Immunoglobulin E as a Biomarker in Asthma

Longitudinal relationships between early-life homelessness and school-aged asthma and wheezing

BACKGROUND

Homelessness is a disruptive life event with profound impacts on children's health. It remains unclear, however, whether homelessness in early life has an enduring association with asthma and wheezing among school-aged children.

OBJECTIVE

To test whether early-life homelessness is prospectively associated with asthma and wheezing during school-aged years.

METHODS

We draw on data from 9242 children from the Avon Longitudinal Study of Parents and Children. Children were categorised as 'ever' or 'never' homeless based on maternal reports from the prenatal period through age 5 years. Children were assigned a binary indicator of asthma/wheezing based on maternal reports of asthma and wheezing at ages 6.8, 7.6 and 8.6 years. We used multilevel logistic regression models to test the association of interest in both bivariate analyses and models adjusted for a broad set of potential confounders. We conducted sensitivity analyses using generalised estimating equations and considering asthma and wheezing separately to test the robustness of the results.

RESULTS

Between 12.1% and 14.3% of children had asthma or wheezing at ages 6.8, 7.6 and 8.6 years, and these conditions were more common among ever homeless participants. Ever-homeless children displayed higher odds of asthma or wheezing than never-homeless children (OR: 1.59, 95% CI 1.02 to 2.48) after adjustment for child, maternal and household risk factors. Sensitivity analyses yielded similar results.

CONCLUSION

Early-life homelessness is prospectively associated with asthma and wheezing among school-aged children and should be prioritised by interventions promoting healthy child development.

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.

Novel Serum Biomarkers for Patients with Allergic Asthma Phenotype

In distinguishing the allergic asthma (AA) phenotype, it has been identified that specific biomarkers could assist; however, none of them are considered ideal. This study aimed to analyze three groups of biologically active substances in the serum. Twenty steroid-free AA patients, sensitized to Dermatophagoides pteronyssinus, and sixteen healthy subjects (HSs) were enrolled in this study. Blood samples were collected from all patients. Additionally, all AA patients underwent a bronchial allergen challenge (BAC) with Dermatophagoides pteronyssinus, all of which were positive, and blood samples were collected again 24 h later. The concentrations of ten biologically active substances were measured in the serum samples, using enzyme-linked immunosorbent assay (ELISA) and the Luminex® 100/200™ System technology for bead-based multiplex and singleplex immunoassays. Descriptive and analytical statistical methods were used. A p-value of 0.05 or lower was considered statistically significant. The soluble interleukin 5 receptor subunit alpha (sIL-5Rα) and thioredoxin 1 (TRX1) concentrations were significantly increased, whereas those of tyrosine-protein kinase Met (MET), pentraxin 3 (PTX3), and I C-telopeptide of type I collagen (ICTP) were decreased in the AA group compared with the HS group. A significant positive correlation was noted for sIL-5Rα with fractional exhaled nitric oxide (FeNO), blood eosinophil (EOS) count, and total immunoglobulin E (IgE) levels, and a negative correlation was noted with forced expiratory volume in 1 s (FEV1). Moreover, PTX3 showed negative correlations with blood EOS count and total IgE levels, whereas ICTP exhibited a negative correlation with the blood EOS count. In conclusion, this study demonstrated that the serum concentrations of MET, PTX3, TRX1, ICTP, and particularly sIL-5Rα could potentially serve as biomarkers of the AA phenotype.

IL18 Gene Polymorphism Is Associated with Total IgE in Adult Subjects with Asthma

The allergic asthma phenotype is characterized by a T helper type 2 (Th2) immune response, based on Immunoglobulin E (IgE)-mediated type 1 hypersensitivity reactions. Total IgE is the sum of all IgE types produced by the human body and is used as a biomarker of inflammation in asthma. We analysed data collected in 143 asthma cases (median age 42.1 years) from the general Italian population (GEIRD survey; 2008-2010) to identify single nucleotide polymorphisms (SNPs) in candidate genes that are associated with total IgE in adult subjects with asthma. These patients reported respiratory symptoms in response to perennial allergens and provided data on 166 SNPs tagging 50 candidate genes or gene regions. Replication of the statistically significant results was performed in 842 asthma cases from other European countries (ECRHS II survey; 1998-2002). SNP rs549908 in interleukin 18 (IL18) gene was significantly associated with total IgE in GEIRD, and this result was replicated in ECRHS II. SNP rs1063320 in the human leukocyte antigen G (HLA-G) gene was identified in GEIRD, but this association was not replicated in ECRHS II. Further investigating IL18 and its biological pathways could be important for developing new therapeutic targets, due to its involvement in inflammatory response processes.

Comparison between clinical trials and real-world evidence studies on biologics for severe asthma

In recent years, the more widespread availability of biological drugs with specific mechanisms of action has led to significant breakthroughs in the management of severe asthma. Over time, numerous randomised clinical trials have been conducted to evaluate the efficacy and safety of these biologics and define the eligibility criteria of patients suitable for various therapeutic options. These studies were conducted under controlled conditions not always applicable to real life. For this and other reasons, real-world evidence and pragmatic studies are required to provide useful information on the effectiveness of biological drugs and their safety, even in the long term. Because differences in outcomes have sometimes emerged between clinical trials and real-life studies, it is important to clarify the causes of these discrepancies and define the significance of the results of studies conducted in the course of daily clinical practice. Thus, a scientific debate is ongoing, and no consensus has been reached. The purpose of this narrative review is to analyse the differences between randomised trials and real-world evidence studies, focusing on their roles in guiding clinicians among different therapeutic options and understanding the reasons for the large discrepancies often found in the results obtained.

Current advances in antibody-based serum biomarker studies: From protein microarray to phage display

PURPOSE

This review aims to summarize the technological advances in the field of antibody-based biomarker studies by proteome microarray and phage display. In addition, the possible development directions of this field are also discussed.

EXPERIMENTAL DESIGN

We have focused on the antibody profiling by proteome microarray and phage display, including the technological advances, the tools/resources constructed, and the characteristics of both platforms.

RESULTS

With the help of tools/resources and technological advances in proteome microarray and phage display, the efficiency of profiling antibody-based biomarkers in serum samples has been greatly improved.

CONCLUSIONS

In the past few years, proteome microarray and phage display, especially the latter one, have already demonstrated their capacity and efficiency for biomarker identification. In the near future, we believe that more antibody-based biomarkers could be identified, and some of them could eventually be developed into real clinical applications.

Machine-learning algorithms for asthma, COPD, and lung cancer risk assessment using circulating microbial extracellular vesicle data and their application to assess dietary effects

Although mounting evidence suggests that the microbiome has a tremendous influence on intractable disease, the relationship between circulating microbial extracellular vesicles (EVs) and respiratory disease remains unexplored. Here, we developed predictive diagnostic models for COPD, asthma, and lung cancer by applying machine learning to microbial EV metagenomes isolated from patient serum and coded by their accumulated taxonomic hierarchy. All models demonstrated high predictive strength with mean AUC values ranging from 0.93 to 0.99 with various important features at the genus and phylum levels. Application of the clinical models in mice showed that various foods reduced high-fat diet-associated asthma and lung cancer risk, while COPD was minimally affected. In conclusion, this study offers a novel methodology for respiratory disease prediction and highlights the utility of serum microbial EVs as data-rich features for noninvasive diagnosis.

Artificial intelligence (AI) has enabled researchers to intercept microbial messages bearing clinically useful information about of a variety of respiratory disorders. The organisms that comprise our microbiome communicate via the release of tiny, biomolecule-laden membrane bubbles called ‘extracellular vesicles’ (EVs) into the bloodstream. EVs are also influenced by human disease. South Korean researchers led by Yoon-Keun Kim of MD Healthcare, Seoul, and Young-Koo Jee of Dankook University College of Medicine, Cheonan, have used an AI algorithm to assemble EV-based profiles that can discriminate between healthy people and those with conditions like asthma or lung cancer. Their analysis of 1727 patient serum samples revealed microbial signatures that enabled accurate diagnosis of several respiratory disorders. Preliminary experiments in mice suggest that certain dietary changes could help shift the microbiome of high-risk individuals towards a healthier profile.

Eosinophilic Asthma, Phenotypes-Endotypes and Current Biomarkers of Choice

Asthma phenotyping and endotyping are constantly evolving. Currently, several biologic agents have been developed towards a personalized approach to asthma management. This review will focus on different eosinophilic phenotypes and Th2-associated endotypes with eosinophilic inflammation. Additionally, airway remodeling is analyzed as a key feature of asthmatic eosinophilic endotypes. In addition, evidence of biomarkers is examined with a predictive value to identify patients with severe, uncontrolled asthma who may benefit from new treatment options. Finally, there will be a discussion on the results from clinical trials regarding severe eosinophilic asthma and how the inhibition of the eosinophilic pathway by targeted treatments has led to the reduction of recurrent exacerbations.

Pollen Allergy Screening with Allergen-Specific and Total Immunoglobulin E Titers

Background

Allergic rhinitis is a typical type I hypersensitivity reaction, commonly caused by inhalant allergens. Accurate identification of the causative antigen is important for rapid diagnosis and treatment initiation.

Objective

This study examined the efficiency of serum-based allergen-specific immunoglobulin E and total immunoglobulin E antibody titers in screening for pollen allergy. We also examined the effect of cross-reactive carbohydrate determinants on specific immunoglobulin E titers in screening for pollen allergy, one of the causes of false positivity in specific immunoglobulin E measurements.

Methods

A questionnaire was used to evaluate the symptoms of pollinosis among participants who underwent a medical examination. One hundred and thirty-two participants reported pollen allergy symptoms and 127 reported an absence of symptoms. Specific immunoglobulin E levels were measured using the AlaSTAT 3g Allergy method. Seventeen components, including four types of cross-reactive carbohydrate determinant-specific immunoglobulin E antibodies, were measured and evaluated comparatively.

Results

The sensitivity and specificity of the tests in predicting the presence or absence of pollen allergy were analyzed. The values of the areas under the curves for immunoglobulin E antibody levels against cedar, cypress, orchard grass, and ragweed pollen were 0.87, 0.82, 0.63, and 0.56, respectively. A cross-reactive carbohydrate determinant-related false-positive effect on the pollen specific immunoglobulin E titer was noted in pollen screening.

Conclusion

Cedar pollen-specific immunoglobulin E titers showed sufficient accuracy for use in pollen allergy screening. The study of cross-reactive carbohydrate determinants suggested that subjects who tested positive for pollen often had false-positive results due to the impact of cross-reactive carbohydrate determinants.

Protective effects on ovalbumin-induced mouse asthma models and qualitative and quantitative analysis of multiple compounds in Gerberae Piloselloidis Herba

Gerberae Piloselloidis Herba is widely used to treat cough and asthma in China. However, its effects on allergic asthma as related to its chemical compositions have not been fully elucidated, and there is a scarcity of methods to determine multi-component contents for quality control. In this study, protective effects of Gerberae Piloselloidis Herba on ovalbumin-induced asthma models were investigated, while qualitative and quantitative analyses of multiple constituents in Gerberae Piloselloidis Herba were conducted by using an ultrahigh-performance liquid chromatography -Q Exactive hybrid quadrupole-orbitrap high-resolution accurate mass spectrometry and an ultrahigh-performance liquid chromatography -photodiode array detection. The results showed that Gerberae Piloselloidis Herba could significantly mitigate asthma symptoms, reduce eosinophils counts in the bronchoalveolar lavage fluid, as well as decrease IgE, IL-5 and IL-13 concentration, and inflammatory cellular infiltration in lung tissues. A total of 51 compounds were tentatively identified, in which the content of 10 representative compounds was determined in 24 batches of Gerberae Piloselloidis Herba by using an ultrahigh-performance liquid chromatography method with good linearity, precision, repeatability, accuracy and stability. This research presents a comprehensive strategy combining biological activity evaluation with chemical profiling, providing a useful and comprehensive reference for further application and quality control of Gerberae Piloselloidis Herba. This article is protected by copyright. All rights reserved.

Long noncoding RNA LINC-PINT retards the abnormal growth of airway smooth muscle cells via regulating the microRNA-26a-5p/PTEN axis in asthma

BACKGROUND

Asthma is a chronic respiratory disease worldwide. This study aimed to explore the functions of the long noncoding RNA LINC-PINT (LINC-PINT) in asthma and to determine its underlying molecular mechanisms.

METHODS

Rat asthma model was established with ovalbumin sensitization and challenge. The serum level of IgE, airway hyperresponsiveness (AHR), airway inflammation, and pathological changes of lung were evaluated. Airway smooth muscle cells (ASMCs) were stimulated with platelet-derived growth factor-BB (PDGF-BB) to mimic the asthma-like condition at cellular level. QRT-PCR was performed to detect the expression of LINC-PINT, microRNA-26a-5p (miR-26a-5p), and PTEN. MTT and transwell assays were performed to measure the viability and migration of ASMCs. The protein expression of airway remodelling marker MMP-1 and MMP-9 was measured by western blot. The interactions among LINC-PINT, miR-26a-5p, and PTEN were determined by dual-luciferase reporter assay.

RESULTS

The expression of LINC-PINT and PTEN was decreased, while miR-26a-5p expression was increased in PDGF-BB-stimulated ASMCs. In vivo, overexpression of LINC-PINT decreased the serum level of IgE, AHR, airway inflammation, and pathological changes of lung in asthma rat model. In vitro, up-regulation of LINC-PINT decreased the viability, migration, and MMP-1 and MMP-9 protein expression in PDGF-BB-stimulated ASMCs. Dual-luciferase reporter assay determined that LINC-PINT targeted miR-26a-5p, and miR-26a-5p targeted PTEN in ASMCs. Feedback approaches confirmed that miR-26a-5p up-regulation or PTEN down-regulation reversed the suppressive effect of LINC-PINT overexpression on the abnormal growth of ASMCs.

CONCLUSIONS

LINC-PINT overexpression retarded the abnormal growth of ASMCs by regulating the miR-26a-5p/PTEN axis, offering a potential therapeutic target for asthma.

Biomarkers in Different Asthma Phenotypes

Asthma is the most common respiratory disease. It has multiple phenotypes thatcan be partially differentiated by measuring the disease’s specific characteristics—biomarkers. The pathogenetic mechanisms are complex, and it is still a challenge to choose suitable biomarkers to adequately stratify patients, which became especially important with the introduction of biologicals in asthma treatment. Usage of biomarkers and an understanding of the underlying pathobiological mechanisms lead to the definition of endotypes. Asthma can be broadly divided into two endotypes, T2-high and T2-low. The right combination of various biomarkers in different phenotypes is under investigation, hoping to help researchers and clinicians in better disease evaluation since theindividual approach and personalized medicine are imperative. Multiple biomarkers are superior to a single biomarker.

Chlamydia pneumoniae immunoglobulin E antibody levels in patients with asthma compared with non-asthma

Chlamydia pneumoniae is an obligate intracellular bacterium that causes respiratory infection in adults and children. There is evidence for an association between atypical bacterial pathogens and asthma pathogenesis. We sought to determine whether past C. pneumoniae infection triggers C. pneumoniae- IgE antibodies (Abs) in asthmatics and non-asthmatics, who had detectable IgG titers. C. pneumoniae IgE Abs were quantified using enzyme immunoassay (EIA). C. pneumoniae IgE Ab levels were higher in asthmatics compared with non-asthmatics. There was no correlation found between total serum IgE levels and specific C. pneumoniae IgE Ab levels. C. pneumoniae infection may trigger IgE-specific responses in asthmatics.

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.