Endotypes of difficult-to-control asthma in inner-city African American children

Childhood asthma phenotypes and endotypes: a glance into the mosaic

BACKGROUND

Asthma is an inflammatory lung disease that constitutes the most common noncommunicable chronic disease in childhood. Childhood asthma shows large heterogeneity regarding onset of disease, symptoms, severity, prognosis, and response to therapy.

MAIN BODY

Evidence suggests that this variability is due to distinct pathophysiological mechanisms, which has led to an exhaustive research effort to understand and characterize these distinct entities currently designated as "endotypes." Initially, studies focused on identifying specific groups using clinical variables yielding different "clinical phenotypes." In addition, the identification of specific patterns based on inflammatory cell counts and cytokine data has resulted in "inflammatory endotypes." More recently, an increasing number of molecular data from high-throughput technology ("omics" data) have allowed to investigate more complex "molecular endotypes."

CONCLUSION

A better definition and comprehension of childhood asthma heterogeneity is key for improving diagnosis and treatment. This review aims at summarizing the current knowledge on this topic and discusses some limitations in their application as well as recommendations for future studies.

Race/ethnicity-stratified fine-mapping of the MHC locus reveals genetic variants associated with late-onset asthma

Introduction: Asthma is a chronic disease of the airways that impairs normal breathing. The etiology of asthma is complex and involves multiple factors, including the environment and genetics, especially the distinct genetic architecture associated with ancestry. Compared to early-onset asthma, little is known about genetic predisposition to late-onset asthma. We investigated the race/ethnicity-specific relationship among genetic variants within the major histocompatibility complex (MHC) region and late-onset asthma in a North Carolina-based multiracial cohort of adults. Methods: We stratified all analyses by self-reported race (i.e., White and Black) and adjusted all regression models for age, sex, and ancestry. We conducted association tests within the MHC region and performed fine-mapping analyses conditioned on the race/ethnicity-specific lead variant using whole-genome sequencing (WGS) data. We applied computational methods to infer human leukocyte antigen (HLA) alleles and residues at amino acid positions. We replicated findings in the UK Biobank. Results: The lead signals, rs9265901 on the 5' end of HLA-B, rs55888430 on HLA-DOB, and rs117953947 on HCG17, were significantly associated with late-onset asthma in all, White, and Black participants, respectively (OR = 1.73, 95%CI: 1.31 to 2.14, p = 3.62 × 10^-5; OR = 3.05, 95%CI: 1.86 to 4.98, p = 8.85 × 10^-6; OR = 19.5, 95%CI: 4.37 to 87.2, p = 9.97 × 10^-5, respectively). For the HLA analysis, HLA-B*40:02 and HLA-DRB1*04:05, HLA-B*40:02, HLA-C*04:01, and HLA-DRB1*04:05, and HLA-DRB1*03:01 and HLA-DQB1 were significantly associated with late-onset asthma in all, White, and Black participants. Conclusion: Multiple genetic variants within the MHC region were significantly associated with late-onset asthma, and the associations were significantly different by race/ethnicity group.

Association of mold levels in urban children's homes with difficult-to-control asthma

BACKGROUND

Mold sensitization and exposure are associated with asthma severity, but the specific species that contribute to difficult-to-control (DTC) asthma are unknown.

OBJECTIVE

We sought to determine the association between overall and specific mold levels in the homes of urban children and DTC asthma.

METHODS

The Asthma Phenotypes in the Inner-City study recruited participants, aged 6 to 17 years, from 8 US cities and classified each participant as having either DTC asthma or easy-to-control (ETC) asthma on the basis of treatment step level. Dust samples had been collected in each participant's home (n = 485), and any dust remaining (n = 265 samples), after other analyses, was frozen at -20^oC. The dust samples (n = 265) were analyzed using quantitative PCR to determine the concentrations of the 36 molds in the Environmental Relative Moldiness Index. Logistic regression was performed to discriminate specific mold content of dust from homes of children with DTC versus ETC asthma.

RESULTS

Frozen-dust samples were available from 54% of homes of children with DTC (139 of 253) and ETC asthma (126 of 232). Only the average concentration of the mold Mucor was significantly (P < .001) greater in homes of children with DTC asthma. In homes with window air-conditioning units, the Mucor concentration contributed about a 22% increase (1.6 odds ratio; 95% CI, 1.2-2.2) in the ability to discriminate between cases of DTC and ETC asthma.

CONCLUSIONS

Mucor levels in the homes of urban youth were a predictor of DTC asthma, and these higher Mucor levels were more likely in homes with a window air-conditioner.

A genome-wide association study of bronchodilator response in participants of European and African ancestry from six independent cohorts

Introduction

Bronchodilator response (BDR) is a measurement of acute bronchodilation in response to short-acting β2-agonists, with a heritability between 10 and 40%. Identifying genetic variants associated with BDR may lead to a better understanding of its complex pathophysiology.

Methods

We performed a genome-wide association study (GWAS) of BDR in six adult cohorts with participants of European ancestry (EA) and African ancestry (AA) including community cohorts and cohorts ascertained on the basis of obstructive pulmonary disease. Validation analysis was carried out in two paediatric asthma cohorts.

Results

A total of 10 623 EA and 3597 AA participants were included in the analyses. No single nucleotide polymorphism (SNP) was associated with BDR at the conventional genome-wide significance threshold (p<5×10-8). Performing fine mapping and using a threshold of p<5×10-6 to identify suggestive variants of interest, we identified three SNPs with possible biological relevance: rs35870000 (within FREM1), which may be involved in IgE- and IL5-induced changes in airway smooth muscle cell responsiveness; rs10426116 (within ZNF284), a zinc finger protein, which has been implicated in asthma and BDR previously; and rs4782614 (near ATP2C2), involved in calcium transmembrane transport. Validation in paediatric cohorts yielded no significant SNPs, possibly due to age-genotype interaction effects.

Conclusion

Ancestry-stratified and ancestry-combined GWAS meta-analyses of over 14 000 participants did not identify genetic variants associated with BDR at the genome-wide significance threshold, although a less stringent threshold identified three variants showing suggestive evidence of association. A common definition and protocol for measuring BDR in research may improve future efforts to identify variants associated with BDR.

Pediatric problematic severe asthma: Recent advances in management

Problematic severe asthma remains a significant challenge to manage, accounting for the majority of healthcare utilization among children with asthma. The heterogeneity is recognized and the clinical phenotypes of "difficult-to-treat" asthma (DA) and "severe therapy-resistant asthma" (STRA) help to guide management. Recent evidence supports molecular distinctions between these phenotypes and shows poor correlations between peripheral and airway markers of inflammation, especially in STRA. Airway neutrophils in the context of childhood severe asthma have been explored, but their role in disease causation, protection, or as bystanders remain unknown, and thus, treatment implications are unclear. Several novel management strategies, including once-daily maintenance therapy, single-device maintenance and reliever therapy, and novel biological treatments are being increasingly used for DA and STRA. However, pediatric data for efficacy of novel treatments is scarce, and when available, is restricted to adolescents. The aim of this review is to highlight recent advances in objective biomarkers that aid stratification and management of childhood severe asthma and to highlight gaps in pediatric evidence. Specifically, the urgent need for efficacy studies to improve the management of problematic severe asthma in children younger than 12 years.

The effects of gene × environment interactions on silver nanoparticle toxicity in the respiratory system: An adverse outcome pathway

The Adverse Outcome Pathway (AOP) framework is serving as a basis to integrate new data streams in order to enhance the power of predictive toxicology. AOP development for engineered nanomaterials (ENM), including silver nanoparticles (AgNP), is currently lagging behind other chemicals of regulatory interest due to our limited understanding of the mechanism by which underlying genetics or diseases directly modify host response to AgNP exposures. This also highlights the importance of considering the Aggregate Exposure Pathway (AEP) framework, which precedes the AOP framework and outlines source to target site exposure. The AEP and AOP frameworks interface at the target site, where a molecular initiating event (MIE) occurs and is followed by key events (KE) for adverse cellular and organ responses along a biological pathway and ends with the adverse organism response. The primary goal of this study is to use AgNP to interrogate the AEP-AOP framework by organizing and integrating in vitro dose-response data and in vivo exposure-response data from previous studies to evaluate the effects of interactions between host genetic and acquired factors, or gene × environment interactions (G × E), on AgNP toxicity in the respiratory system. Using this framework will help us to identify plausible key event relationships (KER) between MIE and adverse organism responses when KE are not measured using the same assay in order to derive future predictive models, guide research, and support development of tools for making risk-based, regulatory decisions on ENM. This article is categorized under: Toxicology and Regulatory Issues in Nanomedicine > Toxicology of Nanomaterials Toxicology and Regulatory Issues in Nanomedicine > Regulatory and Policy Issues in Nanomedicine.

Defining pediatric asthma: phenotypes to endotypes and beyond

Asthma is the most common chronic pediatric lung disease that has traditionally been defined as a syndrome of airway inflammation characterized by clinical symptoms of cough and wheeze. Highlighting the complex and heterogeneous nature of asthma, this review summarizes recent advances in asthma classification that are based on pathobiology, and thereby directly addresses limitations of existent definitions of asthma. By reviewing and contrasting clinical and mechanistic features of adult and childhood asthma, the review summarizes key biomarkers that distinguish childhood asthma subtypes. While atopy and its severity are important features of childhood asthma, there is evidence to support the existence of a childhood asthma endotype distinct from the atopic endotype. Although biomarkers of non-atopic asthma are an area of future research, we summarize a clinical approach that includes existing measures of airway-specific and systemic measures of atopy, co-existing morbidities, and disease severity and control, in the definition of childhood asthma, to empower health care providers to better characterize asthma disease burden in children. Identification of biomarkers of non-atopic asthma and the contribution of genetics and epigenetics to pediatric asthma burden remains a research need, which can potentially allow delivery of precision medicine to pediatric asthma. IMPACT: This review highlights asthma as a complex and heterogeneous disease and discusses recent advances in the understanding of the pathobiology of asthma to demonstrate the need for a more nuanced definitions of asthma. We review current knowledge of asthma phenotypes and endotypes and put forth an approach to endotyping asthma that may be useful for defining asthma for clinical care as well as for future research studies in the realm of personalized medicine for asthma.

Effect of pharmacists' interventions on health outcomes of children with asthma: A systematic review

METHODS

A literature search was performed in January 23, 2018 at the Embase, LILACS, OpenThesis, PubMed, Cochrane Library, and Web of Science databases through January 23, 2018, using keywords related to "asthma," "pharmacist," and "children." This systematic review followed the methodologic standards recommended by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We included intervention studies on the effect of pharmacists' interventions on pediatric patients with asthma, performed in hospital or ambulatory care settings, with presenting process and outcome indicators as a result of pharmacists' interventions. The methodologic quality of the included studies was assessed independently by 2 researchers. The Cohen kappa index was used to measure the degree of agreement between the 2 investigators.

RESULTS

The search yielded 3671 records, of which 5 were included in this review. Most of these studies were conducted in the United States (n = 2) and in outpatient clinics (n = 4). All studies described components of pharmacists' interventions. The most reported category concerning pharmacists' work process was the initial assessment of patients' conditions, with the assessment of outcomes (at baseline and follow-up) as the only category present in all studies. The most assessed outcomes at baseline were asthma control, emergency department visits, medication use and technique, and adherence to asthma therapy. At follow-up, emergency department visits were the most evaluated outcome (n = 2), and no study assessed economic outcomes. The average consultation time ranged from 20 to 45 minutes, and the number of encounters ranged from 2 to 3.

CONCLUSION

This study highlighted the limited number of studies, most with low quality, on the impact of the pharmacist on pediatric asthma. The most assessed outcome was the number of emergency department visits, with positive results after interventions. Heterogeneity regarding assessed outcomes and work processes was noted, which limited comparison of the results and interventions.

Nasal interferon responses to community rhinovirus infections are similar in controls and children with asthma

BACKGROUND

Rhinovirus (RV) is the main cause of asthma exacerbations in children. Some studies reported that persons with asthma have attenuated interferon (IFN) responses to experimental RV infection compared with healthy individuals. However, responses to community-acquired RV infections in controls and children with asthma have not been compared.

OBJECTIVE

To evaluate nasal cytokine responses after natural RV infections in people with asthma and healthy children.

METHODS

We compared nasal cytokine expression among controls and children with asthma during healthy, virus-negative surveillance weeks and self-reported RV-positive sick weeks. A total of 14 controls and 21 patients with asthma were studied. Asthma disease severity was based on symptoms and medication use. Viral genome was detected by multiplex polymerase chain reaction. Nasal cytokine protein levels were determined by multiplex assays.

RESULTS

Two out of 47 surveillance weeks tested positive for RV, illustrating an asymptomatic infection rate of 5%. A total of 38 of 47 sick weeks (81%) tested positive for the respiratory virus. Of these, 33 (87%) were positive for RV. During well weeks, nasal interleukin 8 (IL-8), IL-12, and IL-1β levels were higher in children with asthma than controls. Compared with healthy virus-negative surveillance weeks, IL-8, IL-13, and interferon beta increased during colds only in patients with asthma. In both controls and children with asthma, the nasal levels of interferon gamma, interferon lambda-1, IL-1β, IL-8, and IL-10 increased during RV-positive sick weeks. During RV infection, IL-8, IL-1β, and tumor necrosis factor-α levels were strongly correlated.

CONCLUSION

In both controls and patients with asthma, natural RV infection results in robust type II and III IFN responses.

Cytokine levels in children and adults with wheezing and asthma show specific patterns of variability over time

Levels of cytokines are used for in-depth characterization of patients with asthma; however, the variability over time might be a critical confounder. To analyze the course of serum cytokines in children, adolescents and adults with asthma and in healthy controls and to propose statistical methods to control for seasonal effects. Of 532 screened subjects, 514 (91·5%) were included in the All Age Asthma Cohort (ALLIANCE). The cohort included 279 children with either recurrent wheezing bronchitis (more than two episodes) or doctor-diagnosed asthma, 75 healthy controls, 150 adult asthmatics and 31 adult healthy controls. Blood samples were collected and 25 μl serum was used for analysis with the Bio-Plex Pr human cytokine 27-Plex assay. Mean age, body mass index and gender in the three groups of wheezers, asthmatic children and adult asthmatics were comparable to healthy controls. Wheezers (34·5%), asthmatic children (78·7%) and adult asthmatics (62·8%) were significantly more often sensitized compared to controls (4·5, 22 and 22·6%, respectively). Considering the entire cohort, interleukin (IL)-1ra, IL-4, IL-9, IL-17, macrophage inflammatory protein (MIP)-1- α and tumor necrosis factor (TNF)- α showed seasonal variability, whereas IL-1β, IL-7, IL-8, IL-13, eotaxin, granulocyte colony-stimulating factor (G-CSF), interferon gamma-induced protein (IP)-10, MIP-1 β and platelet-derived growth factor (PDGF)-BB did not. Significant differences between wheezers/asthmatics and healthy controls were observed for IL-17 and PDGF-BB, which remained stable after adjustment for the seasonality of IL-17. Seasonality has a significant impact on serum cytokine levels in patients with asthma. Because endotyping has achieved clinical importance to guide individualized patient-tailored therapy, it is important to account for seasonal effects.

The Effects of Genotype × Phenotype Interactions on Transcriptional Response to Silver Nanoparticle Toxicity in Organotypic Cultures of Murine Tracheal Epithelial Cells

The airway epithelium is critical for maintaining innate and adaptive immune responses, and occupational exposures that disrupt its immune homeostasis may initiate and amplify airway inflammation. In our previous study, we demonstrated that silver nanoparticles (AgNP), which are engineered nanomaterials used in multiple applications but primarily in the manufacturing of many antimicrobial products, induce toxicity in organotypic cultures derived from murine tracheal epithelial cells (MTEC), and those differentiated toward a "Type 2 [T2]-Skewed" phenotype experienced an increased sensitivity to AgNP toxicity, suggesting that asthmatics could be a sensitive population to AgNP exposures in occupational settings. However, the mechanistic basis for this genotype × phenotype (G × P) interaction has yet to be defined. In this study, we conducted transcriptional profiling using RNA-sequencing to predict the enrichment of specific canonical pathways and upstream transcriptional regulators to assist in defining a mechanistic basis for G × P effects on AgNP toxicity. Organotypic cultures were derived from MTEC across 2 genetically inbred mouse strains (A/J and C57BL/6J mice), 2 phenotypes ("Normal" and "T2-Skewed"), and 1 AgNP exposure (an acute 24 h exposure) to characterize G × P effects on transcriptional response to AgNP toxicity. The "T2-Skewed" phenotype was marked by increased pro-inflammatory T17 responses to AgNP toxicity, which are significant predictors of neutrophilic/difficult-to-control asthma and suggests that asthmatics could be a sensitive population to AgNP exposures in occupational settings. This study highlights the importance of considering G × P effects when identifying these sensitive populations, whose underlying genetics or diseases could directly modify their response to AgNP exposures.

Inner-City Asthma in Childhood

The inner-city is a well-established and well-studied location that includes children at high risk for high asthma prevalence and morbidity. A number of intrinsic and extrinsic risk factors contribute to asthma in inner-city populations. This review seeks to explore these risk factors and evaluate how they contribute to increased asthma morbidity. Previous literature has identified risk factors such as race and ethnicity, prematurity, obesity, and exposure to aeroallergens and pollutants. Environmental and medical interventions aimed at individual risk factors and specific asthma phenotypes have contributed to improved outcomes in the inner-city children with asthma.

Toward clinically applicable biomarkers for asthma: An EAACI position paper

Inflammation, structural, and functional abnormalities within the airways are key features of asthma. Although these processes are well documented, their expression varies across the heterogeneous spectrum of asthma. Type 2 inflammatory responses are characterized by increased levels of eosinophils, FeNO, and type 2 cytokines in blood and/or airways. Presently, type 2 asthma is the best-defined endotype, typically found in patients with allergic asthma, but surprisingly also in nonallergic patients with (severe) asthma. The etiology of asthma with non-type 2 inflammation is less clear. During the past decade, targeted therapies, including biologicals and small molecules, have been increasingly integrated into treatment strategies of severe asthma. These treatments block specific inflammatory pathways or single mediators. Single or composite biomarkers help to identify patients who will benefit from these treatments. So far, only a few inflammatory biomarkers have been validated for clinical application. The European Academy of Allergy & Clinical Immunology Task Force on Biomarkers in Asthma was initiated to review different biomarker sampling methods and to investigate clinical applicability of new and existing inflammatory biomarkers (point-of-care) to support diagnosis, targeted treatment, and monitoring of severe asthma. Subsequently, we discuss existing and novel targeted therapies for asthma as well as applicable biomarkers.

Inner-City Asthma in Children

Asthma in inner-city children is often severe and difficult to control. Residence in poor and urban areas confers increased asthma morbidity even after adjusting for ethnicity, age, and gender. Higher exposure to household pests, such as cockroaches and mice, pollutants and tobacco smoke exposure, poverty, material hardship, poor-quality housing, differences in health care quality, medication compliance, and heath care access also contribute to increased asthma morbidity in this population. Since 1991, the National Institutes of Allergy and Infectious Diseases established research networks: the National Cooperative Inner-City Asthma Study (NCICAS), the Inner-City Asthma Study (ICAS), and the Inner-City Asthma Consortium (ICAC), to improve care for this at risk population. The most striking finding of the NCICAS is the link between asthma morbidity and the high incidence of allergen sensitization and exposure, particularly cockroach. The follow-up ICAS confirmed that reductions in household cockroach and dust mite were associated with reduction in the inner-city asthma morbidity. The ICAC studies have identified that omalizumab lowered fall inner-city asthma exacerbation rate; however, the relationship between inner-city asthma vs immune system dysfunction, respiratory tract infections, prenatal environment, and inner-city environment is still being investigated. Although challenging, certain interventions for inner-city asthma children have shown promising results. These interventions include family-based interventions such as partnering families with asthma-trained social workers, providing guidelines driven asthma care as well as assured access to controller medication, home-based interventions aim at elimination of indoor allergens and tobacco smoke exposure, school-based asthma programs, and computer/web-based asthma programs.

A strategy for high-dimensional multivariable analysis classifies childhood asthma phenotypes from genetic, immunological, and environmental factors

Background

Associations between childhood asthma phenotypes and genetic, immunological, and environmental factors have been previously established. Yet, strategies to integrate high‐dimensional risk factors from multiple distinct data sets, and thereby increase the statistical power of analyses, have been hampered by a preponderance of missing data and lack of methods to accommodate them.

Methods

We assembled questionnaire, diagnostic, genotype, microarray, RT‐qPCR, flow cytometry, and cytokine data (referred to as data modalities) to use as input factors for a classifier that could distinguish healthy children, mild‐to‐moderate allergic asthmatics, and nonallergic asthmatics. Based on data from 260 German children aged 4‐14 from our university outpatient clinic, we built a novel multilevel prediction approach for asthma outcome which could deal with a present complex missing data structure.

Results

The optimal learning method was boosting based on all data sets, achieving an area underneath the receiver operating characteristic curve (AUC) for three classes of phenotypes of 0.81 (95%‐confidence interval (CI): 0.65‐0.94) using leave‐one‐out cross‐validation. Besides improving the AUC, our integrative multilevel learning approach led to tighter CIs than using smaller complete predictor data sets (AUC = 0.82 [0.66‐0.94] for boosting). The most important variables for classifying childhood asthma phenotypes comprised novel identified genes, namely PKN2 (protein kinase N2), PTK2 (protein tyrosine kinase 2), and ALPP (alkaline phosphatase, placental).

Conclusion

Our combination of several data modalities using a novel strategy improved classification of childhood asthma phenotypes but requires validation in external populations. The generic approach is applicable to other multilevel data‐based risk prediction settings, which typically suffer from incomplete data.

Phenotypes/endotypes-driven treatment in asthma

PURPOSE OF REVIEW

Target therapy is the necessary step towards personalized medicine. The definition of asthma phenotypes and underlying mechanisms (endotypes) represent a key point in the development of new asthma treatments. Big data analysis, biomarker research and the availability of monoclonal antibodies, targeting specific cytokines is leading to the rapid evolution of knowledge. In this review, we sought to outline many of the recent advances in the field.

RECENT FINDINGS

Several attempts have been made to identify asthma phenotypes, sometimes with contrasting results. More success has been obtained concerning the pathogenetic mechanism of specific asthma patterns with the consequent identification of biomarkers and development of effective ad hoc treatment.

SUMMARY

We are in the middle of an extraordinary revolution of our mode of thinking about and approaching asthma. All the effort in the identification of clusters of patients with different disease clinical patterns, prognosis and response to treatment is closely linked to the identification of endotypes (Th2-low and Th2-high). This approach has allowed the development of the specific treatments (anti IgE, Anti IL5 and IL5R) that are now available and is leading to new ones.

Asthma in inner city children: recent insights: United States

PURPOSE OF REVIEW

Children living in US inner cities experience disparate burdens of asthma, especially in severity, impairment, exacerbations, and morbidity. Investigations seeking to better understand the factors and mechanisms underlying asthma prevalence, severity, and exacerbation in children living in these communities can lead to interventions that can narrow asthma disparities and potentially benefit all children with asthma. This update will focus on recent (i.e. late 2016-2017) advances in the understanding of asthma in US inner city children.

RECENT FINDINGS

Studies published in the past year expand understanding of asthma prevalence, severity, exacerbation, and the outcomes of guidelines-based management of these at-risk children, including: asthma phenotypes in US inner city children that are severe and difficult-to-control; key environmental determinants and mechanisms underlying asthma severity and exacerbations (e.g. allergy-mediated exacerbation susceptibility to rhinovirus); the importance of schools as a place for provocative exposures (e.g. mouse allergen, nitrogen dioxide) as well as a place where asthma care and outcomes can be improved; and the development and validation of clinically useful indices for gauging asthma severity and predicting exacerbations.

SUMMARY

These recent studies provide a trove of actionable findings that can improve asthma care and outcomes for these at-risk children.

Endotypes in allergic diseases

PURPOSE OF REVIEW

The precision medicine concept is both appealing and challenging. We review here the recent findings in the endotype-driven approach for major allergic diseases.

RECENT FINDINGS

Stratified medicine for different allergic diseases can identify patients who are more likely to benefit or experience an adverse reaction in response to a given therapy and anticipate their long-term outcome and vital risk. In addition, this approach potentially facilitates drug development and prevention strategies.

SUMMARY

The endotype-driven approach in allergic diseases has tremendous potential, but there are notable barriers in reaching the new world of precision medicine. Multidimensional endotyping integrating visible properties with multiple biomarkers is recommended for both type 2 and nontype 2 allergic diseases to provide evidence that a certain pathway is the key driver for a given patient. Significant healthcare system changes are required to achieve the expected targets.

Precision medicine and phenotypes, endotypes, genotypes, regiotypes, and theratypes of allergic diseases

A rapidly developing paradigm for modern health care is a proactive and individualized response to patients' symptoms, combining precision diagnosis and personalized treatment. Precision medicine is becoming an overarching medical discipline that will require a better understanding of biomarkers, phenotypes, endotypes, genotypes, regiotypes, and theratypes of diseases. The 100-year-old personalized allergen-specific management of allergic diseases has particularly contributed to early awareness in precision medicine. Polyomics, big data, and systems biology have demonstrated a profound complexity and dynamic variability in allergic disease between individuals, as well as between regions. Escalating health care costs together with questionable efficacy of the current management of allergic diseases facilitated the emergence of the endotype-driven approach. We describe here a precision medicine approach that stratifies patients based on disease mechanisms to optimize management of allergic diseases.

Expression of corticosteroid-regulated genes by PBMCs in children with asthma

BACKGROUND

Variability in response to inhaled corticosteroids (ICSs) can result in less than optimal asthma control. Development of biomarkers assessing the therapeutic efficacy of corticosteroids is important.

OBJECTIVE

We sought to examine whether in vitro PBMC responses to corticosteroids relate to the clinical ICS response.

METHODS

PBMCs were collected from 125 children with asthma (6-17 years) at enrollment (visit 0 [V0]) and after 1 year of bimonthly guidelines-based management visits (visit 6 [V6]). Difficult-to-control and easy-to-control asthma were defined as requiring daily therapy with 500 μg or more of fluticasone propionate (FLU) with or without a long-acting β-agonist versus 100 μg or less of FLU in at least 4 visits. mRNA levels of glucocorticoid receptor α and corticosteroid transactivation (FK506-binding protein 5) and transrepression markers (IL-8 and TNF-α) were measured by using RT-PCR in freshly isolated cells and in response to 10-8 mol/L FLU.

RESULTS

Compared with PBMCs from patients with easy-to-control asthma, PBMCs from those with difficult-to-control asthma had significantly lower glucocorticoid receptor α levels at V0 (P = .05). A 30% increase in IL-8 suppression by FLU (P = .04) and a trend for increased TNF-α suppression by FLU between V0 and V6 (P = .07) were observed in patients with easy-to-control asthma. In contrast, no changes between V0 and V6 in IL-8 and TNF-α suppression by FLU were observed in patients with difficult-to-control asthma. Corticosteroid-mediated transactivation (FK506-binding protein 5 induction by FLU) increased in the PBMCs of patients with difficult-to-control and easy-to-control asthma between V0 and V6 (P = .05 and P = .03, respectively).

CONCLUSIONS

PBMCs of children with difficult-to-control asthma treated with guidelines-based therapy and requiring high-dose ICSs had reduced in vitro responsiveness to corticosteroids.

Elevated Serum Interleukin-8 Level as a Preferable Biomarker for Identifying Uncontrolled Asthma and Glucocorticosteroid Responsiveness

BACKGROUND

To explore the clinical significance of serum interleukin-8 (IL-8) level as a biomarker for uncontrolled asthma in order to improve our understanding of asthma phenotypes and facilitate the development of new therapeutic agents in the future.

MATERIALS AND METHODS

A total of 246 uncontrolled asthma patients and 50 healthy controls were selected from an outpatient clinic during October 2015 and April 2016. The clinical data were collected, and the levels of IL-8, IL-6, tumor necrosis factor-α (TNF-α), and immunoglobulin (IgE) were measured in peripheral blood via ELISA assay. The level of serum IL-8 was compared between the glucocorticosteroid groups, receiving inhaled corticosteroids (ICs), oral corticosteroids (OCs), and intravenous corticosteroids (GCs), respectively. Changes in the serum IL-8 level were compared between asthmatics with good and poor glucocorticosteroid responsiveness.

RESULTS

The serum IL-8 level in uncontrolled asthmatics (87.45 pg/mL; 5-7500) was significantly higher than that of the healthy controls (10.9 pg/mL; 6.8-39.65; P< 0.001). The increase in the serum IL-8 level above the normal range occurred in 58.13% of uncontrolled asthmatics. The area under curve (AUC) for serum IL-8 level, indicative of uncontrolled asthma, was 0.816 (95% CI, 0.7605 to 0.8721; P< 0.0001), which was greater than the AUC of fractional exhaled nitric oxide (AUC, 0.711; 95% CI, 0.6057 to 0.8153; P= .0188). The serum IL-8 level showed a significant positive relationship with blood neutrophil count (P= 0.0004), neutrophil percentage (P= 0.027), serum TNF-α protein (P< 0.0001), forced expiratory volume/forced vital capacity (FEV₁/FVC) ratio (P< 0.05), and rate of FEV₁ change after bronchodilation. The level of IL-8 in patients requiring OCs or GCs treatment was significantly higher than that of ICs patients (186 and 235 pg/mL vs. 61 pg/mL; P< 0.0001). The reduction in the serum IL-8 level was more significant in asthmatic patients with good responsiveness (277 pg/mL (65.3-3124) to 67.8 pg/mL (5-1408); P< 0.0001), compared to those with poor responsiveness (218 pg/mL (64.8-7500) vs. 197 pg/mL (56.9-5238); P= 0.49).

CONCLUSION

The increase in serum IL-8 level can be used as a preferable biomarker to identify asthma status and initial treatment in asthmatics. The change in IL-8 level also reflects the response to glucocorticosteroids in uncontrolled asthma. These exploratory results suggest an association between the pathophysiology, inflammation, and clinical outcomes of asthma. This raises the possibility of developing new agents for IL-8 inhibition and helps provide more precise and personalized asthma care.