Relationships of allergic sensitization, total immunoglobulin E and blood eosinophils to asthma severity in children of the EGEA Study

Association between interleukin-6-174G/C gene polymorphism and asthma severity: exploring the role of total serum IgE, blood eosinophils, and FeNO as markers of type 2 inflammation

BACKGROUND

While a connection has been established between serum interleukin-6 (IL-6) levels and the IL-6 gene (- 174G/C) polymorphism in allergic diseases such as asthma, its specific association with severe asthma remains unexplored. This study examined the relationship between the IL-6 (- 174G/C) gene polymorphism and mild and severe asthma, focusing on its influence on type 2 inflammation.

METHODS

Our study comprised 98 patients with mild asthma and 116 with severe asthma. Additionally, we recruited 121 healthy participants to serve as controls for comparative analyses. The IL-6 gene (- 174G/C) polymorphism was assessed utilizing the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method.

RESULTS

In our study, the risk of mild asthma exhibited a significant fourfold increase in individuals with the GG genotype pattern compared to healthy controls, yielding an odds ratio (OR) of 4.4 (p < 0.001). Conversely, we found no significant correlation between the IL-6 - 174G/C gene polymorphism and severe asthma when compared to the healthy control group. However, a noteworthy pattern emerged when we compared subgroups of mild and severe asthma. The risk of severe asthma increased fivefold in individuals with the GC polymorphism pattern, with an OR of 4.99 (p < 0.001), while the likelihood of mild asthma showed a similar fourfold increase with the GG polymorphism pattern, OR = 4.4 (p < 0.001). Consequently, we observed a significantly higher frequency of the C allele in patients with severe asthma, whereas the G allele was more prevalent in individuals with mild asthma (p = 0.05). Additionally, the correlation between markers of type 2 inflammation and the dominant model of the IL-6 gene -174G/C polymorphism (CC + CG vs GG) revealed a significant increase in total serum immunoglobulin E (IgE), Blood Eosinophil Counts (BEC), and Fractional Exhaled Nitric Oxide (FeNO) levels in asthmatic patients with the CC + CG gene pattern compared to those with GG, with p-values of 0.04, 0.03, and 0.04, respectively. Furthermore, after adjusting for other risk factors, the likelihood of developing severe asthma increased from fourfold to eightfold, with an OR of 8.12 (p = 0.01) with (CC + CG) gene pattern. Other predictors for severe asthma included older age and childhood-onset disease (OR = 1.13 and 19.19, p < 0.001). Allergic rhinitis (AR) and nasal polyps (NP) also demonstrated a substantial association with an increased risk of severe asthma, with odds ratios of 5 and 32.29 (p = 0.01 and < 0.001), respectively. Additionally, elevated Body Mass Index (BMI), BEC, and FeNO were linked to severe asthma, with ORs of 1.11, 1.00, and 1.04, respectively (p = 0.04, 0.05, and 0.001).

CONCLUSION

This study illuminated the intricate relationship between the IL-6 gene polymorphism, type 2 inflammation markers, and diverse risk factors in shaping asthma severity. As a significant association between the GG polymorphism of the IL-6 gene (- 174G/C) and mild asthma was found, while possessing at least one C allele, whether in a homozygous (CC) or heterozygous (CG) combination, independently predicts the likelihood of severe asthma.

Correlation of vitamin D receptor genotypes, specific IgE levels and other variables with asthma control in children

INTRODUCTION

Asthma is a common condition affecting millions of children globally. The main goal of this study is to assess factors related to asthma management, particularly atopy level and the impact of genetic variants of the vitamin D receptor (VDR) gene.

METHODS

Asthmatic children were enrolled in an outpatient respiratory clinic. Information on patients' medication adherence, medical and medication factors, and sociodemographic were gathered. Spirometry FEV1% and FVC% measurements, and the asthma control test were used to evaluate the severity of asthma, and genotyping of the VDR gene and radioallergosorbent test (RAST) were conducted. Regression analyses were conducted to evaluate variables associated with asthma control and spirometry measures.

RESULTS

A total of 313 participants (67.4% males) were recruited in the current study. The mean age was 9.37 (±3.45) years. The mean score for adherence was 4.26 (±2.52), and only 46% of the participants had controlled asthma. Forward conditional stepwise binary regression showed that low and moderate Inhaled corticosteroids (ICS) dose (OR= 0.42 (95% CI 0.20-0.90), p = 0.026; OR = 0.371 (95% CI 0.2-0.72), p = 0.003, respectively) decreased the odds of being in the controlled asthma group, while higher inhaler score (OR = 2.75 (95% CI 2.17-3.49, p < 0.001)) increased the odds of being in the controlled asthma group. However, results found no association between VDR genotype and asthma control, spirometry values or hospitalization due to asthma.

CONCLUSIONS

The results indicated that many of the asthma patients had poorly controlled asthma. Factors that were associated with poor asthma control included poor inhaler technique.

Patterns of aeroallergen sensitization in asthma patients identified by latent class analysis: A cross-sectional study in China

BACKGROUND

This cross-sectional study aimed to identify latent sensitization profiles of asthma patients in mainland China, unveiling the association between regional differences and sensitization patterns.

METHODS

1056 asthma participants from 10 medical centers divided into eastern and western cohorts were clustered into four individual sensitization patterns, respectively, by using an unsupervised statistical modeling method, latent class analysis (LCA), based on the levels of 12 aeroallergens specific IgE reactivities. Moreover, differences in clinical characteristics and environmental exposures were compared in different sensitization patterns.

RESULTS

Four distinct sensitization patterns in the two cohorts were defined as follows, respectively. Eastern cohort: Class 1: "High weed pollen and house dust mites (HDMs) sensitization" (8.87%), Class 2: "HDMs dominated sensitization" (38.38%), Class 3: "High HDMs and animal dander sensitization" (6.95%), Class 4: "Low/no aeroallergen sensitization" (45.80%). Western cohort: Class 1: "High weed pollen sensitization" (26.14%), Class 2: "High multi-pollen sensitization" (15.02%), Class 3: "HDMs-dominated sensitization" (10.33%), Class 4: "Low/no aeroallergen sensitization" (48.51%). Of note, the significant statistical difference in age, asthma control test score (ACT) and comorbidities were observed within or between different sensitization patterns. Exposure factors in different sensitization patterns were pointed out.

CONCLUSIONS

Asthmatic patients with distinct sensitization patterns were clustered and identified through the LCA method, disclosing the relationship between sensitization profiles of multiple aeroallergens and geographical differences, providing novel insights and potential strategies for atopic disease monitoring, management and prevention in clinical practice.

Differentially expressed microRNAs in peripheral blood cell are associated with downregulated expression of IgE in nonallergic childhood asthma

Childhood asthma is a heterogeneous disease characterized by chronic airway inflammation, leading to a broad range of clinical presentations. Nonallergic asthma is asthma without allergic sensitization. Both clinical manifestations and immunopathological mechanisms of nonallergic childhood asthma were rarely investigated. We aimed to compare the clinical features between nonallergic and allergic childhood asthma and apply microRNA to explore the underlying mechanism of nonallergic childhood asthma. We enrolled 405 asthmatic children (76 nonallergic, 52 allergic with total IgE < 150 IU/mL and 277 allergic with total IgE > 150 IU/mL). Clinical characteristics were compared between groups. Comprehensive miRNA sequencing (RNA-seq) was performed using peripheral blood from 11 nonallergic and 11 allergic patients with elevated IgE, respectively. Differentially expressed miRNA (DEmiRNA) were determined with DESeq2. Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) analysis was performed to determine functional pathways involved. Publicly available mRNA expression data was applied to investigate the predicted target mRNA networks via Ingenuity Pathway Analysis (IPA). The average age of nonallergic asthma was significantly younger (5.614 ± 2.743 vs 6.676 ± 3.118 years-old). Higher severity and worse control were more common in nonallergic asthma (two-way ANOVA, P < 0.0001). Long-term severity was higher, and intermittent attacks persisted in nonallergic patients. We identified 140 top DEmiRNAs based on false discovery rate (FDR) q-value < 0.001. Forty predicted target mRNA gene were associated with nonallergic asthma. The enriched pathway based on GO included Wnt signaling pathway. IgE expression was predicted to be downregulated by a network involving simultaneous interaction with IL-4, activation of IL-10 and inhibition of FCER2. Nonallergic childhood asthma were distinct in their younger age, higher long-term severity and more persistent course. Differentially expressed miRNA signatures associate with downregulation of total IgE expression and predicted target mRNA genes related molecular networks contribute to canonical pathways of nonallergic childhood asthma. We demonstrated the negative role of miRNAs involved in regulating IgE expression indicating differences between asthma phenotypes. Identification of biomarkers of miRNAs could contribute to understand the molecular mechanism of endotypes in nonallergic childhood asthma, which can potentially allow delivery of precision medicine to pediatric asthma.

Fungal Aeroallergen Sensitization Patterns among Airway-Allergic Patients in Zagazig, Egypt

BACKGROUND

Airway allergies such as asthma and allergic rhinitis, as well as their comorbidities, are increasing worldwide, causing significant socioeconomic health burdens to societies. It is estimated that between 3% and 10% of the population is allergic to fungi. The type of fungal sensitization varies from one geographical region to another. The present study aimed to identify the common fungal aeroallergen sensitization patterns among airway-allergic patients residing in the Zagazig locality, Egypt, in order to obtain a better understanding of fungal allergy, in addition to improving the awareness and management strategies for those patients.

METHODS

The present cross-sectional study included 200 allergic rhinitis and asthma patients. Sensitization to fungal aeroallergens was evaluated by skin prick testing and in vitro measurement of total and specific immunoglobulin E.

RESULTS

As determined by a skin prick test, 58% of the patients studied were allergic to mixed molds. Alternaria alternata was the predominant fungal aeroallergen among the studied patients (72.2%), which was followed by Aspergillus fumigatus (53.45%), Penicillium notatum (52.6%), Candida albicans (34.5%), and Aspergillus niger (25%).

CONCLUSION

Mixed mold sensitization ranked fourth among the most frequent aeroallergens in airway-allergic patients, and Alternaria alternata was the most frequently encountered fungal aeroallergen in the Zagazig locality.

Predictive characteristics to discriminate the longitudinal outcomes of childhood asthma: a retrospective program-based study

BACKGROUND

Childhood asthma is an inflammatory disease with heterogeneous outcomes. We sought to determine the impact of total IgE, blood eosinophil, allergen sensitization, and inhaled corticosteroid (ICS) on longitudinal outcomes and to identify characteristics for discriminating different outcomes.

METHODS

We conducted a retrospective study in 383 childhood asthma patients and another 313 patients with blood eosinophil data only receiving regular program-based visits from September 1, 2004, to December 31, 2018. Peak expiratory flow (PEF) variability, PEF predicted %, asthma severity, and asthma control at each visit were assessed as clinical outcomes.

RESULTS

Our data show that the percentage of blood eosinophils was significantly associated with increased asthma severity (OR: 1.043, 95% CI: 1.002-1.086, P = 0.0392). Mold sensitization was significantly associated with asthma severity (OR: 2.2485, 95% CI: 1.3253-3.8150, P = 0.0027). Characteristics including sensitization status plus ICS dosage had the best area under the receiver operating characteristic curve (AUC) value for predicting longitudinal PEF predicted % (0.6609), PEF variability (0.6885), asthma severity (0.5918), and asthma control (0.6441), respectively.

CONCLUSIONS

We showed that the risk for adverse clinical outcomes at follow-up differed between serum IgE, blood eosinophil, and allergen sensitization identified at baseline. Sensitization and ICS dosage were predictive characteristics of long-term clinical outcomes.

IMPACT

The unique aspects of the study are its longitudinal assessment of patients receiving guideline-based asthma management program to help characterize the stability of the clinical outcomes over time. Characteristics including allergen sensitization and ICS dosage demonstrated an improved capability for distinguishing between better and worse clinical outcomes. Through longitudinal serial assessment, this study indicates the risk for adverse clinical outcomes differed between children with serum IgE/blood eosinophil/allergen sensitization characterized at baseline.

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.

Treatment by biomarker-informed endotype vs guideline care in children with difficult-to-treat asthma

BACKGROUND

Asthma is heterogeneous, contributing to difficulty in disease management.

OBJECTIVE

To develop a biomarker-informed treatment model for difficult-to-treat (DTT) asthma and conduct a pilot feasibility study.

METHODS

School-aged children (n = 21) with DTT asthma were enrolled and completed 3 medical visits (V1-V3). V2 and V3 were completed approximately 3.5 months and 12 months after V1, respectively. At V1, guideline care and adherence interventions were initiated, and blood samples were collected for asthma biomarker assessment. A personalized treatment algorithm was developed based on biomarkers (treatment by endotype) and was implemented at V2. Asthma outcomes were compared from V1 to V2 (guideline-based care) to V2 to V3 (guideline + biomarker-informed care).

RESULTS

Overall retention was 86%. There was an even distribution of participants with allergy, without allergy, and with mixed allergies. The participants received an average of 5.9 interventions (range, 3-9). The allergic phenotype was characterized by increased CDHR3 risk genotype and high transepidermal water loss. High serum interleukin-6 level was most notable in the mixed allergic subgroup. The nonallergic phenotype was characterized by vitamin D deficiency and poor steroid treatment responsiveness. The personalized treatment plans were associated with decreased emergency department visits (median, 1 vs 0; P = .04) and increased asthma control test scores (median, 22.5 vs 23.0; P = .01).

CONCLUSION

The biomarker-based treatment algorithm triggered interventions on top of guideline care in all children with DTT asthma studied, supporting the need for this type of multipronged approach. Our findings identify the minimal biomarker set that is informative, reveal that this treatment-by-endotype intervention is feasible and may be superior to guideline care alone, and provide a strong foundation for a definitive trial.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT04179461.

Clinical characteristics, cytokine profiles and plasma IgE in adults with asthma

Asthma is a disease with complicated network of inflammatory responses of cytokines and ImmunoglobulinE (IgE). The aim of this study was to explore the clinical characteristics, cytokine profile and plasma IgE in the Malaysian population. This is a cross-sectional study involving physician-diagnosed asthma patients (n = 287) recruited from the Chest Clinic, University of Malaya Medical Centre (UMMC). Blood (8 mL) was taken after consent was obtained. The peripheral blood leucocytes (PBL) were cultured in presence of a mitogen for 72 h to quantify cytokines [Interleukin-5(IL-5), Interleukin-9 (IL-9), Interleukin-12 Beta (IL-12ꞵ) and granulocyte-macrophage colony-stimulating factor (GM-CSF)] and plasma was used to quantify IgE levels with commercial ELISA kits. Results were compared against the same biomarkers in healthy subjects (n = 203). In addition, the amount of the biomarkers in the asthma patients were compared with their disease severity and clinical characteristics. Statistical tests in the SPSS software (Mann-Whitney U test and the Kruskal Wallis) were used to compare cytokine production and plasma IgE levels. The mean plasma IgE level was markedly higher (p < 0.0001) in asthmatics compared to controls. There were higher levels of IL-5, IL-9, IL-12ꞵ and GM-CSF (p < 0.0001) produced by cultured PBL from asthma patients compared to controls. However, our results did not expose a significant association between these cytokine levels and severity and clinical symptoms of asthma. However, there was a marked association between asthma severity and blood lymphocyte count [ꭓ²(2) = 6.745, p < 0.05]. These findings support the roles played by cytokines and IgE in the airway inflammation in asthma. The findings of this study provide new information about inflammatory cytokines in Malaysian asthma patients.

The Role of Atopy in COPD and Asthma

Common to several allergic diseases is the generation of immunoglobulin E (IgE) by plasma cells, when exposed to an innocuous antigen. Asthma and chronic obstructive pulmonary disease (COPD) are two prevalent chronic airway inflammatory diseases. Asthma is mediated in some patients through eosinophilic inflammatory mechanisms that include allergic sensitization and Th2-mediated immune airway response. COPD, on the other hand is mainly considered a Th1-mediated inflammatory process with neutrophilic predominance or a non-Th2 inflammation, occasionally associated with the presence of airway bacteria or viruses. IgE production appears to play an important role in the development of both COPD and asthma, as it has been associated to respiratory symptoms, lung function, bacterial and viral infections, airway remodeling and bronchial hyperreactivity in both diseases. The aim of this review is to summarize all current data concerning the role of specific and total IgE in COPD and asthma and to highlight similarities and differences in view of possible therapeutic interventions.

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 T_H2-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 T_H2 pathway, have been shown to be effective in the treatment of allergic asthma.

Acute associations between PM2.5 and ozone concentrations and asthma exacerbations among patients with and without allergic comorbidities

Acute effects of outdoor air pollution on asthma exacerbations may vary by asthma phenotype (allergic vs nonallergic). Associations of ambient PM_2.5 and ozone concentrations with acute asthma visits (office, urgent, emergency, and hospitalization) were investigated using electronic medical records. International Classification of Disease codes were used to identify asthmatics, and classify them based on the presence or absence of an allergic comorbidity in their medical records. Daily 24-h average PM_2.5, 8-h maximum ozone, and mean temperature were obtained from a centralized monitor. Using a time-stratified case-crossover approach, pollutant concentrations were modeled using moving averages and distributed lag nonlinear models (lag 0-6) to examine lag associations and nonlinear concentration-response. The adjusted odds ratios for a 10 µg/m³ increase in 3-day moving average (lag 0-2) PM_2.5 in the two-pollutant models among patients with and without allergic comorbidities were 1.10 (95% confidence interval [CI]: 1.07, 1.13) and 1.05 (95% CI: 1.02, 1.09), respectively; and for a 20 ppb increase in 3-day moving average (lag 0-2) ozone were 1.08 (95% CI: 1.02, 1.14) and 1.00 (95% CI: 0.95, 1.05), respectively. Estimated odds ratios among patients with allergic comorbidities were consistently higher across age, sex, and temperature categories. Asthmatics with an allergic comorbidity may be more susceptible to ambient PM_2.5 and ozone.

Monoclonal Antibody Therapy in Childhood Asthma

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

Comparison of bronchial and nasal allergen provocation in children and adolescents with bronchial asthma and house dust mite sensitization

BACKGROUND

Bronchial allergen provocation (BAP) is an established tool for the diagnosis of allergy in patients with asthma, but its use is limited by the potential risk of severe asthmatic reactions. Nasal provocation testing (NPT) may be an alternative safe method and does not require sophisticated equipment.

OBJECTIVE

The aim of this prospective study was to evaluate the concordance of both methods in patients with asthma and house dust mite (HDM) sensitization.

METHODS

A total of 112 patients with HDM sensitization underwent BAP and had the following parameters analysed: decrease in FEV1, exhaled NO, and total and specific IgE. Within 12 weeks, NPT with HDM was performed in 74 patients with a median age of 9 years (range, 5-16 years). The results were evaluated using the Lebel score which quantifies major symptoms like rhinorrhea, nasal obstruction, sneezes and minor symptoms, such as pruritus, conjunctivitis and pharyngitis.

RESULTS

Fifty-seven of 74 patients had an early asthmatic reaction, of which 41 were identified using the Lebel score. The Lebel score had a sensitivity of 71.9% and a positive predictive value (PPV) of 89.1%. In addition, an eNO ≥ 10 ppb (AUC 0.78), a specific IgE Dermatophagoïdes pteronyssinus ≥ 25.6 kU/L (AUC 0.76) and a specific IgE Dermatophagoïdes farinae ≥ 6.6 kU/L (AUC 0.78) were good predictors of an early asthmatic reaction.

CONCLUSION

A sequential use of NPT prior to BAP is justified to establish the relevance of HDM allergy. In patients with a negative NPT, BAP is still recommended to rule out a HDM-induced asthmatic reaction.

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

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

dIvergEnt: How IgE Axis Contributes to the Continuum of Allergic Asthma and Anti-IgE Therapies

Asthma is an airway disease characterised by chronic inflammation with intermittent or permanent symptoms including wheezing, shortness of breath, chest tightness, and cough, which vary in terms of their occurrence, frequency, and intensity. The most common associated feature in the airways of patients with asthma is airway inflammation. In recent decades, efforts have been made to characterise the heterogeneous clinical nature of asthma. The interest in improving the definitions of asthma phenotypes and endotypes is growing, although these classifications do not always correlate with prognosis nor are always appropriate therapeutic approaches. Attempts have been made to identify the most relevant molecular and cellular biomarkers underlying the immunopathophysiological mechanisms of the disease. For almost 50 years, immunoglobulin E (IgE) has been identified as a central factor in allergic asthma, due to its allergen-specific nature. Many of the mechanisms of the inflammatory cascade underlying allergic asthma have already been elucidated, and IgE has been shown to play a fundamental role in the triggering, development, and chronicity of the inflammatory responses within the disease. Blocking IgE with monoclonal antibodies such as omalizumab have demonstrated their efficacy, effectiveness, and safety in treating allergic asthma. A better understanding of the multiple contributions of IgE to the inflammatory continuum of asthma could contribute to the development of novel therapeutic strategies for the disease.

Allergen-specific immunoglobulin E and allergic rhinitis severity

Background:

Allergic rhinitis (AR) is a common disorder. The diagnosis is based on the concordance between allergy sensitization and history. Serum allergen specific immunoglobulin E (sIgE) assessment allows characterization of the relevant sensitizing allergens. Presently, Allergic Rhinitis and its Impact on Asthma (ARIA) classification subdivides AR based on symptoms severity and duration. However, the relationship between sIgE levels and symptom severity is still a matter of debate.

Objective:

Therefore, this study aimed at relating sIgE levels with symptom severity assessed by ARIA classification in a group of patients with AR.

Methods:

We enrolled 217 patients with AR (123 women; median age, 39.5 years). The sIgE levels (expressed in kUA/L) to house-dust mite were detected by the fluorescence enzyme immunoassay in peripheral blood samples. The IgE calibrators were traceable to the second international reference preparation 75/502 of human serum IgE from the World Health Organization. Symptom severity was assessed by ARIA classification.

Results:

We found a significant difference in sIgE levels in patients with mild intermittent versus mild persistent symptoms (p < 0.05), mild intermittent versus moderate-to-severe persistent symptoms (p < 0.001), moderate-to-severe intermittent versus moderate-to-severe persistent symptoms (p < 0.01), and mild persistent versus moderate-to-severe persistent symptoms (p < 0.05).

Conclusion:

Analysis of these findings indicated that the sIgE level to house-dust mite might be a reliable biomarker for symptom severity in patients with AR. This outcome might be clinically relevant, particularly in candidates for immunotherapy.

Association between asthma and female sex hormones

CONTEXT AND OBJECTIVE:

The relationship between sex hormones and asthma has been evaluated in several studies. The aim of this review article was to investigate the association between asthma and female sex hormones, under different conditions (premenstrual asthma, use of oral contraceptives, menopause, hormone replacement therapy and pregnancy).

DESIGN AND SETTING:

Narrative review of the medical literature, Universidade Federal do Tocantins (UFT) and Universidade Federal de São Paulo (Unifesp).

METHODS:

We searched the CAPES journal portal, a Brazilian platform that provides access to articles in the MEDLINE, PubMed, SciELO, and LILACS databases. The following keywords were used based on Medical Subject Headings: asthma, sex hormones, women and use of oral contraceptives.

RESULTS:

The associations between sex hormones and asthma remain obscure. In adults, asthma is more common in women than in men. In addition, mortality due to asthma is significantly higher among females. The immune system is influenced by sex hormones: either because progesterone stimulates progesterone-induced blocking factor and Th2 cytokines or because contraceptives derived from progesterone and estrogen stimulate the transcription factor GATA-3.

CONCLUSIONS:

The associations between asthma and female sex hormones remain obscure. We speculate that estrogen fluctuations are responsible for asthma exacerbations that occur in women. Because of the anti-inflammatory action of estrogen, it decreases TNF-α production, interferon-γ expression and NK cell activity. We suggest that further studies that highlight the underlying physiopathological mechanisms contributing towards these interactions should be conducted.

Can we predict allergen-induced asthma in patients with allergic rhinitis?

BACKGROUND

A high percentage of patients with allergic rhinitis (AR) exhibit signs of bronchial hyperreactivity (BHR), and approximately 30% may develop asthma later in life.

OBJECTIVE

The aim of this study was to identify predictors for allergen-induced asthma in patients with AR.

METHODS

Hundred patients with AR selected by public posting and 20 healthy controls were enrolled. Twenty-three patients with concomitant physician-diagnosed asthma and four with a negative allergy test were excluded from further analysis. The remaining 73 subjects with AR underwent bronchial allergen provocation (BAP), which is considered the gold standard for the diagnosis of clinically relevant allergen-specific asthma. The following parameters were measured to explore predictors for an early and late asthmatic response (EAR and LAR): standardised questionnaire, skin prick test (SPT), total IgE, specific IgE to grass pollen, FEV1, PD20FEV1 methacholine, exhaled nitric oxide (eNO) and eosinophils.

RESULTS

Early asthmatic reaction was equally distributed between patients with and without signs of possible asthma by questionnaire (56.8% vs. 48.3%). The following cut-off values showed the best combination of sensitivity and specificity for an EAR: specific IgE grass pollen 18.5 kU/L (AUC 0.83), SPT 8.5 mm (AUC 0.76), total IgE 95.5 kU/L (AUC 0.73), FEV1 102.4% (AUC 0.69), PD20FEV1 methacholine 1.67 mg (AUC 0.74), eNO 18.05 ppB (AUC 0.64) and eosinophils 115/mm(3) (AUC 0.58).

CONCLUSIONS AND CLINICAL RELEVANCE

There is a considerable discordance between reported asthma signs and diagnosed disease by BAP. Simple measurement of allergen-specific IgE for grass pollen was the best predictor of allergen-induced asthma in patients with AR.

Toll-like receptor 1 N248S polymorphism affects T helper 1 cytokine production and is associated with serum immunoglobulin E levels in Taiwanese allergic patients

BACKGROUND/PURPOSE

This study was carried out to investigate whether toll-like receptor-1 (TLR1) rs4833095 (N248S) variant, common in the Taiwanese population, contributes to pathogenesis of allergy.

METHODS

TLR2/1 ligand Pam3CSK4-stimulated cytokine production in peripheral blood mononuclear cells and monocyte-derived dendritic cells of different genotypes were measured via enzyme-linked immunosorbent assay. Ninety-three Taiwanese allergic patients (with asthma, allergic rhinitis, or atopic dermatitis) and 76 controls were recruited for genotyping. Serum immunoglobulin E (IgE) levels were evaluated in 60 allergic patients.

RESULTS

The homozygous TLR1 C variant allele carrier had increased Pam3CSK4-induced tumor necrosis factor-α and interleukin-12 responses in peripheral blood mononuclear cells and monocyte-derived dendritic cells, respectively. Furthermore, although the C/C genotype was not associated with susceptibility to atopic diseases, it was correlated with lower total IgE levels in sera of allergic patients.

CONCLUSION

Our data suggest that the TLR1 N248S polymorphism might play a role in Th1/Th2 differentiation, and the determination of serum IgE levels. However, interactions with other genetic and environmental factors might be required to contribute to risk of allergic diseases in our population.

Longitudinal increase in total IgE levels in patients with adult asthma: an association with poor asthma control

Background

Immunoglobulin (Ig) E is well-known to play a critical role in allergic diseases. We investigated the association between longitudinal change in total IgE level and the asthma control in patients with adult asthma.

Methods

For this retrospective study, 154 patients with asthma aged 21–82 years were recruited from the allergy and pulmonary units of the Showa University Hospital. Data on longitudinal changes in IgE over the preceding 10 years were collected and logarithmically transformed. Associations between longitudinal change in IgE and clinical characteristics including asthma control test (ACT) score, asthma control, pulmonary function test, and antigen specific IgE, were assessed.

Results

Patients with increased IgE tended to have significantly higher mean age, more episodes of acute exacerbation within a year, lower ACT scores, and used oral corticosteroids more frequently than those with decreased or unchanged IgE. The prevalence of uncontrolled asthma was higher in patients with increased IgE than in those with decreased or unchanged IgE. Mean %FEV₁ and FEV_1% were lower in patients with increased IgE than in those with decreased or unchanged IgE. Moreover, the prevalence of Aspergillus-specific IgE was higher in patients with increased IgE than in those with decreased or unchanged IgE.

Conclusions

These data suggest that a longitudinal increase in total IgE is associated with both poor asthma control and Aspergillus-specific IgE in patients with adult asthma.

Potential benefit of omalizumab in respiratory diseases

OBJECTIVE

To provide an overview of primary and secondary mechanisms associated with anti-IgE therapy and their relation to other potential indications in diseases affecting the respiratory tract.

DATA SOURCES

Literature from PubMed searches for publications providing insight into secondary mechanisms resulting from anti-IgE therapy and publications reporting on the use of omalizumab to treat conditions that affect the respiratory tract, other than severe atopic asthma.

STUDY SELECTIONS

Clinical trials or case reports were identified for asthma in patients without atopy, allergic rhinitis, nasal polyposis, and allergic bronchopulmonary aspergillosis.

RESULTS

There is substantial evidence from controlled trials supporting a benefit for allergic rhinitis. Case reports and series on more than 50 patients with allergic bronchopulmonary aspergillosis have been published, including patients with or without cystic fibrosis; most have reported benefits in terms of decreased steroid use, exacerbation rates, and, in patients with cystic fibrosis, improvement in lung function. Several small controlled studies on nasal polyposis have shown equivocal results. One small controlled trial in patients with nonatopic asthma showed a significant improvement for lung function but not in exacerbation rate or asthma scores.

CONCLUSION

Recent insight into the immunopathology of respiratory diseases should be used to identify patient populations likely to respond to anti-IgE therapy. Controlled clinical trials are needed to confirm efficacy and determine the clinical significance of the effects of omalizumab in these populations.

Childhood allergic asthma is not a single phenotype

OBJECTIVE

IgE-mediated allergic asthma phenotype appears to be heterogeneous. We set out to define distinct allergic phenotypes by unsupervised cluster analysis.

STUDY DESIGN

A total of 18 variables were analyzed: sex and age, eczema and food allergy, asthma duration, asthma severity and control, severe exacerbations, total IgE level, allergic sensitization, fractional exhaled nitric oxide, and functional parameters. Clusters obtained were cross-tabulated with environmental parameters.

RESULTS

Four clusters were identified in 125 children (average age 8.9 years): (1) 57 children constituted the "House dust mite Sensitization and Mild Asthma" cluster, 98% of these were monosensitized and had mild asthma (74%); (2) 12 children had "Pollen Sensitization with Severe Exacerbations," 92 % with severe exacerbations and pollen sensitization; (3) 20 children had "Multiple Allergies and Severe Asthma," with 95% having moderate to severe asthma, and a significantly decreased forced expiratory flow rate at 25%-75% of forced vital capacity, 100% had eczema and higher values of IgE (1123 kU/L) and fractional exhaled nitric oxide (67 ppb) (this cluster was associated with molds at home [P = .004]); and (4) 36 children had "Multiple Allergic Sensitizations and Mild Asthma," 97% of these with multiple sensitizations and 100% mild asthma.

CONCLUSIONS

The identification of 2 novel severe allergic asthma phenotypes "Pollen Sensitization with Severe Exacerbations"and "Multiple Allergies and Severe Asthma" could lead to specific targeted treatment.

Burden of illness of patients with allergic asthma versus non-allergic asthma

OBJECTIVE

Allergic and non-allergic asthma share similar symptoms, but differ in that allergic asthma is triggered by inhaled allergens. This study compared healthcare resource utilization (HCRU) and costs between these groups using US employer-based claims data.

METHODS

Health insurance claims from Truven Marketscan database (2002Q1-2010Q2) were analyzed. Included patients had ≥2 asthma diagnoses and ≥1 year of eligibility prior to and following the date of first asthma diagnosis. Patients with ≥1 diagnosis for allergic asthma and ≥1 diagnosis for other allergic conditions formed the allergic asthma cohort whereas patients without any of these diagnoses formed the non-allergic asthma cohort. Allergic and non-allergic asthma patients were matched 1:1. HCRU and costs during the study period were compared between cohorts using incidence rate ratios (IRR) and bootstrap methods.

RESULTS

Sixty four thousand four hundred and seventy three allergic and non-allergic asthma patients were matched (mean age = 30; 57.1% female; mean CCI = 0.2), with 7.1% and 0.36% having received an allergy test during the baseline period, respectively. During the study period, allergic asthma patients had significantly more asthma-related pharmacy dispensings (IRR[95% CI] = 2.25[2.22-2.28], p < 0.001) and asthma-related outpatient visits (IRR[95% CI] = 2.29[2.27-2.32], p < 0.001). Allergic asthma patients incurred 39% greater per-patient-per-year all-cause costs (allergic: $4008; non-allergic: $2889, p < 0.001) and 79% greater asthma-related costs (allergic: $1063; non-allergic: $592, p < 0.001) than non-allergic asthma patients.

CONCLUSIONS

These results indicate, even in a relatively healthy population, allergic asthma is associated with greater HCRU and costs. Guideline-recommended IgE allergy tests should be employed in distinguishing the two forms of asthma, to optimize patient management and reduce costs.

Sensitization profile in differential diagnosis: allergic asthma vs. chronic (nonspecific) cough syndrome

BACKGROUND

In the subgroup of children with chronic cough, distinguishing children with allergic asthma from those with non-specific respiratory symptoms is difficult. We have focused on determination of diagnostic efficiency of serum total IgE, sIgE, and skin prick test in differentiation of asthmatic children from children with nonspecific respiratory symptoms.

MATERIAL AND METHODS

A total of 131 children with median age of 7.5 years were enrolled in study and divided into 2 groups; children with allergic asthma (N=71) and children with chronic cough (N=60). Participants underwent the standard allergological examination, including skin prick test and measurement of total IgE, and following 3 allergen-specific IgE antibodies against aeroallergens: Dermatophagoides pteronyssinus, Ambrosia artemisiifolia, and Phleum pratense.

RESULTS

The percentage of patients with elevated level of total and sIgE was higher in children with allergic asthma than in children with chronic cough syndrome (P=0.0001). In children with asthma, sIgE had a better diagnostic value than total IgE. The best diagnostic efficiency of cut-off values for sIgE was shown for Der p sIgE. Skin prick test to all allergens had 78.82% sensitivity and 91.3% specificity in differentiating the 2 tested groups. The highest sensitivity and specificity in skin prick test was proved for Dermatophagoides pteronyssinus.

CONCLUSIONS

The sensitization profile consisting of total IgE, sIgE levels, and SPT clearly distinguishes children with allergic asthma from children with chronic nonspecific cough, but still with overlap. Therefore, diagnosis should always be confirmed by a thorough allergy investigation.

[Respiratory allergens and asthma exacerbation]

INTRODUCTION

Asthma exacerbations are characterized by a progressive aggravation of respiratory symptoms such as dyspnea, cough, wheezing or chest tightness.

BACKGROUND

The relationship between allergy and asthma exacerbations has been evaluated by epidemiological studies based on various criteria such as oral corticosteroid requirement, emergency room visits and hospital admission for asthma. Many studies have observed that deteriorating asthma can be related to increased exposure to allergens, particularly allergens from house dust mite, cockroach, cat, rodent, mold or pollen. Several studies have demonstrated that sensitization to respiratory allergens and allergen exposure increases the risk of exacerbation of asthma. When asthma exacerbations are work-related, occupational allergens may be implicated.

CONCLUSIONS AND PERSPECTIVES

Most studies provide evidence that allergen exposure contributes to the risk of asthma exacerbations, but other precipitating factors, such as viruses, can interact and increase the risk.

Clinical features cannot distinguish allergic from non-allergic asthma in children

OBJECTIVE

Environmental allergens are a major trigger of asthma, but not all asthmatics are allergic. This study was designed to review clinical characteristics in children with allergic and non-allergic asthma, based on responsiveness to allergy skin tests, in order to identify a combination of features that could distinguish allergic from non-allergic asthma in children.

METHODS

Medical records of 321 children who had allergy skin testing were reviewed, and demographic and clinical data were compared between allergic and non-allergic patients.

RESULTS

Approximately two-thirds of the asthmatic children had at least one positive skin test. These allergic patients were more likely to have a history of eczema or Medicaid insurance, but these findings had poor predictive value. There was no difference between allergic patients and non-allergic patients in terms of family history of atopy or asthma, home tobacco smoke exposure, age of onset of asthma, gender, rate of obesity, or asthma severity. Among the allergic asthma patients, neither the number of positive skin tests nor specific individual allergic sensitivities correlated with age of onset of asthma or asthma severity.

CONCLUSIONS

This study failed to identify any combination of features that could reliably distinguish allergic from non-allergic asthma in children. Thus, all children with asthma should undergo allergy testing in order to identify potential allergic triggers in allergic patients and to avoid the institution of unnecessary environmental control measures in non-allergic patients.

Maternal depression related to infant's wheezing

OBJECTIVE

To assess whether maternal psychological status is related to infant's wheezing.

STUDY DESIGN

In a case-control study conducted in Paris in cases aged less than 36 months suffering from wheezing and matched healthy controls, mothers filled a standardized questionnaire on child's health and the State Trait Anxiety Inventory form Y-B and the Beck Depression Inventory short form. Cases underwent also routine clinical and biological assessments. The statistical analysis used the propensity score analysis to control for selection bias.

RESULTS

Hundred and thirty-eight wheezers and hundred and nine controls participated in the study. After adjustment for confounders, maternal depressive symptoms at the period of the survey according to the Beck Inventory were more significantly found in the cases than in others (p < 0.01). A trend was found for maternal depression during pregnancy. Among the cases, 10.6% suffered from severe asthma, 84.8% took inhaled corticosteroids (ICs), 17.4% had positive specific immunoglobulin E (IgE) to allergens and 11.5% hypereosinophilia. The more the mother was depressed according to the Beck Inventory, the more the infant's asthma was severe (OR = 4.25, 95% CI: 1.14, 15.9 between severe infant's wheezing and severe maternal depression). No relationship was observed between mother's depressive symptoms and ICs taken by the infant, allergic sensitization or eosinophilia.

CONCLUSION

Our findings support the hypothesis of a link between maternal depression and infant's wheezing and its severity early in life independent of allergic status. Consequences of our study include the need to assess depressive symptoms in mothers of infants with asthma.

Influence of degree of specific allergic sensitivity on severity of rhinitis and asthma in Chinese allergic patients

BACKGROUND

The association between sensitizations and severity of allergic diseases is controversial.

OBJECTIVE

This study was to investigate the association between severity of asthma and rhinitis and degree of specific allergic sensitization in allergic patients in China.

METHOD

A cross-sectional survey was performed in 6304 patients with asthma and/or rhinitis from 4 regions of China. Patients completed a standardized questionnaire documenting their respiratory and allergic symptoms, their impact on sleep, daily activities, school and work. They also underwent skin prick tests with 13 common aeroallergens. Among the recruited subjects, 2268 provided blood samples for serum measurement of specific IgE (sIgE) against 16 common aeroallergens.

RESULTS

Significantly higher percentage of patients with moderate-severe intermittent rhinitis were sensitized to outdoor allergens while percentage of patients sensitized to indoor allergens was increased with increasing severity of asthma. Moderate-severe intermittent rhinitis was associated with the skin wheal size and the level of sIgE to Artemisia vulgaris and Ambrosia artemisifolia (p < 0.001). Moderate-severe asthma was associated with increasing wheal size and sIgE response to Dermatophagoides (D.) pteronyssinus and D. farinae (p < 0.001). Moderate-severe rhinitis and asthma were also associated with increase in number of positive skin prick test and sIgE.

CONCLUSIONS

Artemisia vulgaris and Ambrosia artemisifolia sensitizations are associated with the severity of intermittent rhinitis and D. pteronyssinus and D. farinae sensitizations are associated with increasing severity of asthma in China. Increase in number of allergens the patients are sensitized to may also increase the severity of rhinitis and asthma.

Inflammatory markers in childhood asthma

The major characteristic of asthma is persistent airway inflammation that fails to resolve spontaneously. Dysregulation of pro- and anti-inflammatory mechanisms is responsible for the development of chronic inflammation. The inflammatory reaction is mediated by numerous cells and their mediators. Detection and quantification of airway inflammation in children are subject to many requirements, e.g., use of biologic samples obtained in a non-invasive way; use of standardized analytical methods to determine biomarkers that can identify inflammation processes (inflammation itself, oxidative stress, apoptosis and remodelling); determining the role of systemic inflammation; assessment of correlation of various biomarkers of inflammation with clinical parameters and their diagnostic efficacy; providing a tool(s) to monitor diseases, and to evaluate adequacy of therapy; and predicting the clinical course of inflammation and prognosis of asthma. Using standardized analyses, it is now possible to determine direct markers of local inflammation, i.e., fractional nitric oxide (marker of oxidative stress) in exhaled breath, pH (marker of acid stress) in breath condensate, and indirect markers in blood/serum, i.e., eosinophil granulocytes (indicating migration), eosinophil cationic protein (marker of activated eosinophil granulocytes) and C-reactive protein (marker of systemic inflammation). However, none of these biomarkers are specific for asthma. Further standardization of the known pulmonary biomarkers of local inflammation and identification of new ones will allow for longitudinal follow-up of inflammation in children with asthma.

Methacholine and adenosine 5'-monophosphate (AMP) responsiveness, and the presence and degree of atopy in children with asthma

The relationship between atopy and bronchial hyperresponsiveness (BHR), both key features of asthma, remains to be clarified. BHR is commonly evaluated by bronchial challenges using direct and indirect stimuli. The aim of this study was to investigate the degree of BHR to methacholine (direct stimulus) and adenosine 5'-monophosphate (AMP) (indirect stimulus) according to the presence and degree of atopy in children with asthma. We performed a retrospective analysis of data from 120 children presenting with a diagnosis of asthma. These children were characterized by skin-prick tests (SPTs), spirometry and bronchial challenges with methacholine and AMP. Atopy was defined by at least one positive reaction to SPTs, and its degree was measured using serum total IgE levels, number of positive SPTs and atopic scores (sum of graded wheal size). A provocative concentration causing a 20% decline in FEV(1) (PC(20) ) was determined for each challenge. Patients with atopy(n=94) had a significantly lower AMP PC(20) than non-atopic patients (n=26), whereas methacholine PC(20) was not different between the two groups. Among the patients with atopy, there was no association between methacholine PC(20) and any atopy parameter. In contrast, a significant association was found between AMP PC(20) and the degree of atopy reflected in serum total IgE, number of positive SPTs and atopic scores (anova trend test, p=0.002, 0.001, 0.003, respectively). AMP responsiveness was associated with the presence and degree of atopy, whereas such a relationship was not observed for methacholine responsiveness. These findings suggest that atopic status may be better reflected by bronchial responsiveness assessed by AMP than by methacholine.

Are chronic urticaria, analgesic intolerance and seasonal rhinitis markers of different severities and phenotypes of the asthma they accompany?

BACKGROUND

Asthma is a heterogeneous disease that presents with different clinical phenotypes. We aimed to compare the patients with asthma diagnosis alone with the patients, who, in addition to their asthma had accompanying analgesic intolerance (AI), chronic urticaria (CU) or seasonal rhinitis (SR) if there are any distinctions and specific characteristics of these defined patient groups.

METHODS

Eighty-four asthma patients diagnosed with SR, 46 with CU, 75 with AI and 71 patients with asthma alone were enrolled to the study retrospectively. The reference group for the comparisons was the group with asthma diagnosis alone.

RESULTS

The mean age of all patients was 37.2±13 (15-80) and 70.7% of them were females. Asthma patients with SR had a significantly earlier onset of asthma (age: 27.4±10.8 and 34.5±15.9; respectively, p<0.01), significantly better pulmonary function tests and were significantly more atopic (92.9% and 28.8%; p<0.001). Moderate-to-severe asthma significantly correlated with older age at the time of diagnosis, older age of asthma onset, higher body mass index, less atopy and fewer pollen sensitivity. Asthma severity of patients with SR was significantly milder than the reference group (OR: 0.6, 95% CI 0.5-0.8). Asthma with AI tended to be more severe although the relation was insignificant (OR:1.6 95% CI:0.8-3.5).

CONCLUSIONS

Asthma patients with SR have significantly milder and earlier onset of asthma, better pulmonary function tests and are significantly more atopic while asthma with AI tends to be more severe. Asthma with CU does not show a specific phenotypic characteristic.

Asthma, allergy, and IgE levels in NYC head start children

BACKGROUND

Among preschool-age children in New York City neighborhoods with high asthma hospitalization rates, we analyzed the associations of total immunoglobulin E (IgE), specific IgE to common indoor allergens, and allergy symptoms with asthma.

METHODS

Parents of children in New York City Head Start programs were asked to complete a questionnaire covering demographic factors, health history (including respiratory conditions), lifestyle, and home environment. Children's serum samples were analyzed for total IgE and specific IgE antibodies to cockroach, dust mite, mouse, and cat allergens by immunoassay. Logistic regression was used to model the association between asthma and IgE, controlling for age, gender, ethnicity/national origin, BMI, parental asthma, smokers in the household, and allergy symptoms (e.g., runny nose, rash).

RESULTS

Among 453 participating children (mean age 4.0+/-0.5 years), 150 (33%) met our criteria for asthma. In our multivariable logistic regression models, children with asthma were more likely than other children to be sensitized to each allergen, to be sensitized to any of the four allergens (OR=1.6, 95% CI 1.0-2.6), or to be in the highest quartile of total IgE (OR=3.1, 95% CI 1.5-6.4). Allergy symptoms based on questionnaire responses were independently associated with asthma (OR=3.7, 95% CI 2.3-5.9).

CONCLUSIONS

Among preschool-aged urban children, asthma was associated with total IgE and sensitization to cat, mouse, cockroach, and dust mite allergens. However, allergy symptoms were more prevalent and more strongly associated with asthma than was any allergen-specific IgE; such symptoms may precede elevated specific IgE or represent a different pathway to asthma.

Factors affecting bronchial hyperreactivity in asthmatic children

Bronchial hyperresponsiveness (BHR), the exaggerated airway narrowing in response to nonspesific stimuli, is a common characteristic of asthma. One hundred thirty-five children who were diagnosed asthma in the outpatient clinic of Gazi University Hospital, Pediatric Allergy and Asthma Department between January 2007 and January 2008 were retrospectively analysed from the asthma database of the division. BHR was not found to be different according to sex. Younger the age of the patient, more severe was BHR (p = 0.096, r = 0.164). Younger the age at onset of the symptoms, the more severe was the BHR (p < 0.001, r = 0.307). Patients who had an asthmatic first degree relative and who were exposed to passive smoking at home, had more severe BHR (p = 0.006 and p = 0.032, respectively). There were more hospitalizations among the asthmatic children with moderate-severe BHR (p = 0.027) however no correlation was found between chronic asthma severity and the degree of BHR). In this study we found that age, age at onset of symptoms, having a parent with asthma, exposure to tobacco smoke and baseline lung function are related to BHR measured at referral. Serum levels of Ig E or skin prick test positivity were not found to have any effect on BHR severity. Considering BHR severity, we could not reveal any relation between atopic and nonatopic children. However among atopic subjects, the ones with indoor allergen sensitization had more severe BHR.

Severe asthma in childhood: assessed in 10 year olds in a birth cohort study

BACKGROUND

Limited information is available regarding the prevalence of severe asthma in children. The present study aimed at investigating the prevalence of severe asthma in an urban child population; secondarily evaluating the applicability of the chosen definition by clinical characteristics.

METHODS

Children enrolled in the prospective birth cohort; the Environment and Childhood Asthma Study in Oslo; were reinvestigated at the age of 10 years (n = 1019). A representative population based cohort of 616 children [mean age 10.9 (SD 0.9) years] with lung function measurements at birth was used for prevalence estimates, whereas all 1019 children (154 with current asthma) attending the 10-year follow-up were included for verification of the definition of severe asthma. Clinical investigations included spirometry, tests of bronchial hyperresponsiveness, skin prick tests and exhaled nitric oxide. Severe asthma was defined as poorly controlled asthma despite treatment with > or = 800 microg budesonide or equivalent; assessed by a detailed structured interview.

RESULTS

The population point prevalence at age 10 years of current severe asthma was 0.5% (three of 616) and among children with current asthma 4.5% (three of 67). The 10/154 children identified as suffering from severe asthma more often had severe bronchial hyperresponsiveness (PD(20) methacholine <1 micromol) (60%vs 22%, P = 0.015), lower median forced expiratory volume in 1 s/forced vital capacity ratio (93%vs 99%, P = 0.04) and higher body mass index (mean BMI 22.3 vs 18.3, P < 0.001) than nonsevere current asthmatics.

CONCLUSIONS

The prevalence of severe asthma was 0.5% in all 10-year olds, and 4.5% among current asthmatics. The severe asthma definition applied in this study is supported by results of clinical investigations.

High-sensitivity C-reactive protein: a predicative marker in severe asthma

BACKGROUND AND OBJECTIVE

Serum levels of high-sensitivity CRP (hs-CRP) are associated with asthma but the relationship between higher levels of hs-CRP and the degree of asthma severity remains unclear. This study investigated whether hs-CRP is associated with asthma severity as well as with other clinical indices of asthma activity (pulmonary function, total serum IgE, and peripheral blood eosinophil counts).

METHODS

Levels of hs-CRP and clinical indices of asthma were determined among 177 control subjects and 281 asthmatic patients (84 intermittent, 30 mild, 63 moderate and 104 severe).

RESULTS

The level of hs-CRP was examined as both a continuous variable and by quartiles (<0.23, 0.23-0.51, 0.51-1.42 and >or=1.42 mg/L) in the five groups. Compared with the first quartile of hs-CRP, patients with higher levels were at increased risk of severe asthma independently of other clinical indices (adjusted OR 3.49, 95% CI: 1.51-8.12 for the third quartile; adjusted OR 6.46, 95% CI: 2.85-16.62 for fourth quartile, respectively).

CONCLUSIONS

These findings suggest that hs-CRP might be a sensitive marker for severe asthma.

FCER2: a pharmacogenetic basis for severe exacerbations in children with asthma

BACKGROUND

Although inhaled corticosteroids (ICSs) generally protect against severe exacerbations in asthma, they may result in elevated IgE levels, which are associated with exacerbations.

OBJECTIVE

To determine whether variation in the low-affinity IgE receptor gene, FCER2, is associated with severe exacerbations defined as emergency department visits and/or hospitalizations in patients with asthma on ICSs.

METHODS

We resequenced, then genotyped 10 FCER2 single nucleotide polymorphisms (SNPs) in 311 children randomized to inhaled budesonide as part of the Childhood Asthma Management Program. We evaluated the association of FCER2 variants with IgE levels and presence or absence of severe exacerbations over the 4-year clinical trial. We also evaluated differences in cellular expression of the novel FCER2 SNP, T2206C.

RESULTS

In white subjects, 3 FCER2 SNPs were significantly associated (P < .05) with elevated 4-year IgE level; each was also associated with increased severe exacerbations. Final multivariable models demonstrated associations between T2206C and severe exacerbations in both white and African American children (hazard ratio, 3.95; 95% CI, 1.64-9.51; and hazard ratio, 3.08; 95% CI, 1.00-9.47), despite ICS use. Interaction models supported a true gene-environment effect in white subjects (interaction P = .004). T2206C was also associated with decreased FCER2 expression (P = .02).

CONCLUSION

FCER2 predicts the likelihood of treatment protocol success in asthma. The associations of T2206C with IgE level, severe exacerbations, and FCER2 expression may provide a mechanistic basis for the observed findings.

CLINICAL IMPLICATIONS

Genetic variation in FCER2 may help form a prognostic model for ICS response in asthma.

[Environmental factors for asthma severity and allergy: results from the EGEA study]

INTRODUCTION

EGEA (Epidemiological study on the genetics and environment of asthma, bronchial hyperresponsiveness and atopy), a case control and family study including 2048 individuals, was initiated to look for environmental and genetic risk factors for asthma. A synthesis of the results obtained since 2002 on phenotypic and environmental aspects of asthma severity and allergy are presented in this article.

METHODS AND RESULTS

The results support a role for hormonal factors in asthma severity and in various allergic markers of asthma. A greater body mass index was related to a more severe asthma in women with early menarche. Associations between markers of allergy (eosinophils, IgE and atopy) and hormonal dependent events in women (premenstrual asthma, menopause and oral contraceptive use) have been found. In asthmatics, exposure to agents known to be associated with occupational asthma, active and passive smoking were associated with an increased clinical asthma severity score. The study underlines the protective role of country living and exposure to pets in early life on allergy markers in adulthood, supporting the hygiene hypothesis.

CONCLUSIONS

New hypothesis will be tested in the near future from the second stage of this survey.

Association between IgE levels and asthma severity among African American, Mexican, and Puerto Rican patients with asthma

BACKGROUND

High levels of IgE are associated with asthma. Whether higher levels of IgE are associated with more severe asthma is still unclear.

OBJECTIVE

To determine whether IgE is associated with asthma severity among Latino and African American subjects with asthma.

METHODS

We assessed lung function and asthma severity among African American, Mexican, and Puerto Rican patients with asthma with high IgE levels (> or =100 IU/mL; n = 492) and compared these values to those of patients with asthma with low IgE levels (<100 IU/mL; n = 247). We also examined IgE as a continuous variable among these groups.

RESULTS

Patients with asthma with high IgE had a lower mean FEV(1) (87.6 +/- 17.1, percent of predicted) than patients with asthma with low IgE (91.5 +/- 17.0; P = .031). Regardless of race and ethnicity, baseline FEV(1), forced expiratory flow, and FEV(1)/forced vital capacity were lower among subjects with high IgE than among subjects with low IgE (P = .031, P < .0001, P = .0001, respectively). In addition, 54.7% of patients with asthma with high IgE had been previously hospitalized, compared with 44.1% of patients with asthma with low IgE (odds ratio, 1.33; 95% CI, 1.04-1.71).

CONCLUSION

Higher IgE is associated with lower baseline lung function and more severe asthma among these populations.

CLINICAL IMPLICATIONS

Among patients with asthma from 3 ethnically distinct groups, total IgE levels are inversely correlated with baseline lung function and asthma severity.

Sensitization to Ascaris lumbricoides and severity of childhood asthma in Costa Rica

BACKGROUND

Little is known about sensitization (defined as a positive IgE) to helminths and disease severity in patients with asthma.

OBJECTIVES

To examine the relationship between sensitization (defined as a positive IgE) to Ascaris lumbricoides and measures of asthma morbidity and severity in a Costa Rican population with low prevalence of parasitic infection but high prevalence of parasitic exposure.

METHODS

Cross-sectional study of 439 children (ages 6 to 14 years) with asthma. Linear regression and logistic regression were used for the multivariate statistical analysis.

RESULTS

After adjustment for parental education and other covariates, sensitization to Ascaris lumbricoides was associated with having at least 1 positive skin test to allergens (odds ratio, 5.15; 95% CI, 2.36-11.21; P < .001), increased total serum IgE and eosinophils in peripheral blood, reductions in FEV(1) and FEV(1)/forced vital capacity, increased airway responsiveness and bronchodilator responsiveness, and hospitalizations for asthma in the previous year (odds ratio, 3.08; 95% CI, 1.23-7.68; P = .02).

CONCLUSION

Sensitization to Ascaris lumbricoides is associated with increased severity and morbidity of asthma among children in Costa Rica. This association is likely mediated by an increased degree of atopy among children with asthma who are sensitized to Ascaris.

CLINICAL IMPLICATIONS

In areas with a low prevalence of helminthiasis such as Costa Rica, Ascaris sensitization may be an important marker of severe atopy and disease morbidity in children with asthma.

Correlation between asthma severity and serum IgE in asthmatic children sensitized to Dermatophagoides pteronyssinus

BACKGROUND

We undertook this study to test the possible correlation between serum concentration of total and specific IgE antibodies and asthma severity in asthmatic children sensitized to the house dust mite Dermatophagoides pteronyssinus.

METHODS

The study included 157 asthmatic children aged 5-15 years (8 +/- 3 years). Clinical diagnosis was based on personal and family history, physical examination, pulmonary function testing and skin tests. Asthma severity was determined according to GINA guidelines. In vitro tests included serum concentration of total and specific IgE.

RESULTS

All asthmatic children had elevated serum concentration of total IgE. The children with elevated serum concentration of total IgE also showed an increased serum concentration of specific IgE. Asthma of higher higher severity was present in patients with total IgE concentration >288.0 kIU/L (AUC = 0.736) and specific IgE to Dermatophagoides pteronyssinus >44.1 kIUA/L (AUC = 0.843). Intermittent asthma was present in 76.9% of children with specific IgE concentration <44.1 kIUA/L. The positive predictive value suggested with 79.2% probability that a child with a concentration of specific IgE to Dermatophagoides pteronyssinus >44.1 kIUA/L would have a more severe form of asthma.

CONCLUSIONS

Asthmatic children with higher asthma severity have a higher serum concentration of both total IgE (>288.0 kIU/L) and specific IgE to Dermatophagoides pteronyssinus (>44.1 kIUA/L), respectively.

Interrelationships of quantitative asthma-related phenotypes in the Epidemiological Study on the Genetics and Environment of Asthma, Bronchial Hyperresponsiveness, and Atopy

BACKGROUND

Delineating asthma subphenotypes is of interest to understand the cause of the disease. Few studies have addressed the interrelationships of quantitative asthma-related traits.

OBJECTIVE

We sought to study the interrelationships of allergy markers and FEV(1) in relation to asthma and sex in children and adults.

METHODS

Total IgE levels, skin prick test (SPT) positivity, eosinophil counts, and FEV(1) were assessed in 299 asthmatic cases (children and adults) recruited in chest clinics and 309 nonasthmatic population-based control subjects in the French Epidemiological Study on the Genetics and Environment of Asthma, Bronchial Hyperresponsiveness, and Atopy.

RESULTS

Allergy parameters were significantly higher in asthmatic cases than in control subjects for children and adults and for both sexes. Sex and age modified the pattern of concordance of high IgE levels, SPT positivity, and eosinophilia among asthmatic cases, with the greatest overlap in male children (64%) and the lowest in male adults (18%). Patterns of change over the lifespan of IgE levels, eosinophil counts, and FEV(1)/height(2) varied, with the acceleration of FEV(1) decrease being particularly evident in asthmatic adults. In adult cases and control subjects, SPT positivity (particularly to indoor allergens) was significantly related to IgE levels but not to eosinophil counts. The association of eosinophil counts with IgE levels was evident only in children. Environmental factors (smoking, pets, and country living) did not alter the patterns observed.

CONCLUSIONS

Each allergy-related phenotype showed a distinct relation with asthma, with the role for eosinophils being different than that for IgE levels and SPT responses.

CLINICAL IMPLICATIONS

Taking age and sex into account is essential for understanding the interrelationships of the various allergy-related phenotypes to asthma status.

Relationship between IgE and specific aeroallergen sensitivity in Alaskan native children

BACKGROUND

The relationship between atopic disease and serum IgE levels varies among populations and geographic regions. The close association of atopy with IgE may not occur in subarctic populations as it does in developed countries in temperate climates.

OBJECTIVE

To evaluate the relationship between total and specific IgE concentrations and clinical atopy in 5- to 8-year-old Alaskan native children.

METHODS

Medical record reviews, interviews, physical examinations, serum IgE measurements, and radioallergosorbent testing (RAST) were performed.

RESULTS

The IgE geometric mean was 122.1 IU/mL. Fifty-eight percent of patients had IgE levels greater than 70 IU/mL, and 17% had levels greater than 1,000 IU/mL; 14% had RAST values greater than 0.35 kU/L. Both IgE levels greater than 70 IU/mL and greater than 1,000 IU/mL were associated with RAST values greater than 0.35 IU/L (P = .004) and early wheezing (P = .005) but not with current wheezing, asthma, eczema, or a history of allergies. A RAST value greater than 3.51 kU/L was associated with eczema (P = .04) but not with allergies or wheezing. Children with current wheezing were more likely to have allergies (P = .03) but not eczema, an IgE level greater than 70 IU/mL, or a positive RAST value. Children hospitalized with respiratory syncytial virus (RSV) were not more likely than controls to have current wheezing.

CONCLUSIONS

Elevated serum IgE concentrations, including levels greater than 1,000 IU/mL, are common among Alaskan native children; positive RAST reactions to aeroallergens are not. The IgE levels do not relate to wheezing, eczema, a history of allergies, or past hospitalization for RSV infection but likely reflect infections other than RSV and environmental factors in subarctic indigenous populations.