Biomarkers and severe asthma: a critical appraisal

Biomonitoring Environmental Exposure in Syrian Refugees in Lebanon

Over one million Syrian refugees have been residing in substandard living conditions in Lebanon for the past decade. Non-invasive biomonitoring of fractional exhaled nitric oxide (FeNO) as a pulmonary inflammation biomarker was conducted following and preceding indoor environmental assessments (which revealed elevated mould counts in informal tented settlements and non-residential shelters) to further evaluate effects of environmental exposure to indoor contaminants. Results of biomonitoring (n = 57) provided some insight regarding existing respiratory conditions and the possible implementation of minimally invasive methods to establish susceptibility profiles in Syrian refugees amid limited access to healthcare. The clinical interpretation of FeNO results suggested possible persistent exposure to allergens in addition to significant type 2 inflammation in some subjects. These findings warrant the need to expand this study, investigate other biomarkers, and attempt to correlate findings with environmental conditions to evaluate if a dose-response relationship exists.

Biomarkers in asthma, potential for therapeutic intervention

Asthma is a heterogeneous disease characterized by multiple phenotypes with varying risk factors and therapeutic responses. This Commentary describes research on biomarkers for T2-"high" and T2-"low" inflammation, a hallmark of the disease. Patients with asthma who exhibit an increase in airway T2 inflammation are classified as having T2-high asthma. In this endotype, Type 2 cytokines interleukins (IL)-4, IL-5, and IL-13, plus other inflammatory mediators, lead to increased eosinophilic inflammation and elevated fractional exhaled nitric oxide (FeNO). In contrast, T2-low asthma has no clear definition. Biomarkers are considered valuable tools as they can help identify various phenotypes and endotypes, as well as treatment response to standard treatment or potential therapeutic targets, particularly for biologics. As our knowledge of phenotypes and endotypes expands, biologics are increasingly integrated into treatment strategies for severe asthma. These treatments block specific inflammatory pathways or single mediators. While single or composite biomarkers may help to identify subsets of patients who might benefit from these treatments, only a few inflammatory biomarkers have been validated for clinical application. One example is sputum eosinophilia, a particularly useful biomarker, as it may suggest corticosteroid responsiveness or reflect non-compliance to inhaled corticosteroids. As knowledge develops, a meaningful goal would be to provide individualized care to patients with asthma.

Serum biomarkers of remodeling in severe asthma with fixed airway obstruction and the potential role of KL-6

Over 3% of asthmatic patients are affected by a particularly severe form of the disease ("severe asthma", SA) which is often refractory to standard treatment. Airway remodeling (AR), which can be considered a critical characteristic of approximately half of all patients with SA and currently thought to be the main mechanism triggering fixed airway obstruction (FAO), seems to be a key factor affecting a patient's outcome. Despite the collective efforts of internationally renowned experts, to date only a few biomarkers indicative of AR and no recognizable biomarkers of lung parenchymal remodeling have been identified. This work examines the pathogenesis of airway and lung parenchymal remodeling and the serum biomarkers that may be able to identify the severe asthmatic patients who may develop FAO. The study also aims to examine if Krebs von den Lungen-6 (KL-6) could be considered a diagnostic biomarker of lung structural damage in SA.

New insights into the pathophysiology and therapeutic targets of asthma and comorbid chronic rhinosinusitis with or without nasal polyposis

Asthma and chronic rhinosinusitis with nasal polyps (CRSwNP) or without (CRSsNP) are chronic respiratory diseases. These two disorders often co-exist based on common anatomical, immunological, histopathological, and pathophysiological basis. Usually, asthma with comorbid CRSwNP is driven by type 2 (T2) inflammation which predisposes to more severe, often intractable, disease. In the past two decades, innovative technologies and detection techniques in combination with newly introduced targeted therapies helped shape our understanding of the immunological pathways underlying inflammatory airway diseases and to further identify several distinct clinical and inflammatory subsets to enhance the development of more effective personalized treatments. Presently, a number of targeted biologics has shown clinical efficacy in patients with refractory T2 airway inflammation, including anti-IgE (omalizumab), anti-IL-5 (mepolizumab, reslizumab)/anti-IL5R (benralizumab), anti-IL-4R-α (anti-IL-4/IL-13, dupilumab), and anti-TSLP (tezepelumab). In non-type-2 endotypes, no targeted biologics have consistently shown clinical efficacy so far. Presently, multiple therapeutical targets are being explored including cytokines, membrane molecules and intracellular signalling pathways to further expand current treatment options for severe asthma with and without comorbid CRSwNP. In this review, we discuss existing biologics, those under development and share some views on new horizons.

Biomarkers in severe asthma: Identifying the treatable trait

Asthma is a chronic condition of bronchial hyper-reactivity associated with inflammation ranges from mild to severe form. It affects 1 - 18% of the population globally and it is estimated that > 300million people in the world have asthma. Of this 5 - 10% have severe asthma. while the proportion of patients suffering from severe are smaller, the morbidity and mortality are higher in this group. With the advances in our understanding of the pathophysiology of asthma there is a need to understand the role of various biomarkers. We live in an era of precision medicine and today there is a clear unmet need to understand targeted therapies. This review aims to raise awareness to the available biomarkers used in clinical practice in India and their role in predicting response to targeted therapies.

Immunogenicity of a novel anti-allergic vaccine based on house dust mite purified allergens and a combination adjuvant in a murine prophylactic model

The outer-membrane-derived proteoliposome (PL) of Neisseria meningitidis has been reported as a potent vaccine adjuvant, inducing a Th1-skewed response. This work aimed to assess the immunogenicity of a novel anti-allergic vaccine candidate based on allergens from Dermatophagoides siboney house dust mite and a combination adjuvant containing PL and Alum. In a preventative experimental setting, BALB/c mice were administered with three doses containing 2 µg of Der s1 and 0.4 µg Der s2 allergen, PL and Alum, at 7 days intervals, by subcutaneous route. Furthermore, mice were subjected to an allergen aerosol challenge for 6 consecutive days. Serum IgE, IgG1, and IgG2a allergen-specific antibodies were assessed by ELISA. Cytokine levels in supernatants of D. siboney stimulated lymphocyte cultures and in bronchoalveolar lavage (BAL) were measured by ELISA. Lung tissues were subjected to histological examination. The vaccine prevented the development of both, systemic (IgE) and local allergic responses (featuring lower IL-4, and IL-5 levels in BAL) upon allergen exposure by the inhalant route. Histological examination showed also a diminished allergic inflammatory response in the lungs. After the allergen challenge, cytokine levels in stimulated lymphocyte cultures showed lower values of IL-13 and augmented IFN-γ and IL-10. The vaccine induced a mixed IgG2a/IgG1 antibody response; although only IgG2a was PL-dependent. Both, IgG1/IgE and IgG2a/IgE ratios, showed significantly greater values in vaccinated mice. The findings support a preventative anti-allergic effect associated with the induction of a Th1-like IFN-γ/IL-10 response. IgG1/IgE and IgG2a/IgE ratios could be useful biomarkers for translation into clinical trials.

Critical evaluation of asthma biomarkers in clinical practice

The advent of personalized medicine has revolutionized the whole approach to the management of asthma, representing the essential basis for future developments. The cornerstones of personalized medicine are the highest precision in diagnosis, individualized prediction of disease evolution, and patient-tailored treatment. To this aim, enormous efforts have been established to discover biomarkers able to predict patients' phenotypes according to clinical, functional, and bio-humoral traits. Biomarkers are objectively measured characteristics used as indicators of biological or pathogenic processes or clinical responses to specific therapeutic interventions. The diagnosis of type-2 asthma, prediction of response to type-2 targeted treatments, and evaluation of the risk of exacerbation and lung function impairment have been associated with biomarkers detectable either in peripheral blood or in airway samples. The surrogate nature of serum biomarkers, set up to be less invasive than sputum analysis or bronchial biopsies, has shown several limits concerning their clinical applicability. Routinely used biomarkers, like peripheral eosinophilia, total IgE, or exhaled nitric oxide, result, even when combined, to be not completely satisfactory in segregating different type-2 asthma phenotypes, particularly in the context of severe asthma where the choice among different biologics is compelling. Moreover, the type-2 low fraction of patients is not only an orphan of biological treatments but is at risk of being misdiagnosed due to the low negative predictive value of type-2 high biomarkers. Sputum inflammatory cell analysis, considered the highest specific biomarker in discriminating eosinophilic inflammation in asthma, and therefore elected as the gold standard in clinical trials and research models, demonstrated many limits in clinical applicability. Many factors may influence the measure of these biomarkers, such as corticosteroid intake, comorbidities, and environmental exposures or habits. Not least, biomarkers variability over time is a confounding factor leading to wrong clinical choices. In this narrative review, we try to explore many aspects concerning the role of routinely used biomarkers in asthma, applying a critical view over the "state of the art" and contemporarily offering an overview of the most recent evidence in this field.

The Role of Systems Biology in Deciphering Asthma Heterogeneity

Asthma is one of the most common and lifelong and chronic inflammatory diseases characterized by inflammation, bronchial hyperresponsiveness, and airway obstruction episodes. It is a heterogeneous disease of varying and overlapping phenotypes with many confounding factors playing a role in disease susceptibility and management. Such multifactorial disorders will benefit from using systems biology as a strategy to elucidate molecular insights from complex, quantitative, massive clinical, and biological data that will help to understand the underlying disease mechanism, early detection, and treatment planning. Systems biology is an approach that uses the comprehensive understanding of living systems through bioinformatics, mathematical, and computational techniques to model diverse high-throughput molecular, cellular, and the physiologic profiling of healthy and diseased populations to define biological processes. The use of systems biology has helped understand and enrich our knowledge of asthma heterogeneity and molecular basis; however, such methods have their limitations. The translational benefits of these studies are few, and it is recommended to reanalyze the different studies and omics in conjugation with one another which may help understand the reasons for this variation and help overcome the limitations of understanding the heterogeneity in asthma pathology. In this review, we aim to show the different factors that play a role in asthma heterogeneity and how systems biology may aid in understanding and deciphering the molecular basis of asthma.

Identification of Hub Genes and Potential Biomarkers for Childhood Asthma by Utilizing an Established Bioinformatic Analysis Approach

Childhood asthma represents a heterogeneous disease resulting from the interaction between genetic factors and environmental exposures. Currently, finding reliable biomarkers is necessary for the clinical management of childhood asthma. However, only a few biomarkers are being used in clinical practice in the pediatric population. In the long run, new biomarkers for asthma in children are required and would help direct therapy approaches. This study aims to identify potential childhood asthma biomarkers using a genetic-driven biomarkers approach. Herein, childhood asthma-associated Single Nucleotide Polymorphisms (SNPs) were utilized from the GWAS database to drive and facilitate the biomarker of childhood asthma. We uncovered 466 childhood asthma-associated loci by extending to proximal SNPs based on r2 > 0.8 in Asian populations and utilizing HaploReg version 4.1 to determine 393 childhood asthma risk genes. Next, the functional roles of these genes were subsequently investigated using Gene Ontology (GO) term enrichment analysis, a Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway, and a protein−protein interaction (PPI) network. MCODE and CytoHubba are two Cytoscape plugins utilized to find biomarker genes from functional networks created using childhood asthma risk genes. Intriguingly, 10 hub genes (IL6, IL4, IL2, IL13, PTPRC, IL5, IL33, TBX21, IL2RA, and STAT6) were successfully identified and may have been identified to play a potential role in the pathogenesis of childhood asthma. Among 10 hub genes, we strongly suggest IL6 and IL4 as prospective childhood asthma biomarkers since both of these biomarkers achieved a high systemic score in Cytohubba’s MCC algorithm. In summary, this study offers a valuable genetic-driven biomarker approach to facilitate the potential biomarkers for asthma in children.

Current Understanding of Asthma Pathogenesis and Biomarkers

Asthma is a heterogeneous lung disease with variable phenotypes (clinical presentations) and distinctive endotypes (mechanisms). Over the last decade, considerable efforts have been made to dissect the cellular and molecular mechanisms of asthma. Aberrant T helper type 2 (Th2) inflammation is the most important pathological process for asthma, which is mediated by Th2 cytokines, such as interleukin (IL)-5, IL-4, and IL-13. Approximately 50% of mild-to-moderate asthma and a large portion of severe asthma is induced by Th2-dependent inflammation. Th2-low asthma can be mediated by non-Th2 cytokines, including IL-17 and tumor necrosis factor-α. There is emerging evidence to demonstrate that inflammation-independent processes also contribute to asthma pathogenesis. Protein kinases, adapter protein, microRNAs, ORMDL3, and gasdermin B are newly identified molecules that drive asthma progression, independent of inflammation. Eosinophils, IgE, fractional exhaled nitric oxide, and periostin are practical biomarkers for Th2-high asthma. Sputum neutrophils are easily used to diagnose Th2-low asthma. Despite progress, more studies are needed to delineate complex endotypes of asthma and to identify new and practical biomarkers for better diagnosis, classification, and treatment.

Diagnosis of Hymenoptera Venom Allergy: State of the Art, Challenges, and Perspectives

Hymenoptera venom allergy is the most common cause of anaphylaxis in adults and the second-most frequent in children. The proper diagnosis of this life-threatening allergy remains a challenge. This review focuses on the current knowledge regarding diagnostics of Hymenoptera venom allergy. The paper includes a brief description of the representatives of Hymenoptera order and the composition of their venoms. Then, diagnostic tests for allergy to Hymenoptera venom are described. Common diagnostic problems, especially double positivity in tests for IgE antibodies specific to honeybee and wasp venom, are also discussed. Special attention is paid to the search for new diagnostic capabilities using modern methodologies. Multidimensional molecular analysis offers an opportunity to characterize changes in body fluids associated with Hymenoptera venom allergy and yields a unique insight into the cell status. Despite recent developments in the diagnostics of Hymenoptera venom allergy, new testing methodologies are still needed to answer questions and doubts we have.

Allergic Asthma in the Era of Personalized Medicine

Allergic asthma is the most common asthma phenotype and is characterized by IgE sensitization to airborne allergens and subsequent typical asthmatic symptoms after exposure. A form of type 2 (T2) airway inflammation underlies allergic asthma. It usually arises in childhood and is accompanied by multimorbidity presenting with the occurrence of other atopic diseases, such as atopic dermatitis and allergic rhinitis. Diagnosis of the allergic endotype is based on in vivo (skin prick tests) and/or in vitro (allergen-specific IgE levels, component-resolved diagnosis (CRD)) documentation of allergic sensitization. Biomarkers identifying patients with allergic asthma include total immunoglobulin E (IgE) levels, fractional exhaled nitric oxide (FeNO) and serum eosinophil counts. The treatment of allergic asthma is a complex procedure and requires a patient-tailored approach. Besides environmental control involving allergen avoidance measurements and cornerstone pharmacological interventions based on inhaled drugs, allergen-specific immunotherapy (AIT) and biologics are now at the forefront when it comes to personalized management of asthma. The current review aims to shed light on the distinct phenotype of allergic asthma, ranging over its current definition, clinical characteristics, pathophysiology and biomarkers, as well as its treatment options in the era of precision medicine.

Serum Periostin Level in Children with Asthma

OBJECTIVES

To determine the average serum periostin level in children with asthma between 6 and 16 y of age, and to find out if the levels correlated with markers of eosinophilic inflammation, asthma control, and severity.

METHODS

Children under follow-up at a tertiary care centre were enrolled. Children with conditions causing elevated serum periostin other than asthma, or history of systemic steroid use in the past 6 mo were excluded. Serum total IgE and periostin were estimated by ELISA.

RESULTS

The median (IQR) serum periostin level was 52.6 (45.4, 58.3) ng/mL. Levels did not vary with age, gender, duration of symptoms, positive family history, or history of exacerbations in the last 6 mo. There was no significant correlation with anthropometric parameters or their z scores, or markers of eosinophilic inflammation in blood including serum total IgE, eosinophil percentage or absolute eosinophil count. There was no difference in median periostin levels of children with different asthma symptom control or asthma severity.

CONCLUSIONS

In a group of 26 Indian children with physician-diagnosed asthma, serum periostin showed no significant correlation to markers of eosinophilic inflammation.

Identification of key genes and pathways between mild-moderate and severe asthmatics via bioinformatics analysis

Severe asthma is the main reason for death and disability caused by asthma. However, effective biomarkers for severe asthma have not been identified. Here, we aimed to identify potential biomarkers in severe asthma. We identified 202 differentially expressed genes (DEGs) between severe asthma and mild-moderate asthma after integrating the results from GSE69683 and GSE27011 datasets. The enrichment analysis indicated that 202 DEGs were associated with metabolism- and immune-related processes. 10 hub genes were identified by Cytoscape and five of these genes’ AUC (area under the curve) values were greater than 0.6 in GSE69683. The AUC value reached to 0.701 when combined SEC61A1 and ALDH18A1 expression. The expression of the five hub genes was verified in an external dataset. The network analysis revealed that transcription factor (TF) WT1, ZEB1, RERE, FOSL1, and miR-20a may be involved in the development of asthma. In addition, we found cyclosporine and acetaminophen could interact with these hub genes and may be negatively associated with most of the five hub genes according to previous reports. Overall, key genes were identified between mild-moderate and severe asthmatics, which contributed to the understanding of the development of asthma.

Derangement of cell cycle markers in peripheral blood mononuclear cells of asthmatic patients as a reliable biomarker for asthma control

In asthma, most of the identified biomarkers pertain to the Th2 phenotype and no known biomarkers have been verified for severe asthmatics. Therefore, identifying biomarkers using the integrative phenotype-genotype approach in severe asthma is needed. The study aims to identify novel biomarkers as genes or pathways representing the core drivers in asthma development, progression to the severe form, resistance to therapy, and tissue remodeling regardless of the sample cells or tissues examined. Comprehensive reanalysis of publicly available transcriptomic data that later was validated in vitro, and locally recruited patients were used to decipher the molecular basis of asthma. Our in-silicoanalysis revealed a total of 10 genes (GPRC5A, SFN, ABCA1, KRT8, TOP2A, SERPINE1, ANLN, MKI67, NEK2, and RRM2) related to cell cycle and proliferation to be deranged in the severe asthmatic bronchial epithelium and fibroblasts compared to their healthy counterparts. In vitro, RT qPCR results showed that (SERPINE1 and RRM2) were upregulated in severe asthmatic bronchial epithelium and fibroblasts, (SFN, ABCA1, TOP2A, SERPINE1, MKI67, and NEK2) were upregulated in asthmatic bronchial epithelium while (GPRC5A and KRT8) were upregulated only in asthmatic bronchial fibroblasts. Furthermore, MKI76, RRM2, and TOP2A were upregulated in Th2 high epithelium while GPRC5A, SFN, ABCA1 were upregulated in the blood of asthmatic patients. SFN, ABCA1 were higher, while MKI67 was lower in severe asthmatic with wheeze compared to nonasthmatics with wheezes. SERPINE1 and GPRC5A were downregulated in the blood of eosinophilic asthmatics, while RRM2 was upregulated in an acute attack of asthma. Validation of the gene expression in PBMC of locally recruited asthma patients showed that SERPINE1, GPRC5A, SFN, ABCA1, MKI67, and RRM2 were downregulated in severe uncontrolled asthma. We have identified a set of biologically crucial genes to the homeostasis of the lung and in asthma development and progression. This study can help us further understand the complex interplay between the transcriptomic data and the external factors which may deviate our understanding of asthma heterogeneity.

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.

Blood and Salivary Amphiregulin Levels as Biomarkers for Asthma

Background: Amphiregulin (AREG) expression in asthmatic airways and sputum was shown to increase and correlate with asthma. However, no studies were carried out to evaluate the AREG level in blood and saliva of asthmatic patients. Objective: To measure circulating AREG mRNA and protein concentrations in blood, saliva, and bronchial biopsies samples from asthmatic patients. Methods: Plasma and Saliva AREG protein concentrations were measured using ELISA while PBMCs, and Saliva mRNA expression was measured by RT qPCR in non-severe, and severe asthmatic patients compared to healthy controls. Primary asthmatic bronchial epithelial cells and fibroblasts were assessed for AREG mRNA expression and released soluble AREG in their conditioned media. Tissue expression of AREG was evaluated using immunohistochemistry of bronchial biopsies from asthmatic patients and healthy controls. Publicly available transcriptomic databases were explored for the global transcriptomic profile of bronchial epithelium, and PBMCs were explored for AREG expression in asthmatic vs. healthy controls. Results: Asthmatic patients had higher AREG protein levels in blood and saliva compared to control subjects. Higher mRNA expression in saliva and primary bronchial epithelial cells plus higher AREG immunoreactivity in bronchial biopsies were also observed. Both blood and saliva AREG levels showed positive correlations with allergic rhinitis status, atopy status, eczema status, plasma periostin, neutrophilia, Montelukast sodium use, ACT score, FEV1, and FEV1/FVC. In silico analysis showed that severe asthmatic bronchial epithelium with high AREG gene expression is associated with higher neutrophils infiltration. Conclusion: AREG levels measured in a minimally invasive blood sample and a non-invasive saliva sample are higher in non-allergic severe asthma.

CLINICAL IMPLICATIONS

This is the first report to show the higher level of AREG levels in blood and saliva of non-allergic severe asthma.

Real-life retrospective observational study to determine the prevalence and economic burden of severe asthma in Spain

Objective: We determined the percentage of patients with severe asthma and exacerbations and evaluated the costs of the disease based on blood eosinophil counts.Methods: A retrospective observational study based on the review of medical records in Spain was carried out. Patients ≥18 years of age requiring care during the years 2014-2015; diagnosed with asthma with at least 2 years of continuous records (at least one year prior to the index date defined as the first asthma medication prescription and at least one year after the index date) were included. Study groups: eosinophil counts <300 cells/μl and ≥300 cells/μl. Main variables: comorbidity, clinical parameters, exacerbations and annual asthma total costs.Results: A total of 268 severe asthmatic patients in Spain were included, representing 6.3% of the asthma population, with 58.6% having eosinophil count ≥300 cells/μl and 41.4% eosinophil count <300 cells/μl. The mean age was 56.1 years (63.4% women). Patients with eosinophilic inflammation (≥300 cells/μl) had lower FEV1 values (54.3% vs. 60.7%; p < .001), poorer treatment adherence (65.6% vs. 77.3%; p < .001), and a greater mean number of exacerbations (3.3 vs. 1.9; p < .001). Exacerbations were correlated to FEV1 (β=‒.606), eosinophils (β = .255), immunoglobulin E (β = .152), and age (β = .128), p < .001. The mean total asthma annual cost (ANCOVA) was 6222 vs. 4152 euros, respectively (p = .016). Health costs were associated with age (β = .323), FEV1 (β = .239), eosinophils (β = .177) and exacerbations (β = .158), p < .01.Limitations: Those inherent to retrospective studies; the possible inaccuracy of diagnostic coding referring to severe asthma and other comorbidities and the external validity of the results.Conclusions: Health costs of patients with severe asthma were high. Total annual asthma costs and resource use were greater in patients with ≥300 cells/μl. Age, eosinophilia, exacerbations and FEV1 were associated with greater resource utilization and costs for the health system.

Allergic Endotypes and Phenotypes of Asthma

Allergic asthma is defined as asthma associated with sensitization to aeroallergens, which leads to asthma symptoms and airway inflammation. Allergic asthma is the most common asthma phenotype. The onset of allergic asthma is most often in childhood and is usually accompanied by other comorbidities including atopic dermatitis and allergic rhinitis. It is often persistent although there is a wide variation in disease severity. It is a TH2-driven process. Biomarkers have been identified to distinguish patients with allergic asthma, particularly serum IgE levels, tests to indicate sensitization to aeroallergens such as specific IgE or skin prick test positivity, blood and sputum eosinophil levels, fraction of exhaled nitric oxide, and periostin. Treatments for allergic asthma include environmental control measures, allergen immunotherapy, and glucocorticoids. Biologics, targeting the TH2 pathway, have been shown to be effective in the treatment of allergic asthma.

Plasma Galectin-3 and urine proteomics predict FEV1 improvement in omalizumab-treated patients with severe allergic asthma: Results from the PROXIMA sub-study

Background

Patients with severe allergic asthma (SAA) when treated with omalizumab may exhibit different extent of response. Identifying biomarkers that can predict the extent of treatment effectiveness in patients can be useful in personalizing omalizumab treatment.

Methods

Patients from the longitudinal phase of the PROXIMA study were selected for this ancillary study. After 12 months of omalizumab treatment, patients were categorized according to their response to treatment as: "clinical responder" (Asthma Control Questionnaire [ACQ] total score <1 at Month 12 and/or with a reduction in number of exacerbation versus the previous year); "functional responder" (an increment of ≥0.1 L in forced expiratory volume in 1 s [FEV₁] at Month 12 versus baseline); and "super responder" (among clinical responders group, who also showed a functional response). Plasma galectin-3 (GAL-3) levels were quantified using a micro titer plate-based enzyme linked immunosorbent assay kit.

Results

The Majority of patients (86.36%) in sub-study population were identified as clinical responders. Of the total patients identified as clinical responders, 64.86% were identified as super responders. A statistically significant difference in the baseline plasma GAL-3 levels between responders and non-responders was observed only in the functional responders group (P = 0.0446). Patients with plasma GAL-3 level of ≥11 ng/mL had a greater probability of being a super responder (P = 0.0118) or a functional responder (P = 0.0032).

Conclusion

Our findings support the use of plasma GAL-3 as a predictive marker to stratify responders and identify super responders and functional responders to omalizumab treatment in patients with severe allergic asthma using less invasive sample like plasma.

Perspectives in allergen immunotherapy: 2019 and beyond

The seventh "Future of the Allergists and Specific Immunotherapy (FASIT)" workshop held in 2019 provided a platform for global experts from academia, allergy clinics, regulatory authorities and industry to review current developments in the field of allergen immunotherapy (AIT). Key domains of the meeting included the following: (a) Biomarkers for AIT and allergic asthma; (b) visions for the future of AIT; (c) progress and data for AIT in asthma and the updates of GINA and EAACI Asthma Guidelines (separated for house dust mite SCIT, SLIT tablets and SLIT drops; patient populations) including a review of clinically relevant endpoints in AIT studies in asthma; (d) regulatory prerequisites such as the "Therapy Allergen Ordinance" in Germany; (e) optimization of trial design in AIT clinical research; (f) challenges planning and conducting phase III (field) studies and the future role of Allergen Exposure Chambers (AEC) in AIT product development from the regulatory point of view. We report a summary of panel discussions of all six domains and highlight unmet needs and possible solutions for the future.

Immune induction of airway remodeling

Airway remodeling is accepted to be a determining component within the natural history of asthma. It is a phenomenon characterized by changes in the airways structures that marches in parallel with and can be influenced by airway inflammation, floating at the interface between both natural and adaptive immunity and physical and mechanical cells behavior. In this review we aimed to highlight the comprehensive, yet not exhaustive, evidences of how immune cells induce, regulate and adapt to the recognized markers of airway remodeling. Mucous cell hyperplasia, epithelial dysfunction and mesenchymal transition, extracellular matrix protein synthesis and restructuration, fibroblast to myofibroblast transition, airway smooth muscle proliferation, bioactive and contractile properties, and vascular remodeling encompass complex physiopathological mechanisms that can be induced, suppressed or regulated by different cellular and molecular pathways. Growth factors, cytokines, chemokines and adhesion molecules expressed or derived either from the immune network of cells infiltrating the asthmatic airways and involving T helper lymphocytes, immune lymphoid cells, dendritic cells, eosinophils, neutrophils, mast cells or by the structural components such as epithelial cells, fibroblasts, myocytes, airway smooth muscle cells concur with protein cellular matrix component and metalloproteases in modifying the airway structure in a detrimental way. The consequences in lung function decline, fixed airway obstruction and clinical severity of the disease suggest the possibility of identify among the immune molecular pathway of remodeling some biological parameters or signal pathway to be either a good tracer for monitoring the disease evolution or a target for hypothetical phenotypes and endotypes. In the era of personalized medicine, a biomarker of remodeling might predict a response to small-molecule inhibitors or biologicals potentially targeting a fundamental aspect of asthma pathogenesis that impacts on the low responsiveness to airway inflammation directed treatments.

Immunological biomarkers in severe asthma

Severe asthma is heterogeneous in its clinical presentation, underlying pathophysiology, course and response to therapy. Clinical and physiological assessment of severe asthma is often inadequate in predicting underlying disease mechanisms and or response to medications. With the emergence of novel targeted therapies in severe asthma, the need for reproducible, easily measured biomarkers became obvious but only few are currently available for clinical use. These biomarkers along with the clinical presentation of the patient play an important role in identifying phenotypes and endotypes, predicting the clinical course and prognosis and improving the precision therapeutic approach to asthma.

Partially-oxidized phosphorene sensor for the detection of sub-nano molar concentrations of nitric oxide: a first-principles study

The development of new techniques or instruments for detecting and accurately measuring biomarker concentrations in living organisms is essential for early diagnosis of diseases, and for tracking the effectiveness of treatments. In chronic diseases, such as asthma, precise phenotyping can help predict the response of patients to treatments and reduce the risk of complications. Fractional exhaled nitric oxide (Fe_NO) is a positive biomarker for eosinophilic asthma in humans, and it can be directly detected in the respiratory tract, at very low and volatile concentrations, which makes real-time measurement a challenge. This work describes the first-principles design and characterization of a molecular- and back-gated electronic field-effect transistor device for the detection and measurement of ultra-low Fe_NO concentrations (pM-nM) from a person' s exhaled breath, as a cost-efficient alternative to the slower and more expensive techniques based on off-line sputum characterization via mass spectrometry. The proposed device uses a partially oxidized phosphorene semiconducting channel material for Fe_NO detection, allowing nM L^-1 concentration measurements of this analyte in an array configuration with an effective sensing surface area of 8.775 μm², which results in a predicted limit of detection (LOD) of 19 nM L^-1. In spite of the limited stability of phosphorene in oxygen-rich and humid environments, the proposed device would be practical for mobile applications with disposable sensors.

Functional roles of the human ribonuclease A superfamily in RNA metabolism and membrane receptor biology

The human ribonuclease A (hRNase A) superfamily is comprised of 13 members of secretory RNases, most of which are recognized as catabolic enzymes for their ribonucleolytic activity to degrade ribonucleic acids (RNAs) in the extracellular space, where they play a role in innate host defense and physiological homeostasis. Interestingly, human RNases 9-13, which belong to a non-canonical subgroup of the hRNase A superfamily, are ribonucleolytic activity-deficient proteins with unclear biological functions. Moreover, accumulating evidence indicates that secretory RNases, such as human RNase 5, can be internalized into cells facilitated by membrane receptors like the epidermal growth factor receptor to regulate intracellular RNA species, in particular non-coding RNAs, and signaling pathways by either a ribonucleolytic activity-dependent or -independent manner. In this review, we summarize the classical role of hRNase A superfamily in the metabolism of extracellular and intracellular RNAs and update its non-classical function as a cognate ligand of membrane receptors. We further discuss the biological significance and translational potential of using secretory RNases as predictive biomarkers or therapeutic agents in certain human diseases and the pathological settings for future investigations.

A novel microRNA miR-1165-3p as a potential diagnostic biomarker for allergic asthma

CONTEXT

A further examination of a novel miRNA,miR-1165-3p as a biomarker for asthma, which was previously implicated in helper T cells (Th2) in a murine asthma model.

OBJECTIVE

To determine whether serum miR-1165-3p can serve as a potential diagnostic biomarker for allergic asthma.

METHODS

Serum miR-1165-3p was quantified via quantitative real-time PCR (qRT-PCR) in asthmatic and control samples. Serum miR-1165-3p levels were compared between groups and the clinical diagnostic abilities of miR-1165-3p were evaluated. The analyses utilized included a student's t test, one-way ANOVA, and the generation of receiver operating characteristic (ROC) curves.

RESULTS

Serum miRNA-1165-3p levels were significantly elevated in asthmatics when compared to the healthy controls. Furthermore, the sensitivity and specificity of serum miR-1165-3p were found to be 83% and 68.2%. Additionally, serum miR-1165-3p levels were also found to be significantly elevated in patients with allergic rhinitis (AR) or allergic bronchopulmonary aspergillosis (ABPA).

CONCLUSIONS

This study showed that serum miR-1165-3p can potentially be utilized as a noninvasive biomarker that is able to aid in the diagnosis and characterization of allergic asthma.

Controversies and opportunities in severe asthma

PURPOSE OF REVIEW

Despite currently available treatments, many asthma patients remain inadequately controlled, but identifying distinct patient populations (phenotypes/endotypes) may optimize their management. This review discusses some of the controversies and opportunities for improved disease control in severe asthma.

RECENT FINDINGS

Currently approved anti-immunoglobulin E and anti-interleukin 5 biologics, which target specific pathways instead of using a 'one size fits all' strategy, are efficacious and well tolerated therapies for severe asthma. The appropriate use of these biologics, and of those in development (e.g., benralizumab and dupilumab), should be aided by further understanding of asthma phenotypes and endotypes, utilizing appropriate biomarkers.Oral corticosteroids are often added as maintenance therapy for patients with severe uncontrolled asthma, but their use is associated with significant adverse effects and should be considered a last option. The true cost of this therapy, including the cost of morbidities associated with its use, remains to be determined.Severe asthma in pediatrics poses a unique opportunity for possible prevention strategies and the potential for primary prevention. Although several avenues for primary prevention are being explored and are out of the scope of this review, we focus our discussion on the use of omalizumab, which has been recently explored in clinical trials.

SUMMARY

Appropriate use of biologics in severe asthma should be supported by further understanding of biomarkers predicting response to targeted therapy. Because of their association with significant adverse effects, add-on oral corticosteroids should be considered a last treatment option for patients with uncontrolled severe asthma. Finally, severe asthma in pediatrics poses a unique opportunity for potential prevention strategies.

Serum periostin levels following small bone fractures, long bone fractures and joint replacements: an observational study

BACKGROUND

In asthma, serum periostin may potentially be used as a biomarker in the management of patients with Type-2 eosinophilic airway inflammation. However, serum periostin may be influenced by factors other than Type 2 inflammation, potentially confounding its interpretation. We aimed to measure change in periostin following bone injury.

METHODS

102 adults without asthma were recruited into three groups: joint replacement surgery, long bone fracture, short bone fracture. Participants underwent seven measurements of serum periostin over 26 weeks after bone injury, and prior to surgery in the joint replacement group. Differences in periostin were measured using a ratio of geometric mean (RGM), with comparison made with pre-surgery (joint replacement) or 26 week (long and short fracture) reference measurements.

RESULTS

In the joint replacement group, periostin fell within 48 h (RGM 0.80, 95% CI 0.75-0.86), then increased to a maximum at 8 weeks (RGM 1.89, 1.77-2.02) and by 26 weeks remained above the reference measurement (RGM 1.27, 1.19-1.36). In the long bone fracture group, periostin was reduced at 48 h (RGM 0.76, 0.71-0.83) and then progressively increased to a maximum at 8 weeks (RGM 1.15, 1.06-1.23) compared with the reference measurement. In the short bone fracture group, periostin was reduced at 48 h (RGM 0.9, 0.85-0.95) but was not different from after week 1 compared with the reference measurement.

CONCLUSIONS

Serum periostin levels are influenced by bone injury. The timing and extent of bone injury needs consideration if periostin is used as a biomarker in the management of eosinophilic asthma.Trial registration This trial was prospectively registered with the Australia New Zealand Trials Registry on Feb 7 2014, (ACTRN12614000151639: https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=363881).

Biomarkers for severe allergic asthma in children: could they be useful to guide disease control and use of omalizumab?

INTRODUCTION

Although symptom controls in asthmatic children can be achieved through compliant use of conventional medication, some children have uncontrolled severe persistent asthma, especially if they are allergic. For these children, omalizumab (approved by the EMA and FDA in children aged > 6 years) could be a therapeutic option. However, response to omalizumab varies from one child to another. Predictive biomarkers of omalizumab effectiveness could be useful to monitor response to treatment. Area covered: The authors searched in the PubMed database for publications related to the use of biomarkers in allergic asthma. Supported by their own experience in phenotyping asthma in children, they analyzed whether these biomarkers could be useful in assessing response to omalizumab. Expert commentary: Th2 inflammation in children with allergic asthma can be assessed by measuring several biomarkers (blood eosinophil, serum ECP or periostin, FeNO). While a single measurement may be insufficient, a combination of biomarkers assessments may improve the follow-up of children treated by omalizumab.

Tralokinumab for the treatment of severe, uncontrolled asthma: the ATMOSPHERE clinical development program

Tralokinumab, a fully human IgG₄ monoclonal antibody, specifically neutralizes IL-13. The ATMOSPHERE clinical development program comprised four randomized, placebo-controlled clinical trials and an open-label study that aimed to assess the efficacy and safety of tralokinumab for the treatment of severe, uncontrolled asthma. The two pivotal trials (STRATOS 1 and STRATOS 2; NCT02161757 and NCT02194699) evaluated the efficacy and safety of tralokinumab, with STRATOS 1 identifying a subgroup most likely to demonstrate enhanced response to treatment. Further trials have assessed the ability of tralokinumab to reduce oral corticosteroid use (TROPOS; NCT02281357) and determined its mechanistic effects (MESOS; NCT02449473). An open-label study in Japanese individuals (NCT02902809) assessed the long-term safety and tolerability of tralokinumab in this population.

Severe bronchial asthma in children: a review of novel biomarkers used as predictors of the disease

Severe asthma or therapy-resistant asthma in children is a heterogeneous disease that affects all age-groups. Given its heterogeneity, precision in diagnosis and treatment has become imperative, in order to achieve better outcomes. If one is thus able to identify specific patient phenotypes and endotypes using the appropriate biomarkers, it will assist in providing the patient with more personalized and appropriate treatment. However, there appears to be a huge diagnostic gap in severe asthma, as there is no single test yet that accurately determines disease phenotype. In this paper, we review the published literature on some of these biomarkers and their possible role in bridging this diagnostic gap. We also highlight the cellular and molecular mechanisms involved in severe asthma, in order to show the basis for the novel biomarkers. Some markers useful for monitoring therapy and assessing airway remodeling in the disease are also discussed. A review of the literature was conducted with PubMed to gather baseline data on the subject. The literature search extended to articles published within the last 40 years. Although biomarkers specific to different severe asthma phenotypes have been identified, progress in their utility remains slow, because of several disease mechanisms, the variation of biomarkers at different levels of inflammation, changes in relying on one test over time (eg, from sputum eosinophilia to blood eosinophilia), and the degree of invasive tests required to collect biomarkers, which limits their applicability in clinical settings. In conclusion, several biomarkers remain useful in recognizing various asthma phenotypes. However, due to disease heterogeneity, identification and utilization of ideal and defined biomarkers in severe asthma are still inconclusive. The development of novel serum/sputum-based biomarker panels with enhanced sensitivity and specificity may lead to prompt diagnosis of the disease in the future.

Expression of DACT1 in children with asthma and its regulation mechanism

The aim of the present study was to detect DACT1 expression levels in the lungs of children with asthma, and to investigate its role and molecular mechanisms in regulating the expression of inflammatory factors in RAW264.7 cells. DACT1, DACT2 and DACT3 expression was analyzed in biopsy specimens from 10 cases of newly diagnosed children with asthma and 10 healthy controls by reverse transcription-quantitative polymerase chain reaction, and their expression was confirmed in RAW264.7 cells. DACT1 expression was silenced by small interfering RNA or enhanced by transfection of pcDNA-3.1-DACT1 in RAW264.7 cells, and expression of β-catenin and inflammatory factors, interleukin (IL) 5, IL6 and IL13, was analyzed. Nuclear translocation of β-catenin was detected by western blot analysis, and the effect of DACT1 on β-catenin was investigated with rescue experiments. Regulation of the Wnt signaling pathway by DACT1 and β-catenin was analyzed in RAW264.7 cells after recombinant Wnt5A stimulation. DACT1, DACT2 and DACT3 were significantly upregulated in specimens from children with asthma compared with controls (P<0.05) and the expression of DACT1 was significantly more increased compared with DACT2 and DACT3 (P<0.05). Inhibition of DACT1 expression significantly suppressed IL5, IL6 and IL13 mRNA expression levels compared with the control (P<0.05), while upregulated DACT1 expression significantly increased IL5, IL6 and IL13 mRNA expression (P<0.05). DACT1 inhibited the expression and nuclear translocation of β-catenin, while overexpression of β-catenin significantly inhibited the biological function of DACT1 (P<0.05). Overexpression of β-catenin also significantly suppressed the upregulation of IL5, IL6 and IL13 mRNA induced by pcDNA3.1-DACT1 transfection (P<0.05). Following the addition of Wnt5A, overexpression of DACT1 inhibited the expression and nuclear translocation of β-catenin, and upregulated IL5, IL6 and IL13 mRNA expression. In conclusion, DACT1 was indicated to be upregulated in lung tissues from children with asthma, which could induce higher pro-inflammatory factor expression. DACT1 may act via inhibiting the expression and nuclear translocation of β-catenin, a factor in the Wnt signaling pathway. The present results suggested that DACT1 may be a potential target for the treatment of asthma.

The current and future role of biomarkers in type 2 cytokine-mediated asthma management

Assessment and management of asthma is complicated by the heterogeneous pathophysiological mechanisms that underlie its clinical presentation, which are not necessarily reflected in standardized management paradigms and which necessitate an individualized approach to treatment. This is particularly important with the emerging availability of a variety of targeted forms of therapy that may only be appropriate for use in particular patient subgroups. The identification of biomarkers can potentially aid diagnosis and inform prognosis, help guide treatment decisions and allow clinicians to predict and monitor response to treatment. Biomarkers for asthma have been identified from a variety of sources, including airway, exhaled breath and blood. Biomarkers from exhaled breath include fractional exhaled nitric oxide, measurement of which can help identify patients most likely to benefit from inhaled corticosteroids and targeted anti-immunoglobulin E therapy. Biomarkers measured in blood are relatively non-invasive and technically more straightforward than those measured from exhaled breath or directly from the airway. The most well established of these are the blood eosinophil count and serum periostin, both of which have demonstrated utility in identifying patients most likely to benefit from targeted anti-interleukin and anti-immunoglobulin E therapies, and in monitoring subsequent treatment response. For example, serum periostin appears to be a biomarker for responsiveness to inhaled corticosteroid therapy and may help identify patients as suitable candidates for anti-IL-13 treatment. The use of biomarkers can therefore potentially help avoid unnecessary morbidity from high-dose corticosteroid therapy and allow the most appropriate and cost-effective use of targeted therapies. Ongoing clinical trials are helping to further elucidate the role of established biomarkers in routine clinical practice, and a range of other circulating novel potential biomarkers are currently being investigated in the research setting.

Aspergillus fumigatus-sensitive IgE is associated with bronchial hypersensitivity in a murine model of neutrophilic airway inflammation

Neutrophils are the predominant inflammatory cells that infiltrate airways during acute exacerbation of asthma. The importance of A. fumigatus sensitization, and IgE response in the airways in patients with acute asthma is unclear. Rockefeller (RK) mice were sensitized with A. fumigatus extract protein. The animals were subsequently challenged with different degrees of A. fumigatus contamination in the cage bedding. All groups of mice were euthanized to obtain bronchoalveolar lavage fluid (BALF) for cytological and Elisa assays, and lung tissue for histological analysis. Moreover, several bioassays were conducted to determine whether BALF IgE antibodies can activate mast cells. In this study, we demonstrated that exposure of sensitized mice to a known concentration of A. fumigatus conidia produces bronchial hyperreactivity with marked neutrophilic bronchial infiltration and increased BALF IgE, capable of triggering mast cell degranulation. This study suggests that IgE may play a role in bronchial hyperreactivity associated to A. fumigatus exposure in mice. Mice sensitized and challenged with this fungus showed characteristics of severe asthma, with an increase of BALF neutrophils, histological changes consistent with severe asthma and an increase of IgE capable of triggering type I hypersensitivity.

Mediators of Inflammation in Asthma: A Forensic Perspective

In the clinical setting, the role of systemic inflammation in patients with asthma has attracted increased attention, and some authors showed that increased IL-6 and high-sensitivity C-reactive protein characterized a group of asthmatic patients. In the realm of forensic pathology, a postmortem diagnosis of asthmatic death can be extremely challenging. The aim of this study was to determine the postmortem serum levels of C-reactive protein, IL-6, and tumor necrosis factor α in a series of severe acute bronchial asthma deaths that underwent medicolegal investigations. A total of 35 autopsy cases were retrospectively selected and included deaths in asthmatic subjects (related and unrelated to severe acute bronchial asthma, in situations characterized or not by systemic inflammation) as well as deaths in nonasthmatic individuals (in situations characterized or not by systemic inflammation). Our findings suggest that IL-6 is selectively increased in the systemic circulation of individuals with asthma, irrespective of whether the cause of death depends on a fatal asthma attack, compared with other biomarkers. Accordingly, postmortem serum IL-6 values in cases of death during severe acute bronchial asthma can be measured and considered of diagnostic relevance to estimate the magnitude of the systemic inflammation responses characterizing the disease.

Biomarkers and asthma management: an update

PURPOSE OF REVIEW

Asthma is heterogeneous with different endotypes/phenotypes. Response to corticosteroids is variable and novel biological therapies are proving useful. Biomarkers allow individualization of treatment. This review provides an update on available data regarding asthma biomarkers with focus on their utility for prediction of response to steroidal and new biological therapies.

RECENT FINDINGS

Blood eosinophils are a biomarker with acceptable accuracy as a surrogate for sputum eosinophilia, are associated with relevant outcomes, and are more readily measureable. New evidence supports fraction of exhaled nitric oxide (FENO)-based treatment algorithms for cost-effective maintenance of asthma control/quality of life. Serum and sputum-derived periostin are biomarkers of lung function decline and associated with eosinophilic airway inflammation. Transcriptomics show promise for endotyping; their role in management remains to be determined. Biomarker panels may improve predictive value as shown for the combination of FENO/urinary bromotyrosine in prediction of steroid responsiveness. Novel biological therapies are proving effective in biomarker-selected populations.

SUMMARY

Biomarkers including blood eosinophils and FENO are proving to have utility for the effective administration of steroidal and novel biological therapies in asthma, allowing individualized treatment. Transcriptomics can discriminate subtypes of asthma and may have a role in delivery of individualized therapy.

Regulation of Eosinophil Recruitment and Activation by Galectins in Allergic Asthma

Eosinophils are differentiated granulocytes that are recruited from the bone marrow to sites of inflammation via the vascular system. Allergic asthma is characterized by the presence of large numbers of eosinophils in the lungs and airways. Due to their capacity to rapidly release inflammatory mediators such as cytokines, chemokines, growth factors, and cytotoxic granule proteins upon stimulation, eosinophils play a critical role in pro-inflammatory processes in allergen-exposed lungs. Identifying key players and understanding the molecular mechanisms directing eosinophil trafficking and recruitment to inflamed airways is a key to developing therapeutic strategies to limit their influx. Recent studies have brought to light the important role of glycans and glycan binding proteins in regulating recruitment of eosinophils. In addition to the role of previously identified eosinophil- and endothelial-expressed adhesion molecules in mediating eosinophil trafficking and recruitment to the inflamed airways, studies have also indicated a role for galectins (galectin-3) in this process. Galectins are mammalian lectins expressed by various cell types including eosinophils. Intracellularly, they can regulate biological processes such as cell motility. Extracellularly, galectins interact with β-galactosides in cell surface-expressed glycans to regulate cellular responses like production of inflammatory mediators, cell adhesion, migration, and apoptosis. Eosinophils express galectins intracellularly or on the cell surface where they interact with cell surface glycoconjugate receptors. Depending on the type (galectin-1, -3, etc.) and location (extracellular or intracellular, endogenous or exogenously delivered), galectins differentially regulate eosinophil recruitment, activation, and apoptosis and thus exert a pro- or anti-inflammatory outcome. Here, we have reviewed information pertaining to galectins (galectin-1, -3 -9, and -10) that are expressed by eosinophils themselves and/or other cells that play a role in eosinophil recruitment and function in the context of allergic asthma and their potential use as disease biomarkers or therapeutic targets for immunomodulation.

Bronchial epithelium in children: a key player in asthma

Bronchial epithelium is a key element of the respiratory airways. It constitutes the interface between the environment and the host. It is a physical barrier with many chemical and immunological properties. The bronchial epithelium is abnormal in asthma, even in children. It represents a key component promoting airway inflammation and remodelling that can lead to chronic symptoms. In this review, we present an overview of bronchial epithelium and how to study it, with a specific focus on children. We report physical, chemical and immunological properties from ex vivo and in vitro studies. The responses to various deleterious agents, such as viruses or allergens, may lead to persistent abnormalities orchestrated by bronchial epithelial cells. As epithelium dysfunctions occur early in asthma, reprogramming the epithelium may represent an ambitious goal to induce asthma remission in children.

Bronchial epithelium is a morphological and functional dysregulated gatekeeper in asthmatic childrenhttp://ow.ly/Y4MaM

Galectin-3: an early predictive biomarker of modulation of airway remodeling in patients with severe asthma treated with omalizumab for 36 months

Background

Bronchial asthma is a heterogeneous disease characterized by three cardinal features: chronic inflammation, variable airflow obstruction, and airway hyperresponsiveness. Asthma has traditionally been defined using nonspecific clinical and physiologic variables that encompass multiple phenotypes and are treated with nonspecific anti-inflammatory therapies. Based on the modulation of airway remodeling after 12 months of anti-immunoglobulin E (IgE) treatment, we identified two phenotypes (omalizumab responder, OR; and non-omalizumab responder, NOR) and performed morphometric analysis of bronchial biopsy specimens. We also found that these two phenotypes were correlated with the presence/absence of galectin-3 (Gal-3) at baseline (i.e., before treatment). The aims of the present study were to investigate the histological and molecular effects of long-term treatment (36 months) with anti-IgE and to analyze the behavior of OR and NOR patients.

Methods

All patients were treated with the monoclonal antibody anti-IgE omalizumab for 36 months. The bronchial biopsy specimens were evaluated using morphometric, eosinophilic, and proteomic analysis (MudPIT). New data were compared with previous data, and unsupervised cluster analysis of protein profiles was performed.

Results

After 36 months of treatment with omalizumab, reduction of reticular basement membrane (RBM) thickness was confirmed in OR patients (Gal-3-positive at baseline); similarly, the protein profiles (over 500 proteins identified) revealed that, in the OR group, levels of proteins specifically related to fibrosis and inflammation (e.g., smooth muscle and extracellular matrix proteins (including periostin), Gal-3, and keratins decreased by between 5- and 50-fold. Eosinophil levels were consistent with molecular data and decreased by about tenfold less in ORs and increased by twofold to tenfold more in NORs. This tendency was confirmed (p < 0.05) based on both fold change and DAVE algorithms, thus indicating a clear response to anti-IgE treatment in Gal-3-positive patients.

Conclusions

Our results showed that omalizumab can be considered a disease-modifying treatment in OR. The proteomic signatures confirmed the presence of Gal-3 at baseline to be a biomarker of long-term reduction in bronchial RBM thickness, eosinophilic inflammation, and muscular and fibrotic components in omalizumab-treated patients with severe asthma. Our findings suggest a possible relationship between Gal-3 positivity and improved pulmonary function.

Electronic supplementary material

The online version of this article (doi:10.1186/s13601-017-0143-1) contains supplementary material, which is available to authorized users.

Periostin: The bone and beyond

In recent years the relationship between bone, metabolism and many pathophysiologic mechanisms involving other organs and the immune system, was increasingly apparent. This observation concerns vitamin D, osteopontin and periostin (PO). PO is expressed in the periosteum of long bones but also in many other tissues and organs, including heart, kidney, skin and lungs, being enhanced by mechanical stress or injury. PO has a relevant physiological function in promoting injury repair in a large number of tissues. However, its overexpression was observed in different diseases characterized by inflammation, fibrosis and tumorigenesis. Here we review the current knowledge on the role of PO in physiologic and pathologic pathways of different diseases. A specific focus regards the correlation between the level of PO and lung diseases and the identification of PO also as an inflammatory key effector in asthma, strongly associated with airways eosinophilia. In fact PO seems to be a useful biomarker of "Th2-high" asthma compared to "Th2-low" asthma phenotype and a predictor of response to therapeutic agents. Currently, a growing number of studies suggests a possible role of PO as a new diagnostic marker and/or therapeutic target for different diseases and its usefulness in clinical practice should be supported and confirmed by further and larger studies.

Serum periostin level is not associated with allergic rhinitis or allergic sensitization in Korean children

OBJECTIVES

Periostin is a matricellular protein, synthesized in the airway epithelium and induced by interleukin (IL)-4 and IL-13. The significance of periostin as a biomarker of T helper type 2 cell (Th2)-induced airway inflammation, and as a measure of the response to Th2-targeted therapy, has recently been highlighted. We explored the relationship between serum periostin and allergic rhinitis in Korean children.

METHODS

Data for fifth and sixth grade children from six randomly selected elementary schools located in Jeju and Seogwipo City, Korea, were investigated. Serum periostin levels were determined by enzyme-linked immunosorbent assay. Sex, school grade, body mass index, and presence of allergic nasal symptoms were obtained via a self-reported survey and skin prick testing was performed.

RESULTS

There were no significant differences between groups, when stratification was applied according to sex, grade, presence of atopy, and presence of allergic nasal symptoms. Sex and body mass index were significantly associated with serum periostin levels in multivariate linear regression analysis. However, allergic rhinitis was not associated with serum periostin levels.

CONCLUSION

Allergic rhinitis or allergic sensitization in Korean children did not influence serum periostin levels. Further studies are required to investigate the significance of serum periostin levels in pediatric allergic rhinitis.

Personalized Medicine in Allergy

Allergic disease is among the most common pathologies worldwide and its prevalence has constantly increased up to the present days, even if according to the most recent data it seems to be slightly slowing down. Allergic disease has not only a high rate of misdiagnosis and therapeutic inefficacy, but represents an enormous, resource-absorbing black hole in respiratory and general medicine. The aim of this paper is to summarize principal therapeutic innovations in atopic disease management befallen in the recent years in terms of personalized/precision medicine.

The puzzle of immune phenotypes of childhood asthma

Asthma represents the most common chronic childhood disease worldwide. Whereas preschool children present with wheezing triggered by different factors (multitrigger and viral wheeze), clinical asthma manifestation in school children has previously been classified as allergic and non-allergic asthma. For both, the underlying immunological mechanisms are not yet understood in depth in children. Treatment is still prescribed regardless of underlying mechanisms, and children are not always treated successfully. This review summarizes recent key findings on the complex mechanisms of the development and manifestation of childhood asthma. Whereas traditional classification of childhood asthma is primarily based on clinical symptoms like wheezing and atopy, novel approaches to specify asthma phenotypes are under way and face challenges such as including the stability of phenotypes over time and transition into adulthood. Epidemiological studies enclose more information on the patient’s disease history and environmental influences. Latest studies define endotypes based on molecular and cellular mechanisms, for example defining risk and protective single nucleotide polymorphisms (SNPs) and new immune phenotypes, showing promising results. Also, regulatory T cells and recently discovered T helper cell subtypes such as Th9 and Th17 cells were shown to be important for the development of asthma. Innate lymphoid cells (ILC) could play a critical role in asthma patients as they produce different cytokines associated with asthma. Epigenetic findings showed different acetylation and methylation patterns for children with allergic and non-allergic asthma. On a posttranscriptional level, miRNAs are regulating factors identified to differ between asthma patients and healthy controls and also indicate differences within asthma phenotypes. Metabolomics is another exciting chapter important for endotyping asthmatic children. Despite the development of new biomarkers and the discovery of new immunological molecules, the complex puzzle of childhood asthma is still far from being completed. Addressing the current challenges of distinct clinical asthma and wheeze phenotypes, including their stability and underlying endotypes, involves addressing the interplay of innate and adaptive immune regulatory mechanisms in large, interdisciplinary cohorts.

Interleukin-5 pathway inhibition in the treatment of eosinophilic respiratory disorders: evidence and unmet needs

PURPOSE OF REVIEW

Human eosinophils were first identified and named by Paul Ehrlich in 1879 on the basis of the cell's granular uptake of eosin. Although eosinophils represent approximately 1% of peripheral blood leukocytes, they have the propensity to leave the blood stream and migrate into inflamed tissues. Eosinophils and their mediators are critical effectors to asthma and eosinophilic granulomatosis with polyangiitis (EGPA). Eosinophils are equipped with a large number of cell-surface receptors and produce specific cytokines and chemokines.

RECENT FINDINGS

Eosinophils are the major source of interleukin-5 and highly express the interleukin-5Rα on their surface. Clinical trials evaluating monoclonal antibodies to interleukin-5 (mepolizumab and reslizumab) and its receptor interleukin-5Rα (benralizumab) have been or are underway in patients with eosinophilic asthma, EGPA and chronic obstructive pulmonary disease (COPD). Overall, targeting interleukin-5/interleukin-5Rα is associated with a marked decrease in blood and sputum eosinophilia, the number of exacerbations and improvement of some clinical parameters in adult patients with severe eosinophilic asthma. Pilot studies suggest that mepolizumab might be a glucocorticoid-sparing treatment in patients with EGPA. A preliminary study found that benralizumab did not reduce the exacerbations and did modify lung function in patients with eosinophilic COPD.

SUMMARY

The review examines recent advances in the biology of eosinophils and how targeting the interleukin-5 pathway might offer benefit to some patients with severe asthma, EGPA, and COPD. Interleukin-5/interleukin-5Rα-targeted treatments offer promises to patients with eosinophilic respiratory disorders.