as the control group. All the subjects were required to complete data acquisition, asthma control test, asthma control test scale, fractional exhaled nitric oxide, airway resistance and pulmonary function tests, BPT or BDT.

RESULTS

The interval from onset to a definite diagnosis of TA BDT(+) was longer than that of TA BPT(+), while that of CVA was the shortest (P=0.022). The pulmonary functional parameters of TA BDT (+) was significantly lower than those of the other 3 groups (P<0.05). MMEF, MEF₇₅, MEF₅₀, and MEF₂₅ in patients with TA BDT(+), TA BPT(+) and CVA were significantly lower than those in the control group (P<0.01). The resonant frequency, respiratory impedance, resistance at 5 Hz, resistance at 20 Hz, and reactance at 5 Hz were significant higher in patients with TA BDT (+) than in the control subjects, while these parameters showed no significant differences among TA BPT (+), CVA and control groups. The airway resistance in TA BPT(+), CVA, and control groups increased after BPT, and the patients with TA BPT(+) showed greater changes in airway resistance than those in CVA and control groups. In CVA patients, FeNO showed a strong positive correlation with respiratory impedance (r=0.523, P=0.038), resistance at 5 Hz (r=0.542, P=0.030), and resistance at 20 Hz (r=0.524, P=0.037), and the airway responsiveness showed a strong positive correlation with resistance at 20 Hz (Rho=-0.512, P=0.043).

CONCLUSION

CVA is the early stage of TA, and CVA, TA BPT(+), and TA BDT(+) may represent different stages of asthma. Uncontrolled, prolonged CVA may evolve into TA BPT (+), whose further progression can cause damages of the pulmonary function and small airway function and leads eventually to TA BDT (+).

Heterogeneity of obesity-asthma association disentangled by latent class analysis, the SAPALDIA cohort

Although evidence for the heterogeneity of asthma accumulated, consensus for definitions of asthma phenotypes is still lacking. Obesity may have heterogeneous effects on various asthma phenotypes. We aimed to distinguish asthma phenotypes by latent class analysis and to investigate their associations with different obesity parameters in adults using a population-based Swiss cohort (SAPALDIA). We applied latent class analysis to 959 self-reported asthmatics using information on disease activity, atopy, and age of onset. Associations with obesity were examined by multinomial logistic regression, after adjustments for age, sex, smoking status, educational level, and study centre. Body mass index, percent body fat, waist hip ratio, waist height ratio, and waist circumference were used as obesity measure. Four asthma classes were identified, including persistent multiple symptom-presenting asthma (n = 122), symptom-presenting asthma (n = 290), symptom-free atopic asthma (n = 294), and symptom-free non-atopic asthma (n = 253). Obesity was positively associated with symptom-presenting asthma classes but not with symptom-free ones. Percent body fat showed the strongest association with the persistent multiple symptom-presenting asthma. We observed heterogeneity of associations with obesity across asthma classes, indicating different asthma aetiologies.

Quantitative computed tomographic imaging-based clustering differentiates asthmatic subgroups with distinctive clinical phenotypes

BACKGROUND

Imaging variables, including airway diameter, wall thickness, and air trapping, have been found to be important metrics when differentiating patients with severe asthma from those with nonsevere asthma and healthy subjects.

OBJECTIVE

The objective of this study was to identify imaging-based clusters and to explore the association of the clusters with existing clinical metrics.

METHODS

We performed an imaging-based cluster analysis using quantitative computed tomography-based structural and functional variables extracted from the respective inspiration and expiration scans of 248 asthmatic patients. The imaging-based metrics included a broader set of multiscale variables, such as inspiratory airway dimension, expiratory air trapping, and registration-based lung deformation (inspiration vs expiration). Asthma subgroups derived from a clustering method were associated with subject demographics, questionnaire results, medication history, and biomarker variables.

RESULTS

Cluster 1 was composed of younger patients with early-onset nonsevere asthma and reversible airflow obstruction and normal airway structure. Cluster 2 was composed of patients with a mix of patients with nonsevere and severe asthma with marginal inflammation who exhibited airway luminal narrowing without wall thickening. Clusters 3 and 4 were dominated by patients with severe asthma. Cluster 3 patients were obese female patients with reversible airflow obstruction who exhibited airway wall thickening without airway narrowing. Cluster 4 patients were late-onset older male subjects with persistent airflow obstruction who exhibited significant air trapping and reduced regional deformation. Cluster 3 and 4 patients also showed decreased lymphocyte and increased neutrophil counts, respectively.

CONCLUSIONS

Four image-based clusters were identified and shown to be correlated with clinical characteristics. Such clustering serves to differentiate asthma subgroups that can be used as a basis for the development of new therapies.

Are physician productivity and quality of care related?

This study examines the relationship between clinical quality of care and physician productivity in the public sector clinical setting. This longitudinal study takes place in Jefferson County, Alabama using data from six public sector clinics. Data representing 21 physicians across 13 consecutive quarters representing 44,765 person observations were analyzed. Four variables were selected to represent quality of care for this pediatric patient population; two of which pertained to antibiotic use and two pertained to asthma care. Findings from multivariate analyses examining each quality of care measure and controlling for other visit and practice characteristics indicate that three of the four quality measures were significantly related to productivity. Specifically, the percent of asthma patients with documented asthma severity classification was negatively related to physician productivity (ß = -.24, p = .04), although the magnitude of this relationship was small. The percent of asthma patients prescribed an inhaled corticosteroid who also had a severity classification was negatively related to physician productivity (ß = -.23, p = .03) and the percent of patients prescribed oral antibiotics was marginally negatively related to physician productivity (ß = -.09, p = .09). In general, findings suggest that a relationship exists between quality of healthcare and physician productivity. Future research should continue to examine this relationship across other disciplines and healthcare settings.

[Morphological changes in the respiratory organs in chronic obstructive pulmonary disease]

The basis for airway remoldeling in patients with chronic obstructive pulmonary disease (COPD) is tissue changes contributing to thickening of the walls of the airway and its obstruction. As the disease becomes severer, there are increases in mucosal metaplasia, submucosal hypertrophy, peribronchial fibrosis, and airway smooth muscle mass. Drug therapy for COPD does not virtually lead to regression of airway obstruction, except when eosinophilia is present.

[Severe asthma]

The objectives of this work were to investigate the frequency of severe asthma (SA) according to WHO definition and to compare SA patients' characteristics with those of non-severe asthma (NSA); secondly, to investigate the level of control reached throughout a period of regular treatment. Between 1-1-2005 and 12-31-2014, 471 medical records from patients with bronchial asthma assisted in Buenos Aires City were analyzed. SA frequency was 40.1% (189/471), being significantly higher among patients from the public health system (47.7%, 108/226 vs. 33%, 81/245, p = 0.001). SA patients were older than NSA ones (51.3 ± 17.4 vs. 42.6 ± 17.1 years, p = 0.000), presented longer time since onset of the disease (median 30 vs. 20 years, p = 0.000), lower educational levels (secondary level or higher 41.7% vs. 58.1%, p = 0.000), lower frequency of rhinitis (47% vs. 60.6%, p = 0.004), more severe levels of airway obstruction (FEV% 50.2 ± 13.7 vs. 77.7 ± 12.4, p = 0.000), more frequent antecedents of Near Fatal Asthma (11.1% vs. 2.8%, p = 0.000), higher levels of serum IgE (median of 410 vs. 279 UI/l, p = 0.01) and higher demand of systemic steroids requirements and hospitalizations (68.7% vs. 50.7%, p = 0.000 and 37.5% vs. 15.9%, p = 0.000, respectively). A 30.6% of SA patients (58/189) reached a follow-up period of 12 months, 13 (22.5%) of whom reached the controlled asthma level. The frequency of SA found seems to be considerable. Multicenter studies to investigate the levels of control reached by SA patients with access to proper treatment are recommended.

Data-driven asthma endotypes defined from blood biomarker and gene expression data

The diagnosis and treatment of childhood asthma is complicated by its mechanistically distinct subtypes (endotypes) driven by genetic susceptibility and modulating environmental factors. Clinical biomarkers and blood gene expression were collected from a stratified, cross-sectional study of asthmatic and non-asthmatic children from Detroit, MI. This study describes four distinct asthma endotypes identified via a purely data-driven method. Our method was specifically designed to integrate blood gene expression and clinical biomarkers in a way that provides new mechanistic insights regarding the different asthma endotypes. For example, we describe metabolic syndrome-induced systemic inflammation as an associated factor in three of the four asthma endotypes. Context provided by the clinical biomarker data was essential in interpreting gene expression patterns and identifying putative endotypes, which emphasizes the importance of integrated approaches when studying complex disease etiologies. These synthesized patterns of gene expression and clinical markers from our research may lead to development of novel serum-based biomarker panels.

[The degree of asthma severity in children and the level of maternal anxiety and depression]

Care for sick children most often falls to mothers, which may affect their mental state, causing the states of depression and anxiety.

AIM

The aim of this study was to determine the relationship between the severity of asthma in children and the level of anxiety and depression in mothers, taking into account the importance of the material status of the family, the educational level of the mothers, the presence of critical events, as well as the coexistence of allergic diseases in other family members.

MATERIALS AND METHODS

The study included 60 mothers of children with bronchial asthma. Age of mothers in the investigated families was on average 37.28 +/- 6.24 years, and most had a high school education (55.0%) or higher (28.3%). 16.7% of mothers and 8.3% fathers suffered from asthma. 13.3% of mothers of children with asthma were brought child alone. To assess the level of anxiety the inventory for measuring state and trait anxiety (STAI - State Trait Anxiety Inventory) developed by Spielberger, Gorsuch'a and Lushene'a was applied. To determine the changes in depressive the Beck Depression Inventory (BDI - Beck Depression Inventory questionnaire) was used. The Student's t test was included for two independent populations and a comparison of the results obtained in the questionnaire for diagnosing the level of anxiety and depression. For other parameters the correlation coefficient r-Pearson rank and Kendall's tau were performed.

RESULTS

Mothers of children with moderate asthma compared to mothers of children with mild asthma had higher levels of anxiety (both state and properties), and also a slightly higher level of depression. Maternal age was connected positively and moderately strongly with the number held by children (r = 0.380; p = 0.003) and age of a child with asthma (r = 0.613, p = 0.0005). The duration of the child's disease was associated positively and moderately strongly with the level of state anxiety mother (X-1) (r = 0.345; p = 0.007) and a bit less and also positively with the levels of depression (r = 0.227; p = 0.081). Maternal age (r = -0.428; p = 0.018) and the number of children held by them (r = -0.365; p = 0.047) were correlated moderately strongly and negatively with their level of state anxiety (X-1). Very strong and positive relationship links the level of trait anxiety (X-2) mothers with their levels of depression (r = 0.729; p = 0.0005).

CONCLUSIONS

The study revealed that there is a relationship between the severity of asthma in children and felt by the mother's level of anxiety. Not confirmed suspicions that the level of depression in mothers depends on the severity of asthma in children. The structure of the relationship between maternal anxiety and depression and other characteristics was analyzed in the work differs between groups. Analyzed the relationship between the family situation and other variable factors and the severity of asthma in children have not been confirmed.

[Phenotype specific therapy of COPD]

COPD is not a homogenous disease but consists of at least four different phenotypes: Emphysema, COPD with chronic bronchitis, asthma-COPD overlap syndrome (ACOS), and COPD with recurrent exacerbations. With differentiation, treatment can be designed phenotype-specific. Some modern drugs are not indicated in all phenotypes.

Inflammatory patterns in asthmatic children based on alveolar nitric oxide determination

INTRODUCTION

Nitric oxide (NO) levels can be measured at proximal (maximum airway NO flux [J'aw(NO)]) and distal (alveolar NO concentration [C(ANO)]) levels. Four inflammatory patterns have been described in asthmatic individuals, although their relevance has not been well established. The objective was to determine J'aw(NO) and C(ANO) in order to establish four inflammatory categories in asthmatics.

MATERIAL AND METHODS

Cross-sectional study of a sample consisting of healthy and asthmatic children. Exhaled NO was determined at multiple flows. J'aw(NO) and C(ANO) were obtained according to the two-compartment model. The asthma control questionnaire (ACQ) and spirometry were administered to asthmatic children. Patients were categorized as type I (normal J'aw(NO) and C(ANO)), type II (elevated J'aw(NO) and normal C(ANO)), type III (elevated J'aw(NO) and C(ANO)) and type IV (normal J'aw(NO) and elevated C(ANO)). Correlation between FE(NO,50), J'aw(NO) and C(ANO) was analyzed using Spearman's R Correlation Test. Analysis of variance and paired comparisons were performed using the Bonferroni correction.

RESULTS

One hundred sixty-two children were studied, of whom 49 (32.23%) were healthy controls and 103 (67.76%) asthmatics. In the control subjects, FE(NO,50) (ppb)(median and range) was 11.5 (1.6 to 27.3), J'aw(NO) (pl/s) was 516 (98.3 to 1470) and C(ANO) (ppb) was 2.2 (0.1 to 4.5). Forty-four (42.7%) of the asthmatic participants were categorized as type I, 41 (39.8%) as type II, 14 (13.5%) as type III and 4 (3.88%) as type IV. Good correlation was observed between J'aw(NO) and FE(NO,50) (r=0.97). There was no association between J'aw(NO) and C(ANO). FEV1/FVC decreased significantly in type III (mean 79.8±7.5). Morbidity was significantly higher in types III and IV.

CONCLUSIONS

Normal values obtained are similar to those previously reported. Asthmatics with high C(ANO) showed higher morbidity. No correlation was found between proximal and distal inflammation.

Aligning mouse models of asthma to human endotypes of disease

Substantial gains in understanding the pathophysiologic mechanisms underlying asthma have been made using preclinical mouse models. However, because asthma is a complex, heterogeneous syndrome that is rarely due to a single allergen and that often presents in the absence of atopy, few of the promising therapeutics that demonstrated effectiveness in mouse models have translated into new treatments for patients. This has resulted in an urgent need to characterize T helper (Th) 2-low, non-eosinophilic subsets of asthma, to study models that are resistant to conventional treatments such as corticosteroids and to develop therapies targeting patients with severe disease. Classifying asthma based on underlying pathophysiologic mechanisms, known as endotyping, offers a stratified approach for the development of new therapies for asthma. In preclinical research, new models of asthma are being utilized that more closely resemble the clinical features of different asthma endotypes, including the presence of interleukin-17 and a Th17 response, a biomarker of severe disease. These models utilize more physiologically relevant sensitizing agents, exacerbating factors and allergens, as well as incorporate time points that better reflect the natural history and chronicity of clinical asthma. Importantly, some models better represent non-classical asthma endotypes that facilitate the study of non-Th2-driven pathology and resemble the complex nature of clinical asthma, including corticosteroid resistance. Placing mouse asthma models into the context of human asthma endotypes will afford a more relevant approach to the understanding of pathophysiological mechanisms of disease that will afford the development of new therapies for those asthmatics that remain difficult to treat.

Introduction to asthma and phenotyping

Asthma is an inflammatory disorder characterized by airway obstruction, airway hyperresponsiveness, and airway inflammation, all of which are variable among patients and variable in time within any specific patient. Understanding the mechanism that underlies this observed variability, and using that understanding to advance the science of asthma and the care of asthmatic patients, is an essential purpose of developing phenotypes. Clinical phenotypes have been used for decades, but overlap each other, and do not map cleanly to either pathophysiologic mechanism or with therapeutic response. Molecular phenotyping, although as yet only partially developed, offers the promise of dissecting the mechanistic underpinnings of the variability of asthma and of providing predictive therapeutics for the benefit of patients with this common and troubling disease.

Heterogeneity of response to therapy

As noted in prior chapters, US national and international guidelines provide a consistent approach to initial management of asthma, based on easily observed physical and physiologic findings, and a detailed history. From those data, a rational initial therapeutic regimen can be prescribed. In many cases, such therapy results in near complete control of asthma symptoms, restoration of normal lung physiology, and elimination of exacerbations. In fact, such improvement is frequent enough that therapeutic responsiveness to asthma treatments was thought to be nearly universal. However, it is not uncommon for patients to return with incomplete, or even trivial improvement in these clinical metrics of control (Langmack and Martin Curr Opin Pulm Med 16:13-18, 2010). In this chapter, we review the current literature on the variability of response to commonly used therapeutic agents in asthma.

Inhaled environmental allergens and toxicants as determinants of the asthma phenotype

The driving environmental factors behind the development of the asthma phenotype remain incompletely studied and understood. Here, we present an overview of inhaled allergic/atopic and mainly nonallergic/nonatopic or toxicant shapers of the asthma phenotype, which are present in both the indoor and outdoor environment around us. The inhaled allergic/atopic factors include fungus, mold, animal dander, cockroach, dust mites, and pollen; these allergic triggers and shapers of the asthma phenotype are considered in the context of their ability to drive the immunologic IgE response and potentially induce interactions between the innate and adaptive immune responses, with special emphasis on the NADPH-dependent reactive oxygen-species-associated mechanism of pollen-associated allergy induction. The inhaled nonallergic/nonatopic, toxicant factors include gaseous and volatile agents, such as sulfur dioxide, ozone, acrolein, and butadiene, as well as particulate agents, such as rubber tire breakdown particles, and diesel exhaust particles. These toxicants are reviewed in terms of their relevant chemical characteristics and hazard potential, ability to induce airway dysfunction, and potential for driving the asthma phenotype. Special emphasis is placed on their interactive nature with other triggers and drivers, with regard to driving the asthma phenotype. Overall, both allergic and nonallergic environmental factors can interact to acutely exacerbate the asthma phenotype; some may also promote its development over prolonged periods of untreated exposure, or possibly indirectly through effects on the genome. Further therapeutic considerations should be given to these environmental factors when determining the best course of personalized medicine for individuals with asthma.

[Effects of thymic stromal lymphopoietin (TSLP) genotypes on asthma phenotypes defined by the atopy cluster -influence of smoking habits-]

INTRODUCTION

We have previously reported that a distinct sensitization pattern was associated with thymic stromal lymphopoietin (TSLP) genotype. The aim of this study is to identify the characteristics of asthma phenotypes determined by a cluster analysis of IgE responsiveness and the relationship between these phenotypes and TSLP genotypes.

PATIENTS AND METHODS

We studied 297 patients of adult asthma and 1571 non-asthmatic healthy adults from Ibaraki, a prefecture in central Japan and Kamishihoro, a cedar-free, birch-dominant town in northern Japan. Levels of total serum IgE and specific IgE antibodies towards 14 major inhaled allergens were measured. With the use of these measures, cluster analysis was applied to classify the phenotypes of adult asthma. We also examined the genetic effects of 2 TSLP functional single nucleotide polymorphism (SNPs) on the development of each asthma phenotype using multinomial logistic regression analysis.

RESULTS

The cluster analysis identified four distinct clinical phenotypes of asthma, including "Dust mite dominant" (A, N=82), "Multiple pollen" (B, N=14), "Cedar dominant" (C, N=44), and "Low reactivity" (D, N=154). Asthma phenotype A consisted of younger patients with elevated IgE levels and decreased pulmonary function. Asthma phenotype B was characterized by sensitization by many pollen allergens. Asthma phenotype C was not formed in Kamishihoro. Asthma phenotype D was a group of older women who are less atopic. In current or past smokers, both TSLP SNPs (rs2289276 and rs3860933) were associated with the asthma phenotype D (odds ratio 2.11 [1.36-3.30] and 2.11 [1.34-3.33], respectively).

CONCLUSION

In patients with adult asthma who are less atopic, the genetic polymorphisms of TSLP may have some important roles in the development of the disease in smokers.

[Severe asthma--where are we today?]

Severe asthma is defined by persistent symptoms and frequent exacerbations despite intensive asthma therapy. The prevalence is estimated to be 5-10% of all asthmatics. Severe asthma is responsible for a major burden of illness including low quality of life and a disproportionate use of health-care resources. The clinical assessment of severe asthma must include verification of the correct diagnosis, adherence to medication, excluding differential diagnosis and identification and treatment of aggravating co-morbidities and trigger factors.

Utility of initial prehospital end-tidal carbon dioxide measurements to predict poor outcomes in adult asthmatic patients

STUDY OBJECTIVE

To determine if an initial (before treatment) prehospital end-tidal carbon dioxide (EtCO2) measurement in adult, non-chronic obstructive pulmonary disease (COPD), asthmatic patients predicts patient outcomes.

METHODS

This is a retrospective chart review of EtCO2 assessment data in a convenience sample of adult, asthmatic patients transported via advanced life support (ALS) units to a large, urban, academic hospital. Initial EtCO2 measurements were obtained routinely on all respiratory distress patients in the field, and emergency department physicians were unaware of the results. Data were analyzed using descriptive statistics, including percentages, means, and 95% confidence intervals (CI).

RESULTS

We reviewed data for prehospital initial EtCO2 measurements on 299 unique asthma patients (repeat visits by same patient were not included). Mean (SD) age was 43.1 years (12.5) and 142 (47.5%) were male. The mean EtCO2 measurement was 38.8 mmHg (SD ± 9.5; CI: 37.7-39.9; range: 14-82). Examination of initial EtCO2 measurements by deciles revealed that extreme values, in the lowest (14-28 mmHg) and highest (50-82 mmHg) deciles, experienced more markers of poor outcome than less extreme measurements. Patients were thus dichotomized by extreme (n = 59) or nonextreme (n = 240) EtCO2 measurements. More extreme patients were ultimately intubated (30.5 vs. 5.8%; p < 0.001; positive predictive value (ppv) = 30.5% ), and/or admitted to the intensive care unit (ICU) (28.8 vs. 6.7%; p <0.001; ppv = 28.8%), and/or died (5.1 vs. 0%; p = 0.007 [Fisher's exact test]; ppv = 5.1%), than nonextreme patients, respectively.

CONCLUSION

Extreme (both low and high) prehospital initial EtCO2 measurements may be associated with markers of poor patient outcomes. Future work will prospectively determine whether the addition of this information improves early recognition of severe asthma episodes beyond clinical assessment.

[Bronchial hypersensitivity in children with the neutrophilic phenotype of bronchial asthma and GSTM1 and GSTT1 gene polymorphism]

INTRODUCTION

The relationship between bronchial hypersensitivity as the key phenomenon ofbronchial asthma and detoxication GSTM1 or GSTT1 gene polymorphism in children with neutrophilic phenotype of this disease remains unclear

MATERIALS AND METHODS

33 children with bronchial asthma of neutrophile phenotype were examined in histamine and dosed physical exercise (running) tests. In addition GSTM1 and GSTT1 genotyping was performed.

RESULTS

Histamine test revealed bronchial hypersensitivity (HTC < 0.3 mg/ml) in 30.7% of the children with GSTMI and/or GSTTI deletions versus 12.5% of those without deletions (P phi < 0.05). The relative risk ofhypersensitivity to histamine (HTC < 0.3 mg/mI) in the presence of deletions was estimnated as 3.1 (95% CI 1.4-6.4), at OR 2.4 (95% CI 1.08-3.1) andAR = 0.18.

CONCLUSION

Children with the neutrophilic phenotype of bronchial asthma having deletions in the GSTT1/GSTM1 system are characterized by bronchial hypersensitivity to histamine and dosed physical exercises.