TBX21: a functional variant predicts improvement in asthma with the use of inhaled corticosteroids

Correlation of TBX21 gene polymorphisms with ankylosing spondylitis in a Chinese population

Genome-wide association studies analysis has revealed associations between ankylosing spondylitis (AS) and loci on the TBX21 gene across various populations. This study aimed to investigate if there is a connection between a higher risk of AS in a Chinese population and two polymorphism loci on the TBX21 gene. To achieve this, we performed a case-control investigation involving 363 patients with AS and 907 healthy individuals. Genotyping was carried out using the iPLEX Gold genotyping assay. The analysis of genotypes and haplotypes was performed using SPSS 23.0 and SHEsis software. The results revealed no statistically significant correlation between the two specified single-nucleotide polymorphisms of TBX21 (rs11657479 C/T and rs4794067 C/T) and susceptibility to AS. However, upon conducting stratification analysis, our findings demonstrated a significant association between rs11657479 and susceptibility to human leucocyte antigen (HLA)-B27+ AS in allelic (C vs. T: odds ratio [OR] = 1.52, 95%CI = 1.09-2.11, corrected p [pc] = .028), heterozygous (CT vs. TT: OR = 1.63, 95%CI = 1.13-2.34, pc = .016) and dominant (CT + CC vs. TT: OR = 1.60, 95%CI = 1.12-2.28, pc = .018) models. Furthermore, the haplotype rs4794067/C-rs11657479/C of TBX21 was found to increase the risk of HLA-B27+ AS cases. In conclusion, our findings indicate a correlation between TBX21 gene polymorphism and HLA-B27+ AS patients within the Chinese population.

Aflatoxin B1 can aggravate BALB/c mice allergy to ovalbumin through changing their Th2 cells immune responses

Foods contaminated by Aflatoxin B₁ (AFB₁) frequently happen in the world and can cause a lot healthy damages to human beings, meanwhile, some of these foods are easily irritate food allergy. To investigate the effect of AFB₁ exposure on food allergy, three doses of AFB₁ were set, including 0.3 μg/kg · bw (LDAF), 7.5 μg/kg · bw (MDAF), and 100.0 μg/kg · bw (HDAF), respectively; food allergy model was constructed by the BALB/c mice allergy to ovalbumin (OVA). The changes of titer in OVA-specific immunoglobulin E (IgE), IgG, IgG1, IgG2a, as well as level of the mMCP-1 in sera were determined by enzyme linked immunosorbent assay (ELISA), respectively; the levels of interleukin (IL-4, IL-5, IL-13) and interferon (IFN)-γ in spleen were separately assessed using ELISA kits, and their relative genes expression were verified by Real-time fluorescence quantitative PCR (Q-PCR); the population of Th1/Th2/Treg cells were analyzed by flow cytometry. Results showed that when OVA-allergic mice were exposed to AFB₁, the production of OVA-specific IgE, IL-4, IL-5 and IL-13, and mMCP-1 were all increased, whereas the level of IFN-γ was decreased; the Th1/Th2 balance was disrupted and the development of Th cells tilted to the Th2 phenotype. The study would contribute to further understand the risk of fungal toxins in food allergy.

Heterogeneity of Treatment Response to Asthma

The definition of asthma has evolved over the years with significant heterogeneity of the disease increasingly recognized. Complex gene and environment interactions result in different pheno-endotypes of asthma that respond differently to the same treatment. Multiple studies have revealed pharmacogenomic and endophenotypic factors that predict treatment response to standard therapies for asthma. Recent advances in biologic medications have enabled a more tailored approach to the care of patients with moderate to severe asthma, taking into consideration clinical traits and measurable biomarkers. This chapter will review heterogeneity in treatment response to different medication classes for asthma: inhaled and systemic corticosteroids, beta-2 agonists, leukotriene modifiers, muscarinic antagonists, macrolides, and biologics.

The Genetic Factors of the Airway Epithelium Associated with the Pathology of Asthma

Asthma is a chronic disease of the airways characterized by inflammation, tightened muscles, and thickened airway walls leading to symptoms such as shortness of breath, chest tightness, and cough in patients. The increased risk of asthma in children of asthmatics parents supports the existence of genetic factors involved in the pathogenesis of this disease. Genome-wide association studies have discovered several single nucleotide polymorphisms associated with asthma. These polymorphisms occur within several genes and can contribute to different asthma phenotypes, affect disease severity, and clinical response to different therapies. The complexity in the etiology of asthma also results from interactions between environmental and genetic factors. Environmental exposures have been shown to increase the prevalence of asthma in individuals who are genetically susceptible. This review summarizes what is currently known about the genetics of asthma in relation to risk, response to common treatments, and gene-environmental interactions.

Pharmacogenomics of Leukotriene Modifiers: A Systematic Review and Meta-Analysis

Pharmacogenetics research on leukotriene modifiers (LTMs) for asthma has been developing rapidly, although pharmacogenetic testing for LTMs is not yet used in clinical practice. We performed a systematic review and meta-analysis on the impact of pharmacogenomics on LTMs response. Studies published until May 2022 were searched using PubMed, EMBASE, and Cochrane databases. Pharmacogenomics/genetics studies of patients with asthma using LTMs with or without other anti-asthmatic drugs were included. Statistical tests of the meta-analysis were performed with Review Manager (Revman, version 5.4, The Cochrane Collaboration, Copenhagen, Denmark) and R language and environment for statistical computing (version 4.1.0 for Windows, R Core Team, Vienna, Austria) software. In total, 31 studies with 8084 participants were included in the systematic review and five studies were also used to perform the meta-analysis. Two included studies were genome-wide association studies (GWAS), which showed different results. Furthermore, none of the SNPs investigated in candidate gene studies were identified in GWAS. In candidate gene studies, the most widely studied SNPs were ALOX5 (tandem repeats of the Sp1-binding domain and rs2115819), LTC4S-444A/C (rs730012), and SLCO2B1 (rs12422149), with relatively inconsistent conclusions. LTC4S-444A/C polymorphism did not show a significant effect in our meta-analysis (AA vs. AC (or AC + CC): −0.06, 95%CI: −0.16 to 0.05, p = 0.31). AA homozygotes had smaller improvements in parameters pertaining to lung functions (−0.14, 95%CI: −0.23 to −0.05, p = 0.002) in a subgroup of patients with non-selective CysLT receptor antagonists and patients without inhaled corticosteroids (ICS) (−0.11, 95%CI: −0.14 to −0.08, p < 0.00001), but not in other subgroups. Variability exists in the pharmacogenomics of LTMs treatment response. Our meta-analysis and systematic review found that LTC4S-444A/C may influence the treatment response of patients taking non-selective CysLT receptor antagonists for asthma, and patients taking LTMs not in combination with ICS for asthma. Future studies are needed to validate the pharmacogenomic influence on LTMs response.

Heterogeneous Condition of Asthmatic Children Patients: A Narrative Review

Currently, asthma represents the most common chronic disorder in children, showing an increasingly consistent burden worldwide. Childhood asthma, similar to what happens in adults, is a diversified disease with a great variability of phenotypes, according to genetic predisposition of patients, age, severity of symptoms, grading of risk, and comorbidities, and cannot be considered a singular well-defined disorder, but rather a uniquely assorted disorder with variable presentations throughout childhood. Despite several developments occurring in recent years in pediatric asthma, above all, in the management of the disease, some essential areas, such as the improvement of pediatric asthma outcomes, remain a hot topic. Most treatments of the type 2 (T2) target phenotype of asthma, in which IL-4, IL-5, and IL-13 modulate the central signals of inflammatory reactions. Although, there may be an unresolved need to identify new biomarkers used as predictors to improve patient stratification using disease systems and to aid in the selection of treatments. Moreover, we are globally facing many dramatic challenges, including climate change and the SARS-CoV2 pandemic, which have a considerable impact on children and adolescent asthma. Preventive strategies, including allergen immunotherapy and microbiome evaluation, and targeted therapeutic strategies are strongly needed in this population. Finally, the impact of asthma on sleep disorders has been reviewed.

Pharmacogenomics and Pediatric Asthmatic Medications

Asthma is a respiratory condition often stemming from childhood, characterized by difficulty breathing and/or chest tightness. Current treatment options for both adults and children include beta-2 agonists, inhaled corticosteroids (ICS), and leukotriene modifiers (LTM). Despite recommendations by the Global Initiative for Asthma, a substantial number of patients are unresponsive to treatment and unable to control symptoms. Pharmacogenomics have increasingly become the front line of precision medicine, especially with the recent use of candidate gene and genome- wide association studies (GWAS). Screening patients preemptively could likely decrease adverse events and therapeutic failure. However, research in asthma, specifically in pediatrics, has been low. Although numerous adult trials have evaluated the impact of pharmacogenomics and treatment response, the lack of evidence in children has hindered progress towards clinical application. This review aims to discuss the impact of genetic variability and response to asthmatic medications in the pediatric population.

Multiomics Analysis Identifies BIRC3 as a Novel Glucocorticoid Response-Associated Gene

BACKGROUND

Inhaled corticosteroid (ICS) response among patients with asthma is influenced by genetics, but biologically actionable insights based on associations have not been found. Various glucocorticoid response omics datasets are available to interrogate their biological effects.

OBJECTIVE

We sought to identify functionally relevant ICS response genetic associations by integrating complementary multiomics datasets.

METHODS

Variants with p-values<10^-4 from a previous ICS response genome-wide association study were re-ranked based on integrative scores determined from: i) glucocorticoid receptor (GR)- and ii) RNA polymerase II (RNAP II)-binding regions inferred from ChIP-Seq data for three airway cell types, iii) glucocorticoid response element (GRE) motifs, iv) differentially expressed genes in response to glucocorticoid exposure according to 20 transcriptomic datasets, and v) expression quantitative trait loci (eQTLs) from GTEx. Candidate variants were tested for association with ICS response and asthma in six independent studies.

RESULTS

Four variants had significant (q-value<0.05) multiomics integrative scores. These variants were in a locus consisting of 52 variants in high LD (r²≥0.8) near GR-binding sites by the gene BIRC3. Variants were also BIRC3 eQTLs in lung, and two were within/near putative GRE motifs. BIRC3 had increased RNAP II occupancy and gene expression with glucocorticoid exposure in two ChIP-Seq and 13 transcriptomic datasets. Some BIRC3 variants in the 52-variant locus were associated (p-value<0.05) with ICS response in three independent studies and others with asthma in one study.

CONCLUSION

BIRC3 should be prioritized for further functional studies of ICS response.

CLINICAL IMPLICATION

Genetic variation near BIRC3 may influence ICS response in people with asthma.

High Th2 cytokine levels and upper airway inflammation in human inherited T-bet deficiency

We have described a child suffering from Mendelian susceptibility to mycobacterial disease (MSMD) due to autosomal recessive, complete T-bet deficiency, which impairs IFN-γ production by innate and innate-like adaptive, but not mycobacterial-reactive purely adaptive, lymphocytes. Here, we explore the persistent upper airway inflammation (UAI) and blood eosinophilia of this patient. Unlike wild-type (WT) T-bet, the mutant form of T-bet from this patient did not inhibit the production of Th2 cytokines, including IL-4, IL-5, IL-9, and IL-13, when overexpressed in T helper 2 (Th2) cells. Moreover, Herpesvirus saimiri-immortalized T cells from the patient produced abnormally large amounts of Th2 cytokines, and the patient had markedly high plasma IL-5 and IL-13 concentrations. Finally, the patient's CD4+ αβ T cells produced most of the Th2 cytokines in response to chronic stimulation, regardless of their antigen specificities, a phenotype reversed by the expression of WT T-bet. T-bet deficiency thus underlies the excessive production of Th2 cytokines, particularly IL-5 and IL-13, by CD4+ αβ T cells, causing blood eosinophilia and UAI. The MSMD of this patient results from defective IFN-γ production by innate and innate-like adaptive lymphocytes, whereas the UAI and eosinophilia result from excessive Th2 cytokine production by adaptive CD4+ αβ T lymphocytes.

Evaluation of efficacy of nebulized low molecular weight heparin as an adjunctive extra treatment for acute mild-moderate asthma attack; a randomized clinical trial study

BACKGROUND

Asthma is the most common chronic disorders of the respiratory tract. This study aimed to evaluate the effect of low-molecular-weight heparins (LMWHs) in the treatment of acute asthma.

METHODS

In this randomized clinical trial, patients with acute asthma attacks were enrolled. The patients were divided randomly into two groups. Patients in the intervention group received nebulized LMWH (1 mg/kg) with albuterol (2.5 mg) every 20 min for 10 min. The patients in the control group received nebulized albuterol with the same dose. Then peak expiratory flow rates (PEFR) and forced expiratory volume in 1 s (FEV1), and hemodynamic parameters in both groups were assessed for every 20 min.

RESULTS

In total 70 patients enrolled in this study. We found that the mean PEFR at 40 min was higher in the LMWH group than the control group (202.51 L/min and 180.2 L/min) (p = 0.001). Moreover, this difference remains significant in the 60th minute (p < 0.001). Further, FEV1 was significantly higher in the LMWH group after 60 min (1.82 L/min vs 1.48 L/min, p < 0.001). Moreover, we found that the hemodynamic parameters were sustainable in the intervention group.

CONCLUSION

The study suggests that LMWH in mild-moderate asthma attacks may be beneficial in the short term and could be prescribed in addition to standard albuterol therapy.

Genetic Determinants of Poor Response to Treatment in Severe Asthma

Severe asthma is a multifactorial disorder with marked phenotypic heterogeneity and complex interactions between genetics and environmental risk factors, which could, at least in part, explain why during standard pharmacologic treatment, many patients remain poorly controlled and at an increased risk of airway remodeling and disease progression. The concept of “precision medicine” to better suit individual unique needs is an emerging trend in the management of chronic respiratory diseases. Over the past few years, Genome-Wide Association Studies (GWAS) have revealed novel pharmacogenetic variants related to responses to inhaled corticosteroids and the clinical efficacy of bronchodilators. Optimal clinical response to treatment may vary between racial/ethnic groups or individuals due to genetic differences. It is also plausible to assume that epigenetic factors play a key role in the modulation of gene expression patterns and inflammatory cytokines. Remarkably, specific genetic variants related to treatment effectiveness may indicate promising pathways for novel therapies in severe asthma. In this review, we provide a concise update of genetic determinants of poor response to treatment in severe asthma and future directions in the field.

Human T-bet Governs Innate and Innate-like Adaptive IFN-γ Immunity against Mycobacteria

Inborn errors of human interferon gamma (IFN-γ) immunity underlie mycobacterial disease. We report a patient with mycobacterial disease due to inherited deficiency of the transcription factor T-bet. The patient has extremely low counts of circulating Mycobacterium-reactive natural killer (NK), invariant NKT (iNKT), mucosal-associated invariant T (MAIT), and Vδ2+ γδ T lymphocytes, and of Mycobacterium-non reactive classic TH1 lymphocytes, with the residual populations of these cells also producing abnormally small amounts of IFN-γ. Other lymphocyte subsets develop normally but produce low levels of IFN-γ, with the exception of CD8+ αβ T and non-classic CD4+ αβ TH1∗ lymphocytes, which produce IFN-γ normally in response to mycobacterial antigens. Human T-bet deficiency thus underlies mycobacterial disease by preventing the development of innate (NK) and innate-like adaptive lymphocytes (iNKT, MAIT, and Vδ2+ γδ T cells) and IFN-γ production by them, with mycobacterium-specific, IFN-γ-producing, purely adaptive CD8+ αβ T, and CD4+ αβ TH1∗ cells unable to compensate for this deficit.

Pharmacogenomic Response of Inhaled Corticosteroids for the Treatment of Asthma: Considerations for Therapy

There is a large interindividual variability in response to ICSs in asthma. About 70% of the variance in ICS response is likely due at least partially to genetically determined characteristics of target genes. In this article, we examine the effects on the ICS response of gene variations in the corticosteroid pathway, and in the pharmacokinetics of corticosteroids, and also those outside the corticosteroid pathway, which have the potential to influence corticosteroid activity. Although the available evidence indicates that responses to ICSs in asthma are influenced by different genetic variants, there are still deep uncertainties as to whether a real association between these genetic variants and corticosteroid response could also possibly exist because there are difficulties in reproducing pharmacogenetic findings. This explains at least partly the insufficient use of pharmacogenomic data when treating asthmatic patients, which creates a real limitation to the proper use of ICSs in an era of precision medicine that links the right patient to the right treatment. Knowing and dealing with the genetic factors that influence the therapeutic ICS response is a fundamental condition for prescribing the right dose of ICS to the right patient at the right time.

Circulating MicroRNAs and Treatment Response in Childhood Asthma

Rationale: Inhaled corticosteroids (ICS) are key treatments for controlling asthma and preventing asthma attacks. However, the responsiveness to ICS varies among individuals. MicroRNAs (miRNAs) have been lauded for their prognostic utility.Objectives: We hypothesized that circulating miRNAs obtained at baseline/prerandomization in the Childhood Asthma Management Program (CAMP) could serve as biomarkers and biologic mediators of ICS clinical response over the 4-year clinical trial period.Methods: We selected baseline serum samples from 462 CAMP subjects subsequently randomized to either ICS (budesonide) or placebo. Samples underwent small RNA sequencing, and read counts were normalized and filtered by depth and coverage. Linear regression was used to associate miRNAs with change in FEV1% (prebronchodilator FEV1 as a percent predicted) over the 4-year treatment period in both main effects and interaction models. We validated the function of the top associated miRNAs by luciferase reporter assays of glucocorticoid-mediated transrepression and predicted response to ICS through logistic regression models.Measurements and Main Results: We identified 7 miRNAs significantly associated with FEV1% change (P ≤ 0.05) and 15 miRNAs with significant interaction (P ≤ 0.05) to ICS versus placebo treatments. We selected three miRNAs for functional validation, of which hsa-miR-155-5p and hsa-miR-532-5p were significantly associated with changes in dexamethasone-induced transrepression of NF-κB. Combined, these two miRNAs were predictive of ICS response over the course of the clinical trial, with an area under the receiver operating characteristic curve of 0.86.Conclusions: We identified two functional circulating miRNAs predictive of asthma ICS treatment response over time.

Asthma and Corticosteroid Responses in Childhood and Adult Asthma

Corticosteroids are the most effective treatment for asthma; inhaled corticosteroids (ICSs) are the first-line treatment for children and adults with persistent symptoms. ICSs are associated with significant improvements in lung function. The anti-inflammatory effects of corticosteroids are mediated by both genomic and nongenomic factors. Variation in the response to corticosteroids has been observed. Patient characteristics, biomarkers, and genetic features may be used to predict response to ICSs. The existence of multiple mechanisms underlying glucocorticoid insensitivity raises the possibility that this might indeed reflect different diseases with a common phenotype.

How does race and ethnicity effect the precision treatment of asthma?

Introduction

Asthma is a common condition that affects large numbers of children and adults, yet the burden of disease is not equally distributed amongst groups. In the United States, African Americans and Puerto Ricans have higher rates of asthma and its complications when compared with European Americans. However, clinical trials and genetic studies have largely focused on the latter group.

Areas covered

Here we examine what is known regarding differences in asthma treatment response by race-ethnicity. We also review existing genetic studies related to the use of asthma medications, paying special attention to studies that included substantial numbers of non-white population groups. Publicly accessible search engines of the medical literature were queried using combinations of the terms asthma, race, ethnicity, pharmacogenomics, and pharmacogenetics, as well as the names of individual asthma medication classes. The list of articles reviewed was supplemented by bibliographies and expert knowledge.

Expert opinion

A substantial and coordinated effort is still needed to both identify and validate genetic biomarkers of asthma medication response, as currently there are no clinically actionable genetic markers available for this purpose. The path to identifying such markers in non-white populations is even more formidable, since these groups are underrepresented in existing data.

Pharmacogenetic Factors Affecting Asthma Treatment Response. Potential Implications for Drug Therapy

Asthma is a frequent disease, mainly characterized by airway inflammation, in which drug therapy is crucial in its management. The potential of pharmacogenomics testing in asthma therapy has been, to date, little explored. In this review, we discuss pharmacogenetic factors affecting asthma treatment, both related to drugs used as controller medications for regular maintenance, such as inhaled corticosteroids, anti-leukotriene agents, long-acting beta-agonists, and the new biologic agents used to treat severe persistent asthma. In addition, we discuss current pharmacogenomics knowledge for rescue medications provided to all patients for as-needed relief, such as short-acting beta-agonists. Evidence for genetic variations as a factor related to drugs response has been provided for the following genes and groups of drugs: Inhaled corticosteroids: FCER2; anti-leukotriene agents: ABCC1, and LTC4S; beta-agonists: ADRB2. However, the following genes require further studies confirming or rejecting association with the response to asthma therapy: ADCY9, ALOX5, ARG1, ARG2, CRHR1, CRHR2, CYP3A4, CYP3A5, CYSLTR1, CYSLTR2, GLCCI1, IL4RA, LTA4H, ORMDL3, SLCO2B1, SPATS2L, STIP1, T, TBX21, THRA, THRB, and VEGFA. Although only a minority of these genes are, at present, listed as associated with drugs used in asthma therapy, in the Clinical Pharmacogenomics Implementation Consortium gene-drug pair list, this review reveals that sufficient evidence to start testing the potential of clinical pharmacogenomics in asthma therapy already exists. This evidence supports the inclusion in pilot pharmacogenetics tests of at least four genes. Hopefully these tests, if proven useful, will increase the efficiency and the safety of asthma therapy.

Regulation of IL-17A and implications for TGF-β1 comodulation of airway smooth muscle remodeling in severe asthma

Severe asthma develops as a result of heightened, persistent symptoms that generally coincide with pronounced neutrophilic airway inflammation. In individuals with severe asthma, symptoms are poorly controlled by high-dose inhaled glucocorticoids and often lead to elevated morbidity and mortality rates that underscore the necessity for novel drug target identification that overcomes limitations in disease management. Many incidences of severe asthma are mechanistically associated with T helper 17 (TH17) cell-derived cytokines and immune factors that mediate neutrophilic influx to the airways. TH17-secreted interleukin-17A (IL-17A) is an independent risk factor for severe asthma that impacts airway smooth muscle (ASM) remodeling. TH17-derived cytokines and diverse immune mediators further interact with structural cells of the airway to induce pathophysiological processes that impact ASM functionality. Transforming growth factor-β1 (TGF-β1) is a pivotal mediator involved in airway remodeling that correlates with enhanced TH17 activity in individuals with severe asthma and is essential to TH17 differentiation and IL-17A production. IL-17A can also reciprocally enhance activation of TGF-β1 signaling pathways, whereas combined TH1/TH17 or TH2/TH17 immune responses may additively impact asthma severity. This review seeks to provide a comprehensive summary of cytokine-driven T cell fate determination and TH17-mediated airway inflammation. It will further review the evidence demonstrating the extent to which IL-17A interacts with various immune factors, specifically TGF-β1, to contribute to ASM remodeling and altered function in TH17-driven endotypes of severe asthma.

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.

Genetic associations of the response to inhaled corticosteroids in asthma: a systematic review

There is wide variability in the response to inhaled corticosteroids (ICS) in asthma. While some of this heterogeneity of response is due to adherence and environmental causes, genetic variation also influences response to treatment and genetic markers may help guide treatment. Over the past years, researchers have investigated the relationship between a large number of genetic variations and response to ICS by performing pharmacogenomic studies. In this systematic review we will provide a summary of recent pharmacogenomic studies on ICS and discuss the latest insight into the potential functional role of identified genetic variants. To date, seven genome wide association studies (GWAS) examining ICS response have been published. There is little overlap between identified variants and methodologies vary largely. However, in vitro and/or in silico analyses provide additional evidence that genes discovered in these GWAS (e.g. GLCCI1, FBXL7, T gene, ALLC, CMTR1) might play a direct or indirect role in asthma/treatment response pathways. Furthermore, more than 30 candidate-gene studies have been performed, mainly attempting to replicate variants discovered in GWAS or candidate genes likely involved in the corticosteroid drug pathway. Single nucleotide polymorphisms located in GLCCI1, NR3C1 and the 17q21 locus were positively replicated in independent populations. Although none of the genetic markers has currently reached clinical practise, these studies might provide novel insights in the complex pathways underlying corticosteroids response in asthmatic patients.

Post-viral atopic airway disease: pathogenesis and potential avenues for intervention

Introduction: In early childhood, wheezing due to lower respiratory tract illness is often associated with infection by commonly known respiratory viruses such as respiratory syncytial virus (RSV) and human rhinovirus (RV). How respiratory viral infections lead to wheeze and/or asthma is an area of active research. Areas covered: This review provides an updated summary of the published information on the development of post-viral induced atopy and asthma and the mechanisms involved. We focus on the contribution of animal models in identifying pathways that may contribute to atopy and asthma following respiratory virus infection, different polymorphisms that have been associated with asthma development, and current options for disease management and potential future interventions. Expert commentary: Currently there are no prophylactic therapies that prevent infants infected with respiratory viruses from developing asthma or atopy. Neither are there curative therapies for patients with asthma. Therefore, a better understanding of genetic factors and other associated biomarkers in respiratory viral induced pathogenesis is important for developing effective personalized therapies.

Integrative approach identifies corticosteroid response variant in diverse populations with asthma

BACKGROUND

Although inhaled corticosteroid (ICS) medication is considered the cornerstone treatment for patients with persistent asthma, few ICS pharmacogenomic studies have involved nonwhite populations.

OBJECTIVE

We sought to identify genetic predictors of ICS response in multiple population groups with asthma.

METHODS

The discovery group comprised African American participants from the Study of Asthma Phenotypes and Pharmacogenomic Interactions by Race-Ethnicity (SAPPHIRE) who underwent 6 weeks of monitored ICS therapy (n = 244). A genome-wide scan was performed to identify single nucleotide polymorphism (SNP) variants jointly associated (ie, the combined effect of the SNP and SNP × ICS treatment interaction) with changes in asthma control. Top associations were validated by assessing the joint association with asthma exacerbations in 3 additional groups: African Americans (n = 803 and n = 563) and Latinos (n = 1461). RNA sequencing data from 408 asthmatic patients and 405 control subjects were used to examine whether genotype was associated with gene expression.

RESULTS

One variant, rs3827907, was significantly associated with ICS-mediated changes in asthma control in the discovery set (P = 7.79 × 10^-8) and was jointly associated with asthma exacerbations in 3 validation cohorts (P = .023, P = .029, and P = .041). RNA sequencing analysis found the rs3827907 C-allele to be associated with lower RNASE2 expression (P = 6.10 × 10^-4). RNASE2 encodes eosinophil-derived neurotoxin, and the rs3827907 C-allele appeared to particularly influence ICS treatment response in the presence of eosinophilic inflammation (ie, high pretreatment eosinophil-derived neurotoxin levels or blood eosinophil counts).

CONCLUSION

We identified a variant, rs3827907, that appears to influence response to ICS treatment in multiple population groups and likely mediates its effect through eosinophils.

Increased pro-inflammatory cytokine-secreting regulatory T cells are correlated with the plasticity of T helper cell differentiation and reflect disease status in asthma

BACKGROUND

Human regulatory T cells (Tregs) are a heterogeneous population which consists of three distinct subpopulations: CD25⁺CD45RA⁺ resting Treg (rTreg) cells; CD25^hiCD45RA^- activated Treg (aTreg) cells, which are both suppressive; and CD25⁺CD45RA^- cytokine-secreting T cells with pro-inflammatory capacity.

OBJECTIVE

We investigated variation in peripheral Treg subpopulations of asthma and explored their potential roles in asthma inflammation.

METHODS

Twenty-eight mild asthma patients, 26 moderate asthma patients, 18 severe asthma patients, and 36 healthy controls were recruited for a cross-sectional study. Phenotyping of peripheral CD4⁺ Tregs was performed based on flow cytometry results.

RESULTS

The proportions of rTreg and aTreg cells among CD4⁺ T cells were higher in mild and moderate asthma patients than in healthy controls. All three groups of asthmatics had a higher proportion of pro-inflammatory Tregs than healthy controls, and these increased with asthma severity. The proportion of IL-17-producing Foxp3⁺ cells and IFN-ɤ-producing Foxp3⁺ cells strongly correlated with T helper 17 (Th17) cells (r = 0.66, p < 0.001) and Th1 cells (r = 0.48, p < 0.001). The pro-inflammatory Treg subpopulation was correlated with the severity of asthma and may be insensitive to corticosteroids.

CONCLUSIONS

Our data suggest that pro-inflammatory Treg subpopulations may be relevant to the plasticity of Th17 and Th1 differentiation and play an important role in the pathogenesis of asthma.

Glucocorticoid-Induced Transcription Factor 1 (GLCCI1) Variant Impacts the Short-Term Response to Intranasal Corticosteroids in Chinese Han Patients with Seasonal Allergic Rhinitis

Background

Genetic correlations with the response to intranasal corticosteroids (INCS) in seasonal allergic rhinitis (SAR) treatment are unknown. This study aimed to evaluate the role of gene polymorphisms in the response to INCS in Chinese Han patients with moderate to severe SAR.

Material/Methods

In this study, 286 Chinese Han patients with SAR were genotyped for 4 candidate genes: the glucocorticosteroid receptor (NR3C1) gene, glucocorticoid-induced transcription factor 1 (GLCCI1) gene, T-box 21 gene (TBX21), and ATP binding cassette subfamily B member 1 (ABCB1) gene. Patients were treated with INCS for 4 weeks. The total nasal symptom score (TNSS), total ocular symptom score (TOSS), and visual analogue scale (VAS) score were assessed at baseline and on week 4. The primary endpoint was the effective rate after 4 weeks of INCS therapy.

Results

In addition to the known contributing factors, one genotype of GLCCI1, namely, rs37973, was significantly associated with the INCS response (OR=0.598, 95% confidence interval: 0.41 to 0.87, P=0.007). The effective rate of the GG group was lower than those of the AA and AG groups (AA vs. GG: 73.7% vs. 51.6%, P=0.007; AG vs. GG: 78.8% vs. 51.6%, P=0.000). In addition, the TNSS, TOSS, and VAS were higher for the patients in the GG group than for those in the AA and AG groups on week 4.

Conclusions

The GLCCI1 rs37973 variant is a risk factor for glucocorticoid resistance in Chinese patients with SAR who receive short-term INCS treatment.

Identification of differentially expressed genes in childhood asthma

Asthma has been the most common chronic disease in children that places a major burden for affected people and their families.An integrated analysis of microarrays studies was performed to identify differentially expressed genes (DEGs) in childhood asthma compared with normal control. We also obtained the differentially methylated genes (DMGs) in childhood asthma according to GEO. The genes that were both differentially expressed and differentially methylated were identified. Functional annotation and protein-protein interaction network construction were performed to interpret biological functions of DEGs. We performed q-RT-PCR to verify the expression of selected DEGs.One DNA methylation and 3 gene expression datasets were obtained. Four hundred forty-one DEGs and 1209 DMGs in childhood asthma were identified. Among which, 16 genes were both differentially expressed and differentially methylated in childhood asthma. Natural killer cell mediated cytotoxicity pathway, Jak-STAT signaling pathway, and Wnt signaling pathway were 3 significantly enriched pathways in childhood asthma according to our KEGG enrichment analysis. The PPI network of top 20 up- and downregulated DEGs consisted of 822 nodes and 904 edges and 2 hub proteins (UBQLN4 and MID2) were identified. The expression of 8 DEGs (GZMB, FGFBP2, CLC, TBX21, ALOX15, IL12RB2, UBQLN4) was verified by qRT-PCR and only the expression of GZMB and FGFBP2 was inconsistent with our integrated analysis.Our finding was helpful to elucidate the underlying mechanism of childhood asthma and develop new potential diagnostic biomarker and provide clues for drug design.

Pharmacogenetics of asthma: toward precision medicine

PURPOSE OF REVIEW

Although currently available drugs to treat asthma are effective in most patients, a proportion of patients do not respond or experience side-effects; which is partly genetically determined. Pharmacogenetics is the study of how genetic variations influence drug response. In this review, we summarize prior results and recent studies in pharmacogenetics to determine if we can use genetic profiles for personalized treatment of asthma.

RECENT FINDINGS

The field of pharmacogenetics has moved from candidate gene studies in single populations toward genome-wide association studies and meta-analysis of multiple studies. New technologies have been used to enrich results, and an expanding number of genetic loci have been associated with therapeutic responses to asthma drugs. Prospective, genotype-stratified treatment studies have been conducted for β2-agonists, showing attenuated response in children carrying the Arg16 variant in the β2-adrenoreceptor gene.

SUMMARY

Although there has been much progress, many findings have not been replicated and currently known genetic loci only account for a fraction of variability in drug response. More research is necessary to translate into clinical practice. A polygenic predictive approach integrated in complex networks with other 'omics' technologies could aid to achieve this goal. Finally, to change clinical practice, studies that compare precision medicine with traditional medicine are needed.

Association between TAAR6 polymorphisms and airway responsiveness to inhaled corticosteroids in asthmatic patients

BACKGROUND

Genetic polymorphisms may be responsible for the wide variation in response to inhaled corticosteroids in asthmatic patients. We had previously reported that one polymorphism rs7772821, located on the 3'-UTR of trace amine-associated receptor 6 (TAAR6), is significantly associated with percentile changes in the forced expiratory volume in 1 s (%ΔFEV1) after inhaled corticosteroid treatment in asthmatics using a genome-wide association study. The aim of the present study was to validate the association between 15 single-nucleotide polymorphisms (SNPs) on the TAAR6 and airway responsiveness to inhaled corticosteroids in the asthmatics.

METHODS

The %ΔFEV1 induced by 4 weeks' treatment with inhaled fluticasone propionate (1000 μg daily) was measured in 246 asthmatics. The 15 SNPs of TAAR6 were genotyped using a TaqMan assay. An association analysis between %ΔFEV1 and TAAR6 polymorphisms was carried out using a linear regression model controlling for age, sex, smoking status, presence of atopy, and baseline FEV1 as covariates.

RESULTS

Among the 15 SNPs and seven haplotypes of TAAR6, rs7772821 (T>G) on the 3'-UTR showed the strongest correlation with inhaled corticosteroid-induced %ΔFEV1 (Pcorr=0.002 in the codominant model, Pcorr=0.03 in the dominant model, Pcorr=0.01 in the recessive model). The %ΔFEV1 of the rs7772821T>G minor homozygotes (60.77%) was higher than that of patients harboring either the rs7772821 T/G or T/T genotypes (21.32 and 31.60%, respectively).

CONCLUSION

The TAAR6 rs7772821 polymorphism may be one of the important genetic factors for predicting the response to treatment with inhaled corticosteroids in asthmatics.

Review on Pharmacogenetics and Pharmacogenomics Applied to the Study of Asthma

Nearly one-half of asthmatic patients do not respond to the most common therapies. Evidence suggests that genetic factors may be involved in the heterogeneity in therapeutic response and adverse events to asthma therapies. We focus on the three major classes of asthma medication: β-adrenergic receptor agonist, inhaled corticosteroids, and leukotriene modifiers. Pharmacogenetics and pharmacogenomics studies have identified several candidate genes associated with drug response.In this chapter, the main pharmacogenetic and pharmacogenomic studies in addition to the future perspectives in personalized medicine will be reviewed. The ideal treatment of asthma would be a tailored approach to health care in which adverse effects are minimized and the therapeutic benefit for an individual asthmatic is maximized leading to a more cost-effective care.

Pharmacogenetics and interstitial lung disease

PURPOSE OF REVIEW

Interstitial lung disease (ILD) is comprised of a heterogeneous group of disorders with highly variable natural histories and response to therapies. Pharmacogenetics focuses on the variability in drug response because of the presence of genetic factors that influence drug metabolism or disease activity. In this article, we review relevant drug-specific and disease-specific polymorphisms that may influence therapeutic response, and then highlight a recently identified drug-gene interaction in patients with idiopathic pulmonary fibrosis (IPF).

RECENT FINDINGS

The emergence of high-throughput genomic technology has allowed for identification of gene polymorphisms associated with susceptibility to specific disease states, including IPF and several connective tissue diseases known to cause ILD. IPF risk loci span a diverse group of genes, while most associated with connective tissue disease are critical to immune signaling. A recent pharmacogenetic analysis of patients enrolled in an IPF clinical trial identified a variant within TOLLIP to be associated with differential response to N-acetylcysteine therapy.

SUMMARY

Though few pharmacogenetic investigations have been conducted in patients with ILD to date, ample opportunities for pharmacogenetic exploration exist in this patient population. Such exploration will advance our understanding of specific ILDs and help usher in an era of personalized medicine.

Derp1-modified dendritic cells attenuate allergic inflammation by regulating the development of T helper type1(Th1)/Th2 cells and regulatory T cells in a murine model of allergic rhinitis

The CD4⁺CD25⁺Foxp3⁺ regulatory T cells (Tregs) are known to regulate Th2-induced allergic rhinitis (AR). In this study, we evaluated the efficacy of Derp1-modified dendritic cells (DCs) in AR immunotherapy. Derp1 was synthesized and transfected into DCs to generate Derp1-modified DCs. Phenotypes of Derp1-modified DCs were analyzed with flow cytometry using antibodies against DC markers CD11c, CD11b, CD59, CD103 and Toll-like receptor 1(TLR1). Four groups of subject mice were formed; the controls were treated with immature DCs, while the AR mice models were sensitized with Derp1(AR) and treated with DCs(DC-AR) or Derp1-modified DCs (Derp1DC-AR). The frequency of sneezing and scratching, eosinophil cell count, and Th1/Th2 ratio in the spleen were measured for all groups. The percentage of CD4⁺CD25⁺Foxp3⁺ Tregs in peripheral blood mononuclear cells was measured using flow cytometry; serum IgE, IgG1, and histamine were measured using enzyme-linked immunosorbent assay; expression levels of transcription factors T-bet, GATA3, Foxp3+ and IL-10 were analyzed using reverse transcription-polymerase chain reaction, and Western blot used in analyzed expression of Foxp3+ and IL-10 in nasal mucosa. Treatment with Derp1-modified DCs ameliorated the allergic response. The Derp1DC-AR group had significantly lower eosinophil cell count and the IgE, IgG1, and histamine levels than the AR and DC-AR groups, and higher mRNA levels of Th1 transcription factors T-bet, IL-10 and Foxp3 in nasal mucosa than DC-AR mice, but Th2 transcription factors GATA3 mRNA expression level has the opposite results. Furthermore, the Th1/Th2 ratio and percentage of CD4⁺CD25⁺Foxp3⁺ Tregs was significantly lower in the AR group (p<0.05), but higher in the Derp1DC-AR group than in the control group (p<0.01). Thus, the Derp1-modified DCs increased the percentage of CD4⁺CD25⁺Foxp3⁺Tregs and influenced the balance of Th1/Th2, showing an immunotherapeutic effect against AR.

Pharmacogenetics and the treatment of asthma

Heterogeneity defines both the natural history of asthma as well as patient's response to treatment. Pharmacogenomics contribute to understand the genetic basis of drug response and thus to define new therapeutic targets or molecular biomarkers to evaluate treatment effectiveness. This review is initially focused on different genes so far involved in the pharmacological response to asthma treatment. Specific considerations regarding allergic asthma, the pharmacogenetics aspects of polypharmacy and the application of pharmacogenomics in new drugs in asthma will also be addressed. Finally, future perspectives related to epigenetic regulatory elements and the potential impact of systems biology in pharmacogenetics of asthma will be considered.

Effects of genetic factors to inhaled corticosteroid response in children with asthma: a literature review

Numerous studies have examined the association between pharmacogenetic effects and the response to inhaled corticosteroids (ICS) in patients with asthma. In fact, several single nucleotide polymorphisms of a number of candidate genes have been identified that might influence the clinical response to ICS in children with asthma. Their direct or indirect effects depend on their role in the inflammatory process in asthma or the anti-inflammatory action of corticosteroids, respectively. Among the genes identified, variants in T-box 21 (TBX21) and Fc fragment of IgE receptor II (FCER2) contribute indirectly to the variability in the response to ICS by altering the inflammatory mechanisms in asthma, while other genes such as corticotropin releasing hormone receptor 1 (CRHR1), nuclear receptor subfamily 3 group C member 1 (NR3C1), stress induced phosphoprotein 1 (STIP1), dual specificity phosphatase 1 (DUSP1), glucocorticoid induced 1 (GLCCI1), histone deacetylase 1 (HDAC), ORMDL sphingolipid biosynthesis regulator 3 (ORMDL3), and vascular endothelial growth factors (VEGF) directly affect this variability through the anti-inflammatory mechanisms of ICS. The results to date indicate various potential genetic factors associated with the response to ICS, which could be utilized to predict the individual therapeutic response of children with asthma to ICS. Clinical trials are underway and their results are greatly anticipated. Further pharmacogenetic studies are needed to fully understand the effects of genetic variation on the response to ICS in children with asthma.

Pharmacogenomics of inhaled corticosteroids and leukotriene modifiers: a systematic review

BACKGROUND

Pharmacogenetics studies of anti-inflammatory medication of asthma have expanded rapidly in recent decades, but the clinical value of their findings remains limited.

OBJECTIVE

To perform a systematic review of pharmacogenomics and pharmacogenetics of inhaled corticosteroids (ICS) and leukotriene modifiers (LTMs) in patients with asthma.

METHODS

Articles published between 1999 and June 2015 were searched using PubMed and EMBASE. Pharmacogenomics/genetics studies of patients with asthma using ICS or LTMs were included if ≥1 of the following outcomes were studied: lung function, exacerbation rates or asthma symptoms. The studies of Single Nucleotide Polymorphisms (SNPs) that had been replicated at least once were assessed in more detail.

RESULTS

In total, 59 publications were included in the systematic review: 26 addressed LTMs (including two genomewide Genome-Wide association studies [GWAS]) and 33 addressed ICS (including four GWAS). None of the GWAS reported similar results. Furthermore, none of the SNPs assessed in candidate gene studies were identified in a GWAS. No consistent reports were found for candidate gene studies of LTMs. In candidate gene studies of ICS, the most consistent results were found for rs28364072 in FCER2. This SNP was associated with all three outcomes of poor response, and the largest effect was reported with the risk of exacerbations (hazard ratio, 3.95; 95% CI, 1.64-9.51).

CONCLUSION AND CLINICAL RELEVANCE

There is a lack of replication of genetic variants associated with poor ICS or LTM response. The most consistent results were found for the FCER2 gene [encoding for a low-affinity IgE receptor (CD23)] and poor ICS response. Larger studies with well-phenotyped patients are needed to assess the clinical applicability of ICS and LTM pharmacogenomics/genetics.

Genetic associations of the response to inhaled corticosteroids in children during an asthma exacerbation

BACKGROUND

Genetic associations of the response to inhaled corticosteroids (ICSs) during an asthma exacerbation are unknown.

OBJECTIVE

To evaluate the role of genetic variants in the therapeutic response to high-dose ICS in children with moderate-to-severe asthma exacerbations.

METHODS

Eighty-two children (56 boys/26 girls, mean age 9.6 ± 3.2 years) with moderate-severe asthma exacerbation were genotyped for eight single-nucleotide polymorphisms that were a priori associated with ICS response in chronic asthma treatment: glucocorticosteroid receptor (NR3C1) rs41423247; corticotrophin-releasing hormone receptor1 (CRHR1) rs242939, rs242941, and rs1876828; T-box 21 (TBX21) rs2240017; glucocorticoid-induced transcript 1 (GLCCl1); and T gene rs3099266 and rs2305089. Children were treated with a single high-dose (4000 μg) fluticasone propionate given by a nebulizer followed by 1000 μg/day of inhaled fluticasone propionate for 6 days. Primary outcome measure was the improvement in FEV1 at 4 h.

RESULTS

Mean FEV1 was 71.7 ± 14.2% at presentation. Overall, fluticasone treatment resulted in a significant improvement in asthma score and FEV1 (p < 0.0001 for both). Children with the GG genotype at NR3C1 rs41423247 (n = 26) had a higher improvement in FEV1 [24.2% (interquartile range 11.5-36.3)] compared to those with CG+CC (n = 19), [7.9% (interquartile range 6.1-24.6) (p = 0.006)].

CONCLUSION

Homozygosity for the G allele at rs41423247 of the glucocorticosteroid receptor (NR3C1) gene is associated with a higher improvement in FEV1 at 4 h in children with moderate-to-severe asthma exacerbation treated with high-dose ICS. This observation may have important clinical implications especially for children who use systemic steroids frequently for recurrent asthma exacerbations.

No evidence of large genetic effects on steroid response in asthma patients

BACKGROUND

Inhaled corticosteroids (ICSs) are considered the most effective anti-inflammatory therapy for asthma control and management; however, there is substantial treatment response variability.

OBJECTIVE

We sought to identify genetic markers of ICS response by conducting the largest pharmacogenetic investigation to date in 2672 ICS-treated patients with asthma.

METHODS

Genotyping and imputation was performed in fluticasone furoate (FF) or fluticasone propionate-treated patients with asthma from 3 phase IIB and 4 phase IIIA randomized, double-blind, placebo-controlled, parallel group, multicenter studies. The primary end point analyzed was change in trough FEV₁ (ΔFEV₁) from baseline to 8 to 12 weeks of treatment.

RESULTS

More than 9.8 million common genetic variants (minor allele frequency ≥ 1%) were analyzed to test for association with ΔFEV₁. No genetic variant met the prespecified threshold for statistical significance.

CONCLUSIONS

This study provides no evidence to confirm previously reported associations between candidate genetic variants and ICS response (ΔFEV₁) in patients with asthma. In addition, no variant satisfied the criterion for genome-wide significance in our study. Common genetic variants are therefore unlikely to prove useful as predictive biomarkers of ICS response in patients with asthma.

Potential Role of Hepatitis C Virus Alternate Reading Frame Protein in Negative Regulation of T-Bet Gene Expression

Hepatitis C virus (HCV) is a major cause of chronic liver disease and has led to cirrhosis or hepatocellular carcinoma in a majority of infected individuals. We have previously demonstrated that the HCV alternate reading frame protein (F protein) is related to Th1/Th2 bias in chronic hepatitis C (CHC) patients, and we aimed to explore the relative molecular mechanisms here. A total of 104 cases including CHC patients and healthy donors were enrolled. T-bet and GATA-3 expression levels were analyzed in peripheral blood mononuclear cells (PBMCs). The levels of signal transducer and activator of transcription-1/-6(STAT1/6) and phosphorylated STAT1/6(pSTAT1/6) in PBMCs were measured by Western blotting. Our results showed that the levels of T-bet in PBMCs, as well as the levels of gamma interferon (IFN-γ) in sera, were decreased in anti-F protein antibody seropositive patients compared with anti-F protein antibody seronegative patients, whereas the levels of GATA-3 did not show difference between the two groups. Moreover, the decreased pSTAT1 and increased pSTAT6 were observed in PBMCs by HCV core/F protein stimulation with constant STAT1/6 expression. Taken together, it suggested that T-bet may be involved in Th1/Th2 bias induced by HCV F protein, and the disruption of STAT phosphorylation may participate in this mediation.

Magnesium nebulization utilization in management of pediatric asthma (MagNUM PA) trial: study protocol for a randomized controlled trial

BACKGROUND

Up to 30 % of children with acute asthma are refractory to initial therapy, and 84 % of this subpopulation needs hospitalization. Finding safe, noninvasive, and effective strategies to treat this high-risk group would substantially decrease hospitalizations, healthcare costs, and the psycho-social burden of the disease. Whereas intravenous magnesium (Mg) is effective in severe refractory asthma, its use is sporadic due to safety concerns, with the main treatment goal being to prevent intensive care unit admission. In contrast, nebulized Mg is noninvasive, allows higher pulmonary drug concentrations, and has a much higher safety potential due to the lower rate of systemic delivery. Previous studies of inhaled Mg show disparate results due to the use of unknown/inefficient delivery methods and other methodological flaws.

METHODS/DESIGN

The study is a randomized double-blind controlled trial in seven Canadian pediatric Emergency Departments (two-center pilot 2011 to 2014, Canada-wide November 2014 to December 2017). The trial will include 816 otherwise healthy children who are 2 to 17 years old, having had at least one previous wheezing episode, have received systemic corticosteroids, and have a Pediatric Respiratory Assessment Measure (PRAM) ≥ 5 points after three salbutamol and ipratropium treatments for a current acute asthma exacerbation. Eligible consenting children will receive three experimental treatments of nebulized salbutamol with either 600 mg of Mg sulfate or placebo 20 min apart, using an Aeroneb Go nebulizer, which has been shown to maximize pulmonary delivery while maintaining safety. The primary outcome is hospitalization within 24 h of the start of the experimental therapy for persistent respiratory distress or supplemental oxygen. Secondary outcomes include all-cause hospitalization within 24 h, PRAM, vital signs, number of bronchodilator treatments by 240 min, and the association between the difference in the primary outcome between the groups, age, gender, baseline PRAM, atopy, and "viral induced wheeze" phenotype (Fig. 1).

DISCUSSION

If effective, inhaled Mg may represent an effective strategy to minimize morbidity in pediatric refractory acute asthma. Unlike previous works, this trial targets nonresponders to optimized initial therapy who are the most likely to benefit from inhaled Mg. Future dissemination of results will include knowledge translation, incorporation into a Cochrane Review, presentation at scientific meetings, and a peer-reviewed publication.

TRIAL REGISTRATION

NCTO1429415 , registered 2 September 2011.

Addressing corticosteroid insensitivity in adults with asthma

Corticosteroids are the most effective treatment for asthma, but the therapeutic response varies markedly between individuals, with up to one third of patients showing evidence of insensitivity to corticosteroids. This article summarizes information on genetic, environmental and asthma-related factors as well as demographic and pharmacokinetic variables associated with corticosteroid insensitivity in asthma. Molecular mechanisms proposed to explain corticosteroid insensitivity are reviewed including alterations in glucocorticoid receptor subtype, binding and nuclear translocation, increased proinflammatory transcription factors and defective histone acetylation. Current therapies and future interventions that may restore corticosteroid sensitivity in asthma are discussed, including small molecule drugs and biological agents. In the future, biomarkers may be used in the clinic to predict corticosteroid sensitivity in patients with poorly controlled asthma.

Predicting asthma outcomes

This review addresses predictors of remission or persistence of wheezing and asthma from early childhood through adulthood. Early childhood wheezing is common, but predicting who will remit or have persistent childhood asthma remains difficult. By adding parental history of asthma and selected infant biomarkers to the history of recurrent wheezing, the Asthma Predictive Index and its subsequent modifications provide better predictions of persistence than simply the observation of recurrent wheeze. Sensitization, especially to multiple allergens, increases the likelihood of development of classic childhood asthma. Remission is more likely in male subjects and those with milder disease (less frequent and less severe symptoms), less atopic sensitization, a lesser degree of airway hyperresponsiveness, and no concomitant allergic disease. Conversely, persistence is linked strongly to allergic sensitization, greater frequency and severity of symptoms, abnormal lung function, and a greater degree of airway hyperresponsiveness. A genetic risk score might predict persistence more accurately than family history. Remission of established adult asthma is substantially less common than remission during childhood and adolescence. Loss of lung function can begin early in life and tracks through childhood and adolescence. Despite therapy which controls symptoms and exacerbations, the outcomes of asthma appear largely resistant to pharmacologic therapy.

Asthma risk factors

BACKGROUND

Bronchial asthma is one of the most common chronic diseases in childhood, with a current prevalence of 6% to 9%, but a prevalence that is increasing at an alarming rate. Asthma is a complex genetic disorder with strong environmental influence. It imposes a growing burden on our society in terms of morbidity, quality of life, and healthcare costs. Despite large-scale efforts, only a few asthma genes have been confirmed, suggesting that the genetic underpinning of asthma is highly complex.

METHODS

A review of the literature was performed regarding atopic and nonatopic asthma risk factors, including environmental risk factors and genetic studies in adults and children.

RESULTS

Several environmental risk factors have been identified to increase the risk of developing asthma such as exposure to air pollution and tobaccos smoke as well as occupational risk factors. In addition atopy, stress, and obesity all can increases the risk for asthma in genetically susceptible persons.

CONCLUSION

Asthma represents a dysfunctional interaction with our genes and the environment to which they are exposed, especially in fetal and early infant life. The increasing prevalence of asthma in all age groups indicate that our living environment and immunity are in imbalance with each other reacting with airway inflammation to the environmental exposures and often non-harmful proteins, such as allergens causing the current "asthma and allergy epidemic." Because of the close relationship between asthma and chronic rhinosinusitis, it is important that otolaryngologists have a good understanding of asthma, the etiologic factors associated with disease, and its evaluation and management.

Severe asthma in children

Severe asthma in children is characterized by sustained symptoms despite treatment with high doses of inhaled corticosteroids or oral corticosteroids. Children with severe asthma may fall into 2 categories, difficult-to-treat asthma or severe therapy-resistant asthma. Difficult-to-treat asthma is defined as poor control due to an incorrect diagnosis or comorbidities, or poor adherence due to adverse psychological or environmental factors. In contrast, treatment resistant is defined as difficult asthma despite management of these factors. It is increasingly recognized that severe asthma is a highly heterogeneous disorder associated with a number of clinical and inflammatory phenotypes that have been described in children with severe asthma. Guideline-based drug therapy of severe childhood asthma is based primarily on extrapolated data from adult studies. The recommendation is that children with severe asthma be treated with higher-dose inhaled or oral corticosteroids combined with long-acting β-agonists and other add-on therapies, such as antileukotrienes and methylxanthines. It is important to identify and address the influences that make asthma difficult to control, including reviewing the diagnosis and removing causal or aggravating factors. Better definition of the phenotypes and better targeting of therapy based upon individual patient phenotypes is likely to improve asthma treatment in the future.

Personalized medicine in children with asthma

Personalized medicine for children with asthma aims to provide a tailored management of asthma, which leads to faster and better asthma control, has less adverse events and may be cost saving. Several patient characteristics, lung function parameters and biomarkers have been shown useful in predicting treatment response or predicting successful reduction of asthma medication. As treatment response to the main asthma therapies is partly genetically determined, pharmacogenetics may open the way for personalized medicine in children with asthma. However, the number of genes identified for the various asthma drug response phenotypes remains small and randomized controlled trials are lacking. Biomarkers in exhaled breath or breath condensate remain promising but did not find their way from bench to bedside yet, except for the fraction of exhaled nitric oxide. E-health will most likely find its way to clinical practice and most interventions are at least non-inferior to usual care. More studies are needed on which interventions will benefit most individual children.

Asthma pharmacogenetics and the development of genetic profiles for personalized medicine

Human genetics research will be critical to the development of genetic profiles for personalized or precision medicine in asthma. Genetic profiles will consist of gene variants that predict individual disease susceptibility and risk for progression, predict which pharmacologic therapies will result in a maximal therapeutic benefit, and predict whether a therapy will result in an adverse response and should be avoided in a given individual. Pharmacogenetic studies of the glucocorticoid, leukotriene, and β₂-adrenergic receptor pathways have focused on candidate genes within these pathways and, in addition to a small number of genome-wide association studies, have identified genetic loci associated with therapeutic responsiveness. This review summarizes these pharmacogenetic discoveries and the future of genetic profiles for personalized medicine in asthma. The benefit of a personalized, tailored approach to health care delivery is needed in the development of expensive biologic drugs directed at a specific biologic pathway. Prior pharmacogenetic discoveries, in combination with additional variants identified in future studies, will form the basis for future genetic profiles for personalized tailored approaches to maximize therapeutic benefit for an individual asthmatic while minimizing the risk for adverse events.

Genetics of allergic diseases

Genome-wide association studies (GWAS) have been employed in the field of allergic disease, and significant associations have been published for nearly 100 asthma genes/loci. An outcome of GWAS in allergic disease has been the formation of national and international collaborations leading to consortia meta-analyses, and an appreciation for the specificity of genetic associations to sub-phenotypes of allergic disease. Molecular genetics has undergone a technological revolution, leading to next-generation sequencing strategies that are increasingly employed to hone in on the causal variants associated with allergic diseases. Unmet needs include the inclusion of diverse cohorts and strategies for managing big data.

Pharmacogenomics in asthma therapy: where are we and where do we go?

The response to drug treatment in asthma is a complex trait and is markedly variable even in patients with apparently similar clinical features. Pharmaco-genomics, which is the study of variations of human genome characteristics as related to drug response, can play a role in asthma therapy. Both a traditional candidate-gene approach to conducting genetic association studies and genome-wide association studies have provided an increasing list of genes and variants associated with the three major classes of asthma medications: β2-agonists, inhaled corticosteroids, and leukotriene modifiers. Moreover, a recent integrative, systems-level approach has offered a promising opportunity to identify important pharmacogenomics loci in asthma treatment. However, we are still a long way away from making this discipline directly relevant to patients. The combination of network modeling, functional validation, and integrative omics technologies will likely be needed to move asthma pharmacogenomics closer to clinical relevance.

Genetic variation of TBX21 gene increases risk of asthma and its severity in Indian children

T-box transcription factor protein (TBX21) is encoded by the TBX21 gene in human. It is crucial for naive T lymphocyte development, interferon-γ production, airway hyperresponsiveness and regulation of corticosteroid response in asthmatics. Polymorphisms rs4794067 and rs16947078 of TBX21 were found to be associated with acetylsalicylic acid-induced and allergic asthma, respectively. We examined whether sequence variants of TBX21 gene are associated with asthma and its severity in Indian population. In a hospital-based case-control study, 240 asthmatic children and 240 healthy controls were investigated for the association of TBX21 rs4794067 (C>T) and rs16947078 (G>A) polymorphisms with asthma and its severity using PCR-restriction fragment length polymorphism method. Heterozygous (CT) (odds ratio (OR)=2.33; P=0.001) and variant (TT) (OR=6.25; P=0.001) genotypes of rs4794067 were demonstrated significant risk of asthma. However, in asthma severity variant (TT) genotype revealed significant increase risk (intermittent: OR=5.9, P=0.001; mild: OR=8.0, P=0.001; moderate: OR=3.2, P=0.041; and severe: OR=43.6, P=0.001) in all subgroups. Furthermore, haplotypes TG (OR=2.83; P=0.001) and TA (OR=2.54; P=0.001) of TBX21 were associated with an increased risk of asthma. Conversely, rs16947078 G>A polymorphism was not associated with any asthma/asthma severity risk. These data suggest that TBX21 gene variation may modify individual's susceptibility to asthma and its severity in Indian population. However, further validation in large population-based studies is needed to confirm the finding.