Early exposure to house-dust mite and cat allergens and development of childhood asthma: a cohort study. Multicentre Allergy Study Group

Early-Life Allergen Exposure and Its Influence on Risk of Atopic Disease

Childhood allergic diseases and asthma have their origins in early life, and allergen exposures during this period could be a critical determinant of the progression to tolerance versus disease. Mechanisms for sensitization may be different but overlapping for food and aeroallergen sensitization in children. This suggests differences in how exposure to food and aeroallergens influence allergic sensitization. For food allergy, introducing foods such as peanut and egg proteins into the diet at an early age reduces the risk of peanut and egg allergy, respectively, across a broad demographic, whereas evidence is less established for other foods. The relationship between allergen exposure and sensitization to aeroallergens is more complex but critical, given the close relationship between specific immunoglobulin E and respiratory disease. Several factors could mediate the progression from allergen exposure and allergic sensitization versus tolerance, including epithelial barrier function and altered immune development at the skin and mucosal surfaces, exposure to irritants and pollutants, and genetic susceptibility. Collectively, the current evidence base provides a compelling rationale for the primary prevention of food allergy by introducing common allergens such as peanut and egg early. In contrast, primary prevention of aeroallergen sensitization is more complex and perhaps more challenging to achieve by manipulating allergen exposures. Even so, recent advances in understanding how the microbiome and environmental toxins and irritants modulate the mucosal immune response have identified potential new strategies for primary prevention of food and aeroallergen sensitization.

Guidance for type 2 inflammatory biomarkers

Type 2 inflammation in the airways and lungs is inflammation induced by type 2 cytokines such as IL-4, IL-5, and IL-13, produced primarily by type 2 helper T cells and type 2 innate lymphoid cells, and causes changes in the physiology and structure of the airways. Type 2 inflammation is currently in the spotlight because of its direct link to the treatment of several airway and lung diseases. Abundant evidences have accumulated that inflammatory biomarkers such as blood eosinophils, fractional exhaled nitric oxide, and IgE are essential clinical tools in the diagnosis and management of asthma and COPD. It is well known that asthma and COPD have diverse inflammatory phenotypes even when clinical features are similar, and it has been demonstrated that assessment of airway inflammation with biomarkers can improve diagnostic accuracy, determine safer and more effective treatment strategies, and predict future risks such as exacerbations and lung function decline. The Japanese Respiratory Society has published clinical practice guidelines for the evaluation of type 2 inflammation in the airways and lungs. In addition to asthma and COPD, the guide covers a wide range of airway and lung diseases, including interstitial lung disease, allergic bronchopulmonary mycosis, allergic rhinitis, and eosinophilic chronic rhinosinusitis. It also provides comprehensive guidelines covering a variety of clinical biomarkers. The purpose of this guidance is to provide evidences for the interpretation of type 2 inflammation measurements and to promote the widespread use of inflammation assessment to further improve the efficiency of airway and respiratory disease management.

Isotype diversity of antibodies specific for component allergens in the context of allergic diseases: eosinophilic esophagitis (EoE), asthma, and the alpha-gal syndrome (AGS)

From the earliest days of studying the reagins in allergic sera that give rise to the Prausnitz-Kuestner reaction, there was evidence that there were other types of antibodies (Ab) specific for allergens, particularly those induced by immunotherapy. By 1980, not only was IgE recognized and could be measured, but the presence of other isotypes including IgG and IgA in patients with IgE was well established. From that time onwards the development of monoclonal antibodies made it possible to distinguish and measure antibodies of other isotypes such as IgG4, IgG2, and IgG3. Over the past 40 years two things have dominated the field- firstly, the techniques for measuring isotype specific antibodies to allergens have improved steadily. Secondly, several different allergic diseases or phenomena have been identified in which isotype diversity of the antibodies has become a major issue. Prior to 1990 only occasional cases of eosinophilic esophagitis (EoE) had been identified, but since then they have become common. Most of the cases have positive skin tests and/or IgE Ab to cow's milk or wheat, but it became obvious that most cases of EoE are not primarily related to IgE. Today it is clear that IgG4 Ab to these allergens play a significant role in cases of EoE. In 2000 the first reports of children developing tolerance to cat allergen appeared. Today it is clear that this tolerance depends on high levels of IgG4 antibodies and there is increasing evidence that the IgG4 response is primarily against Fel d 1. The most recent novel allergic disease is the alpha-gal syndrome (AGS). This condition is based on IgE antibodies specific for the oligosaccharide galactose alpha,1-3-galactose, which are primarily induced by tick bites. However, in this case it was already well known that all immunocompetent primates have made IgG and IgM antibodies to this oligosaccharide. Furthermore, it is not clear whether the IgG isotypes, particularly IgG1 and IgG3, play a role in the inflammatory response to the oligosaccharide. Overall, it is clear that current and future investigation of allergic diseases requires careful assessment of allergen specific antibodies of diverse isotypes in addition to IgE.

High risk of asthma among early teens is associated with quantitative differences in mite and cat allergen specific IgE and IgG4: a modified Th2 related antibody response revisited

BACKGROUND

Although proteins derived from cats are an important contributor to indoor allergen exposure in relation to asthma, it has been known for at least twenty years that some children who live in a house with a cat can become clinically tolerant to these animals. In 2001, we reported that children exposed to high levels of cat allergens made high levels of IgG4 antibodies to the cat allergen Fel d 1, and we coined the term "a modified Th2 response". However, this phenomenon is still poorly understood.

METHODS

We studied serum antibodies among 616 individuals in the Viva unselected birth cohort recruited at their early teen visit (mean age 13.1 SD 0.8). IgE and IgG4 antibodies were measured by ImmunoCAP to inhaled allergens as well as the best characterised component allergens of cat, Fel d 1, Fel d 2, Fel d 4, and Fel d 7, and the dust mite allergens Der p 1, Der p 2, Der p 10, and Der p 23.

FINDINGS

The results confirm that young teens living in a home with a cat make high levels of IgG4 specific for cat allergens, and that those antibodies, and specifically those to Fel d 1 are negatively associated with asthma. By contrast, the IgG4 responses to Fel d 4 and Fel d 7 are significantly lower and have no significant association with asthma. Perhaps more surprisingly, a similar effect is seen in relation to dust-mite allergens. Although the allergen Der p 1 is a major part of the IgE response to mite allergens, this protein also induced high prevalence and levels of IgG4 antibodies and has a less strong relationship to asthma than IgE to Der p 2 or Der p 23. Indeed, values of specific IgE to Der p 1 >3.5 IU/mL were not significantly related to asthma (OR 1.5 CI 0.8-2.8, p = 0.3, Chi2 test). The prevalence and levels of specific IgG4 to these less abundant allergens are significantly lower for Der p 2 and almost absent for Der p 23.

INTERPRETATION

High exposure to specific allergens in household dust can enhance production of both sIgE and sIgG4 antibodies, while allergens where abundance is significantly lower in dust can induce sIgE with limited or no sIgG4. The result is that the less abundant allergens, i.e., Fel d 4, Fel d 7, Der p 2, and Der p 23, may have a significantly higher relevance to asthma than expected because they induce less sIgG4.

FUNDING

This work was funded by R01-AI20565 (TPM) and support for the IgE and IgG4 assays provided by Phadia/Thermo Fisher Kalamazoo, Michigan. Project Viva is also supported by NIH R01HD034568 and R24ES.

Zinc Deficiency and Zinc Supplementation in Allergic Diseases

In recent decades, it has become clear that allergic diseases are on the rise in both Western and developing countries. The exact reason for the increase in prevalence has not been conclusively clarified yet. Multidimensional approaches are suspected in which diet and nutrition seem to play a particularly important role. Allergic diseases are characterized by a hyper-reactive immune system to usually harmless allergens, leading to chronic inflammatory diseases comprising respiratory diseases like asthma and allergic rhinitis (AR), allergic skin diseases like atopic dermatitis (AD), and food allergies. There is evidence that diet can have a positive or negative influence on both the development and severity of allergic diseases. In particular, the intake of the essential trace element zinc plays a very important role in modulating the immune response, which was first demonstrated around 60 years ago. The most prevalent type I allergies are mainly based on altered immunoglobulin (Ig)E and T helper (Th)2 cytokine production, leading to type 2 inflammation. This immune status can also be observed during zinc deficiency and can be positively influenced by zinc supplementation. The underlying immunological mechanisms are very complex and multidimensional. Since zinc supplements vary in dose and bioavailability, and clinical trials often differ in design and structure, different results can be observed. Therefore, different results are not surprising. However, the current literature suggests a link between zinc deficiency and the development of allergies, and shows positive effects of zinc supplementation on modulating the immune system and reducing allergic symptoms, which are discussed in more detail in this review.

Treatment of Allergies to Fur Animals

Allergy to fur animals is becoming an increasingly common clinical problem in everyday medical practice. Depending on the route of exposure to the allergen, patients present with many, often non-specific symptoms. The most common illnesses among people with allergies to the above-mentioned allergens are as follows: allergic rhinitis, allergic conjunctivitis, atopic bronchial asthma, food allergy, allergic contact dermatitis, and sometimes anaphylactic shock. In recent years, there has been a change in the holistic approach to the treatment of allergy patients. The method of treatment should be tailored to a specific patient, taking into account his or her predispositions, economic possibilities, and therapeutic goals. The article describes the main methods of treating allergies, focusing primarily on allergies to fur animals. Allergy treatment always requires great care, and qualification for specific types of therapy should be preceded by a thorough and accurate diagnosis.

Allergen skin test responses in broad U.S. asthma population in those with and without rhinitis

Background: Asthma and allergic rhinitis are pathologically interlinked conditions. Despite skin testing (ST) being pivotal for evaluating allergic sensitization, U.S. data that date back to 1960s on ST reactivity patterns in subjects with asthma remain sparse. Objective: The purpose of this study was to elucidate seasonal, perennial ST responses, and their relationship with asthma severity, early versus late onset disease, and immunoglobulin E (IgE) levels. Methods: Five hundred patients with asthma were randomly selected from the National Jewish Health electronic medical record over a 3-year span. Demographic, clinical, and allergen ST reactivity data for a battery of seasonal and perennial allergens were procured, including total IgE levels, asthma onset, and severity, by using t-tests, χ² tests, and Analysis of Variance (ANOVA), patterns of reactivity were assessed for overall, seasonal, and perennial allergens in relation to IgE levels, asthma onset, and severity. Results: Of the 500 patients, 398 were analyzed. 63.3% were women, 50.1% had adult-onset asthma, and 86.1% had rhinitis; 75.3% tested positive to one or more allergens, with men demonstrating higher overall (p = 0.039) and perennial (p = 0.035) sensitization. ST reactivity varied based on the presence of rhinitis for seasonal (p = 0.028) but not perennial (p = 0.733) allergens. Asthma severity was not significantly associated with ST reactivity (p > 0.10). ST positivity for perennial (p < 0.001) but not seasonal (p = 0.128) allergens was higher in childhood-onset asthma versus adult-onset asthma despite both groups having a large percentage of reactors. Elevated IgE levels correlated with ST reactivity (p < 0.01). Conclusion: Our study represents a unique comprehensive evaluation of ST reactivity in a U.S. asthma population, which is lacking in the literature, when factoring in asthma onset, severity, and IgE levels. Our findings underscore the importance of allergen sensitization in asthma, regardless of severity, concurrent rhinitis symptoms, or asthma onset, which challenge some of the prevailing assumptions about the relationship between allergen sensitization and asthma onset.

Sociodemographic inequities in food allergy: Insights on food allergy from birth cohorts

A large and growing corpus of epidemiologic studies suggests that the population-level burden of pediatric FA is not equitably distributed across major sociodemographic groups, including race, ethnicity, household income, parental educational attainment, and sex. As is the case for more extensively studied allergic disease states such as asthma and atopic dermatitis epidemiologic data suggest that FA may be more prevalent among certain populations experiencing lower socioeconomic status (SES), particularly those with specific racial and ethnic minority backgrounds living in highly urbanized regions. Emerging data also indicate that these patients may also experience more severe FA-related physical health, psychosocial, and economic outcomes relating to chronic disease management. However, many studies that have identified sociodemographic inequities in FA burden are limited by cross-sectional designs that are subject to numerous biases. Compared with cross-sectional study designs or cohorts established later in life, birth cohorts offer advantages relative to other study designs when investigators seek to understand causal relationships between exposures occurring during the prenatal or postnatal period and the atopic disease status of individuals later in life. Numerous birth cohorts have been established across recent decades, which include evaluation of food allergy-related outcomes, and a subset of these also have measured sociodemographic variables that, together, have the potential to shed light on the existence and possible etiology of sociodemographic inequities in food allergy. This manuscript reports the findings of a comprehensive survey of the current state of this birth cohort literature and draws insights into what is currently known, and what further information can potentially be gleaned from thoughtful examination and further follow-up of ongoing birth cohorts across the globe.

The pharmacotherapeutic management of allergic rhinitis in people with asthma

INTRODUCTION

Up to 90% of asthmatic patients have comorbid allergic rhinitis (AR). Although appropriate therapy of AR can improve asthma symptoms and management, AR is often underdiagnosed and under-treated in asthmatics.A non-systematic literature research was conducted on AR as a comorbidity and risk factor of asthma. Latest international publications in medical databases, international guidelines, and the Internet were reviewed.

AREAS COVERED

Based on the conducted literature research there is proved evidence of the necessity of diagnosis and treatment of AR in patients with asthma because it affects health care utilization. Therefore, it is recommended in national and global guidelines.

EXPERT OPINION

AR increases the risk of asthma development and contributes to the severity of an existing asthma. Early treatment of AR with drugs as intranasal steroids, antihistamines, leukotriene receptor antagonists, and especially allergen-specific immunotherapy can reduce the risk of asthma development and the concomitant medication use in addition to severity of symptoms in AR and asthma.

Retrospective Analysis of Allergen Distribution Dynamics in Central Taiwan

Introduction: Allergy is a type Ⅰ hypersensitivity reaction to certain substances (allergens) such as environmental factors, food and drugs. Allergies are a significant public health issue, and therefore, understanding the distribution patterns of allergens in specific regions is important. This study aimed to retrospectively analyse allergen distribution patterns in Central Taiwan over a 5 years period (2018-2022). Methods: Data of patients who had allergen sensitization testing using the OPTIGEN® Allergen-Specific IgE Assay from the 1st of January 2018 to the 31st of December 2022 were reviewed retrospectively. Statistical analyses were performed to determine the prevalence and distribution of allergens in our study population. Results: A total of 8,444 patients (3,784 males and 4,660 females) who attended the Asia University Hospital for allergen detection were enrolled in this study. Dermatophagoides farina (41.8%), Dermatophagoides pteronyssinus (37.9%), house dust (24.6%), cockroach mix (17.7%), crab (12.6%), clam (9.8%), shrimp (9.1%), cat dander (8.1%), pig weed (8%) and peanut (7.8%) were identified as the ten allergens that most commonly induced sensitization in our study population. Additionally, crab, clam, shrimp, peanut and beef were the five most common food allergens. Conclusion: In summary, our findings contribute significantly to the knowledge on allergen distribution in Central Taiwan. Our identification of prevalent allergens may contribute to an improved understanding of the epidemiology of allergies in this region.

Allergic bronchopulmonary aspergillosis with atopic, nonatopic, and sans asthma-Factor analysis

BACKGROUND

Allergic bronchopulmonary aspergillosis (ABPA) develops in the presence or absence of asthma, either atopic or nonatopic. We have tried to explore the essential components in the pathogenesis of the disease, which are either consistent and variable according to the presence and type of asthma.

METHODS

Non-cystic fibrosis ABPA cases satisfying Asano's criteria were extracted from a prospective registry of ABPA and related diseases in Japan between 2013 and 2023. According to the type of preceding asthma, ABPA was classified into three groups: ABPA sans asthma (no preceding asthma), ABPA with atopic asthma, and ABPA with nonatopic asthma. Exploratory and confirmatory factor analyses were performed to identify the components that determined the clinical characteristics of ABPA.

RESULTS

Among 106 cases of ABPA, 25 patients (24%) had ABPA sans asthma, whereas 57 (54%) and 24 (23%) had ABPA with atopic and nonatopic asthma, respectively. Factor analysis identified three components: allergic, eosinophilic, and fungal. Patients with atopic asthma showed the highest scores for the allergic component (p < .001), defined by total and allergen-specific IgE titers and lung opacities, and the lowest scores for the fungal component defined by the presence of specific precipitin/IgG or positive culture for A. fumigatus. Eosinophilic components, including peripheral blood eosinophil counts and presence of mucus plugs/high attenuation mucus in the bronchi, were consistent among the three groups.

CONCLUSION

The eosinophilic component of ABPA is considered as the cardinal feature of ABPA regardless of the presence of preceding asthma or atopic predisposition.

EAACI Molecular Allergology User's Guide 2.0

Since the discovery of immunoglobulin E (IgE) as a mediator of allergic diseases in 1967, our knowledge about the immunological mechanisms of IgE-mediated allergies has remarkably increased. In addition to understanding the immune response and clinical symptoms, allergy diagnosis and management depend strongly on the precise identification of the elicitors of the IgE-mediated allergic reaction. In the past four decades, innovations in bioscience and technology have facilitated the identification and production of well-defined, highly pure molecules for component-resolved diagnosis (CRD), allowing a personalized diagnosis and management of the allergic disease for individual patients. The first edition of the "EAACI Molecular Allergology User's Guide" (MAUG) in 2016 rapidly became a key reference for clinicians, scientists, and interested readers with a background in allergology, immunology, biology, and medicine. Nevertheless, the field of molecular allergology is moving fast, and after 6 years, a new EAACI Taskforce was established to provide an updated document. The Molecular Allergology User's Guide 2.0 summarizes state-of-the-art information on allergen molecules, their clinical relevance, and their application in diagnostic algorithms for clinical practice. It is designed for both, clinicians and scientists, guiding health care professionals through the overwhelming list of different allergen molecules available for testing. Further, it provides diagnostic algorithms on the clinical relevance of allergenic molecules and gives an overview of their biology, the basic mechanisms of test formats, and the application of tests to measure allergen exposure.

Environmental influences on childhood asthma: Allergens

Allergen exposure is associated with the development of allergen-specific sensitization, but their relationship is influenced by other contemporaneous exposures (such as microbial exposure) and the genetic predisposition of the host. Clinical outcomes of the primary prevention studies that tested the effectiveness of allergen avoidance in pregnancy and early life on the subsequent development of sensitization and asthma published to date are inconsistent. Therefore, we cannot provide any evidence-based advice on the use of allergen avoidance for the primary prevention of these conditions. The evidence about the impact of allergen exposure among and among sensitized children with asthma is more consistent, and the combination of sensitization and high exposure to sensitizing allergen increases airway inflammation, triggers symptoms, adversely impacts upon disease control, and is associated with poorer lung function in preschool age. However, there are differing opinions about the role of inhalant allergen avoidance in asthma management, and recommendations differ in different guidelines. Evidence from more recent high-quality trials suggests that mite allergen-impermeable bed encasings reduce hospital attendance with asthma attacks and that multifaceted targeted environmental control improves asthma control in children. We therefore suggest a pragmatic approach to allergen avoidance in the management of childhood asthma for clinical practice, including the recommendations to: (1) tailor the intervention to the patient's sensitization and exposure status by using titer of allergen-specific IgE antibodies and/or the size of the skin test as indicators of potential response; (2) use a multifaceted allergen control regime to reduce exposure as much as possible; and (3) start intervention as early as possible upon diagnosis.

A singleplex IgE test to a mixture of molecules from multiple airborne allergen sources: Innovating in vitro screening of respiratory allergies

BACKGROUND

In vitro immunoglobulin E (IgE) tests can be better standardized if based on molecules rather than extracts. However, singleplex screening tests for respiratory or food allergies are still based on extracts only.

TARGET

To validate a novel singleplex IgE screening test for respiratory allergies, based on a mix of major allergenic molecules Der p 1, Der p 2, Fel d 1, Can f 1, Can f 2, Can f 3, Can f 5, Bet v 1, Phl p 1, and Art v 1 (Molecular SX01, NOVEOS, HYCOR, USA), and requiring only four microliters (μl) of serum.

METHODS

We examined six subsets of sera from participants of the German Multicenter Allergy Study (MAS) birth cohort enrolling 1314 newborns during 1990: (1) monosensitized (n = 58); (2) polysensitized (n = 24); (3) nonsensitized, with total IgE levels above (n = 24) or (4) below (n = 24) 300 kU/L; (5) sensitized to milk and/or egg but not to airborne allergens (n = 24); and (6) sera of children aged ≤5 years at their earliest IgE monosensitization to airborne allergens (n = 41). Sera were analyzed with the novel molecular SX01 test (NOVEOS) and with three categories of comparators: ImmunoCAP Phadiatop SX01, extracts, and molecules of D. pteronyssinus, cat, dog, grass, and birch. Sensitivity, specificity, positive and negative predictive values were calculated. Quantitative interrelationships were determined using Spearman's rank-order correlation coefficient and Bland-Altmann plots.

RESULTS

The molecular SX01 test predicted the outcome of IgE tests based on molecules, extracts, or Phadiatop in 188 (96.4%), 171 (87.7%), and 171 (87.7%) of the 195 sera, respectively. Accordingly, sensitivity was 93.5%, 89.0%, and 82.4%, whereas specificity was 100%, 97.6%, and 96.1% when compared with molecular, extract, and Phadiatop tests, respectively. Inconsistent outcomes were largely confined to sera with IgE-Ab levels around the cutoff value of 0.35 kU/L, except for 5/195 (2.5%) sera, containing high levels of IgE to Phl p 5 and/or Alt a 1 only. IgE levels measured by the molecular SX01 test and with IgE tests to molecules, extracts, and Phadiatop were highly correlated (rho 0.90; p < .001), (rho 0.87, p < .001), (rho 0.84, p < .001), respectively. The novel molecular SX01 test detected IgE-Ab in 27/28 (sensitivity 96.4%) of the sera of preschool children at their earliest IgE sensitization to the same molecules.

DISCUSSION

Our study validates the prototype of a novel category of IgE test, based on molecular mixes. The test's rather good precision and accuracy in early screening IgE sensitization to airborne allergens in German children may be further improved by adding a few other molecules, such as Phl p 5 and Alt a 1.

Der p 23-specific IgE response throughout childhood and its association with allergic disease: A birth cohort study

BACKGROUND

The Dermatophagoides pteronyssinus molecule Der p 23 is a major allergen whose clinical relevance has been shown in cross-sectional studies. We longitudinally analysed the trajectory of Der p 23-specific IgE antibody (sIgE) levels throughout childhood and youth, their early-life determinants and their clinical relevance for allergic rhinitis and asthma.

METHODS

We obtained sera and clinical data of 191 participants of the German Multicentre Allergy Study, a prospective birth cohort. Serum samples from birth to 20 years of age with sIgE reactivity to Der p 23 in a customised semiquantitative microarray were newly analysed with a singleplex quantitative assay. Early mite exposure was assessed by measuring the average content of Der p 1 in house dust at 6 and 18 months.

RESULTS

Der p 23-sIgE levels were detected at least once in 97/191 participants (51%). Prevalence of Der p 23 sensitisation and mean sIgE levels increased until age 10 years, plateaued until age 13 years and were lowest at age 20 years. Asthma, allergic rhinitis (AR) and atopic dermatitis (AD) were more prevalent in Der p 23-sensitised children, including those with monomolecular but persistent sensitisation (11/97, 11%). A higher exposure to mites in infancy and occurrence of AD before 5 years of age preceded the onset of Der p 23 sensitisation, which in turn preceded a higher incidence of asthma.

CONCLUSIONS

Der p 23 sensitisation peaks in late childhood and then decreases. It is preceded by early mite exposure and AD. Asthma and AR can occur in patients persistently sensitised to Der p 23 as the only mite allergen, suggesting the inclusion of molecular testing of Der p 23-sIgE for subjects with clinical suspicion of HDM allergy but without sIgE to other major D.pt. allergens.

Filaggrin loss-of-function mutations are associated with persistence of egg and milk allergy

BACKGROUND

A genetic defect in the epidermal barrier protein filaggrin plays a major role in the etiology of eczema and associated allergic airways diseases. However, it is still controversial to what extend loss-of-function (LOF) mutations in the filaggrin gene (FLG) contribute to the development and persistence of food allergies.

OBJECTIVE

We tested association of FLG LOF mutations with allergic reactions to diverse foods and investigated their potential effect on the persistence of early food allergies.

METHODS

We recruited 890 children with challenge-proven food allergy for the German Genetics of Food Allergy Study (GOFA). Longitudinal data were available for 684 children. All children were clinically characterized, including their allergic responses to specific foods, and genotyped for the four most common LOF mutations in FLG; R501X, 2282del4, R2447X, and S3247X. Associations between FLG mutations and food allergies were analyzed by logistic regression using the German Multicenter Allergy Study cohort as control population.

RESULTS

FLG mutations were associated with allergies to diverse foods including hen's egg (HE), cow's milk (CM), peanut, hazelnut, fish, soy, cashew, walnut, and sesame with similar risk estimates. Effects remained significant after adjusting for the eczema status. Interestingly, FLG mutations increased the risk of a persistent course of HE and CM allergy.

CONCLUSION

Using the gold standard for food allergy diagnosis, we demonstrate that FLG LOF mutations confer a risk of any food allergy independent of eczema. They predispose to the persistence of HE and CM allergy and should be considered in the assessment of tolerance development.

Newborn DNA methylation and asthma acquisition across adolescence and early adulthood

BACKGROUND

Little is known about the association of newborn DNA methylation (DNAm) with asthma acquisition across adolescence and early adult life.

OBJECTIVE

We aim to identify epigenetic biomarkers in newborns for asthma acquisition during adolescence or young adulthood.

METHODS

The Isle of Wight Birth Cohort (IOWBC) (n = 1456) data at ages 10, 18 and 26 years were assessed. To screen cytosine-phosphate-guanine site (CpGs) potentially associated with asthma acquisition, at the genome scale, we examined differentially methylated regions (DMR) using dmrff R package and individual CpG sites using linear regression on such associations. For CpGs that passed screening, we examined their enrichment in biological pathways using their mapping genes and tested their associations with asthma acquisitions using logistic regressions. Findings in IOWBC were tested in an independent cohort, the Avon Longitudinal Study of Parents and Children (ALSPAC) cohort.

RESULTS

In total, 2636 unique CpGs passed screening, based on which we identified one biological pathway linked to asthma acquisition during adolescence in females (FDR adjusted p-value = .003 in IOWBC). Via logistic regressions, for females, four CpGs were shown to be associated with asthma acquisition during adolescence, and another four CpGs with asthma acquisition in young adulthood (FDR adjusted p-value < .05 in IOWBC) and these eight CpGs were replicated in ALSPAC (all p-values < .05). DNAm at all the identified CpGs was shown to be temporally consistent, and at six of the CpGs was associated with expressions of adjacent or mapping genes in females (all p-values < .05). For males, 622 CpGs were identified in IOWBC (FDR = 0.01), but these were not tested in ALSPAC due to small sample sizes.

CONCLUSION AND CLINICAL RELEVANCE

Eight CpGs on LHX5, IL22RA2, SOX11, CBX4, ACPT, CFAP46, MUC4, and ATP1B2 genes have the potential to serve as candidate epigenetic biomarkers in newborns for asthma acquisition in females during adolescence or young adulthood.

Early priming of asthma and respiratory allergies: Future aspects of prevention: A statement by the European Forum for Education and Research in Allergy and Airway Disease (EUFOREA) and the EAACI-Clemens von Pirquet Foundation

In order to summarize recent research on the prevention of allergies-particularly asthma-and stimulate new activities for future initiatives, a virtual workshop sponsored by the EAACI Clemens von Pirquet foundation and EUFOREA was held in October 2021. The determinants of the "allergic march" as well as the key messages from intervention studies were reviewed by an international faculty of experts. Several unmet needs were identified, and a number of priorities for future studies were proposed.

Asthma and technology in emerging African American adults (The ATHENA Project): Protocol for a trial using the Multiphase Optimization Strategy framework (Preprint)

Background

Asthma causes substantial morbidity and mortality in the United States, particularly among African American emerging adults (AAEAs; aged 18-30 years), but very few asthma programs have targeted this population. Interventions that provide education and address underlying motivation for managing asthma may be the most effective. However, intensive face-to-face interventions are often difficult to implement in this population.

Objective

The purpose of this study is to develop an effective mobile asthma management intervention to improve control among AAEAs.

Methods

We will assess the ability of multiple technologic components to assist and improve traditional asthma education. The first component is the Motivational Enhancement System for asthma management. It is a mobile 4-session intervention using supported self-regulation and motivational interviewing. Personalized content is based on each participant’s activity level, daily experiences, and goals. The second component is supportive accountability. It is administered by asthma nurses using targeted mobile support (Skype/voice calls) to provide education, promote self-efficacy, and overcome barriers through a motivational interviewing–based framework. The third component is SMS text messaging. It provides reminders for asthma education, medication adherence, and physical activity. The fourth component is physical activity tracking. It uses wearable technology to help meet user-defined physical activity goals. Using a multiphase optimization strategy (MOST) framework, we will test intervention components and combinations of components to identify the most effective mobile intervention. The MOST framework is an innovative, and cost- and time-effective framework that uses engineering principles to produce effective behavioral interventions. We will conduct a component selection experiment using a factorial research design to build an intervention that has been optimized for maximum efficacy, using a clinically significant improvement in asthma. Participants (N=180) will be randomized to 1 of 6 intervention arms. Participants will be recruited from multiple sites of the American Lung Association-Airway Clinical Research Centers network and ambulatory care clinics at the Detroit Medical Center. Data collections will occur at baseline, and 3, 6, and 12 months.

Results

At study completion, we will have an empirically supported optimized mobile asthma management intervention to improve asthma control for AAEAs. We hypothesize that postintervention (3, 6, and 12 months), participants with uncontrolled asthma will show a clinically significant improvement in asthma control. We also hypothesize that improvements in asthma management behaviors (including physical activity), quality of life, symptoms, adherence, and exacerbation (secondary outcomes) will be observed.

Conclusions

AAEAs are disproportionately impacted by asthma, but have been underrepresented in research. Mobile asthma management interventions may help improve asthma control and allow people to live healthier lives. During this project, we will use an innovative strategy to develop an optimized mobile asthma management intervention using the most effective combination of nurse-delivered asthma education, a smartphone app, and text messaging.

International Registered Report Identifier (IRRID)

PRR1-10.2196/37946

Four subtypes of childhood allergic rhinitis identified by latent class analysis

BACKGROUND

Childhood allergic rhinitis (AR) is clinically heterogenous. We aimed to identify distinct phenotypes among children with AR using data-driven techniques and to ascertain their association with patterns of symptoms, allergic sensitization, and comorbidities.

METHODS

We recruited 510 children with physician-diagnosed AR, of whom 205 (40%) had asthma. Latent class analysis (LCA) was performed to identify latent structure within the data set using 17 variables (allergic conjunctivitis, eczema, asthma, family history of asthma, family history of allergic rhinitis, skin sensitization to 8 common allergens, tonsillectomy, adenoidectomy).

RESULTS

A four-class solution was selected as the optimal model based on statistical fit. We labeled latent classes as: (1) AR with grass mono-sensitization and conjunctivitis (n = 361, 70.8%); (2) AR with house dust mite sensitization and asthma (n = 75, 14.7%); (3) AR with pet and grass polysensitization and conjunctivitis (n = 35, 6.9%); and (4) AR among children with tonsils and adenoids removed (n = 39, 7.6%). Perennial AR was significantly more common among children in Class 2 (OR 5.83, 95% CI 3.42-9.94, p < .001) and Class 3 (OR 2.88, 95% CI 1.36-6.13, p = .006). Mild and intermittent AR symptoms were significantly more common in children in Class 2 compared to those in Class 1. AR was more severe in Class 1 compared to other 3 classes, indicating that upper respiratory symptoms are more severe among children with isolated seasonal rhinitis, than in those with rhinitis and coexisting asthma.

CONCLUSION

We have identified 4 phenotypes in school-age children with AR, which were associated with different patterns of clinical symptoms and comorbidities.

Effects of early-life exposure to dust mite allergen and endotoxin on the development of asthma and wheezing: The Japan Environment and Children's Study

BACKGROUND

The effects of early-life exposure to house dust mite allergen and endotoxin on the development of asthma are unclear in the literature. We investigated the association of early-life exposure (0-36 months old) to house dust mite allergen and endotoxin with asthma incidence.

METHODS

In this novel, large-scale, nationwide birth cohort study, 5017 participants were randomly selected from those who met the eligibility criteria. House dust was vacuum-sampled from the children's mattresses within homes and assayed for the presence of dust mite allergen (Der 1) and endotoxin. The participants were classified into four quartiles (Q1-Q4) according to exposure levels. We defined the incidence of asthma and wheezing using questionnaires at 12, 24, and 36 months old. Odds ratios (ORs) of the incidence of asthma and wheezing by age in Der 1 and endotoxin exposure level were estimated using logistic regression.

RESULTS

The cumulative incidence rates of asthma and wheezing during 0-36 months were 10.4% and 38.1%, respectively. Significant ORs were observed in asthma onset during 12-24 months old, asthma onset during 24-36 months old, and wheezing onset during 0-12 months old in the Q4 Der 1 group. In the Q4 endotoxin group, significant positive associations between endotoxin exposure and asthma (OR 2.00, 95% confidence interval [CI]: 1.03-3.85) and wheezing (OR 1.78, 95% CI: 1.01-3.12) onset during 24-36 months old were found.

CONCLUSIONS

Our results indicated that high levels of early-life exposure to Der 1 and endotoxin in mattresses may be involved in the development of asthma.

Revisiting Mild Asthma: Current Knowledge and Future Needs

Asthma is a common chronic airways disease with significant impact on patients, caregivers, and the health-care system. Although most research and novel interventions mainly have focused on patients with uncontrolled severe asthma, most patients with asthma have mild disease. Epidemiologic studies suggest that many patients with mild asthma report frequent exacerbations of the disease and uncontrolled symptoms. However, despite its impact, mild asthma does not have either a uniformly agreed on definition for or a consensus on its clinical and pathophysiologic progression. More recently, the approach to treatment of patients with mild asthma has undergone significant changes primarily based on emerging evidence that airway inflammation in this population is important. This led to clinical research studies that explored the efficacy of as-needed inhaled corticosteroids along with the rescue medications that traditionally have been the mainstay of treatment. Despite some advancement in the field in recent years, many controversies and unmet needs remain. In this review, we examine the current understanding of the pathophysiologic features and management of mild asthma. In addition, we outline unmet needs for future research. We conclude that mild asthma contributes significantly to the morbidity and mortality of asthma and should be the focus of future research.

Exposures in the Indoor Environment and Prevalence of Allergic Conditions in the United States of America

Our study examines the association of the presence of mildew, cockroaches, and pets in homes as well as household dust allergens with the prevalence and/or severity of allergic diseases. No study has concurrently assessed home environment exposures in relation to allergic conditions in the general US population. Data from 5409 participants from the 2005–2006 National Health and Nutrition Examination Survey (NHANES) living in their current homes for ≥one year were analyzed. Multivariate logistic regression analyses between home exposures and allergic diseases prevalence and severity were performed. In adjusted analyses, mildew was associated with higher current asthma, allergies, and allergic rhinitis prevalence; endotoxin, with higher current asthma prevalence; and dust Canis familiaris (Can f) 1, with higher allergic rhinitis prevalence. However, presence of cockroaches and dust Dermatophagoides farinae (Der f) 1 were associated, respectively, with lower current asthma and allergies prevalence. Presence of mildew, dust Der f1, Dermatophagoides pteronyssinus (Der p) 1, Felis domesticus (Fel d) 1, and endotoxin were all associated with asthma and/or wheeze severity. Non-atopic asthma was more frequent with mildew and/or musty smell dust and higher dust Fel d1 concentration, while atopic asthma was more prevalent with higher Can f1 and endotoxin concentrations in dust. This study confirms previous relationships and reports novel associations, generating hypotheses for future research.

Cord blood soluble Fas ligand linked to allergic rhinitis and lung function in seven-year-old children

BACKGROUND

Serum or cord blood soluble Fas ligand (FasL) has been related to asthma, allergic rhinitis, and atopic dermatitis in cross-sectional and short-term follow-up studies. However, the association of cord blood soluble FasL with long-term allergic outcomes has seldom been investigated.

METHODS

The Prediction of Allergies in Taiwanese Children birth cohort study recruited healthy newborns upon delivery. At birth, blood was collected from the umbilical cords of these children, and the cord blood soluble Fas ligand levels were measured. At the age of seven years, the allergic outcome of each child was diagnosed by pediatric allergists and pulmonologists. Tests were conducted to measure the specific immunoglobulin E, fractional exhaled nitric oxide (FeNO), and pulmonary function levels of each child.

RESULTS

Cord blood soluble FasL levels were higher in seven-year-old children with allergic rhinitis (Odds ratio [OR] = 2.41, p = 0.012) and expiratory airway obstruction (the highest forced expiratory volume in 1 second/forced vital capacity < 90%, OR = 2.11, p = 0.022). The FeNO and Dermatophagoides pteronyssinus-specific immunoglobulin E levels of seven-year-old children were positively correlated with cord blood soluble FasL levels (p = 0.006 and 0.02, respectively).

CONCLUSION

In this birth cohort, the cord blood soluble FasL levels were associated with allergic rhinitis, obstructive-type lung function, FeNO, and house dust mite sensitization in 7-year-old children. The cord blood soluble FasL level might be used as a predictor for allergic diseases in children who are 7 years old.

Chitinase-Induced Airway Hyperreactivity and Inflammation in a Mouse Model of Nonallergic Asthma

INTRODUCTION

Environmental exposure to mites and fungi has been proposed to critically contribute to the development of IgE-mediated asthma. A common denominator of such organisms is chitin. Human chitinases have been reported to be upregulated by interleukin-13 secreted in the context of Th2-type immune responses and to induce asthma. We assessed whether chitin-containing components induced chitinases in an innate immune-dependent way and whether this results in bronchial hyperresponsiveness.

MATERIALS AND METHODS

Monocyte/macrophage cell lines were stimulated with chitin-containing or bacterial components in vitro. Chitinase activity in the supernatant and the expression of the chitotriosidase gene were measured by enzyme assay and quantitative PCR, respectively. Non-sensitized mice were stimulated with chitin-containing components intranasally, and a chitinase inhibitor was administered intraperitoneally. As markers for inflammation leukocytes were counted in the bronchoalveolar lavage (BAL) fluid, and airway hyperresponsiveness was assessed via methacholine challenge.

RESULTS

We found both whole chitin-containing dust mites as well as the fungal cell wall component zymosan A but not endotoxin-induced chitinase activity and chitotriosidase gene expression in vitro. The intranasal application of zymosan A into mice led to the induction of chitinase activity in the BAL fluid and to bronchial hyperresponsiveness, which could be reduced by applying the chitinase inhibitor allosamidin.

DISCUSSION

We propose that environmental exposure to mites and fungi leads to the induction of chitinase, which in turn favors the development of bronchial hyperreactivity in an IgE-independent manner.

A systematic review of asthma case definitions in 67 birth cohort studies

BACKGROUND

Birth cohort studies are a valuable source of information about potential risk factors for childhood asthma. To better understand similarities and variations in findings between birth cohort studies, the methodologies used to measure asthma require consideration.

OBJECTIVE

To review and appraise the definitions of "asthma" used in birth cohort studies.

METHODS

A literature search, conducted in December 2017 in the MEDLINE database and birth cohort repositories, identified 1721 citations published since 1990. Information extracted included: study name, year of publication, sample size, sample age, prevalence of asthma (%), study region, source of information about asthma, measured outcome, and asthma case definition. A meta-analysis evaluated whether asthma prevalence in cohorts from Europe and North America varied by the studies' definition of asthma and by their data sources.

RESULTS

The final review included 67 birth cohorts, of which 48 (72%) were from Europe, 14 (21%) from North America, 3 (5%) from Oceania, 1 (1%) from Asia and 1 (1%) from South America. We identified three measured outcomes: "asthma ever", "current asthma", and "asthma" without further specification. Definitions of "asthma ever" were primarily based upon an affirmative parental response to the question whether the child had ever been diagnosed with asthma by a physician. The most frequently used definition of "current asthma" was "asthma ever" and either asthma symptoms or asthma medications in the last 12 months. This definition of "current asthma" was used in 16 cohorts. There was no statistically significant difference in the pooled asthma prevalence in European and North American cohorts that used questionnaire alone versus other data sources to classify asthma.

CONCLUSION

There is substantial heterogeneity in childhood asthma definitions in birth cohort studies. Standardisation of asthma case definitions will improve the comparability and utility of future cohort studies and enable meta-analyses.

Skin prick reactivity among asthmatics in East Africa

Background

The burden of asthma in Africa is high, and yet the disease is not universally prioritised. Data on allergic asthma and its impact on asthma morbidity are limited in Africa. Our aim was to describe the distribution of skin prick positivity among asthmatics in Eastern Africa.

Methods

From August 2016 to May 2018, 1671 asthmatic patients were enrolled from Uganda, Kenya, and Ethiopia as part of the African Severe Asthma Program clinical study. Skin prick testing was performed at baseline using a panel of 12 allergens, and factors associated with skin prick reactivity determined.

Results

Of the 1, 671 patients recruited, 71% were female with a median age of 40 years, 93.6% were aged >15 years and the patterns of asthma symptom frequency was intermittent in 2.9%, mild persistent in 19.9%, moderate persistent in 42.6% and severe persistent in 34.6% at baseline. Self-reported triggers, were dust (92%), cold weather (89%), upper respiratory infections (84%), strong smells (79%) and exposure to tobacco (78%). The majority (90%) of the participants had at least 1 positive allergen reaction, with 0.9% participants reacting to all the 12 allergens. Participants commonly reacted to house dust mites (66%), Blomia tropicalis (62%), and the German cockroach (52%). Patients sensitized to more allergens (>2) had significantly reduced lung function (FEV ≤ 80%; p = 0.001) and were more likely to visit the emergency department due to asthma (p = 0.012). There was no significant relationship between number of allergens and measures of asthma control, quality of life, and other clinical outcomes. Only the country of origin was independently associated with atopy among African asthmatics.

Conclusion

There is a high prevalence of skin prick positivity among East African patients with asthma, with the commonest allergen being house dust mite. Skin reactivity did not correlate well with asthma severity and poor asthma control. The relation between atopy, measured through skin prick testing, and measures of asthma control among asthma patients in Eastern Africa is unclear and needs further study.

Trial registration

The ASAP study was registered prospectively. ClinicalTrials.gov Identifier: NCT03065920; Registration date: February 28, 2017; Last verified: February 28, 2017.

Effect of Exposure to Cats and Dogs on the Risk of Asthma and Allergic Rhinitis: A Systematic Review and Meta-analysis

BACKGROUND

Controversies persist regarding whether exposure to cat or dog increases the risk of asthma and allergic rhinitis.

OBJECTIVE

This meta-analysis aimed to assess the associations between exposure to cats or dogs and the development of asthma and allergic rhinitis.

METHODS

A systematic review was performed to identify case-control and cohort studies before May 2019, evaluating the association between exposure to cats and dogs and the risk of asthma and rhinitis. The risk of bias was assessed using the Newcastle-Ottawa Scale. The odds ratios (ORs) and risk ratios (RRs) were pooled for case-control and cohort studies, respectively. Subgroup analyses were performed on prespecified study-level characteristics.

RESULTS

The meta-analysis of 34 cohort studies showed a protective role of exposure to cats [RR: 0.88, 95% confidence interval (CI): 0.77-0.99] or dogs (RR: 0.85, 95% CI: 0.73-0.97) in the development of asthma. The subgroup analysis of birth cohort (RR: 0.74, 95% CI: 0.56-0.93) and children population (RR: 0.83, 95% CI: 0.70-0.96) also suggested a favorable role of exposure to dogs in the development of asthma. Pooled evidence from 13 case-control studies indicated no significant impact of cats (OR: 1.66, 95% CI: 0.39-2.94) and dogs (OR: 1.22, 95% CI: 0.92-1.52) on the development of asthma. A pooled analysis of five cohort studies showed a favorable effect of exposure to cats (RR: 0.60, 95% CI: 0.33-0.86) or dogs (RR: 0.68, 95% CI 0.44-0.90) on the development of allergic rhinitis.

CONCLUSION

The findings indicated a protective effect of exposure to cats and dogs, especially ownership, on the development of asthma and allergic rhinitis.

Allergen Immunotherapy in Pediatric Asthma: A Pragmatic Point of View

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

Indoor Microbiome and The Rising Asthma Prevalence

The prevalence of asthma has increased in the past few decades in most developed and developing countries. Large-scale, cross-sectional epidemiological studies have reported several factors associated with asthma prevalence and severity, including parental asthma, tobacco smoking, preterm delivery, virus infection, and air pollution. However, a puzzling problem is that the time trends in the prevalence of these risk factors cannot explain the rise in asthma. For example, the prevalence of smoking and clinical pneumonia have been decreasing globally in the past few decades. Recent progress in high-throughput sequencing technology has promoted the progress of microbiome research and established associations between human and indoor microbiomes, and many metabolic, cognitive, and immune diseases including asthma and allergies. In this review, the authors systematically summarise the current literature, standard practice, and analysis pipeline in the field of indoor microbiome and asthma. The strength and limitation of different analytical approaches are discussed, including the utilisation of relative and absolute abundance in the associated studies. The authors discuss new frameworks of integrated microbiome research from different ecological niches, functional profiling from multiomics data, and how these new insights can facilitate understanding of asthma mechanisms and even the development of new personalised treatment strategies for the rising asthma epidemic.

Associations of dog and cat ownership with wheezing and asthma in children: Pilot study of the Japan Environment and children's study

Objectives

No previous study has used repeated measures data to examine the associations of dog/cat ownership with wheezing and asthma prevalence among children. This prospective study used repeated measurers analysis to determine whether dog/cat ownership in childhood is an independent risk factor for wheezing and asthma, after adjustment for gestational, socio-economical, and demographical confounders confounders, in Japan.

Methods

We conducted a multicenter pilot study of the Japan Environment and Children's Study (JECS) during 2009–2010. Among 440 newborn infants enrolled, 410 (52.8% males) were evaluated for dog/cat ownership in the home and history of wheezing and asthma in five follow-up questionnaire surveys (until age 6 years). Dog/cat ownership during follow-up period was categorized into four groups: 7.6% were long-term dog/cat owners, 5.9% were toddler-age owners, 5.9% were preschool-age owners, and 80.7% were never owners.

Results

The prevalence of wheezing during follow-up period increased from 20.8% to 35.4% and the prevalence of asthma increased from 1.3% to 16.3%. A fitted logistic generalized estimating equation models including important confounders showed no significant associations of the interaction between dog and/or cat ownership and follow-up time with the risks of wheezing and asthma. However, the risks of wheezing and asthma were slightly lower for long-term and toddler-age dog/cat owners than for preschool-age and never owners.

Conclusions

The present findings suggest that dog and cat ownership from toddler-age does not increase the risks of wheezing and asthma compared with never owners among Japanese children.

Risk factors for asthma in schoolchildren in Southern Brazil

BACKGROUND

Due to the high prevalence of recurrent wheezing in the pediatric population, it is important to be able to identify environmental risk factors that may affect the etiology of asthma in several regions.

OBJECTIVE

to identify possible risk factors associated with asthma in children (9-12 years old) in Passo Fundo, Rio Grande do Sul, Brazil.

MATERIAL AND METHODS

A total of 1003 school-age children were selected for the cross-sectional study by applying a standardized written questionnaire from the International Study of Asthma and Allergy, and a supplementary questionnaire (ISAAC phase II) was added to address personal, family and environmental factors. Of these, 125 children were excluded because they did not accept to do the skin prick test, resulting in a sample of 878.

RESULTS

Independent risk factors associated with asthma were bronchiolitis before two years old [OR]=3.11; 2.23-4.33, current rhinitis [0R]=2.07; 1.43-3.0; sharing bedroom during the first year of life [OR]=2.03; 1.36-3.04; atopy [OR]=1,82; 1.26-2.50; use of paracetamol more than 12 times a year [OR]=1.68; 1.20-2.31; use of antibiotics in the first six months of life [OR]=1,57 1;13-2.17; maternal asthma [OR]=1.75; 1.05-2.78, having an indoor cat during the first year of life [OR]=1.73, 1.07-2.78; premature birth [OR]=1.60,1.02-2.50.

CONCLUSION

our results show that genetic backgrounds, environmental factors, premature birth, use of antibiotics before six months of life, using paracetamol once per month and the presence of co-morbidities such as rhinitis are the risk factors associated with asthma in Brazilian children.

The Human Microbiota and Asthma

Over the last few decades, advances in our understanding of microbial ecology have allowed us to appreciate the important role of microbial communities in maintaining human health. While much of this research has focused on gut microbes, microbial communities in other body sites and from the environment are increasingly recognized in human disease. Here, we discuss recent advances in our understanding of host-microbiota interactions in the development and manifestation of asthma focusing on three distinct microbial compartments. First, environmental microbes originating from house dust, pets, and farm animals have been linked to asthma pathogenesis, which is often connected to their production of bioactive molecules such as lipopolysaccharide. Second, respiratory microbial communities, including newly appreciated populations of microbes in the lung have been associated with allergic airway inflammation. Current evidence suggests that the presence of particular microbes, especially Streptococcus, Haemophilus, and Morexella species within the airway may shape local immune responses and alter the severity and manifestations of airway inflammation. Third, the gut microbiota has been implicated in both experimental models and clinical studies in predisposing to asthma. There appears to be a "critical window" of colonization that occurs during early infancy in which gut microbial communities shape immune maturation and confer susceptibility to allergic airway inflammation. The mechanisms by which gut microbial communities influence lung immune responses and physiology, the "gut-lung axis," are still being defined but include the altered differentiation of immune cell populations important in asthma and the local production of metabolites that affect distal sites. Together, these findings suggest an intimate association of microbial communities with host immune development and the development of allergic airway inflammation. Improved understanding of these relationships raises the possibility of microbiota-directed therapies to improve or prevent asthma.

Early-life inhalant allergen exposure, filaggrin genotype, and the development of sensitization from infancy to adolescence

Background

We hypothesized that filaggrin (FLG) loss-of-function mutations modify the effect of allergen exposure on the development of allergic sensitization.

Objective

We sought to determine whether early-life exposure to inhalant allergens increases the risk of specific sensitization and whether FLG mutations modulate these odds.

Methods

In a population-based birth cohort we measured mite, cat, and dog allergen levels in dust samples collected from homes within the first year of life. Sensitization was assessed at 6 time points between infancy and age 16 years. Genotyping was performed for 6 FLG mutations.

Results

In the longitudinal multivariable model (age 1-16 years), we observed a significant interaction between FLG and Fel d 1 exposure on cat sensitization, with the effect of exposure being significantly greater among children with FLG mutations compared with those without (odds ratio, 1.36; 95% CI, 1.02-1.80; P = .035). The increase in risk of mite sensitization with increasing Der p 1 exposure was consistently greater among children with FLG mutations, but the interaction did not reach statistical significance. Different associations were observed for dogs: there was a significant interaction between FLG and dog ownership, but the risk of sensitization to any allergen was significantly lower among children with FLG mutations who were exposed to a dog in infancy (odds ratio, 0.16; 95% CI, 0.03-0.86; P = .03).

Conclusions

FLG loss-of-function mutations modify the relationship between allergen exposure and sensitization, but effects differ at different ages and between different allergens.

Asymptomatic toddlers with house dust mite sensitization at risk of asthma and abnormal lung functions at age 7 years

Objective

To evaluate the predictive value of asymptomatic early house dust mite sensitization on allergic outcomes and pulmonary functions in 7-year olds.

Study design

The Prediction of Allergies in Taiwanese Children (PATCH) birth cohort study recruited healthy newborns at birth. At age 1.5–2 years, a Dermatophagoides pteronyssinus-specific immunoglobulin E level ≥ 0.35 kU/L was defined as early sensitization. At age 7 years, allergic outcomes were evaluated by pediatric allergists and pulmonologists, and fractional exhaled nitric oxide and pulmonary functions were measured.

Results

At age 1.5–2 years, 28.0% of toddlers were sensitized to D. pteronyssinus. Among them, 68.2% had no allergic symptoms at that time. At age 7 years, the children with early sensitization had higher risks of asthma (OR = 13.4, 95% CI, 1.2 to 153.0; P = 0.037), allergic rhinitis (OR = 10.2, 95% CI, 2.1 to 49.6; P = 0.004), and atopic dermatitis (OR = 38.5, 95% CI, 2.1 to 696.4; P = 0.014). Notably, even the asymptomatic toddlers with early D. pteronyssinus sensitization had higher probabilities of asthma (12.5% vs. 1.7%, P = 0.040), allergic rhinitis (83.3% vs. 43.1%, P = 0.009), and atopic dermatitis (20.8% vs. 0.0%, P < 0.001) at age 7 years. The asymptomatic toddlers with early sensitization also had higher exhaled nitric oxide levels and higher prevalence of airway hyperresponsiveness at age 7 years.

Conclusion

Asymptomatic toddlers with early house dust mite sensitization have higher risks of developing asthma, allergic rhinitis, atopic dermatitis, and abnormal lung functions at age 7 years.

Dust-mite inducing asthma: what advice can be given to patients?

Introduction: Amongst allergic asthmatics, high allergen exposure increases asthma severity. However, there is no consensus on the role of mite allergen avoidance in the management of asthma, and various guidelines differ in their recommendations. Areas covered: Several systematic reviews/meta-analyses on mite avoidance in the management of asthma have been published, and their findings have been used for a call to provide a recommendation in British guidelines that dust-mite control measures should not be recommended. However, there are several problems with such analysis (such as combining studies in adults and children), and we question whether these are appropriate tools to evaluate available evidence about mite allergen avoidance, and whether it is correct to rely disproportionately on the results of meta-analyses/systematic reviews to inform clinical practice in this area. Recent evidence in children suggests that mite-impermeable bed encasings reduce emergency hospital attendance with severe asthma exacerbations. Expert opinion: The practical questions include how to achieve a sufficient real-life reduction allergen exposure, and how to identify patients who will benefit from effective intervention. The intervention should start early in the natural history of asthma, and consideration for choosing patients should include using the titre of allergen-specific IgE antibodies or the size of skin test wheal as an indicator.

Allergy Development in Adulthood: An Occupational Cohort Study of the Manufacturing of Industrial Enzymes

BACKGROUND

Occupational allergy may serve as a model of allergy development in adults.

OBJECTIVE

We aimed at describing respiratory allergy and IgE sensitization across different exposure strata defined by time, technology, and exposure control.

METHODS

In a retrospective (1970-2017) cohort of industrial enzyme production employees, monitored by an occupational medical center, 5024 individuals were surveyed. Five exposure groups and risk levels for sensitization and allergic disease were analyzed on the basis of demographic characteristics, hiring decade, and smoking status.

RESULTS

Of all persons entering the company 47 years from 1970, 149 developed occupational allergy (incidence rate, 2.72/1000 person-years). In a multivariate cause-specific Cox proportional hazards model, the hazard of allergy was significantly related to decade of recruitment. Compared with the 1970s, the hazard ratio (HR) uniformly decreased from 0.85 (95% CI, 0.57-1.27) in the 1980s to 0.16 (95% CI, 0.05-0.52) in the 2010s. Compared with expected highest exposed group, the HRs were 0.48 (95% CI, 0.31-76) and 0.13 (95% CI, 0.06-0.30) in less exposed production areas and 0.92 (95% CI, 0.48-1.73) and 0.23 (95% CI, 0.10-0.53) in different laboratory areas. The HR of smoking was 2.03 (95% CI, 1.41-2.93). The pattern of sensitizations also showed clear associations to recruitment decade, exposure, and smoking. Among individuals sensitized but not yet allergic, a high IgE level was the only risk factor (HR, 3.03; 95% CI, 1.82-5.04) for subsequent allergy development.

CONCLUSIONS

The impact of exposure is dose-related and linked to the sensitization step, which may subsequently lead to allergy development. For primary prevention of enzyme allergy, exposure control is mandatory and achievable despite increasing production volumes.

Identification of Der f 23 as a new major allergen of Dermatophagoides farinae

House dust mites (HDM) are common allergen sources worldwide. At present, 32 of the 37 internationally recognized HDM allergen groups have been identified in Dermatophagoides farinae. The present study study describes the identification of the first known D. farinae Group 23 allergen (Der f 23). Recombinant Der f 23 protein (rDer f 23) was cloned, expressed and purified. The open reading frame of rDer f 23 was 525 base pairs and encoded a 174-amino acid protein (GenBank accession no., KU166910.1). ELISAs indicated that 72/129 HDM allergic serum samples (55.8%) had specific immunoglobulin E (sIgE) binding activity to rDer f 23. Additionally, 3/10 patients with HDM allergies (30%) exhibited positive skin prick test reactions to rDer f 23. IgE western blot analysis data suggested that only 4/11 HDM allergic sera had a positive sIgE binding result. Sequence homology analysis revealed an extra P2 region (Ser56-Thr117) in Der f 23 that was not present in the D. pteronyssinus homolog, which may affect sIgE binding. Der f 23ΔP2 demonstrated binding with HDM allergic sera, whereas the P2 peptide alone did not. The sIgE binding ability of Der f 23 ΔP2 (Der f 23 with a truncated P2 region) was more marked compared with that of Der f 23 in an IgE ELISA. These data indicate that P2 region in Der f 23 attenuates IgE binding ability. In conclusion, the results of the present study indicate that Der f 23 is a major HDM allergen with predominantly conformational sIgE binding epitopes. The allergenic identification of Der f 23 and its inclusion in World Health Organization/International Union of Immunological Societies database contributes to the theoretical basis underlying the diagnosis and treatment of HDM allergic diseases.

Quantitative filter forensics with residential HVAC filters to assess indoor concentrations

Analysis of the dust from heating, ventilation, and air conditioning (HVAC) filters is a promising long-term sampling method to characterize airborne particle-bound contaminants. This filter forensics (FF) approach provides valuable insights about differences between buildings, but does not allow for an estimation of indoor concentrations. In this investigation, FF is extended to quantitative filter forensics (QFF) by using measurements of the volume of air that passes through the filter and the filter efficiency, to assess the integrated average airborne concentrations of total fungal and bacterial DNA, 36 fungal species, endotoxins, phthalates, and organophosphate esters (OPEs) based on dust extracted from HVAC filters. Filters were collected from 59 homes located in central Texas, USA, after 1 month of deployment in each summer and winter. Results showed considerable differences in the concentrations of airborne particle-bound contaminants in studied homes. The airborne concentrations for most of the analytes are comparable with those reported in the literature. In this sample of homes, the HVAC characterization measurements varied much less between homes than the variation in the filter dust concentration of each analyte, suggesting that even in the absence of HVAC data, FF can provide insight about concentration differences for homes with similar HVAC systems.

Associations between sensitization to perennial/seasonal allergens and childhood asthma

Background: Childhood asthma is an important public health problem worldwide. Risk factors for asthma development include allergic sensitization and exposure to animals. Objective: To identify which (perennial or seasonal) inhalant allergens are associated with asthma and allergic rhinitis in children. Methods: This was a cross-sectional, retrospective study. We evaluated data from medical documentation of 6,000 children (aged 6 – 18 years) with diagnosed asthma and/or allergic rhinitis who had attended our allergy outpatient clinic. Into the analyses we included those subjects who had specific IgE test done during diagnostic procedures to confirm allergen sensitization. Results: We included 5,076 children in the analysis. We showed that among seasonal allergens only sensitization to timothy or birch significantly changed the prevalence of allergic rhinitis and asthma diagnosis. Of the perennial allergens, house dust mite or cat were most closely related with both allergic rhinitis and asthma. Results of ROC curve analysis showed that in atopic children the specific IgE level of seasonal allergens did not significantly change the prevalence of asthma diagnosis. Sensitization to more than one perennial allergen significantly increased the prevalence of allergic rhinitis and asthma. Conclusion: We showed that sensitization to the seasonal allergens timothy and birch as well as to the perennial allergens house dust mite and cat, is associated with asthma and allergic rhinitis in children. Our study determined the role of multiple perennial indoor allergens in the developement of allergic diseases in children. The identification of the specific allergens makes them potential targets for intervention and prevention strategies.

Immunotherapy and Asthma in Children

Allergen immunotherapy (AIT) is still the only disease-modifying treatment strategy for IgE-mediated allergic diseases, with consolidated evidence both in adults and children. AIT is effective in determining clinical improvement of allergic rhinitis and asthma, such as reduced symptoms, medication use, and improvement of quality of life, with a long-lasting effect after cessation of treatment. Results from recent clinical studies have implemented the evidence of effectiveness and safety of allergen immunotherapy for the treatment of allergic asthma, so that the current asthma guidelines now recommend sublingual immunotherapy as an add-on therapy for asthma in adults and adolescents with house dust mite allergy, allergic rhinitis, and exacerbations despite low-to-moderate dose ICS, with forced expiratory volume in 1 second more than 70% predicted. AIT may also reduce the risk of progression from allergic rhinitis to asthma in children and prevent the onset of new sensitizations, thus representing a potentially preventive method of treatment. The aim of this review is to present an updated overview of the clinical indications of AIT, with particular reference to pediatric asthma, of the mechanisms of clinical and immunological tolerance to allergens, and of the potential biomarkers predicting clinical response.

Is Allergen Immunotherapy in Children Disease Modifying? A Review of the Evidence

PURPOSE OF REVIEW

Although evidence supports a beneficial effect of allergen immunotherapy on the symptoms of allergic respiratory disease and food allergy, it is not clear whether immunotherapy modifies the natural history of these conditions.

RECENT FINDINGS

In aeroallergen immunotherapy, studies suggest that prevention of asthma can be attained. Less evident is the ability of immunotherapy to prevent new allergen sensitizations and more studies are needed to test whether immunotherapy can continue suppressing airway symptoms after treatment discontinuation. In food allergen immunotherapy, there is evidence that unresponsiveness to a food challenge can be sustained in some treatment recipients, but little knowledge exists as to the dose and duration of treatment that can optimize this effect. Suggestive evidence exists that allergen immunotherapy can modify allergic disease in children, but definitive studies are lacking. More research in the field is required.

Induction of bystander tolerance and immune deviation after Fel d 1 peptide immunotherapy

BACKGROUND

Treatment of patients with cat allergy with peptides derived from Fel d 1 (the major cat allergen) ameliorated symptoms of cat allergy in phase 2 clinical trials.

OBJECTIVE

We sought to demonstrate that the tolerance induced by Fel d 1 peptide immunotherapy can be exploited to reduce allergic responses to a second allergen, ovalbumin (OVA), in mice sensitized dually to OVA and Fel d 1.

METHODS

Induction of tolerance to OVA was achieved through simultaneous exposure to both allergens after peptide treatment. Functional tolerance to each allergen was assessed in a model of allergic airways disease in which treated mice were protected from eosinophilia, goblet cell hyperplasia, and T_H2 cell infiltration.

RESULTS

Suppression of allergic responses to cat allergen challenge was associated with significant increases in numbers of CD4⁺CD25⁺Foxp3⁺ T cells, IL-10⁺ cells, and CD19⁺IL-10⁺ B cells, whereas the response to OVA was associated with a marked reduction in numbers of T_H2 cytokine-secreting T cells and less prominent changes in outcomes associated with immune regulation.

CONCLUSIONS

These observations suggest that immune tolerance induced by peptide immunotherapy can be used experimentally to treat an allergic response to another allergen and that the molecular mechanisms underlying induction of tolerance to a treatment-specific allergen and a bystander allergen might be different.

Preventing new sensitization and asthma onset by allergen immunotherapy: the current evidence

PURPOSE OF REVIEW

Specific allergen immunotherapy is considered a key candidate for a successful preventive intervention in atopic diseases. The strong association of atopic manifestations such as rhinitis and asthma with atopic sensitizations (specific serum IgE) provide a rationale for early intervention in childhood and adolescence.

RECENT FINDINGS

Currently, the documentation of the disease-modifying intervention effects is limited to the secondary prevention of asthma symptoms in children with allergic rhinoconjunctivitis. These effects appear to be rather allergen specific than nonspecific.

SUMMARY

Documentation on disease modification including a reduction of asthma symptoms in children, particularly with grass pollen tablets has become quite robust. It is not clear up to now, if the new onset of allergic sensitizations can be modified. So far data on primary prevention are not conclusive.

Maternal vegetable intake in early pregnancy and wheeze in offspring at the age of 2 years

BACKGROUND/OBJECTIVES

Vegetable intake during childhood may reduce the risk of subsequent asthma. We verified the effect of maternal intake during pregnancy on asthma risk in offspring, which has rarely been studied.

SUBJECTS/METHODS

In a hospital-based birth cohort study conducted in Tokyo, we administered a food frequency questionnaire at two periods during the respondents' pregnancy: early and mid to late periods. In addition, a questionnaire including the International Study of Asthma and Allergies in Childhood questionnaire was conducted when the offspring were 2 years old. Multivariate Poisson regression adjusting for maternal baseline demographics was used to elucidate the association between maternal vegetable intake and the incidence of wheeze in the offspring.

RESULTS

Among 310 singletons, 82 (26.5%) experienced wheeze at 2 years of age. Women with the highest intake of cruciferous, and folate-rich vegetables during early pregnancy reported a significantly lower prevalence of wheeze in their child at 2 years of age in comparison with those who reported the lowest intake (adjusted risk ratio: 0.48 and 0.47, 95% confidence interval: 0.26-0.89, and 0.25-0.87, respectively). In trend analysis, a higher maternal intake of cruciferous, folate-rich vegetables, and total vegetables during early pregnancy was less likely to be associated with wheeze in the offspring at 2 years old (p for trend: 0.038, <0.001, and 0.028, respectively). Maternal vegetable intake during mid to late pregnancy was not associated with wheeze in the offspring.

CONCLUSIONS

Maternal vegetable intake during early pregnancy may have a protective effect against asthma in offspring at 2 years of age.

Component-resolved microarray analysis of IgE sensitization profiles to Felis catus major allergen molecules in Russian cat-allergic patients

We aimed to determine the profile of IgE reactivity to three major cat allergens, Fel d 1, Fel d 2 and Fel d 4, in cat-allergic patients in the Moscow region in Russia. sIgE levels to recombinant proteins expressed in Escherichia coli (Fel d 1 and Fel d 4) and to Fel d 2 protein purified from cat serum were measured using a microarray method developed in our laboratory. Sera from 174 anonymous subjects with a positive reaction (≥0.35 IU/mL) to cat dander extract (e1, ImmunoCAP) and 56 negative controls were used for IgE testing. Fel d 1 was recognized by 92.5%, Fel d 2 by 29.9% and Fel d 4 by 39.1% of the tested patient sera. The sensitivity to these three proteins was approximately 98% compared to cat dander extract (correlation coefficient to ImmunoCAP is 0.94 with PPV = 0.99 and NPV = 0.95). These predictive values appeared to be even more statistically significant than the divergence between the ISAC IgE test and the extract-based singleplex ImmunoCAP. The combination of the three investigated proteins (Fel d 1, Fel d 2 and Fel d 4) is suitable for in vitro molecular (serological) diagnosis of cat allergy in this region as a complement to cat dander extract. Moreover, with this method, we found distinction between Fel d 2 and other Feline sIgEs formation.

Beta-2 receptor agonist exposure in the uterus associated with subsequent risk of childhood asthma

BACKGROUND

Although the beta-2 receptor agonist (B2RA) is occasionally prescribed in the prenatal period for women with preterm labor, few studies have referred to the long-term effects of intrauterine exposure to B2RA on fetus. We examined the association between intrauterine exposure to B2RA and asthma in the offspring.

METHODS

We obtained data from a hospital-based birth cohort study conducted in Tokyo, Japan. The outcomes of interest were three indicators, consisting of current wheeze, current asthma, and ever asthma at 5 years of age, based on the International Study of Asthma and Allergies in Childhood questionnaire. Logistic regression analysis was used to evaluate the association between intrauterine B2RA exposure and outcomes. To evaluate dose-dependent risk, we categorized children into three groups according to both the cumulative dose and duration (days) and conducted trend analysis.

RESULTS

Of 1158 children, 94 (8.1%) were exposed to B2RA in utero, and 191 (16.5%), 111 (9.6%), and 168 (14.5%) children experienced current wheeze, current asthma, and ever asthma, respectively. After adjusting for confounders, we found an increased risk of current asthma caused by B2RA exposure with an adjusted odds ratio of 2.04 (95% confidence interval: 1.02-4.05). Trend analysis showed that B2RA exposure in utero was associated with a dose-dependent increased risk of current asthma in terms of both cumulative dose and duration (P values for trend were .015 and .017, respectively). These results were similar to those for other outcome measures.

CONCLUSION

Exposure to B2RA in utero could be a risk for childhood asthma.