Mouse allergen. I. The prevalence of mouse allergen in inner-city homes. The National Cooperative Inner-City Asthma Study

Residual profiles and health risk of indoor allergens in China

Exposure to indoor allergens is a principal risk factor for allergic diseases. However, most of the previous studies on indoor allergens focused on very limited kinds of allergens in China. Knowledge of the simultaneous exposure to multiple allergens is still lacking. In this study, the residual profiles of 8 allergens were investigated in 166 dust samples from 11 cities in China. The house dust mite allergens including Der p 1, Der f 1, and Der 2 were detected in the range of <0.02-283.83 μg/g dust. The concentrations of dog allergen Can f 1 and cat allergen Fel d 1 varied widely, from <0.84-22,896.46 μg/g dust for Can f 1 and from <0.02-6298.96 μg/g dust for Fel d 1. Cockroach allergen Bla g 2 was detected in 68% of the samples but at a low level with a maximum of 9.44 μg/g dust. Comparatively low detection frequencies were found for mouse allergen Mus m 1 as 37% and for fungi allergen Asp f 2 as 24%. The frequency of cleaning sheets/bedding was negatively correlated to the levels of house dust mite allergens. The presence of pets indoors was associated with higher levels of pet allergens and lower levels of house dust mite allergens and cockroach allergen. Risk evaluation reveals that at least 4 allergens were found in more than 80% of the rooms and more than 2 allergens with median/high risk were detected in 42% of the rooms, indicating that simultaneous exposure to multiple allergens is prevalent in China.

Effects of Allergen Exposure and Environmental Risk Factors in Schools on Childhood Asthma

PURPOSE OF REVIEW

This review aims to assess the prevalence of common allergen exposures and environmental risk factors for asthma in schools, examine the underlying mechanisms of these environmental risk factors, and explore possible prevention strategies.

RECENT FINDINGS

Cockroach, mouse, dust mites, fungi, viral infections, ozone pollution, and cleaning products are common allergen exposures and environmental risk factors in schools which may affect asthma morbidity. Novel modifiable environmental risk factors in schools are also being investigated to identify potential associations with increased asthma morbidity. While several studies have investigated the benefit of environmental remediation strategies in schools and their impact on asthma morbidity, future studies are warranted to further define the effects of modifiable risk factors in schools and determine whether school mitigation strategies may help improve asthma symptoms in students with asthma.

Indoor Environmental Exposures and Their Relationship to Allergic Diseases

Cockroach, dust mite, cat, dog, mouse, and molds are major indoor allergens that have been associated with the development of allergic diseases and disease morbidity in allergen-sensitized individuals. Physical characteristics, such as allergen particle size, hydrophobicity, and charge, can determine an allergen's propensity to become airborne, location of respiratory tract penetration, and ability to elicit IgE responses in genetically predisposed individuals. Standardization and recent advancements in indoor allergen assessment serve to identify sources and distribution of allergens in a patient's home and public environment, inform public policy, and monitor the efficacy of allergen avoidance and therapeutics. Allergen exposure interventions have yielded mixed results with current US and international asthma guidelines differing on recommendations. A pragmatic, patient-centered approach to allergen avoidance includes: (1) tailoring intervention to the patient's sensitization and exposure status, (2) using a rigorous multifaceted intervention strategy to reduce allergen exposure as much as possible, and (3) beginning the intervention as soon as the patient is diagnosed. Further research into the risks/benefits of early allergen exposure, rapid and affordable in-home allergen assessment, and best practices for environmental control measures for asthma is needed.

Environmental Interventions for Asthma

Exposure and sensitization to environmental factors play a fundamental role in asthma development and is strongly associated with asthma morbidity. While hereditary factors are critical determinants of asthma, exposures to environmental factors are implicated in the phenotypic expression of asthma and have been strongly associated in the risk of its development. Significant interest has thus been geared toward potentially modifiable environmental exposures which may lead to the development of asthma. Allergen exposure, in particular indoor allergens, plays a significant role in the pathogenesis of asthma, and remediation is a primary component of asthma management. In the home, multifaceted and multitargeted environmental control strategies have been shown to reduce home exposures and improve asthma outcomes. In addition to the home environment, assessment of the school, daycare, and workplace environments of patients with asthma is necessary to ensure appropriate environmental control measures in conjunction with medical care. This article will discuss the role of the environment on asthma, review targeted environmental therapy, and examine environmental control measures to suppress environmental exposures in the home and school setting.

Update on indoor allergens and their impact on pediatric asthma

OBJECTIVE

In recent decades, many indoor allergens have been identified, including dust mite, cat, dog, mouse, cockroach, and indoor molds, which have important health effects particularly in sensitized individuals with asthma. This review aims to update our understanding regarding the extent of these exposures in the indoor environment, review strategies for reducing their levels in the environment, and highlight innovative recent trials targeting these exposures and their impact on pediatric asthma morbidity.

DATA SOURCES

Recent practice parameter updates on indoor allergen exposures, seminal studies, and recent peer-reviewed journal articles are referenced.

STUDY SELECTIONS

This review cites recent cohort studies of well-characterized pediatric patients with asthma and innovative randomized controlled trials evaluating exposure to environmental allergens, interventions to limit these exposures, and their outcomes.

RESULTS

Links between indoor aeroallergen exposures and health outcomes have been well established. However, only some allergen reduction interventions have been successful in improving health outcomes.

CONCLUSION

There are many complicating factors involved in allergic exposures and health outcomes. The interplay between patient genetic factors, indoor allergic triggers, airborne irritants and pollutants, and microbial exposures complicates the study of indoor allergen exposures and their impact on asthma morbidity.

The influence of urban exposures and residence on childhood asthma

Children with asthma who live in urban neighborhoods experience a disproportionately high asthma burden, with increased incident asthma and increased asthma symptoms, exacerbations, and acute visits and hospitalizations for asthma. There are multiple urban exposures that contribute to pediatric asthma morbidity, including exposure to pest allergens, mold, endotoxin, and indoor and outdoor air pollution. Children living in urban neighborhoods also experience inequities in social determinants of health, such as increased poverty, substandard housing quality, increased rates of obesity, and increased chronic stress. These disparities then in turn can increase the risk of urban exposures and compound asthma morbidity as poor housing repair is a risk factor for pest infestation and mold exposure and poverty is a risk factor for exposure to air pollution. Environmental interventions to reduce in-home allergen concentrations have yielded inconsistent results. Population-level interventions including smoking bans in public places and legislation to decrease traffic-related air pollution have been successful at reducing asthma morbidity and improving lung function growth. Given the interface and synergy between urban exposures and social determinants of health, it is likely population and community-level changes will be needed to decrease the excess asthma burden in children living in urban neighborhoods.

The role of environmental allergen control in the management of asthma

Allergen exposure may exacerbate asthma symptoms in sensitized patients. Allergen reduction or avoidance measures have been widely utilized; however, there is ongoing controversy on the effectiveness of specific allergen control measures in the management of children with asthma. Often, allergen avoidance strategies are not recommended by guidelines because they can be complex or burdensome, although individual patients may benefit. Here we explore the potential for intervention against exposure to the major allergens implicated in asthma (ie, house dust mites, indoor molds, rodents, cockroaches, furry pets, and outdoor molds and pollens), and subsequent effects on asthma symptoms. We critically assess the available evidence regarding the clinical benefits of specific environmental control measures for each allergen. Finally, we underscore the need for standardized and multifaceted approaches in research and real-life settings, which would result in the identification of more personalized and beneficial prevention strategies.

Pediatric Inner-City Asthma

Inner-city children with asthma are known to have high disease mortality and morbidity. Frequently, asthma in this high-risk population is difficult to control and more severe in nature. Several factors, including socioeconomic hardship, ability to access to health care, adherence to medication, exposure to certain allergens, pollution, crowd environment, stress, and infections, play an important role in the pathophysiology of inner-city asthma. Comprehensive control of home allergens and exposure to tobacco smoke, the use of immune based therapies, and school-based asthma programs have shown promising results in asthma control in this population.

Air Quality as a Key Factor in the Aromatisation of Stores: A Systematic Literature Review

Scientific literature on indoor air quality is categorised mainly into environmental sciences, construction building technology and environmental and civil engineering. Indoor air is a complex and dynamic mixture of a variety of volatile and particulate matter. Some of the constituents are odorous and originate from various sources, such as construction materials, furniture, cleaning products, goods in stores, humans and many more. The first part of the article summarises the knowledge about the substances that are found in the air inside buildings, especially stores, and have a negative impact on our health. This issue has been monitored for a long time, and so, using a better methodology, it is possible to identify even low concentrations of monitored substances. The second part summarises the possibility of using various aromatic substances to improve people’s sense of the air in stores. In recent times, air modification has come to the forefront of researchers’ interest in order to create a more pleasant environment and possibly increase sales.

B cells modulate mouse allergen-specific T cells in nonallergic laboratory animal-care workers

Understanding the mechanisms of allergen-specific immune modulation in nonallergic individuals is key to recapitulate immune tolerance and to develop novel allergy treatments. Herein, we characterized mouse-specific T cell responses in nonallergic laboratory animal-care workers before and after reexposure to mice. PBMCs were collected and stimulated with developed peptide pools identified from high-molecular-weight fractions of mouse allergen extracts. Sizable CD4 T cell responses were noted and were temporarily decreased in most subjects upon reexposure, with the magnitude of decrease positively correlated with time of reexposure but not the duration of the break. Interestingly, the suppression was specific to mouse allergens without affecting responses of bystander antigens. Further, PBMC fractioning studies illustrated that the modulation is unlikely from T cells, while B cell depletion and exchange reversed the suppression of responses, suggesting that B cells may be the key modulators. Increased levels of regulatory cytokines (IL-10 and TGF-β1) in the cell culture supernatant and plasma mouse-specific IgG4 were also observed after reexposure, consistent with B cell–mediated modulation mechanisms. Overall, these results suggest that nonallergic status is achieved by an active, time-related, allergen-specific, B cell-dependent regulatory process upon reexposure, the mechanisms of which should be detailed by further molecular studies.

From workplace to home environment: spreading of mouse allergens by laboratory animal workers

PURPOSE

Laboratory animal workers (LAW) working with laboratory mice are exposed to mouse allergens (MA). If MA are spread to home environments, this might increase the risk for allergies in LAW and their families. This study aimed to assess 1. whether spreading of MA from workplace to home environment takes place; 2. which factors increase spreading of MA.

METHODS

In a cross-sectional study, dust samples were taken on the mattress and seating in homes of LAW (n = 105) and an unexposed comparison group (n = 13). From 89 LAW, additional dust samples were taken from their workplaces. Samples were analysed using Mus m1 ELISA kits [detection limit (DL) 0.2 ng mus m1/ml]. Sociodemographic data, personal history of allergies and cleaning habits, as well as work-related characteristics (LAW only) were assessed by questionnaire. Latent factors were assessed via factor analysis. Tobit models were fitted to analyse the latent factors' contribution to MA spreading.

RESULTS

MA concentration on the seating was significantly higher in home environments of LAW (median = 1.28 ng mus m1/m²) than in the comparison group (median < DL, p = 0.019). The highest workplace MA concentration was found on the floor of the scullery (median = 140,000.00 ng mus m1/m²), followed by hair-covering caps (median = 76.02 ng mus m1/m²). Cage and mouse facility cleaning tasks and infrequent changing of bed linen at home were statistically significantly associated with higher MA concentrations at home.

CONCLUSIONS

Spreading of MA from LAW's workplace to their home environment takes place, especially among LAWs involved in cleaning tasks.

The Indoor Environment and Childhood Asthma

PURPOSE OF REVIEW

Sensitization and exposure to triggers in the indoor environment, including aeroallergens, indoor air pollution, and environmental tobacco smoke, have a significant role in asthma development and morbidity. This review discusses indoor environmental exposures and their effect on children with asthma as well as environmental interventions and their role in improving asthma morbidity.

RECENT FINDINGS

Recent research has emphasized the role of aeroallergen sensitization and exposure in asthma morbidity and the importance of the school indoor environment. There is an established association between indoor exposures and asthma development and morbidity. Recent evidence has highlighted the importance of the indoor environment in childhood asthma, particularly the role of the school indoor environment. While home environmental interventions have had mixed results, interventions in the school environment have the potential to significantly impact the health of children, and ongoing research is needed to determine their effectiveness.

The Role of Environmental Controls in Managing Asthma in Lower-Income Urban Communities

Children living in lower-income urban communities are at much greater risk of developing asthma, going to the emergency department for an asthma attack and being hospitalized for asthma than children living in upper- and middle-income communities. For many asthmatic children living in urban communities, especially those with greater morbidity, the allergic pathway is important in the etiology of the disease. The stages of developing allergic disease can be divided into the onset of allergic sensitization, development of allergic disease and subsequent exacerbations, and it is useful to consider the relevance of interventions at each of these stages. Indoor allergens and environmental exposures are a major contributor to allergic disease, particularly among lower socioeconomic status, urban, minority communities. These exposures include allergens, environmental tobacco smoke, combustion by-products, and mold, all of which can play an important role in asthma progression as well as morbidity. These exposures are often not found in isolation and thus these concomitant exposures need to be considered when conducting environmental interventions. There have been numerous studies looking at both primary and tertiary prevention strategies and the impact on allergic sensitization and asthma with varied results. While the outcomes of these studies have been mixed, what has emerged is the need for tertiary interventions to be targeted to the individual and to reduce all relevant exposures to which an asthmatic child is exposed and sensitized. In addition, effective intervention strategies must also consider other social determinants of asthma morbidity impacting low socioeconomic, urban communities.

Asthma and Allergies in the School Environment

The school is a complex microenvironment of indoor allergens, pollutants, and other exposures. The school represents an occupational model for children and exposures in this environment have a significant health effect. Current research establishes an association between school exposure and asthma morbidity in children. This review will focus on common school environmental exposures (cockroach, rodents, cat, dog, classroom pets, dust mite, fungus, and pollution) and their impact on children with allergies and asthma. Understanding and evaluation of school-based environments is needed to help guide school-based interventions. School-based interventions have the potential for substantial benefit to the individual, school, community, and public health. However, there is a paucity data on school-based environmental interventions and health outcomes. The studies performed to date are small and cross-sectional with no control for home exposures. Randomized controlled school-based environmental intervention trials are needed to assess health outcomes and the cost-effectiveness of these interventions. The School Inner-City Asthma Intervention Study (SICAS 2), a NIH/NIAID randomized controlled clinical trial using environmental interventions modeled from successful home-based interventions, is currently underway with health outcome results pending. If efficacious, these interventions could potentially help further guide school-based interventions potentially with policy implications. In the meanwhile, the allergist/immunologist can continue to play a vital role in improving the quality of life in children with allergies and asthma at school through the use of the ADA policy and Section 504 of the Rehabilitation Act as well as encouraging adoption of toolkits to build successful school-based asthma programs and asthma-friendly schools.

Asthma epidemiology and risk factors

Asthma is a clinical syndrome that affects all age groups. Asthma prevalence worldwide has seen a rapid increase in the latter part of the last century. Recent data has shown that asthma prevalence has plateaued and even decreased in some areas of the world, despite continuing to increase in other areas of the world. Many risk factors have been associated with asthma and the differences in distributions of these risk factors may explain the differences in prevalence. This article will review recent trends in the prevalence of asthma and recent studies that investigate risk factors of asthma.

Aeroallergen Exposure and Spread in the Modern Era

Since the initial discovery of aeroallergens in the 20th century, our understanding of their properties including sources and factors influencing their spread continues to expand. Both habits of daily living and the presence of environmental factors such as exposure to animals or pollution can influence susceptibility to atopic disease. Because relevant allergens may vary in individuals and communities, it is necessary to understand the physical properties of environmental aeroallergens that are associated with clinical disease to explain symptoms and to implement successful integrated interventions. The objective of this review was to present an overview of aeroallergens and the environmental factors influencing their current distribution. Using historical studies along with recent advancements, we will give an up-to-date description of the physical characteristics and aerodynamics of aeroallergens in addition to location, quantities, and timing of exposure.

Indoor Environmental Interventions for Furry Pet Allergens, Pest Allergens, and Mold: Looking to the Future

Over the last 2 to 3 decades, significant advances have been made in understanding the role that indoor allergen exposures play with regard to respiratory health. Multiple studies have confirmed that sensitization and exposure to indoor allergens can be a risk factor for asthma morbidity. Environmental interventions targeting key indoor allergens have been evaluated with the aims of examining their causal effects on asthma-related outcomes and identifying clinically efficacious interventions to incorporate into treatment recommendations. Historically, it appeared that the most successful intervention, as performed in the Inner-City Asthma Study, was individually tailored, targeting multiple allergens in a predominantly low-income, minority, and urban pediatric population. Recent studies suggest that single-allergen interventions may be efficacious when targeting the most clinically relevant allergen for a population. In this article, we review recent literature on home environmental interventions and their effects on specific indoor allergen levels and asthma-related outcomes.

Airborne Rodent Allergen Levels in Dutch Households: A Pilot Study

Little research has been conducted in Europe regarding indoor exposure to airborne rodent allergens. The aims of this study were to gain insight into the prevalence of rodent allergens in airborne dust in Dutch households, to assess whether there is a relationship between rodent sightings and detectable allergens, and to identify risk factors associated with the presence of rodent allergens. Airborne dust was collected from the living rooms of 80 households distributed around central Netherlands by passive sampling using electrostatic dust collectors (EDCs). Samples were analysed for mouse (Mus m 1) and rat (Rat n 1) allergens. Participants completed a questionnaire on household and building characteristics, household pets, cleaning habits and ventilation. Mouse allergen was more prevalent than rat allergen and mouse sightings within the past year more than doubled the odds of detectable mouse allergen. Proximity to green areas, ventilation through an open window and insulation under the living room floor were determinants for detectable mouse allergen. Conversely, proximity to surface water was protective. No significant association was found between asthma and detectable mouse allergen. The passive EDC sampling method was used successfully to detect mouse and rat allergens in homes. The presence of mouse allergen was associated with previous mouse sightings. Risk factors and protective factors associated with the presence and levels of mouse allergen were identified.

Pediatric Inner-City Asthma

Inner-city children with asthma are known to have high disease mortality and morbidity. Frequently, asthma in this high-risk population is difficult to control and more severe in nature. Several factors, including socioeconomic hardship, ability to access to health care, adherence to medication, exposure to certain allergens, pollution, crowd environment, stress, and infections, play an important role in the pathophysiology of inner-city asthma. Comprehensive control of home allergens and exposure to tobacco smoke, the use of immune based therapies, and school-based asthma programs have shown promising results in asthma control in this population.

Update in Pediatric Asthma: Selected Issues

Asthma is a complex condition that affects 14% of the world's children and the approach to management includes both pharmacologic as well as non-pharmacologic strategies including attention to complex socioeconomic status phenomena. After an historical consideration of asthma, allergic and immunologic aspects of asthma in children and adolescents are presented. Concepts of socioeconomic aspects of asthma are considered along with environmental features and complications of asthma disparities. Also reviewed are links of asthma with mental health disorders, sleep disturbances and other comorbidities. A stepwise approach to asthma management is discussed that includes pharmacologic and non-pharmacologic strategies in the pediatric population. The role of immunotherapy and use of various immunomodulators are considered as well.

Characterization and epitope identification of the T cell response in non-allergic individuals exposed to mouse allergen

Background

Exposure to airborne allergens is a frequent trigger of respiratory allergy and asthma in atopic individuals. While allergic patients suffer hypersensitivity reactions to these allergens, non-allergic individuals do not exhibit clinical symptoms despite environmental exposure to these ubiquitous allergen sources. The aim of this study was to characterize T cell responses in non-allergic laboratory workers, who are heavily exposed to mice allergens (Exposed Non-Allergics, ENA) and compare this data to previously published T cell responses measured in mouse (MO)-allergic patients. METHODS: Peripheral mononuclear cells (PBMC) from ENA subjects were expanded for 2 weeks in vitro with mouse urine extract and screened for IFNγ and IL-5 cytokine production in response to mouse antigen-derived peptides by ELISPOT. Ex vivo T cell reactivity in the ENA cohort was performed after 6hr stimulation with peptide pools by intracellular staining of CD154.

Results

Vigorous responses were detected, associated with 147 epitopes derived from 16 mouse antigens. As expected, responses in ENA subjects were somewhat lower than those observed in MO-allergics for both responder frequency and overall response magnitude. While responses in allergics were polarized towards IL-5 production and associated with low IFNγ production, ENA responses were not polarized. The composition of targeted antigens and epitopes was overall similar between the two cohorts, with the majority of T cell reactivity directed against Mus m 1 and other major urinary proteins. However, kappa-casein precursor and odorant binding protein Ib were more abundantly recognized in MO-allergics compared to ENA subjects. Additionally, T cell responses against oligopeptides derived from the low molecular weight fraction of mouse urine were also assessed. Interestingly, no difference in the response frequency, magnitude or polarization between MO-allergic and ENA individuals was observed. Finally, assessment of ex vivo T cell activation also revealed T cell reactivity in the ENA cohort, with a non-significant trend for lower responses compared to MO-allergics.

Conclusion

Exposure to mouse induces potent T cell responses in non-allergic individuals, targeting similar epitopes as seen in allergic patients.

Time for Allergists to Consider the Role of Mouse Allergy in Non-Inner City Children with Asthma

Mouse allergen is endemic in the inner cities of the United States, with research predominantly in the Northeastern United States. A recent practice parameter notes the effect of mouse exposure in asthma in inner cities. However, studies are emerging that find a role of mouse allergen in non-inner cities as well. Mouse sensitization is associated with mouse allergen exposure and has been linked with adverse asthma outcomes including increased asthma symptoms, poorer lung function, and increased risk of exacerbations. There are commercially available extracts for testing for mouse sensitization although they are not standardized. Pest management studies have had varying results, but with decreased allergen exposure, there is a trend toward improved asthma outcomes. Physicians should be aware of the potential for rodent exposure and sensitization and consider screening for mouse allergy in asthmatic children, especially if they are located in the inner city, have poorly controlled asthma, or have a history of mouse infestation in their location. Evidence is emerging that this allergen should be considered in non-inner-city asthmatics as well. Finally, advocacy efforts are necessary to ensure that removal of this allergen is accomplished, when possible, in the environments of asthmatic children sensitized to mouse.

Trends in Racial and Ethnic Disparities in Childhood Asthma in Miami, Florida: 2005-2013

Nationally, racial and ethnic disparities in childhood asthma plateaued from 2005 to 2013. We assessed trends in childhood asthma in Miami, Florida using Youth Risk Behavior Surveillance System (YRBSS) data and emergency department (ED) utilization and hospitalization rates by zip code population characteristics. Asthma prevalence in Miami did not vary significantly by race/ethnicity in YRBSS respondents in 2005 (16.2-17.2%, all groups), but rose in African-Americans and Hispanics and declined in Whites by 2013 to 27.9, 20.9 and 12.6%, respectively (P = 0.02). Median asthma ED visit rates rose from 106.8 (2006-2008) to 138.2 (2011-2013; P = 0.004) per 10,000 children. High-poverty and majority African-American zip codes were 6.3 and 7.3 times more likely to have asthma ED visit rates > 200 than others (P < 0.001). In high-poverty zip codes, majority African-American population was not associated with significantly higher ED utilization. In low-poverty zip codes, the association became stronger. Greater poverty explains much, but not all of Miami African-Americans' higher asthma risk.

Bedroom Allergen Exposure Beyond House Dust Mites

PURPOSE OF REVIEW

The review provides insight into recent findings on bedroom allergen exposures, primarily focusing on pet, pest, and fungal exposures.

RECENT FINDINGS

Large-scale studies and improved exposure assessment technologies, including measurement of airborne allergens and of multiple allergens simultaneously, have extended our understanding of indoor allergen exposures and their impact on allergic disease. Practical, streamlined methods for exposure reduction have shown promise in some settings, and potential protective effects of early-life exposures have been further elucidated through the investigation of specific bacterial taxa. Advances in molecular allergology have yielded novel data on sensitization profiles and cross-reactivity. The role of indoor allergen exposures in allergic disease is complex and remains incompletely understood. Advancing our knowledge of various co-exposures, including the environmental and host microbiome, that interact with allergens in early life will be crucial for the development of efficacious interventions to reduce the substantial economic and social burden of allergic diseases including asthma.

Taming Asthma in School-Aged Children: A Comprehensive Review

Asthma is the most common chronic disease of childhood and the leading cause of childhood morbidity as measured by school absences, emergency department visits, and hospitalizations. Multiple factors play a role in the development, treatment and prevention of childhood asthma including racial/ethnic and socioeconomic disparities, both the home and school environments, and medication use. The goals of this review are to summarize these aspects of asthma in school-aged children and to present an updated review of medications as it relates to treatment strategies that will help in the care of these children. We conclude that phenotypic heterogeneity and appropriate environmental assessments and interventions are important considerations in the management of childhood asthma.

Urinary Peptides As a Novel Source of T Cell Allergen Epitopes

Mouse allergy in both laboratory workers and in inner-city children is associated with allergic rhinitis and asthma, posing a serious public health concern. Urine is a major source of mouse allergens, as mice spray urine onto their surroundings, where the proteins dry up and become airborne on dust particles. Here, we tested whether oligopeptides that are abundant in mouse urine may contribute to mouse allergic T cell response. Over 1,300 distinct oligopeptides were detected by mass spectrometry analysis of the low molecular weight filtrate fraction of mouse urine (LoMo). Posttranslationally modified peptides were common, accounting for almost half of total peptides. A pool consisting of 225 unique oligopeptides of 13 residues or more in size identified within was tested for its capacity to elicit T cell reactivity in mouse allergic donors. Following 14-day in vitro stimulation of PBMCs, we detected responses in about 95% of donors tested, directed against 116 distinct peptides, predominantly associated with Th2 cytokines (IL-5). Peptides from non-urine related proteins such as epidermal growth factor, collagen, and Beta-globin accounted for the highest response (15.9, 9.1, and 8.1% of the total response, respectively). Peptides derived from major urinary proteins (MUPs), kidney androgen-regulated protein (KAP), and uromodulin were the main T cell targets from kidney or urine related sources. Further ex vivo analysis of enrichment of 4-1BB expressing cells demonstrated that LoMo pool-specific T cell reactivity can be detected directly ex vivo in mouse allergic but not in non-allergic donors. Further cytometric analysis of responding cells revealed a bone fide memory T cell phenotype and confirmed their Th2 polarization. Overall, these data suggest that mouse urine-derived oligopeptides are a novel target for mouse allergy-associated T cell responses, which may contribute to immunopathological mechanisms in mouse allergy.

Indoor Environmental Interventions and their Effect on Asthma Outcomes

PURPOSE OF REVIEW

The use of environmental interventions to improve outcomes in asthmatics has long been an elusive goal. While numerous interventions have been studied, the results of clinical trials have been mixed. This review aims to identify combinations of interventions that have been proven to be effective and to propose a model for using them in a clinical setting.

RECENT FINDINGS

An NIH workshop emphasized a need for research to identify effective interventions for reducing indoor exposures and improving asthma outcomes. A number of innovative measures were described, though evidence supporting their use was lacking. A recent systematic review described various interventions for which evidence is available. The greatest challenge for this approach is the same as that for the medical approach to treatment: nonadherence. Given evidence for effective interventions, control of environmental exposures should lead to improved asthma outcomes. Methods to improve adherence need to be identified.

Allergen and Epitope Targets of Mouse-Specific T Cell Responses in Allergy and Asthma

Mouse allergy has become increasingly common, mainly affecting laboratory workers and inner-city households. To date, only one major allergen, namely Mus m 1, has been described. We sought to identify T cell targets in mouse allergic patients. PBMC from allergic donors were expanded with either murine urine or epithelial extract and subsequently screened for cytokine production (IL-5 and IFNγ) in response to overlapping peptides spanning the entire Mus m 1 sequence, peptides from various Mus m 1 isoforms [major urinary proteins (MUPs)], peptides from mouse orthologs of known allergens from other mammalian species and peptides from proteins identified by immunoproteomic analysis of IgE/IgG immunoblots of mouse urine and epithelial extracts. This approach let to the identification of 106 non-redundant T cell epitopes derived from 35 antigens. Three major T cell-activating regions were defined in Mus m 1 alone. Moreover, our data show that immunodominant epitopes were largely shared between Mus m 1 and other MUPs even from different species, suggesting that sequence conservation in different allergens is a determinant for immunodominance. We further identified several novel mouse T cell antigens based on their homology to known mammalian allergens. Analysis of cohort-specific T cell responses revealed that rhinitis and asthmatic patients recognized different epitope repertoires. Epitopes defined herein can be formulated into an epitope "megapool" used to diagnose mouse allergy and study mouse-specific T cell responses directly ex vivo. This analysis of T cell epitopes provides a good basis for future studies to increase our understanding of the immunopathology associated with MO-allergy and asthma.

School Environmental Intervention Programs

Exposure to indoor allergens and pollutants plays a significant part in the development of asthma and its associated morbidity. Inner-city children with asthma are disproportionately affected by these exposures with increased asthma morbidity. Although years of previous research have linked exposures in the urban home environment with significant childhood asthma disease, many of these allergens are also present in inner-city school environments. Therefore, evaluation of the school environment of patients with asthma is also essential. School-based environmental interventions may offer benefit for this problem and has the potential to help many children with asthma at once in a cost-effective manner. It is important that environmental health researchers continue to assess which interventions are most practical and result in the greatest measurable improvements.

Respiratory Allergens from Furred Mammals: Environmental and Occupational Exposure

Furry mammals kept as pets, farm and laboratory animals are important allergen sources. The prevalence of sensitization to furred mammals appears to be increasing worldwide. Several mammalian allergens from diverse species are well characterized with regard to their molecular structure and immunogenicity, and some are already available for component-resolved allergy diagnostics. The distribution of various mammalian allergens has been extensively studied during the past few decades. Animal allergens were found to be ubiquitous in the human environment, even in places where no animals reside, with concentrations differing considerably between locations and geographical regions. This review presents an overview of identified mammalian respiratory allergens classified according to protein families, and compiles the results of allergen exposure assessment studies conducted in different public and occupational environments.

Respiratory Allergens from Furred Mammals: Environmental and Occupational Exposure

Furry mammals kept as pets, farm and laboratory animals are important allergen sources. The prevalence of sensitization to furred mammals appears to be increasing worldwide. Several mammalian allergens from diverse species are well characterized with regard to their molecular structure and immunogenicity, and some are already available for component-resolved allergy diagnostics. The distribution of various mammalian allergens has been extensively studied during the past few decades. Animal allergens were found to be ubiquitous in the human environment, even in places where no animals reside, with concentrations differing considerably between locations and geographical regions. This review presents an overview of identified mammalian respiratory allergens classified according to protein families, and compiles the results of allergen exposure assessment studies conducted in different public and occupational environments.

Care transition interventions for children with asthma in the emergency department

The emergency department (ED) is a critical point of identification and treatment for some of the most high-risk children with asthma. This review summarizes the evidence regarding care transition interventions originating in the ED for children with uncontrolled asthma, with a focus on care coordination and self-management education. Although many interventions on care transition for pediatric asthma have been tested, only a few were actually conducted in the ED setting. Most of these targeted both care coordination and self-management education but ultimately did not improve attendance at follow-up appointments with primary care providers, improve asthma control, or reduce health care utilization. Conducting any ED-based intervention in the current environment is challenging because of the many demands on ED providers and staff, poor communication within and outside of the medical sector, and caregiver/patient burden. The evidence to date suggests that ED care transition interventions should consider expanding beyond the ED to bridge the multiple sectors children with asthma navigate, including health care settings, homes, schools, and community spaces. Patient-centered approaches may also be important to ensure adequate intervention design, enrollment, retention, and evaluation of outcomes important to children and their families.

Indoor Air Quality

Many health care providers are concerned with the role environmental exposures play in the development of respiratory disease. While most individuals understand that outdoor air quality is important to their health status, many are unaware of the detrimental effects indoor air pollution can potentially have on them. The Environmental Protection Agency (EPA) regulates both outdoor and indoor air quality. According to the EPA, indoor levels of pollutants may be up to 100 times higher than outdoor pollutant levels and have been ranked among the top 5 environmental risks to the public. There has been a strong correlation between air quality and health, which is why it is crucial to obtain a complete environmental exposure history from a patient. This article focuses on the effects indoor air quality has on the respiratory system. Specifically, this article will address secondhand smoke, radon, carbon monoxide, nitrogen dioxide, formaldehyde, house cleaning agents, indoor mold, animal dander, and dust mites. These are common agents that may lead to hazardous exposures among individuals living in the United States. It is important for health care providers to be educated on the potential risks of indoor air pollution and the effects it may have on patient outcomes. Health problems resulting from poor indoor air quality are not easily recognized and may affect a patient's health years after the onset of exposure.

New Insights into Cockroach Allergens

PURPOSE OF REVIEW

This review addresses the most recent developments on cockroach allergen research in relation to allergic diseases, especially asthma.

RECENT FINDINGS

The number of allergens relevant to cockroach allergy has recently expanded considerably up to 12 groups. New X-ray crystal structures of allergens from groups 1, 2, and 5 revealed interesting features with implications for allergen standardization, sensitization, diagnosis, and therapy. Cockroach allergy is strongly associated with asthma particularly among children and young adults living in inner-city environments, posing challenges for disease control. Environmental interventions targeted at reducing cockroach allergen exposure have provided conflicting results. Immunotherapy may be a way to modify the natural history of cockroach allergy and decrease symptoms and asthma severity among sensitized and exposed individuals. The new information on cockroach allergens is important for the assessment of allergen markers of exposure and disease, and for the design of immunotherapy trials.

Design of a pragmatic trial in minority children presenting to the emergency department with uncontrolled asthma: The CHICAGO Plan

Among children with asthma, black children are two to four times as likely to have an emergency department (ED) visit and die from asthma, respectively, compared to white children in the United States. Despite the availability of evidence-based asthma management guidelines, minority children are less likely than white children to receive or use effective options for asthma care. The CHICAGO Plan is a three-arm multi-center randomized pragmatic trial of children 5 to 11years old presenting to the ED with uncontrolled asthma that compares: [1] an ED-focused intervention to improve the quality of care on discharge to home, [2] the same ED-focused intervention together with a home-based community health worker (CHW)-led intervention, and [3] enhanced usual care. All children receive spacers for the metered dose inhaler and teaching about its use. The Patient-Reported Outcomes Measurement Information System (PROMIS) Asthma Impact Scale and Satisfaction with Participation in Social Roles at 6months are the primary outcomes in children and in caregivers, respectively. Other patient-reported outcomes and indicators of healthcare utilization are assessed as secondary outcomes. Innovative features of the CHICAGO Plan include early and continuous engagement of children, caregivers, the Chicago Department of Public Health, and other stakeholders to inform the design and implementation of the study and a shared research infrastructure to coordinate study activities. The objective of this report is to describe the development of the CHICAGO Plan, including the methods and rationale for engaging stakeholders, the shared research infrastructure, and other features of the pragmatic clinical trial design.

Effect of an Integrated Pest Management Intervention on Asthma Symptoms Among Mouse-Sensitized Children and Adolescents With Asthma: A Randomized Clinical Trial

IMPORTANCE

Professionally delivered integrated pest management (IPM) interventions can reduce home mouse allergen concentrations, but whether they reduce asthma morbidity among mouse-sensitized and exposed children and adolescents is unknown.

OBJECTIVE

To determine the effect of an IPM intervention on asthma morbidity among mouse-sensitized and exposed children and adolescents with asthma.

DESIGN, SETTING, AND PARTICIPANTS

Randomized clinical trial conducted in Baltimore, Maryland, and Boston, Massachusetts. Participants were mouse-sensitized and exposed children and adolescents (aged 5-17 years) with asthma randomized to receive professionally delivered IPM plus pest management education or pest management education alone. Enrollment occurred between May 2010 and August 2014; the final follow-up visit occurred on September 25, 2015.

INTERVENTIONS

Integrated pest management consisted of application of rodenticide, sealing of holes that could serve as entry points for mice, trap placement, targeted cleaning, allergen-proof mattress and pillow encasements, and portable air purifiers. Infestation was assessed every 3 months, and if infestation persisted or recurred, additional treatments were delivered. All participants received pest management education, which consisted of written material and demonstration of the materials needed to set traps and seal holes.

MAIN OUTCOMES AND MEASURES

The primary outcome was maximal symptom days defined as the highest number of days of symptoms in the previous 2 weeks among 3 types of symptoms (days of slowed activity due to asthma; number of nights of waking with asthma symptoms; and days of coughing, wheezing, or chest tightness) across 6, 9, and 12 months.

RESULTS

Of 361 children and adolescents who were randomized (mean [SD] age, 9.8 [3.2] years; 38% female; 181 in IPM plus pest management education group and 180 in pest management education alone group), 334 were included in the primary analysis. For the primary outcome, there was no statistically significant between-group difference for maximal symptom days across 6, 9, and 12 months with a median of 2.0 (interquartile range, 0.7-4.7) maximal symptom days in the IPM plus pest management education group and 2.7 (interquartile range, 1.3-5.0) maximal symptom days in the pest management education alone group (P = .16) and a ratio of symptom frequencies of 0.86 (95% CI, 0.69-1.06).

CONCLUSIONS AND RELEVANCE

Among mouse-sensitized and exposed children and adolescents with asthma, an intensive year-long integrated pest management intervention plus pest management education vs pest management education alone resulted in no significant difference in maximal symptom days from 6 to 12 months.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01251224.

Recent advances in environmental controls outside the home setting

PURPOSE OF REVIEW

It has been well studied that aeroallergen, mold, and airborne pollutant exposure in the inner-city home environment is associated with significant childhood asthma morbidity. Although the home environment has been extensively studied, the school environment is less well understood.

RECENT FINDINGS

In this article, we discuss the relationship between environmental exposures within the school and daycare environment and pediatric asthma morbidity and novel environmental interventions designed to help mitigate pediatric asthma morbidity.

SUMMARY

Studies assessing environmental exposures outside the home environment and interventions to mitigate these exposures have the potential to reduce pediatric asthma morbidity. Further study in this area should focus on the complex cost benefit analyses of environmental interventions outside the home setting, while controlling for the home environment.

Indoor allergen exposure and asthma outcomes

PURPOSE OF REVIEW

The aim of the present review is to discuss updates on research regarding the relationship between indoor allergen exposure and childhood asthma with a focus on clinical effects, locations of exposure, and novel treatments.

RECENT FINDINGS

Recent data continue to demonstrate that early life sensitization to indoor allergens is a predictor of asthma development later in life. Furthermore, avoidance of exposure to these allergens continues to be important especially given that the vast majority of children with asthma are sensitized to at least one indoor allergen. New research suggests that mouse allergen, more so than cockroach allergen, may be the most relevant urban allergen. Recent evidence reminds us that children are exposed to clinically important levels of indoor allergens in locations away from their home, such as schools and daycare centers. Exposure to increased levels of indoor mold in childhood has been associated with asthma development and exacerbation of current asthma; however, emerging evidence suggests that early exposure to higher fungal diversity may actually be protective for asthma development. Novel treatments have been developed that target TH2 pathways thus decreasing asthmatic responses to allergens. These therapies show promise for the treatment of severe allergic asthma refractory to avoidance strategies and standard therapies.

SUMMARY

Understanding the relationship between indoor allergens and asthma outcomes is a constantly evolving study of timing, location, and amount of exposure.

Indoor Environmental Control Practices and Asthma Management

Indoor environmental exposures, particularly allergens and pollutants, are major contributors to asthma morbidity in children; environmental control practices aimed at reducing these exposures are an integral component of asthma management. Some individually tailored environmental control practices that have been shown to reduce asthma symptoms and exacerbations are similar in efficacy and cost to controller medications. As a part of developing tailored strategies regarding environmental control measures, an environmental history can be obtained to evaluate the key indoor environmental exposures that are known to trigger asthma symptoms and exacerbations, including both indoor pollutants and allergens. An environmental history includes questions regarding the presence of pets or pests or evidence of pests in the home, as well as knowledge regarding whether the climatic characteristics in the community favor dust mites. In addition, the history focuses on sources of indoor air pollution, including the presence of smokers who live in the home or care for children and the use of gas stoves and appliances in the home. Serum allergen-specific immunoglobulin E antibody tests can be performed or the patient can be referred for allergy skin testing to identify indoor allergens that are most likely to be clinically relevant. Environmental control strategies are tailored to each potentially relevant indoor exposure and are based on knowledge of the sources and underlying characteristics of the exposure. Strategies include source removal, source control, and mitigation strategies, such as high-efficiency particulate air purifiers and allergen-proof mattress and pillow encasements, as well as education, which can be delivered by primary care pediatricians, allergists, pediatric pulmonologists, other health care workers, or community health workers trained in asthma environmental control and asthma education.

Difficult-to-control asthma: epidemiology and its link with environmental factors

PURPOSE OF REVIEW

The aim of the present review was to discuss the epidemiology of inadequate asthma control with an examination of contributing environmental factors.

RECENT FINDINGS

Despite advances in asthma therapies, a proportion of patients with asthma continue to have difficulty in gaining adequate asthma control. Asthma severity and control in childhood are of particular importance as they translate to asthma morbidity in adulthood. Children with comorbid severe allergic rhinitis were more likely to have uncontrolled asthma. Recent data suggest that mouse allergen, more so than cockroach allergen, may be the most relevant urban allergen exposure. Tobacco smoke exposure, even passive exposure, leads to increased asthma symptoms and decreased response to inhaled corticosteroids. Efforts to ban smoking in public places have resulted in promising asthma results for entire populations. Energy-saving efforts to tighten a home's air leaks can lead to increased indoor pollutant levels and, therefore, must be accompanied by efforts to reduce, filter, or exchange indoor pollutants. Obesity is independently associated with decreased asthma control. Furthermore, the detrimental effects of pollutant exposure are enhanced in an overweight individual with asthma.

SUMMARY

Lack of asthma control can be because of a complex web of factors including adherence, intrinsic factors, and environmental exposures. Further research into intervention strategies is needed to achieve improved rates of asthma control.

Sensitization to mouse and cockroach allergens and asthma morbidity in urban minority youth: Genes-environments and Admixture in Latino American (GALA-II) and Study of African-Americans, Asthma, Genes, and Environments (SAGE-II)

BACKGROUND

Pest allergen sensitization is associated with asthma morbidity in urban youth but minimally explored in Latino populations. Specifically, the effect of mouse sensitization on the risk of asthma exacerbation has been unexplored in Latino subgroups.

OBJECTIVE

To evaluate whether pest allergen sensitization is a predictor of asthma exacerbations and poor asthma control in urban minority children with asthma.

METHODS

Latino and African American children (8-21 years old) with asthma were recruited from 4 sites across the United States. Logistic regression models evaluated the association of mouse or cockroach sensitization with asthma-related acute care visits or hospitalizations.

RESULTS

A total of 1,992 children with asthma in the Genes-environments and Admixture in Latino American (GALA-II) and Study of African-Americans, Asthma, Genes, and Environments (SAGE-II) cohorts were studied. Asthmatic children from New York had the highest rate of pest allergen sensitization (42% mouse, 56% cockroach), with the lowest rate in San Francisco (4% mouse, 8% cockroach). Mouse sensitization, more than cockroach, was associated with increased odds of acute care visits (adjusted odds ratio [aOR], 1.47; 95% CI, 1.07-2.03) or hospitalizations (aOR, 3.07; 95% CI, 1.81-5.18), even after controlling for self-reported race and site of recruitment. In stratified analyses, Mexican youth sensitized to mouse allergen did not have higher odds of asthma exacerbation. Other Latino and Puerto Rican youth sensitized to mouse had higher odds of hospitalization for asthma (aORs, 4.57 [95% CI, 1.86-11.22] and 10.01 [95% CI, 1.77-56.6], respectively) but not emergency department visits.

CONCLUSION

Pest allergen sensitization is associated with a higher odds of asthma exacerbations in urban minority youth. Puerto Rican and Other Latino youth sensitized to mouse were more likely to have asthma-related hospitalizations than Mexican youth.

Inner-city asthma: special considerations for management

PURPOSE OF REVIEW

Asthma is prevalent in inner-city populations, exhibiting significant morbidity and mortality. This review focuses on the consequential findings of recent literature, providing insight into onset of asthma, complicating factors, prediction of exacerbations, and novel treatment strategies.

RECENT FINDINGS

Analyses of environmental influence on inner-city children demonstrated novel interactions, implicating potentially protective benefits from early life exposures to pests and pets and isolating detrimental effects of air pollution on asthma morbidity. Through detailed characterization of inner-city asthmatics, predictors of seasonal exacerbations surfaced. Focused, season-specific treatment of inner-city asthmatics with omalizumab identified those most likely to benefit from season-tailored therapy. Comparative studies of urban and rural populations revealed that race and household income, rather than location of residence, impose the greatest risk for increased asthma prevalence and morbidity.

SUMMARY

Challenging previously conceived exposure-disease relationships, recent literature has elucidated new avenues in the complex interplay between immunologically active exposures and their effects on inner-city asthma. These findings, and improved understanding of other relevant exposures, could steer the direction of primary (and secondary) disease prevention research. Moreover, careful identification of asthma characteristics has effectively established predictors of exacerbations, highlighting individuals for which additional therapies are warranted and for whom such treatments are most likely to be effective.

Individualized Household Allergen Intervention Lowers Allergen Level But Not Asthma Medication Use: A Randomized Controlled Trial

BACKGROUND

Environmental exposures to indoor allergens are major contributors to asthma symptoms, particularly in inner cities. The effectiveness of household allergen reduction as an adjunct to National Asthma Education Prevention Program guideline-based pharmacologic therapy in asthma has not been prospectively studied.

OBJECTIVE

To study the effect of individualized allergen reduction on ability to reduce asthma pharmacologic therapy over 40 weeks.

METHODS

We performed a randomized controlled trial to determine the effect of multifaceted indoor allergen avoidance measures on the ability to reduce asthma controller therapy in adults and children residing in New York City who were both sensitized and exposed to at least 1 indoor allergen. Asthma treatment and control were optimized in all subjects before randomization.

RESULTS

A total of 125 subjects were randomized to receive individualized household allergen reduction and 122 received a sham intervention. Subjects in the intervention group significantly reduced all measured allergen levels (cat, dog, dust mite allergens in the bedroom, cockroach and mouse allergens in the kitchen and bedroom); those in the control group reduced only dust mite and mouse allergens in the bedroom and cockroach allergen in the kitchen. Participants in the intervention arm reduced National Asthma Education Prevention Program-based therapy from step 4.4 at randomization to 3.50 postintervention (range, 0-6); participants in the control arm reduced medication from step 4.4 to 3.4 (P = .76). There were no differences in other measured asthma outcomes.

CONCLUSIONS

Targeted allergen avoidance measures do not allow for reduction in asthma pharmacologic therapy compared with usual care in patients already receiving optimal controller therapy.

Reducing Exacerbations in the Inner City: Lessons from the Inner-City Asthma Consortium (ICAC)

Asthma exacerbations are important components of asthma morbidity. The Inner-City Asthma Consortium was established in the early 1990s to identify risk factors for and to evaluate treatments to reduce asthma symptoms and exacerbations. Early studies identified atopy and inadequate treatment as important drivers of asthma morbidity. Later studies demonstrated that good adherence to guidelines-based asthma care could virtually eliminate symptoms and reduce but not eliminate exacerbations. Looking at exacerbations by season, risk factors were found to vary across the different seasons. Of the 7 factors identified, allergic status and pulmonary functions were found to be important for exacerbations in all seasons, but allergy had its strongest effect in the fall season. Therefore, additional therapy directed at reducing the role of allergy was evaluated and found to significantly reduce exacerbations even in participants with good symptom control when receiving guidelines-based therapy. Despite this year around aggressive therapy, exacerbations remain albeit at a lower level and with less seasonal variation. Another strategy, the short term use of therapy aimed at reducing the role of allergy begun before the fall season and focused on individuals at high risk for exacerbations, was found to be an effective approach to minimize exacerbations and to limit the amount of therapy necessary.