Allergic Endotypes and Phenotypes of Asthma

The comparison between children and adolescents with asthma provided by the real-world "ControL'Asma" study

OBJECTIVE

Because asthma is a disease that changes over time, the Italian Society of Pediatric Allergy and Immunology launched a nationwide study on asthma control (the ControL'Asma study). The intent was to test the hypothesis that children with asthma could present a different pattern compared to adolescents. In the study, we compared children with adolescents in a real-world setting by analyzing the asthma control grade and other asthma-related parameters.

METHODS

This cross-sectional real-world study included 471 asthmatic children (<age 12) and adolescents (≥age 12), mostly male (n = 326; 69.2%), who were consecutively enrolled at 10 tertiary pediatric allergy clinics. Asthma control level was evaluated according to the Global Initiative for Asthma (GINA) guidelines, the Childhood Asthma Control Test (cACT) questionnaire for children, and the Asthma Control Test (ACT) questionnaire for adolescents, history, rhinitis comorbidity, allergy, clinical examination, lung function, and perception of asthma symptoms assessed by visual analogue scale (VAS).

RESULTS

There was no difference between the age groups in asthma control as determined by both GINA criteria and the cACT/ACT questionnaires. However, adolescents with asthma had significantly more frequent rhinitis comorbidity (p = 0.02; OR = 2.07) and allergy (p = 0.012; OR = 3.72) than children. Asthma severity, lung function, and symptom perception were not different between age groups.

CONCLUSIONS

The current study showed that asthma control is not associated with age in young people. Adolescents with asthma did experience rhinitis and allergy more frequently than children. These findings reflect the progressive nature of the allergic phenotype in young patients.

Novel therapeutic approaches targeting endotypes of severe airway disease

Introduction: Severe asthma and chronic rhinosinusitis (CRS), with nasal polyps (CRSwNP) and without nasal polyps (CRSsNP), are heterogeneous diseases characterized by different mechanistic pathways (endotypes) and variable clinical presentations (phenotypes).Areas covered: This review provides the clinician with an overview of the prevalence and clinical impact of severe chronic upper and lower airways disease and suggests a novel therapeutic approach with biological agents with possible biomarkers. To select relevant literature for inclusion in this review, we conducted a literature search using the PubMed database, using terms 'severe airways disease' AND 'endotype' AND 'treatment.' The literature review was performed for publication years 2010-2020, restricting the articles to humans and English language publications.Expert opinion: The coronavirus disease (COVID-19) pandemic has brought forth many challenges for patients with severe airway disease and healthcare practitioners involved in care. These patients could have an increased risk of developing severe SARS-CoV-2 disease, although treatment with biologics is not associated with a worse prognosis. Eosinopenia on hospital admission plays a key role as a diagnostic and prognostic biomarker.

Biomarkers for Severe Asthma: Lessons From Longitudinal Cohort Studies

Severe asthma (SA) is a heterogeneous disease characterized by uncontrolled symptoms, frequent exacerbations, and lung function decline. The discovery of phenotypes and endotypes of SA significantly improves our understanding of its pathophysiology and allows the advent of biologics blocking multiple molecular targets. The advances have mainly been made in type 2-high asthma associated with elevated type 2 inflammatory biomarkers such as immunoglobulin E (IgE), interleukins (IL)-4, IL-5, and IL-13. Previous clinical trials have demonstrated that type 2 biomarkers, including blood/sputum eosinophils and the fraction of exhaled nitric oxide (FeNO), were correlated to severe airway inflammation, persistent symptoms, frequent exacerbations, and the clinical efficacy of these biomarkers in predicting treatment outcomes of type 2-targeting biologics. However, it is well known that type 2 inflammation is partially attributable to the pathogenesis of SA. Although some recent studies have suggested that type 2-low and mixed phenotypes of asthma are important contributors to the heterogeneity of SA, many questions about these non-type 2 asthma phenotypes remain to be solved. Consequently, many efforts to investigate and find novel biomarkers for SA have also made in their methods. Many cross-sectional experimental studies in large-scale cohorts and randomized clinical trials have proved their value in understanding SA. More recently, real-world cohort studies have been in the limelight for SA research, which is unbiased and expected to give us an answer to the unmet needs of the heterogeneity of SA.

Characterization of Asthma Trajectories from Infancy to Young Adulthood

BACKGROUND

Development of asthma is complicated by the multidimensional nature of the disease.

OBJECTIVE

To identify and characterize trajectories of asthma from infancy to young adulthood, and their associations with lung function and inflammatory and respiratory markers in adolescence and young adulthood.

METHODS

A latent class analysis was performed in a population-based cohort (N = 4089). Parental and self-reported symptoms of asthma were used to investigate asthma development. We characterized background factors, allergic comorbidity, and IgE sensitization and investigated associations with asthma markers.

RESULTS

A 4-class solution of asthma trajectories was identified: never/infrequent (n = 3291 [80.4%]), early-onset transient (n = 307 [7.5%]), adolescent-onset (n = 261 [6.4%]), and persistent asthma (n = 230 [5.6%]). Uncontrolled asthma was equally prevalent in the adolescent-onset and persistent asthma trajectory groups, at both age 16 (41.7% vs 42.4%; P = .90) and 24 years (53.7% vs 52.4%; P = .81). The persistent asthma trajectory group had a higher proportion of eosinophil counts greater than or equal to 0.3 (10⁹ cells/L) at age 24 years compared with the adolescent-onset trajectory group (31.0% vs 18.5%; P < .01).

CONCLUSIONS

The adolescent-onset and persistent asthma trajectory groups had equal burdens of asthma control in adolescence and young adulthood. However, the persistent asthma trajectory group showed more signs of type 2 inflammation than the adolescent-onset trajectory group. This unbiased approach highlights the need of identifying patients with adolescent asthma to optimize care, because they suffer the same lack of asthma control as those with persistent asthma.

Treatable Mechanisms in Asthma

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

Eosinophilia in Asthma Patients Is Protective Against Severe COVID-19 Illness

Background

There is a paucity of information on coronavirus disease 2019 (COVID-19) outcomes in asthmatics.

Objective

To identify risk factors associated with admission and subsequent mortality among COVID-19–infected asthmatics.

Methods

Adults at our institution with a positive polymerase chain reaction for COVID-19 between March 14 and April 27, 2020, were retrospectively identified. Comorbidities, laboratory results, and mortality rates during hospitalization were recorded.

Results

In total, 737 of 951 (77.5%) asthma patients with COVID-19 were seen in the emergency department (ED), and 78.8% of these ED patients (581 of 737) were admitted. Individuals with previously measured mean absolute eosinophil counts (AEC) ≥150 cells/μL were less likely to be admitted (odds ratio [OR] = 0.46, 95% confidence interval [CI]: 0.21-0.98, P = .04), whereas concomitant heart failure (CHF), chronic kidney disease (CKD), and chronic obstructive pulmonary disease (COPD) were risk factors for admission. Hospitalized patients with asthma with peak hospital-measured AEC ≥150 cells/μL (n = 104) were less likely to die compared with those whose AEC remained <150 cells/μL (n = 213) (mortality rate 9.6% vs 25.8%; OR = 0.006, 95% CI: 0.0001-0.64, P = .03). This group had also higher preadmission mean AEC (237 ± 181 vs 163 ± 147 cells/μL, P = .001, OR = 2012, 95% CI: 27.3-14,816). The mortality rate in patients with asthma alone (no associated CHF, CKD, COPD, diabetes, or hypertension) was similar to that of patients without asthma or any of these comorbidities.

Conclusions

In asthmatics, pre-existing eosinophilia (AEC ≥150 cells/μL) was protective from COVID-19–associated admission, and development of eosinophilia (AEC ≥150 cells/μL) during hospitalization was associated with decreased mortality. Preadmission AEC influenced the AEC trend during hospitalization. Having a Th2-asthma phenotype might be an important predictor for reduced COVID-19 morbidity and mortality that should be further explored in prospective and mechanistic studies.

Clinical Determinants of Successful Omalizumab Therapy in Severe Allergic Asthma Patients: 4-Year-Long, Real-Life Observation

Introduction

Omalizumab is a high-cost therapy recommended for the treatment of severe allergic asthma.

Objective

To find clinical parameters that are related to the sustained response to omalizumab.

Patients and Methods

This retrospective, real-life, 4-year follow-up was provided in Poland between March 2013 and May 2019. The success of omalizumab was assessed based on composed subjective and objective criteria. Simple/multiple regression analyses were performed to search for predictors of the response to omalizumab.

Results

A total of 989 severe allergic asthma patients were referred for omalizumab therapy, of whom 854 patients were considered eligible for treatment. At weeks 16 and 52, omalizumab was successful in 84% and 91% of patients, respectively. Treatment effectiveness was maintained up to the 4-year follow-up. Four predictors of the response to omalizumab were found at week 16 and two at week 52. The results at week 16 may be used as predictors of success at week 52 based on the model including baseline FEV1% and change in ACQ-7 and miniAQLQ score at week 16: the area under the ROC curve equals 0.746 [95% CI: 0.672–0.820].

Conclusion

Omalizumab therapy is very effective, with this efficacy sustained after 4 years of treatment. Success of the therapy can be predicted from the baseline FEV1% and clinical improvement (based on ACQ-7 and miniAQLQ scores) at week 16.

Biologics to Treat Severe Asthma in Children and Adolescents: A Practical Update

Background: Severe asthma represents a significant challenge for children and adolescents. At the same time, it often places a burden on patients, caregivers, and society, mainly related to morbidity, mortality, and health care resources. In children and adolescents, severe asthma is mostly characterized by type 2 inflammation, which leads to bronchial eosinophilia that may be suppressed by corticosteroids. However, in this age group, a high dosage of inhaled corticosteroids combined with systemic corticosteroids sometimes results in unacceptable side effects, such as reduced growth velocity and reduced bone mineral density. Therefore, there is increasing and enthusiastic interest in today's biologics, including omalizumab, mepolizumab, reslizumab, benralizumab, and dupilumab. There is growing evidence that they may be effective and safe add-on options for children and adolescents. In 2009, omalizumab was approved by the European Medicines Agency as the first available therapeutic option for allergic asthma in patients as young as 6 years of age, followed by a similar approval by the U.S. Food and Drug Administration in 2016. Previously, omalizumab was marketed for this indication in patients ≥ age 12. Subsequent biologics, namely mepolizumab, reslizumab, and benralizumab, are IL-5 targeted agents that are presently approved in some countries for severe eosinophilic asthma starting at 6 years of age. Dupilumab is targeted against the IL-4 receptor α-chain, and it has been approved in the United States and the European Union as an add-on maintenance therapy in patients ≥12 years of age. Conclusion: This review presents the most recent evidence on approved biologics for the treatment of severe asthma and discusses the unmet needs and future perspective, focusing on the pediatric and adolescent age groups.

RNA Sequencing Keloid Transcriptome Associates Keloids With Th2, Th1, Th17/Th22, and JAK3-Skewing

Keloids are disfiguring, fibroproliferative growths and their pathogenesis remains unclear, inhibiting therapeutic development. Available treatment options have limited efficacy and harbor safety concerns. Thus, there is a great need to clarify keloid pathomechanisms that may lead to novel treatments. In this study, we aimed to elucidate the profile of lesional and non-lesional keloid skin compared to normal skin. We performed gene (RNAseq, qRT-PCR) and protein (immunohistochemistry) expression analyses on biopsy specimens obtained from lesional and non-lesional skin of African American (AA) keloid patients compared to healthy skin from AA controls. Fold-change≥2 and false-discovery rate (FDR)<0.05 was used to define significance. We found that lesional versus normal skin showed significant up-regulation of markers of T-cell activation/migration (ICOS, CCR7), Th2- (IL-4R, CCL11, TNFSF4/OX40L), Th1- (CXCL9/CXCL10/CXCL11), Th17/Th22- (CCL20, S100As) pathways, and JAK/STAT-signaling (JAK3) (false-discovery rate [FDR]<0.05). Non-lesional skin also exhibited similar trends. We observed increased cellular infiltrates in keloid tissues, including T-cells, dendritic cells, mast cells, as well as greater IL-4rα+, CCR9+, and periostin+ immunostaining. In sum, comprehensive molecular profiling demonstrated that both lesional and non-lesional skin show significant immune alternations, and particularly Th2 and JAK3 expression. This advocates for the investigation of novel treatments targeting the Th2 axis and/or JAK/STAT-signaling in keloid patients.

ControL'Asma Project: new insights

The Italian Society of Paediatric Allergy and Immunology has developed the project "ControL'Asma," a nationwide study involved ten third-level pediatric allergy clinics across Italy. The first findings of the "ControL'Asma" project showed that asthma was more frequent in males, had an early onset and allergic phenotype with very frequent rhinitis comorbidity, uncontrolled, and partly controlled asthma affected about the half of subjects, and the assessment of asthma symptom perception by VAS could be a reliable tool in the asthma management.

Use of Sublingual Immunotherapy for Aeroallergens in Children with Asthma

Asthma is a heterogeneous disease that in children is often allergen-driven with a type 2 inflammation. Sublingual immunotherapy represents an important progress in the use of personalized medicine in children with allergic asthma. It is a viable option for house dust mite-driven asthma and in subjects with the asthma associated with allergic rhinitis. The use and indications for isolated asthma caused by other allergens are still controversial owing to heterogeneity of commercially available products and methodological limitations of studies in children. Nevertheless, most studies and meta-analyses found the efficacy of sublingual immunotherapy. Sublingual immunotherapy is safe but cannot be recommended in children with uncontrolled asthma.

Atopic phenotypes and their implication in the atopic march

INTRODUCTION

Eczema, allergic rhinitis, and asthma are traditionally considered atopic (or allergic) diseases. They are complex, multifactorial, and are caused by a variety of different mechanisms, which result in multiple heterogeneous clinical phenotypes. Atopic march is usually interpreted as the sequential development of symptoms from eczema in infancy, to asthma, and then allergic rhinitis. Areas covered: The authors reviewed the evidence on the multimorbidity of eczema, asthma, and rhinitis, and the implication of results of data-driven analyses on the concept framework of atopic march. A literature search was conducted in the PubMed and Web of Science for peer-reviewed articles published until July 2020. Application of Bayesian machine learning framework to rich phenotypic data from birth cohorts demonstrated that the postulated linear progression of symptoms (atopic march) does not capture the heterogeneity of allergic phenotypes. Expert opinion: Eczema, wheeze, and rhinitis co-exist more often than would be expected by chance, but their relationship can be best understood in a multimorbidity framework, rather than through atopic march sequence. The observation of their co-occurrence does not imply any specific relationship between them, and certainly not a progressive or causal one. It is unlikely that a sngle mechanism such as allergic sensitization underpins different multimorbidity manifestations.

Asthma in children and adolescents: the ControL'Asma project

The control of asthma is the objective of asthma management. However, it is difficult to obtain in clinical practice. The Italian Society of Allergy and Clinical Immunology promoted the nationwide project "ControL'Asma" to investigate the real situation in a group of children and adolescents with asthma. The preliminary outcomes demonstrated that many asthmatic subjects do not achieve adequate asthma control. Moreover, asthma in Italian children and adolescents was usually more frequent in males, had an early onset and allergic phenotype with very frequent rhinitis comorbidity, uncontrolled and partly controlled asthma affected about the half of subjects. However, this project suggested that the assessment of asthma symptom perception by VAS could be a reliable tool in the asthma management.

Burden and socioeconomics of asthma, allergic rhinitis, atopic dermatitis and food allergy

INTRODUCTION

Asthma, allergic rhinitis, atopic dermatitis, and food allergy affect approximately 20% of the global population. Few studies describe the burden of the totality of these diseases and only a handful studies provide a comprehensive overview of the socioeconomic impact of these diseases.

AREAS COVERED

For this narrative review, we searched Pubmed using selected keywords and inspected relevant references using a snowballing process. We provide an overview of the socioeconomic burden of allergic diseases (in particular, asthma, allergic rhinitis, atopic dermatitis, and food allergy). The focus of this review is on their epidemiology (incidence, prevalence), burden (disability-adjusted life years, quality of life), and direct and indirect costs (absenteeism and presenteeism). We have put special emphasis on differences between countries.

EXPERT COMMENTARY

Both the prevalence and the burden of allergic diseases are considerable with prevalence varying between 1% and 20%. We identified a plethora of studies on asthma, but studies were generally difficult to compare due to the heterogeneity in measures used. There were only few studies on the burden of food allergy; therefore, more studies on this allergy are required. For future studies, we recommend standardizing epidemiologic, socioeconomic impact, and quality of life measures of allergic diseases.

Plasma P-Selectin Is Inversely Associated with Lung Function and Corticosteroid Responsiveness in Asthma

BACKGROUND

Severe asthma has multiple phenotypes for which biomarkers are still being defined. Plasma P-selectin reports endothelial and/or platelet activation.

OBJECTIVE

To determine if P-selectin is associated with features of asthma in a longitudinal study.

METHODS

Plasmas from 70 adult patients enrolled in the Severe Asthma Research Program (SARP) III at the University of Wisconsin-Madison were analyzed for concentration of P-selectin at several points over the course of 3 years, namely, at baseline (BPS), after intramuscular triamcinolone acetonide (TA) injection, and at 36 months after baseline. Thirty-four participants also came in during acute exacerbation and 6 weeks after exacerbation.

RESULTS

BPS correlated inversely with forced expiratory volume in 1 s (FEV1) and with residual volume/total lung capacity, an indicator of air trapping. BPS was inversely associated with FEV1 change after TA, by regression analysis. FEV1 did not change significantly after TA if BPS was above the median, whereas patients with BPS below the median had significantly increased FEV1 after TA. BPS was higher in and predicted assignment to SARP phenotype cluster 5 ("severe fixed-airflow asthma"). P-selectin was modestly but significantly increased at exacerbation but returned to baseline within 3 years.

CONCLUSIONS

High BPS is associated with airway obstruction, air trapping, the "severe fixed-airflow" cluster, and lack of FEV1 improvement in response to TA injection. P-selectin concentration, which is a stable trait with only modest elevation during exacerbation, may be a useful biomarker for a severe asthma pheno- or endotype characterized by low pulmonary function and lack of corticosteroid responsiveness.

Pragmatic Clinical Perspective on Biologics for Severe Refractory Type 2 Asthma

Patients with severe refractory asthma present a challenging clinical conundrum for practicing clinicians. Biologics that target key mediators in the type 2 inflammation cascade, including IL-4, IL-5, IL-13, and IgE, can be effective strategies for these patients. However, with various biologics available, choosing the optimal one for a particular patient becomes a nuanced decision. We propose a pragmatic algorithm that identifies the optimal biologic class for patients who have specific type 2 disease endotypes. Patients with eosinophilic endotypes fare well with anti-IL-5(rα) medications, comprising mepolizumab, benralizumab, and reslizumab because they have been shown to reduce exacerbations in severe eosinophilic asthma by approximately 50%. In patients with fractional exhaled nitric oxide-high endotypes, anti-IL-4rα such as dupilumab is deemed to be most effective and has demonstrated a 47% reduction in asthma exacerbations. For patients with severe uncontrolled allergic asthma, anti-IgE (omalizumab) is effective and has been shown to confer a 25% reduction in asthma exacerbations. Type 2 comorbidities including chronic rhinosinusitis with nasal polyps, atopic dermatitis, chronic idiopathic urticaria, and eosinophilic esophagitis are important to bear in mind before the prescription of biologics. Further head-to-head studies are indicated to compare biologics in patients with mixed endotypes according to peripheral blood eosinophils, fractional exhaled nitric oxide, and allergic status. The evidence strongly supports endotype-driven prescribing of biologics to achieve clinically relevant outcomes in severe refractory asthma and related comorbidities.

Allergen Immunotherapy in Pediatric Asthma: A Pragmatic Point of View

To date, the only disease-modifying treatment strategy for allergic rhinitis and asthma is allergen immunotherapy (AIT). There is evidence that AIT improves allergic rhinitis and asthma, such as reducing symptom severity and medication use and improving of quality of life, with a long-lasting effect after the end of the course. The recent clinical trials evidenced AIT effectiveness and safety in allergic asthma. Consequently, the current version of the GINA (Global Initiative for Asthma) guidelines recommend AIT as an add-on therapy for asthma. There is also evidence that AIT may exert preventive activity on the possible progression from allergic rhinitis to asthma in children and the onset of new sensitizations. The present review provides a pragmatic summary of the clinical indications of AIT in pediatric asthma, including the immunological mechanisms, the predictive biomarkers, and the safety issues in clinical practice.

Monoclonal Antibody Therapy in Childhood Asthma

PURPOSE OF REVIEW

There has been an explosion of monoclonal antibodies in the treatment of severe uncontrolled adult asthma. Studies have now been published in severe pediatric asthma. There are numerous questions that need to be answered in determining whether these modalities are appropriate and safe in children.

RECENT FINDINGS

This is a narrative review examining the latest pediatric literature on monoclonal antibodies, both approved and in the pipeline, for uncontrolled asthma. Presently, all of the biologics are positioned to treat patients with underlying type 2 high disease. Two monoclonal antibodies are approved for children 6 years of age and older, omalizumab and mepolizumab, with more likely approved in the near future. The effect of these agents in controlling severe pediatric asthma is promising. Data is limited to long-term efficacy and safety, and whether any agent has an effect on the natural history of asthma.

How to compare the efficacy of biologic agents in asthma

OBJECTIVE

The use of biologics in severe asthma has made substantial strides in disease management and fostered a personalized medicine approach; however, how, when, and which biologic to choose are unresolved issues, which form the focus of this review.

DATA SOURCES

The data sources were published literature, including current guidelines, available through PubMed searches and online resources.

STUDY SELECTIONS

Studies and randomized controlled trials pertaining to the use of biologics in various phenotypes and/or endotypes of asthma and comparative analyses between biologics in asthma were included.

RESULTS

Inflammatory constructs in asthma are complex and translate differentially into clinical practice for both disease severity and treatment responsiveness. The utilization of biologics, which target selected components of inflammation, has begun to dramatically improve the course of management for many patients with severe asthma. A retuning of our approach into selecting appropriate patient cohorts or phenotypes for studies and selection of clinically relevant outcomes, which are reflected by existing and novel emerging biomarkers, is enabling a paradigm shift in asthma management. Comparing the efficacy of the available biologics for asthma is challenging as no direct head-to-head studies are available, and indirect comparisons to this query provide varying results.

CONCLUSION

Significant progress has been achieved in the management of severe asthma with treatment of target-specific biologics. Sophisticated algorithms and trial designs, using a combination of available biomarker profiles and clinical characteristics to stratify patient populations into more precise subphenotypes and endotypes to guide our choice of a biologic or therapy, are critically needed but currently not formulated.