Altered epigenetic regulation and increasing severity of bronchial hyperresponsiveness in atopic asthmatic children

Early Prediction of Asthma

The clinical manifestations of asthma in children are highly variable, are associated with different molecular and cellular mechanisms, and are characterized by common symptoms that may diversify in frequency and intensity throughout life. It is a disease that generally begins in the first five years of life, and it is essential to promptly identify patients at high risk of developing asthma by using different prediction models. The aim of this review regarding the early prediction of asthma is to summarize predictive factors for the course of asthma, including lung function, allergic comorbidity, and relevant data from the patient's medical history, among other factors. This review also highlights the epigenetic factors that are involved, such as DNA methylation and asthma risk, microRNA expression, and histone modification. The different tools that have been developed in recent years for use in asthma prediction, including machine learning approaches, are presented and compared. In this review, emphasis is placed on molecular mechanisms and biomarkers that can be used as predictors of asthma in children.

Montelukast Increased IL-25, IL-33, and TSLP via Epigenetic Regulation in Airway Epithelial Cells

The epithelium-derived cytokines interleukin (IL)-25, IL-33, and thymic stromal lymphopoietin (TSLP) are important mediators that initiate innate type 2 immune responses in asthma. Leukotriene receptor antagonists (LTRAs) are commonly used to prevent asthma exacerbations. However, the effects of LTRAs on epithelium-derived cytokines expression in airway epithelial cells are unclear. This study aimed to investigate the effects of LTRAs on the expression of epithelium-derived cytokines in human airway epithelial cells and to explore possible underlying intracellular processes, including epigenetic regulation. A549 or HBE cells in air-liquid interface conditions were pretreated with different concentrations of LTRAs. The expression of epithelium-derived cytokines and intracellular signaling were investigated by real-time PCR, enzyme-linked immunosorbent assay, and Western blot. In addition, epigenetic regulation was investigated using chromatin immunoprecipitation analysis. The expression of IL-25, IL-33, and TSLP was increased under LTRAs treatment and suppressed by inhaled corticosteroid cotreatment. Montelukast-induced IL-25, IL-33, and TSLP expression were mediated by the mitogen-activated protein kinase (MAPK) and nuclear factor-κB (NF-κB) pathways and regulated by histone H3 acetylation and H3K36 and H3K79 trimethylation. LTRAs alone might increase inflammation and exacerbate asthma by inducing the production of IL-25, IL-33, and TSLP; therefore, LTRA monotherapy may not be an appropriate therapeutic option for asthma.

Suppressive Effects of 4-(Phenylsulfanyl) Butan-2-One on CCL-1 Production via Histone Acetylation in Monocytes

The 4-(phenylsulfanyl) butan-2-one (4-PSB-2), a marine-derived compound from soft coral, was proven to have multiple biological activities including neuroprotection and potent anti-inflammatory effects. CC chemokine ligand (CCL)-1 belongs to T helper (Th)2-related chemokines that are involved in the recruitment of Th2 inflammatory cells. Histone acetylation has been recognized as a critical mechanism underlying the regulated cytokine and chemokine production. Our study tried to investigate the anti-inflammatory effect of 4-PSB-2 on CCL-1 production in human monocytes and explore possible underlying intracellular processes, including epigenetic regulation. To confirm our hypothesis, human monocyte THP-1 cell line and primary CD14⁺ cells were pretreated with various concentrations of 4-PSB-2 and then were stimulated with lipopolysaccharide (LPS). The CCL-1 concentration was measured by enzyme-linked immunosorbent assays, and the intracellular signaling pathways and epigenetic regulation of 4-PSB-2 were investigated by using Western blotting and chromatin immunoprecipitation analysis. In this study, we found that 4-PSB-2 had a suppressive effect on LPS-induced CCL-1 production. Moreover, this suppressive effect of 4-PSB-2 was mediated via intracellular signaling such as the mitogen-activated protein kinase and nuclear factor-κB pathways. In addition, 4-PSB-2 could suppress CCL-1 production by epigenetic regulation through downregulating histone H3 and H4 acetylation. In short, our study demonstrated that 4-PSB-2 may have a potential role in the treatment of allergic inflammation.

Understanding Asthma and Allergies by the Lens of Biodiversity and Epigenetic Changes

Exposure to different organisms (bacteria, mold, virus, protozoan, helminths, among others) can induce epigenetic changes affecting the modulation of immune responses and consequently increasing the susceptibility to inflammatory diseases. Epigenomic regulatory features are highly affected during embryonic development and are responsible for the expression or repression of different genes associated with cell development and targeting/conducting immune responses. The well-known, "window of opportunity" that includes maternal and post-natal environmental exposures, which include maternal infections, microbiota, diet, drugs, and pollutant exposures are of fundamental importance to immune modulation and these events are almost always accompanied by epigenetic changes. Recently, it has been shown that these alterations could be involved in both risk and protection of allergic diseases through mechanisms, such as DNA methylation and histone modifications, which can enhance Th2 responses and maintain memory Th2 cells or decrease Treg cells differentiation. In addition, epigenetic changes may differ according to the microbial agent involved and may even influence different asthma or allergy phenotypes. In this review, we discuss how exposure to different organisms, including bacteria, viruses, and helminths can lead to epigenetic modulations and how this correlates with allergic diseases considering different genetic backgrounds of several ancestral populations.

Expression of cPLA2γ mRNA and protein differs the response of PBMC from severe and non-severe asthmatics to bacterial lipopolysaccharide and house dust mite allergen

Chronic inflammation in asthmatics is initiated/exacerbated by many environmental factors, such as bacterial lipopolysaccharide and allergens. Phospholipase A₂ and histone acetyltransferase/deacetylases are enzymes involved in inflammatory process, particularly in lipid inflammatory mediators production and control of transcription of many inflammatory genes, respectively. The aim of the study was to identify differences in the inflammatory process in patients with severe and non-severe asthma, taking as a criterion expression of two groups of enzymes: phospholipases A₂ and histone acetyltransferases/deacetylases. Thirty-two patients with severe, non-severe atopic to house dust mite asthmatics and 14 healthy volunteers were recruited. Peripheral blood mononuclear cells were stimulated with Dermatophagoides pteronyssinus allergen (nDer p1) and bacterial lipopolysaccharide (LPS). The expression of phospholipases A₂ and histone acetyltransferases and deacetylases were assessed using TaqMan Low Density Array Cards. The protein expression was analyzed with immunoblot. Increased expression of phospholipase A2 Group IVC (PLA2G4C) and cytosolic phospholipase A2 gamma (cPLA₂γ) protein was observed in peripheral blood mononuclear cells (PBMC) from severe asthmatics in response to LPS and nDer p1, compared to non-severe asthmatics. nDer p1-stimulated PBMC from severe asthmatics exhibit induced expression of HDAC1 and similar trend was observed in protein concentration. Decreased expression of EP300 occurred in PBMC of severe asthmatics. PBMC from non-severe asthmatics showed decreased expression of HDAC2 and PLA2G15 after LPS treatment. In conclusion, in response to LPS and dust mite allergen, PBMC from severe and non-severe asthmatics modulate expression of selected phospholipase A₂, histone acetyltransferases and deacetylases, while increased expression of cPLA₂γ characterizes PBMC response from severe asthmatics.

Immune network dysregulation precedes clinical diagnosis of asthma

Allergic asthma is a chronic disease beginning in childhood that is characterized by dominant T-helper 2 cell activation without adequate counter-regulation by T-helper 1 cell and regulatory T cell activity. Prior transcriptomic studies of childhood asthma have primarily investigated subjects who already have a disease diagnosis, and have generally taken an approach of differential gene expression as opposed to differential gene interactions. The immune states that predispose towards allergic sensitization and disease development remain ill defined. We thus characterize immune networks of asthmatic predisposition in children at the age of 2, prior to the diagnosis of allergic asthma, who are subsequently diagnosed with asthma at the age of 7. We show extensive differences of gene expression networks and gene regulatory networks in children who develop asthma versus those who do not using transcriptomic data from stimulated peripheral blood mononuclear cells. Moreover, transcription factors that bind proximally to one another share patterns of dysregulation, suggesting that network differences prior to asthma diagnosis result from altered accessibility of gene targets. In summary, we demonstrate non-allergen-specific immune network dysregulation in individuals long before clinical asthma diagnosis.

Epigenetics in Asthma

PURPOSE OF REVIEW

Asthma is one of the most common chronic respiratory diseases linked with increased morbidity and healthcare utilization. The underlying pathophysiological processes and causal relationships of asthma with epigenetic mechanisms are partially understood. Here we review human studies of epigenetic mechanisms in asthma, with a special focus on DNA methylation.

RECENT FINDINGS

Epigenetic studies of childhood asthma have identified specific methylation signatures associated with allergic inflammation in the airway and immune cells, demonstrating a regulatory role for methylation in asthma pathogenesis. Despite these novel findings, additional research in the role of epigenetic mechanisms underlying asthma endotypes is needed. Similarly, studies of histone modifications are also lacking in asthma. Future studies of epigenetic mechanisms in asthma will benefit from data integration in well phenotyped cohorts. This review provides an overview of the current literature on epigenetic studies in human asthma, with special emphasis on methylation and childhood asthma.

The role of epigenetics in respiratory health in urban populations in low and middle-income countries

As urbanization increases in low- and middle-income countries (LMICs), urban populations will be increasingly exposed to a range of environmental risk factors for non-communicable diseases. Inadequate living conditions in urban settings may influence mechanisms that regulate gene expression, leading to the development of non-communicable respiratory diseases. We conducted a systematic review of the literature to assess the relationship between respiratory health and epigenetic factors to urban environmental exposures observed in LMICs using MEDLINE, PubMed, EMBASE, and Google Scholar searching a combination of the terms: epigenetics, chronic respiratory diseases (CRDs), lung development, chronic obstructive airway disease, and asthma. A total of 2835 articles were obtained, and 48 articles were included in this review. We found that environmental factors during early development are related to epigenetic effects that may be associated with a higher risk of CRDs. Epigenetic dysregulation of gene expression of the histone deacetylase (HDAC) and histone acetyltransferase gene families was likely involved in lung health of slum dwellers. Respiratory-related environmental exposures influence HDAC function and deoxyribonucleic acid methylation and are important risk factors in the development of CRD. Additional epigenetic research is needed to improve our understanding of associations between environmental exposures and non-communicable respiratory diseases.

Epigenetic regulation of T-helper cell differentiation, memory, and plasticity in allergic asthma

An estimated 300 million people currently suffer from asthma, which causes approximately 250 000 deaths a year. Allergen-specific T-helper (Th) cells produce cytokines that induce many of the hallmark features of asthma including airways hyperreactivity, eosinophilic and neutrophilic inflammation, mucus hypersecretion, and airway remodeling. Cytokine-producing Th subsets including Th1 (IFN-γ), Th2 (IL-4, IL-5, IL-13), Th9 (IL-9), Th17 (IL-17), Th22 (IL-22), and T regulatory (IL-10) cells have all been suggested to play a role in the development of asthma. Th differentiation involves genetic regulation of gene expression through the concerted action of cytokines, transcription factors, and epigenetic regulators. We describe how Th differentiation and plasticity is regulated by epigenetic histone and DNA modifications, with a focus on the regulation of histone methylation by members of the polycomb and trithorax complexes. In addition, we outline environmental influences that could influence epigenetic regulation of Th cells and discuss the potential to regulate Th plasticity and function through drugs targeting the epigenetic machinery. It is also becoming apparent that epigenetic regulation of allergen-specific memory Th cells may be important in the development and persistence of chronic allergies. Finally, we describe how epigenetic modifiers regulate cytokine memory in Th cells and describe recently identified hybrid, plastic, and pathogenic memory Th subsets the context of allergic asthma.

Glucocorticoids

The most effective anti-inflammatory drugs used to treat patients with airways disease are topical glucocorticosteroids (GCs). These act on virtually all cells within the airway to suppress airway inflammation or prevent the recruitment of inflammatory cells into the airway. They also have profound effects on airway structural cells to reverse the effects of disease on their function. Glucorticosteroids act via specific receptors-the glucocorticosteroid receptor (GR)-which are a member of the nuclear receptor family. As such, many of the important actions of GCs are to modulate gene transcription through a number of distinct and complementary mechanisms. Targets genes include most inflammatory mediators such as chemokines, cytokines, growth factors and their receptors. GCs delivered by the inhaled route are very effective for most patients and have few systemic side effects. However, in some patients, even high doses of topical or even systemic GCs fail to control their disease. A number of mechanisms relating to inflammation have been reported to be responsible for the failure of these patients to respond correctly to GCs and these provide insight into GC actions within the airways. In these patients, the side-effect profile of GCs prevent continued use of high doses and new drugs are needed for these patients. Targeting the defective pathways associated with GC function in these patients may also reactivate GC responsiveness.

Targeting transcription factor lysine acetylation in inflammatory airway diseases

Asthma and chronic obstructive pulmonary disease are inflammatory airway diseases for which alternative therapeutic strategies are urgently needed. Interestingly, HDAC inhibitors show anti-inflammatory effects in mouse models for these diseases. Here we explore underlying mechanisms that may explain these effects. In previous studies, effects of HDAC inhibitors on histone acetylation are often correlated with their effects on gene expression. However, effects of HDAC inhibitors on transcription factors and their acetylation status may be particularly important in explaining these effects. These effects are also cell type-specific. Recent developments (including chemoproteomics and acetylomics) allow for a more detailed understanding of the selectivity of HDAC inhibitors, which will drive their further development into applications in inflammatory airway diseases.

Epigenetics: The New Frontier in the Landscape of Asthma

Over the years, on a global scale, asthma has continued to remain one of the leading causes of morbidity, irrespective of age, sex, or social bearings. This is despite the prevalence of varied therapeutic options to counter the pathogenesis of asthma. Asthma, as a disease per se, is a very complex one. Scientists all over the world have been trying to obtain a lucid understanding of the machinations behind asthma. This has led to many theories and conjectures. However, none of the scientific disciplines have been able to provide the missing links in the chain of asthma pathogenesis. This was until epigenetics stepped into the picture. Though epigenetic research in asthma is in its nascent stages, it has led to very exciting results, especially with regard to explaining the massive influence of environment on development of asthma and its varied phenotypes. However, there remains a lot of work to be done, especially with regard to understanding how the interactions between immune system, epigenome, and environment lead to asthma. But introduction of epigenetics has infused a fresh lease of life in research into asthma and the mood among the scientific community is that of cautious optimism.

Epigenetic regulation of asthma and allergic disease

Epigenetics of asthma and allergic disease is a field that has expanded greatly in the last decade. Previously thought only in terms of cell differentiation, it is now evident the epigenetics regulate many processes. With T cell activation, commitment toward an allergic phenotype is tightly regulated by DNA methylation and histone modifications at the Th2 locus control region. When normal epigenetic control is disturbed, either experimentally or by environmental exposures, Th1/Th2 balance can be affected. Epigenetic marks are not only transferred to daughter cells with cell replication but they can also be inherited through generations. In animal models, with constant environmental pressure, epigenetically determined phenotypes are amplified through generations and can last up to 2 generations after the environment is back to normal. In this review on the epigenetic regulation of asthma and allergic diseases we review basic epigenetic mechanisms and discuss the epigenetic control of Th2 cells. We then cover the transgenerational inheritance model of epigenetic traits and discuss how this could relate the amplification of asthma and allergic disease prevalence and severity through the last decades. Finally, we discuss recent epigenetic association studies for allergic phenotypes and related environmental risk factors as well as potential underlying mechanisms for these associations.

Epigenetics and miRNA emerge as key regulators of smooth muscle cell phenotype and function

Regulation of phenotypic plasticity in smooth muscle requires an understanding of the mechanisms regulating phenotype-specific genes and the processes dysregulated during pathogenesis. Decades of study in airway smooth muscle has provided extensive knowledge of the gene expression patterns and signaling pathways necessary to maintain and alter smooth muscle cell phenotype. With this solid foundation, the importance and complexity of inheritable epigenetic modifications and mechanisms silencing gene expression have now emerged as fundamental components regulating aspects of inflammation, proliferation and remodeling.

Uncontrolled allergic rhinitis and chronic rhinosinusitis: where do we stand today?

State-of-the-art documents like ARIA and EPOS provide clinicians with evidence-based treatment algorithms for allergic rhinitis (AR) and chronic rhinosinusitis (CRS), respectively. The currently available medications can alleviate symptoms associated with AR and RS. In real life, a significant percentage of patients with AR and CRS continue to experience bothersome symptoms despite adequate treatment. This group with so-called severe chronic upper airway disease (SCUAD) represents a therapeutic challenge. The concept of control of disease has only recently been introduced in the field of AR and CRS. In case of poor control of symptoms despite guideline-directed pharmacotherapy, one needs to consider the presence of SCUAD but also treatment-related, diagnosis-related and/or patient-related factors. Treatment-related issues of uncontrolled upper airway disease are linked with the correct choice of treatment and route of administration, symptom-oriented treatment and the evaluation of the need for immunotherapy in allergic patients. The diagnosis of AR and CRS should be reconsidered in case of uncontrolled disease, excluding concomitant anatomic nasal deformities, global airway dysfunction and systemic diseases. Patient-related issues responsible for the lack of control in chronic upper airway inflammation are often but not always linked with adherence to the prescribed medication and education. This review is an initiative taken by the ENT section of the EAACI in conjunction with ARIA and EPOS experts who felt the need to provide a comprehensive overview of the current state of the art of control in upper airway inflammation and stressing the unmet needs in this domain.

Epigenetics in asthma and COPD

Epigenetic mechanisms are likely to play a role in many complex diseases, the extent of which we only beginning to understand. COPD and asthma are two respiratory diseases subject to strong environmental influences depending on underlying genetic susceptibility. Epigenetic mechanisms such as DNA methylation, histone modification and microRNA may be involved in these processes by modulating environmental effects to influence disease development. Given their demonstrated modifiable nature, epigenetic mechanisms may open new possibilities for therapeutic intervention. Here we give an overview of recent developments in the field of respiratory epigenetics in relation to asthma and COPD in the context of our current understanding of mechanisms leading to such diseases.

Epigenetics in asthma and other inflammatory lung diseases

Asthma is a chronic inflammatory disease of the airways. The causes of asthma and other inflammatory lung diseases are thought to be both environmental and heritable. Genetic studies do not adequately explain the heritability and susceptabilty to the disease, and recent evidence suggests that epigentic changes may underlie these processes. Epigenetics are heritable noncoding changes to DNA and can be influenced by environmental factors such as smoking and traffic pollution, which can cause genome-wide and gene-specific changes in DNA methylation. In addition, alterations in histone acetyltransferase/deacetylase activities can be observed in the cells of patients with lung diseases such as severe asthma and chronic obstructive pulmonary disease, and are often linked to smoking. Drugs such as glucocorticoids, which are used to control inflammation, are dependent on histone deacetylase activity, which may be important in patients with severe asthma and chronic obstructive pulmonary disease who do not respond well to glucocorticoid therapy. Future work targeting specific histone acetyltransferases/deacetylases or (de)methylases may prove to be effective future anti-inflammatory treatments for patients with treatment-unresponsive asthma.

Recent advances in the epigenetics and genomics of asthma

PURPOSE OF REVIEW

Epigenetics is the study of heritable changes in gene expression that occur without direct changes in the DNA sequence. Epigenetic mechanisms may explain important observations in asthma, such as the effect of the environment during certain periods in life, transgenerational, and maternal effects and account for some of the missing heritability in asthma. Here, we review recent evidence for the role of epigenetics and genomics in asthma.

RECENT FINDINGS

Environmental factors known to increase asthma risk affect methylation patterns in the genome, yet the link to subsequent asthma development is not yet established. Posttranslational histone modifications and chromatin remodeling are important in establishing T-helper-2 cell differentiation. MicroRNAs have been shown to regulate experimental asthma in mice. Integration of genomic methods leads to increased understanding on how variation at the DNA levels affects mRNA transcription or chromatin remodeling.

SUMMARY

Epigenetic mechanisms regulate gene expression at the DNA, mRNA, and the chromatin level and more studies are needed to establish its role in human asthma. Integration of genomic methods will provide more insight into the complex pathophysiology of asthma.

Perinatal programming of asthma: the role of gut microbiota

Perinatal programming, a dominant theory for the origins of cardiovascular disease, proposes that environmental stimuli influence developmental pathways during critical periods of prenatal and postnatal development, inducing permanent changes in metabolism. In this paper, we present evidence for the perinatal programming of asthma via the intestinal microbiome. While epigenetic mechanisms continue to provide new explanations for the programming hypothesis of asthma development, it is increasingly apparent that the intestinal microbiota plays an independent and potentially interactive role. Commensal gut bacteria are essential to immune system development, and exposures disrupting the infant gut microbiota have been linked to asthma. This paper summarizes the recent findings that implicate caesarean delivery, breastfeeding, perinatal stress, probiotics, and antibiotics as modifiers of infant gut microbiota in the development of asthma.

Histone acetyltransferases are crucial regulators in NF-κB mediated inflammation

Post-translational modifications of proteins, such as acetylation, are important regulatory events in eukaryotic cells. Reversible acetylations of histones and non-histone proteins regulate gene expression and protein activity. Acetylation levels of proteins are regulated by a dynamic equilibrium between acetylation by (histone) acetyltransferases and deacetylation by (histone) deacetylases. Alterations in this equilibrium can result in pathological states. Inflammation is a physiological response that, under certain conditions, turns into a disease. This review focuses on the crucial regulatory roles of protein acetylation in NF-κB-mediated inflammation and the potential applications of small-molecule inhibitors of acetylation for the treatment of inflammatory diseases.

Epigenetics of asthma

Asthma is caused by both heritable and environmental factors. It has become clear that genetic studies do not adequately explain the heritability and susceptibility to asthma. The study of epigenetics, heritable non-coding changes to DNA may help to explain the heritable component of asthma. Additionally, epigenetic modifications can be influenced by the environment, including pollution and cigarette smoking, which are known asthma risk factors. These environmental trigger-induced epigenetic changes may be involved in skewing the immune system towards a Th2 phenotype following in utero exposure and thereby enhancing the risk of asthma. Alternatively, they may directly or indirectly modulate the immune and inflammatory processes in asthmatics via effects on treatment responsiveness. The study of epigenetics may therefore play an important role in our understanding and possible treatment of asthma and other allergic diseases. This article is part of a Special Issue entitled: Biochemistry of Asthma.

The role of epigenetics in the developmental origins of allergic disease

OBJECTIVE

To review current research findings in the field of epigenetics pertaining to the developmental origins of allergic disease.

DATA SOURCES

We examined original research and review articles identified from MEDLINE, OVID, and PubMed that addressed the topic of interest, using the search terms atopy, allergy, asthma, development, IgE, origins, and cord blood paired with epigenetic(s). Relevant references from each article were also procured for review.

STUDY SELECTION

Articles were selected based on their relevance to the contributory role of epigenetic modifications in asthma and other atopic diseases.

RESULTS

There is increasing evidence pointing to the influence of prenatal and early life exposures on the development of allergic disease. A growing body of literature supports the theory that transient environmental pressures can have permanent effects on gene regulation and expression through epigenetic mechanisms. Histone modifications have been associated with degree of bronchial hyperresponsiveness and corticosteroid resistance in asthma. Epigenetic mechanisms can operate independently in various cell types; recent studies have suggested a role in the differentiation of human T cells. Murine studies have revealed that a maternal diet rich in methyl donors can enhance susceptibility to allergic inflammation in the offspring, mediated through increased DNA methylation. Murine studies have also implicated epigenetically modified dendritic cells in the transmission of allergic risk from mothers to offspring.

CONCLUSION

The current literature offers exciting data to support a role for epigenetics in the development and persistence of asthma and allergic rhinitis. However, further human studies are necessary to explore these mechanisms and assess future clinical applicability.

Environmental epigenetics and allergic diseases: recent advances

Significant strides in the understanding of the role of epigenetic regulation in asthma and allergy using both epidemiological approaches as well as experimental ones have been made. This review focuses on new research within the last 2 years. These include advances in determining how environmental agents implicated in airway disease can induce epigenetic changes, how epigenetic regulation can influence T helper cell differentiation and T regulatory cell production, and new discoveries of epigenetic regulation associated with clinical outcomes.

Advances in pediatric asthma in 2009: gaining control of childhood asthma

This year's summary will focus on recent advances in pediatric asthma as reported in Journal of Allergy and Clinical Immunology publications in 2009. New National Asthma Education and Prevention Program asthma guidelines were released in 2007, with a particular emphasis on asthma control. Now that we have worked with the principals of the guidelines for 2 years, new insights are reported on how to implement the guidelines into clinical practice. This year's report will focus on gaps in management that need to be addressed, including health disparities, methods to improve asthma management through opportunities available in school-based asthma programs, and more information on the development of asthma in childhood. This information brings us closer to the point of managing children with controllable asthma and understanding reasons why asthma is not controlled in the remaining children. If we can close these gaps through better communication, improvements in the health care system, and new insights into treatment, we will move closer to better methods to intervene early in the course of the disease and induce clinical remission as quickly as possible in most children.