Exposure to multiple indoor allergens in US homes and its relationship to asthma

Questionnaire Development to Assess Risk Factors for Environmental Diseases of Children in Daejeon

Background: Allergic diseases are common in children and adolescents. It is important to assess the prevalence and risk factors of environmental diseases to implement tailored countermeasures. Methods: This questionnaire study investigated factors associated with environmental diseases in elementary school children with an environmental disease from 150 households in Daejeon Metropolitan City, South Korea in 2021. Results: The participants comprised 55.7% girls and 44.3% boys, and the mean age was 10.1 years with an even age distribution. The typical risk factors observed were the type of roads nearby, the presence of mold or stains within the residence, pet ownership, and frequency of indoor ventilation and cleaning. Notably, 73.2% of the households had an eight-lane road nearby, 40.2% reported leaks, stains, or mold within their homes during the past year, and 37.1% ventilated their homes for less than 30 min. After education on preventing and managing environmental diseases, significant changes were observed in bedding washing frequency, average ventilation duration per session, and duration of humidifier usage (p < 0.05-0.001), with improvements in lifestyle. Conclusions: Our study can be used as a reference for expanding indoor air quality control education for parents with children with an environmental disease and providing tailored environmental consultations.

Adult-onset asthma morbidity and related economic costs in middle age due to intentional chronic absenteeism in high school: An epidemiologic study using the national longitudinal survey of youth 1979 data

OBJECTIVE

Many authors examined the individual and societal impact of school absenteeism. Nevertheless, no empirical study has looked at the potential direct correlation between deliberate school absences and chronic illnesses in mid-adulthood. Our goal is to investigate any potential direct links between purposeful school absences and adult-onset asthma in middle age, as well as measure any associated costs of asthma.

METHODS

Data were sourced from the National Longitudinal Survey of Youth 1979, a nationally representative survey. The outcome measure was self-reported asthma in mid-adulthood. School records of absenteeism from grades nine through twelve were the key explanatory variables. Logistic regressions were performed with controls for demographic, economic and health variables. Predicted probabilities from the regressions were used to quantify costs of adult-onset asthma in middle age due to intentional high school absenteeism.

RESULTS

More years of chronic absenteeism in high school were associated with higher risk of adult-onset asthma in middle age. Four years of chronic absenteeism in high school during the late 1970s through the early 1980s could potentially have incurred between $817 million to $1 billion of asthma related costs in 2002, when these students were in their mid-adulthood. These potential asthma related costs due to high school absenteeism are sizeable considering that this high school cohort only accounted for six percent of the U.S. population.

CONCLUSIONS

Reducing high school absenteeism could lower the incidence of adult-onset asthma in middle age, and its associated future economic burden.

Mechanisms for initiation of food allergy by skin pre-disposed to atopic dermatitis

Food allergy can be life-threatening and often develops early in life. In infants and children, loss-of-function mutations in skin barrier genes associate with food allergy. In a mouse model with skin barrier mutations (Flakey Tail, FT+/- mice), topical epicutaneous sensitization to a food allergen peanut extract (PNE), an environmental allergen Alternaria alternata (Alt) and a detergent induce food allergy and then an oral PNE-challenge induces anaphylaxis. Exposures to these allergens and detergents can occur for infants and children in a household setting. From the clinical and preclinical studies of neonates and children with skin barrier mutations, early oral exposure to allergenic foods before skin sensitization may induce tolerance to food allergens and thus protect against development of food allergy. In the FT+/- mice, oral food allergen prior to skin sensitization induce tolerance to food allergens. However, when the skin of FT+/- pups are exposed to a ubiquitous environmental allergen at the time of oral consumption of food allergens, this blocks the induction of tolerance to the food allergen and the mice can then be skin sensitized with the food allergen. The development of food allergy in neonatal FT+/- mice is mediated by altered skin responses to allergens with increases in skin expression of interleukin 33, oncostatin M and amphiregulin. The development of neonate food allergy is enhanced when born to an allergic mother, but it is inhibited by maternal supplementation with α-tocopherol. Moreover, preclinical studies suggest that food allergen skin sensitization can occur before manifestation of clinical features of atopic dermatitis. Thus, these parameters may impact design of clinical studies for food allergy, when stratifying individuals by loss of skin barrier function or maternal atopy before offspring development of atopic dermatitis.

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.

Benefits of Aeroallergen Testing on Oral Corticosteroid Bursts in Adults with Asthma

BACKGROUND

Aeroallergen testing can improve precision care for persistent asthma and is recommended by the U.S. clinical guidelines. How testing benefits diverse populations of adults with asthma, and the importance of the testing modality used, are not fully understood.

OBJECTIVE

We sought to evaluate whether receipt of aeroallergen testing was associated with a reduction in oral corticosteroid (OCS) bursts.

METHODS

We used electronic health record data to conduct a retrospective, observational cohort study of adults with asthma who were prescribed an inhaled corticosteroid and had an Allergy/Immunology visit in a large health system between 1/1/2017-6/30/2022. Negative binomial regression models were used to evaluate whether OCS bursts in the 12-month period after an initial visit were reduced for patients who received aeroallergen testing. We also measured differences in benefit after excluding patients with chronic obstructive pulmonary disease (COPD) and smoking histories, and whether testing receipt was via skin prick or serum.

RESULTS

668/1,383 (48.3%) patients received testing. Receipt of testing was not associated with fewer bursts in all patients (incidence rate ratio (IRR)=0.83 versus no testing, p=0.059), but it was among never smokers without COPD (417/844 tested, IRR=0.68, p=0.004). The receipt of skin testing was associated with fewer bursts in all patients (418/1,383 tested, IRR=0.77, p=0.02) and among never smokers without COPD (283/844 tested, IRR=0.59 versus no testing, p=0.001).

CONCLUSION

Guideline-concordant aeroallergen testing in the context of Allergy/Immunology care was associated with clinical benefit in a real-life, diverse cohort of adults with asthma. This benefit varied according to patient comorbidities and the testing modality.

Insights from the COCOA birth cohort: The origins of childhood allergic diseases and future perspectives

The ongoing COhort for Childhood Origin of Asthma and allergic diseases (COCOA) study is a prospective birth cohort investigating the origin and natural courses of childhood allergic diseases, including atopic dermatitis, food allergy, allergic rhinitis and asthma, with long-term prognosis. Initiated under the premise that allergic diseases result from a complex interplay of immune development alterations, environmental exposures, and host susceptibility, the COCOA study explores these dynamic interactions during prenatal and postnatal periods, framed within the hygiene and microbial hypotheses alongside the developmental origins of health and disease (DOHaD) hypothesis. The scope of the COCOA study extends to genetic predispositions, indoor and outdoor environmental variables affecting mothers and their offsprings such as outdoor and indoor air pollution, psychological factors, diets, and the microbiomes of skin, gut, and airway. We have embarked on in-depth investigations of diverse risk factors and the pathophysiological underpinnings of allergic diseases. By employing multi-omics approaches-proteomics, transcriptomics, and metabolomics-we gain deeper insights into the distinct pathophysiological processes across various endotypes of childhood allergic diseases, incorporating the exposome using extensive resources within the COCOA study. Integration with large-scale datasets, such as national health insurance records, enhances robustness and mitigates potential limitations inherent to birth cohort studies. As part of global networks focused on childhood allergic diseases, the COCOA study fosters collaborative research across multiple cohorts. The findings from the COCOA study are instrumental in informing precision medicine strategies for childhood allergic diseases, underpinning the establishment of disease trajectories.

Multilevel Risk Factors for Sleep-Disordered Breathing-Related Symptom Burden in an Urban Pediatric Community-Based Sample

BACKGROUND

Pediatric sleep-disordered breathing (SDB) disproportionately affects children with low socioeconomic status (SES). The multilevel risk factors that drive these associations are not well understood.

RESEARCH QUESTION

What are the associations between SDB risk factors, including individual health conditions (obesity, asthma, and allergies), household SES (maternal education), indoor exposures (environmental tobacco smoke [ETS] and pests), and neighborhood characteristics (neighborhood disadvantage), and pediatric SDB symptoms?

STUDY DESIGN AND METHODS

Cross-sectional analyses were performed on 303 children (aged 6-12 years) enrolled in the Environmental Assessment of Sleep Youth study from 2018 to 2022. Exposures were determined by caregiver reports, assays of measured settled dust from the child's bedroom, and neighborhood-level Census data (deriving the Childhood Opportunity Index to characterize neighborhood disadvantage). The primary outcome was the SDB-related symptom burden assessed by the OSA-18 questionnaire total score. Using linear regression models, we calculated associations between exposures and SDB-related symptom burden, adjusting for sociodemographic factors, then health conditions, indoor environment, and neighborhood factors.

RESULTS

The sample included 303 children (39% Hispanic, Latino, Latina, or Spanish origin; 30% Black or African American; 22% White; and 11% other). Increasing OSA-18 total scores were associated with low household SES after adjustment for demographic factors, and with asthma, allergies, ETS, pests (mouse, cockroach, and rodents), and an indoor environmental index (sum of the presence of pests and ETS; 0-2) after adjusting for sociodemographic factors. Even after further adjusting for asthma, allergies, and neighborhood disadvantage, ETS and pest exposure were associated with OSA-18 (ETS: β = 12.80; 95% CI, 7.07-18.53, also adjusted for pest; pest exposure: β = 3.69; 95% CI, 0.44-6.94, also adjusted for ETS).

INTERPRETATION

In addition to associations with ETS, a novel association was observed for indoor pest exposure and SDB symptom burden. Strategies to reduce household exposure to ETS and indoor allergens should be tested as approaches for reducing sleep health disparities.

Characterizing the neuroimmune environment of offspring in a novel model of maternal allergic asthma and particulate matter exposure

Inflammation during pregnancy is associated with an increased risk for neurodevelopmental disorders (NDD). Increased gestational inflammation can be a result of an immune condition/disease, exposure to infection, and/or environmental factors. Epidemiology studies suggest that cases of NDD are on the rise. Similarly, rates of asthma are increasing, and the presence of maternal asthma during pregnancy increases the likelihood of a child being later diagnosed with NDD such as autism spectrum disorders (ASD). Particulate matter (PM), via air pollution, is an environmental factor known to worsen the symptoms of asthma, but also, PM has been associated with increased risk of neuropsychiatric disorders. Despite the links between asthma and PM with neuropsychiatric disorders, there is a lack of laboratory models investigating combined prenatal exposure to asthma and PM on offspring neurodevelopment. Thus, we developed a novel mouse model that combines exposure to maternal allergic asthma (MAA) and ultrafine iron-soot (UIS), a common component of PM. In the current study, female BALB/c mice were sensitized for allergic asthma with ovalbumin (OVA) prior to pregnancy. Following mating and beginning on gestational day 2 (GD2), dams were exposed to either aerosolized OVA to induce allergic asthma or phosphate buffered saline (PBS) for 1 h. Following the 1-h exposure, pregnant females were then exposed to UIS with a size distribution of 55 to 169 nm at an average concentration of 176 ± 45 μg/m3) (SD), or clean air for 4 h, over 8 exposure sessions. Offspring brains were collected at postnatal days (P)15 and (P)35. Cortices and hippocampal regions were then isolated and assessed for changes in cytokines using a Luminex bead-based multiplex assay. Analyses identified changes in many cytokines across treatment groups at both timepoints in the cortex, including interleukin-1 beta (IL-1β), and IL-17, which remained elevated from P15 to P35 in all treatment conditions compared to controls. There was a suppressive effect of the combined MAA plus UIS on the anti-inflammatory cytokine IL-10. Potentially shifting the cytokine balance towards more neuroinflammation. In the hippocampus at P15, elevations in cytokines were also identified across the treatment groups, namely IL-7. The combination of MAA and UIS exposure (MAA-UIS) during pregnancy resulted in an increase in microglia density in the hippocampus of offspring, as identified by IBA-1 staining. Together, these data indicate that exposure to MAA, UIS, and MAA-UIS result in changes in the neuroimmune environment of offspring that persist into adulthood.

Characterizing the Neuroimmune Environment of Offspring in a Novel Model of Maternal Allergic Asthma and Particulate Matter Exposure

Autism spectrum disorders (ASD) are neurodevelopmental disorders characterized by the presence of decreased social interactions and an increase in stereotyped and repetitive behaviors. Epidemiology studies suggest that cases of ASD are on the rise. Similarly, rates of asthma are increasing, and the presence of maternal asthma during pregnancy increases the likelihood of a child being later diagnosed with ASD. Particulate matter (PM), via air pollution, is an environmental factor known to worsen the symptoms of asthma, but also, PM has been associated with increased risk of neuropsychiatric disorders including ASD. Despite the links between asthma and PM with neuropsychiatric disorders, there is a lack of laboratory models investigating combined prenatal exposure to asthma and PM on offspring neurodevelopment. Thus, we developed a novel mouse model that combines exposure to maternal allergic asthma (MAA) and ultrafine iron-soot (UIS), a common component of PM. In the current study, female BALB/c mice were primed for allergic asthma with ovalbumin (OVA) prior to pregnancy. Following mating and beginning on gestational day 2 (GD2), dams were exposed to either aerosolized OVA or phosphate buffered saline (PBS) for 1 hour. Following the 1-hour exposure, pregnant females were then exposed to UIS or clean air for 4 hours. Offspring brains were collected at postnatal days (P)15 and (P)35. Cortices and hippocampal regions were then isolated and assessed for changes in cytokines using a Luminex bead-based multiplex assay. Analyses identified changes in many cytokines across treatment groups at both timepoints in the cortex, including interleukin-1 beta (IL-1β), IL-2, IL-13, and IL-17, which remained elevated from P15 to P35 in all treatment conditions compared to controls. In the hippocampus at P15, elevations in cytokines were also identified across the treatment groups, namely interferon gamma (IFNγ) and IL-7. The combination of MAA and UIS exposure (MAA-UIS) during pregnancy resulted in an increase in microglia density in the hippocampus of offspring, as identified by IBA-1 staining. Together, these data indicate that exposure to MAA, UIS, and MAA-UIS result in changes in the neuroimmune environment of offspring that persist into adulthood.

Assessing Disparities in the Prevalence of Atopic Comorbidities Among Food-Allergic Children

BACKGROUND

Previous studies have reported that Black children with food allergy (FA) have higher risk of atopic comorbidities than White children.

OBJECTIVE

Our study sought to understand if disparities in the prevalence of atopic comorbidities among children with FA are driven by individual and community-level socioeconomic status (SES).

METHODS

We analyzed data from a prospective, multicenter cohort investigating the natural history of pediatric atopy: the Food Allergy Outcomes Related to White and African American Racial Differences (FORWARD) study. A validated, multicomponent area deprivation index (ADI) percentile score was tabulated by the census block group for each subject's home address. The association of ADI with atopic comorbidities in FA was assessed via multivariable regression analysis.

RESULTS

Of the 700 children in this study, the mean ADI was 37.7 (95% confidence interval: 35.6-39.7). The mean ADI was higher in children with asthma (43.3) compared with those without asthma (31.8), which remained significant after adjusting for race (P < .0001). Children with allergic rhinitis (AR) had a higher mean ADI (39.1) compared with those without (33.4) (P = .008). ADI was associated with secondhand smoking, parents' education, and household income. Black children had a higher risk for asthma after adjusting for ADI and SES-related factors.

CONCLUSION

The independent association of ADI with asthma and AR, regardless of race, suggests a role of neighborhood-level socioeconomic deprivation in the development of these conditions among children with FA. Black children with FA remained at higher risk for asthma after adjusting for SES-related variables, which can indicate an independent risk for asthma in these children.

Exacerbation of allergic rhinitis by the commensal bacterium Streptococcus salivarius

Allergic rhinitis (AR)-commonly called hay fever-is a widespread condition that affects the quality of life of millions of people. The pathophysiology of AR remains incompletely understood. In particular, it is unclear whether members of the colonizing nasal microbiota contribute to AR. Here, using 16S ribosomal RNA sequencing, we show that the nasal microbiome of patients with AR (n = 55) shows distinct differences compared with that from healthy individuals (n = 105), including decreased heterogeneity and the increased abundance of one species, Streptococcus salivarius. Using ex vivo and in vivo models of AR, we demonstrate that this commensal bacterium contributes to AR development, promoting inflammatory cytokine release and morphological changes in the nasal epithelium that are characteristic of AR. Our data indicate that this is due to the ability of S. salivarius to adhere to the nasal epithelium under AR conditions. Our study indicates the potential of targeted antibacterial approaches for AR therapy.

Impact of COVID-19 on pediatric asthma-related healthcare utilization in New York City: a community-based study

BACKGROUND

COVID-19 disproportionately affects families of low socioeconomic status and may worsen health disparities that existed prior to the pandemic. Asthma is a common chronic disease in children exacerbated by environmental exposures.

METHODS

A cross-sectional survey was conducted to understand the impact of the initial stage of the pandemic on environmental and social conditions, along with access to care for children with asthma in New York City (NYC). Participants were recruited from a community-based organization in East Harlem and a nearby academic Pediatric Pulmonary clinic and categorized as having either public or private insurance (n = 51).

RESULTS

Factors significantly associated with public compared to private insurance respectively were: increased reports of indoor asthma triggers (cockroach 76% vs 23%; mold 40% vs 12%), reduced income (72% vs 27%), and housing insecurity (32% vs 0%). Participants with public insurance were more likely to experience conditions less conducive to social distancing compared to respondents with private insurance, such as remaining in NYC (92% vs 38%) and using public transportation (44% vs 4%); families with private insurance also had greater access to remote work (81% vs 8%). Families with public insurance were significantly more likely to test positive for SARS-CoV-2 (48% vs 15%) but less likely to have gotten tested (76% vs 100%). Families with public insurance also reported greater challenges accessing office medical care and less access to telehealth, although not statistically significant (44% vs 19%; 68% vs 85%, respectively).

CONCLUSIONS

Findings highlight disproportionate burdens of the pandemic, and how these disparities affect children with asthma in urban environments.

A home visit program for low-income African American children with asthma: Caregivers' perception of asthma triggers and a gap in action

PURPOSE

The goals are to gauge caregivers' knowledge of at-home asthma triggers and identify the areas on which educational campaigns can focus to alleviate a child's asthma symptoms.

DESIGN AND METHODS

Families with children with moderate to severe asthmatic symptoms who had been recently hospitalized or in the emergency room were invited to participate in a home visit program. As part of the home visit, caregivers of the asthmatic children were asked a series of questions on asthma triggers and the measures for eliminating the triggers (N = 218).

RESULTS

Findings show a gap between caregivers' perception of asthma triggers and the actions to mitigate or avoid such triggers.

CONCLUSIONS

Overall findings show that home environments were suboptimal for the management and control of child asthma conditions. Knowledge about home triggers as well as the actions and efforts by caregivers and landlords to mitigate these was found to be inadequate. Even when caregivers are aware of the presence of at-home triggers, actions to minimize exposure to the trigger do not always follow due to a lack of power, resource, and knowledge.

PRACTICE IMPLICATIONS

The findings raise the need for additional research to investigate the reasons for the lack of actions, advocacy for low-income families to live in a healthy environment, continued education and empowerment, and patient/caregiver-doctor partnership. Additionally, the provision of community support through community advocacy and training of culturally competent healthcare providers are needed for the successful management of pediatric asthma among African American children.

NIOSH Dampness and Mold Assessment Tool (DMAT): Documentation and Data Analysis of Dampness and Mold-Related Damage in Buildings and Its Application

Indoor dampness and mold are prevalent, and the exposure has been associated with various illnesses such as the exacerbation of existing asthma, asthma development, current asthma, ever-diagnosed asthma, bronchitis, respiratory infection, allergic rhinitis, dyspnea, wheezing, cough, upper respiratory symptoms, and eczema. However, assessing exposures or environments in damp and moldy buildings/rooms, especially by collecting and analyzing environmental samples for microbial agents, is complicated. Nonetheless, observational assessment (visual and olfactory inspection) has been demonstrated as an effective method for evaluating indoor dampness and mold. The National Institute for Occupational Safety and Health developed an observational assessment method called the Dampness and Mold Assessment Tool (DMAT). The DMAT uses a semi-quantitative approach to score the level of dampness and mold-related damage (mold odor, water damage/stains, visible mold, and wetness/dampness) by intensity or size for each of the room components (ceiling, walls, windows, floor, furnishings, ventilation system, pipes, and supplies and materials). Total or average room scores and factor-or component-specific scores can be calculated for data analysis. Because the DMAT uses a semi-quantitative scoring method, it better differentiates the level of damage compared to the binary (presence or absence of damage) approach. Thus, our DMAT provides useful information on identifying dampness and mold, tracking and comparing past and present damage by the scores, and prioritizing remediation to avoid potential adverse health effects in occupants. This protocol-type article describes the DMAT and demonstrates how to apply it to effectively manage indoor dampness and mold-related damage.

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.

Human allergy to cats: A review for veterinarians on prevalence, causes, symptoms and control

PRACTICAL RELEVANCE

Human allergy to cats affects a substantial and growing proportion of the global population, and cat allergy is regarded as the third most common cause of human respiratory allergies, and the second most common indoor cause. Veterinarians will frequently encounter owners who are cat-allergic, and having an understanding of this disease and the methods available to help control the allergy will assist them in giving appropriate advice, alongside human healthcare professionals.

AIM

The aim of this review is to summarise currently available data on the prevalence, causes, symptoms and control of human allergy to cats. In terms of managing cat allergy, the emphasis is on reviewing current and emerging modalities to reduce environmental exposure to cat allergens rather than on pharmacotherapy or immunotherapy, as it is in these areas in particular that the veterinarian may be able to offer help and advice to complement that of human healthcare professionals.

EVIDENCE BASE

The information in this review is drawn from the current and historical literature on human allergy to cats, and approaches to reduce exposure to cat allergens and manage symptoms of cat allergy.

Multi-Dimensional Assessment and Interdisciplinary Care to Reduce Asthma Readmissions in Safety Net Hospitals

Asthma is a prevalent disease that disproportionately affects socioeconomically underprivileged minorities. In fact, racial and ethnic minorities such as Blacks and Latinos have higher rates of severe asthma, asthma-associated emergency department visits, hospitalizations, and readmissions compared with whites. Such disparities exist due to genetic predispositions and to socioeconomic determinants of health such as environmental factors and limited health-care access. A value-based purchasing program encourages hospitals to improve communication and care coordination to better engage patients and caregivers in discharge plans, and, in turn, reduce avoidable readmissions. The program supports the national goal of improving health care by linking payment to the quality of hospital care. Efforts have been made to address asthma-related complications in these populations, which have been addressed at various levels of the care system, including the patient and family, community, organization, provider/microsystem, and policy. Many of these programs promote patient education and health-care accessibility through interdisciplinary and multi-dimensional approaches, and have been shown to be effective in reducing asthma-associated readmissions and hospitalizations, but these localized approaches have not been largely adopted. The wide-spread implementation of asthma programs is necessary to address factors related to the increased incidence of asthma and associated rates of hospitalizations and readmissions in impoverished, minority populations.

Mechanisms for Alternaria alternata Function in the Skin During Induction of Peanut Allergy in Neonatal Mice With Skin Barrier Mutations

Neonatal mice with heterozygous mutations in genes encoding the skin barrier proteins filaggrin and mattrin (flaky tail mice [FT^+/-]) exhibit oral peanut-induced anaphylaxis after skin sensitization. As we have previously reported, sensitization in this model is achieved via skin co- exposure to the environmental allergen Alternaria alternata (Alt), peanut extract (PNE), and detergent. However, the function of Alt in initiation of peanut allergy in this model is little understood. The purpose of this study was to investigate candidate cytokines induced by Alt in the skin and determine the role of these cytokines in the development of food allergy, namely oncostatin M (Osm), amphiregulin (Areg), and IL-33. RT-qPCR analyses demonstrated that skin of FT^+/- neonates expressed Il33 and Osm following Alt or Alt/PNE but not PNE exposure. By contrast, expression of Areg was induced by either Alt, PNE, or Alt/PNE sensitization in FT^+/- neonates. In scRNAseq analyses, Osm, Areg, and Il33 were expressed by several cell types, including a keratinocyte cluster that was expanded in the skin of Alt/PNE-exposed FT^+/- pups as compared to Alt/PNE-exposed WT pups. Areg and OSM were required for oral PNE-induced anaphylaxis since anaphylaxis was inhibited by administration of neutralizing anti-Areg or anti-OSM antibodies prior to each skin sensitization with Alt/PNE. It was then determined if intradermal injection of recombinant IL33 (rIL33), rAreg, or rOSM in the skin could substitute for Alt during skin sensitization to PNE. PNE skin sensitization with intradermal rIL33 was sufficient for oral PNE-induced anaphylaxis, whereas skin sensitization with intradermal rAreg or rOSM during skin exposure to PNE was not sufficient for anaphylaxis to oral PNE challenge. Based on these studies a pathway for IL33, Areg and OSM in Alt/PNE sensitized FT^+/- skin was defined for IgE induction and anaphylaxis. Alt stimulated two pathways, an IL33 pathway and a pathway involving OSM and Areg. These two pathways acted in concert with PNE to induce food allergy in pups with skin barrier mutations.

Immunologic Strategies for Prevention of Asthma

A new understanding of factors leading to the development of asthma has pointed to potential primary, secondary, and tertiary prevention strategies. Some, such as genetic makeup, are not yet modifiable. Interventions targeting other factors such as maternal intake of vitamin D or environmental control can be used to decrease the risk of asthma development (primary prevention). The benefits of a diversified microbiome could be considered when recommending allergen avoidance and pet ownership. In addition to reducing symptoms, allergen immunotherapy is also worth considering for prevention of new sensitivities (secondary prevention) in addition to the development of asthma. Ongoing studies involving the use of bacterial vaccines and biologics may provide additional strategies for primary prevention of asthma and for reducing symptoms once it has developed (tertiary prevention). As the relative benefits of these strategies are defined, they should have an increasingly important place in the prevention and management of asthma.

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.

Single-cell transcriptomic analysis of allergen-specific T cells in allergy and asthma

CD4⁺ T helper (T_H) cells and regulatory T (T_reg) cells that respond to common allergens play an important role in driving and dampening airway inflammation in patients with asthma. Until recently, direct, unbiased molecular analysis of allergen-reactive T_H and T_reg cells has not been possible. To better understand the diversity of these T cell subsets in allergy and asthma, we analyzed the single-cell transcriptome of ~50,000 house dust mite (HDM) allergen-reactive T_H cells and T_reg cells from asthmatics with HDM allergy and from three control groups: asthmatics without HDM allergy and nonasthmatics with and without HDM allergy. Our analyses show that HDM allergen-reactive T_H and T_reg cells are highly heterogeneous and certain subsets are quantitatively and qualitatively different in individuals with HDM-reactive asthma. The number of interleukin-9 (IL-9)-expressing HDM-reactive T_H cells is greater in asthmatics with HDM allergy compared with nonasthmatics with HDM allergy, and this IL-9-expressing T_H subset displays enhanced pathogenic properties. More HDM-reactive T_H and T_reg cells expressing the interferon response signature (T_HIFNR and T_regIFNR) are present in asthmatics without HDM allergy compared with those with HDM allergy. In cells from these subsets (T_HIFNR and T_regIFNR), expression of TNFSF10 was enriched; its product, tumor necrosis factor-related apoptosis-inducing ligand, dampens activation of T_H cells. These findings suggest that the T_HIFNR and T_regIFNR subsets may dampen allergic responses, which may help explain why only some people develop T_H2 responses to nearly ubiquitous allergens.

Role of interleukins 12B and 17A genetic variation in house dust mites allergy

Background

The house dust mites (HDM) constitute a major cause of allergic diseases all over the world. Genes encoding interleukins 12B and 17A which determine the course of T cell-mediated immune response are prime candidates as allergic disease susceptibility. The purpose of this study was to evaluate whether a single-nucleotide polymorphisms (SNP) of interleukins 12B + 1188A/C (rs3212227) and 17A −197G/A (rs2275913) confers susceptibility to HDM allergic diseases. Through a case-control study, 120 subjects served as 60 dust mites' allergic patients and 60 healthy non-allergic controls. Total immunoglobulin (Ig) E level, eosinophilic count, serum interleukins 4, 10, 12B, and 17A levels for the studied subjects were measured. Then, genotyping of single-nucleotide polymorphisms (SNPs) at +1188A/C for IL12B and −197G/A for IL17A gene were conducted using restriction fragment length polymorphisms (RFLP-PCR).

Results

The present study showed that in HDMs' allergic subjects there was a significant increase in IL12B (+1188 A/C) and IL17A (−197 G/A) genotype variants compared to that of the controls. There was a significant increase in total IgE levels, eosinophil counts, and the levels of both IL-4 and IL-17A, while IL12B was significantly lower in patients compared to that of the controls. There was no significant difference in IL-10 levels between patients and controls.                                                                            

Conclusion

Our findings indicate that IL12B (+1188 A/C) and IL17A (−197G/A) might be associated with an increase in the susceptibility to dust mites’ allergic patients.

Outdoor air pollutants exposure associated with pulmonary function and EBC pH value in atopic asthmatic and non-asthmatic children

OBJECTIVE

Air pollution is associated with the prevalence of respiratory diseases. This study aimed to evaluate the impacts of outdoor air pollutants and indoor Dermatophagoides pteronyssinus 1 (Der p 1) exposure on levels of fractional exhaled nitric oxide (FeNO), exhaled breath condensate (EBC) pH, and pulmonary function in atopic children.

METHODS

This study recruited 59 atopic mild-to-moderate asthmatic children and 23 atopic non-asthmatic children. Data on personal characteristics, FeNO, EBC pH, and pulmonary function were collected. Group 1 allergens of Der p 1 were measured on the tops of mattresses and on bedroom floors in the children's homes, and outdoor air pollutant concentrations were estimated from air quality monitoring stations, using the ordinary kriging method.

RESULTS

Exposure levels of outdoor air pollutants, except for particulate matter (PM)_2.5, for the recruited children met outdoor air quality standards set by the Taiwan Environmental Protection Agency. The lag effect of outdoor PM₁₀ exposure was negatively associated with the forced expiratory volume in one second (FEV₁) [(Lag 1: β=-0.771, p = 0.028), and O₃ (Lag 1-7: β=-2.02, p = 0.04, Lag 1-28: β=-3.213, p = 0.029)]. Median pulmonary function parameters differed significantly in forced vital capacity (FVC) (p = 0.004) and FEV₁ (p = 0.024) values between atopic asthmatic and non-asthmatic children. No association was found between the FeNO/EBC pH level and exposure to Der p 1 allergen and air pollutants in the recruited children.

CONCLUSIONS

Outdoor PM₁₀ and O₃ exposure was associated with reduction in FEV₁ in atopic asthmatic and non-asthmatic children.

Identification of continuous immunoglobulin G epitopes of Dermatophagoides farinae allergens by peptide microarray immunoassay

Dermatophagoides farinae, as a common house dust mite species, is one of the main sources of allergens in the world. At present, Dermatophagoides farinae is found to contain more than 30 groups of allergens. These allergens are used for allergen-specific immunotherapy (AIT) of allergic diseases. During the AIT process, immunoglobulin G (IgG) antibodies can block immunoglobulin E (IgE) antibody-induced allergic reactions in the human body. One of the mechanisms may be that IgG and IgE competitively bind to the same allergic protein, so it is necessary to explore the binding sites (epitopes) of IgG antibodies to allergens. In this study, peptide arrays were constructed to react with the serums from patients with allergic asthma to find the IgG epitopes of several allergens including major allergens (Der f 1, 2) and mid-tier allergens (Der f 4, 5, and 7), and then verified by enzyme-linked immunosorbent assay (ELISA) test. Relevant epitopic sequences were located on the tertiary structure of individual allergens, as reconstructed by homology modeling. One IgG epitope of Der f 1 (90-106aa, NVPSELDLRSLRTVTPI), five IgG epitopes of Der f 4 (61-77aa, ERYQPVSYDIHTRSGDE; 193-209aa, FRSDASTHQWPDDLRSI; 226-242aa, HPFIYHETIYYGGNGIN; 271-287aa, LRWLRNFGTEWGLVPSG; 352-368aa, NDWVGPPTDQHGNILSV), and one IgG epitope of Der f 5 (84-101aa, RYNVEIALKSNEILERDL) were identified. IgG epitopes of Der f 2, 7 were not found. There are overlaps between the IgG and IgE epitopes of Der f 1, 4, and 5. These findings not only reflect the practicality of peptide array and ELISA test in the allergen IgG epitope identification, but also provide more information for further understanding of the human immunological changes during AIT and the molecular mechanisms of IgG blocking IgE activity.

Mechanisms of Particles in Sensitization, Effector Function and Therapy of Allergic Disease

Humans have always been in contact with natural airborne particles from many sources including biologic particulate matter (PM) which can exhibit allergenic properties. With industrialization, anthropogenic and combustion-derived particles have become a major fraction. Currently, an ever-growing number of diverse and innovative materials containing engineered nanoparticles (NPs) are being developed with great expectations in technology and medicine. Nanomaterials have entered everyday products including cosmetics, textiles, electronics, sports equipment, as well as food, and food packaging. As part of natural evolution humans have adapted to the exposure to particulate matter, aiming to protect the individual's integrity and health. At the respiratory barrier, complications can arise, when allergic sensitization and pulmonary diseases occur in response to particle exposure. Particulate matter in the form of plant pollen, dust mites feces, animal dander, but also aerosols arising from industrial processes in occupational settings including diverse mixtures thereof can exert such effects. This review article gives an overview of the allergic immune response and addresses specifically the mechanisms of particulates in the context of allergic sensitization, effector function and therapy. In regard of the first theme (i), an overview on exposure to particulates and the functionalities of the relevant immune cells involved in allergic sensitization as well as their interactions in innate and adaptive responses are described. As relevant for human disease, we aim to outline (ii) the potential effector mechanisms that lead to the aggravation of an ongoing immune deviation (such as asthma, chronic obstructive pulmonary disease, etc.) by inhaled particulates, including NPs. Even though adverse effects can be exerted by (nano)particles, leading to allergic sensitization, and the exacerbation of allergic symptoms, promising potential has been shown for their use in (iii) therapeutic approaches of allergic disease, for example as adjuvants. Hence, allergen-specific immunotherapy (AIT) is introduced and the role of adjuvants such as alum as well as the current understanding of their mechanisms of action is reviewed. Finally, future prospects of nanomedicines in allergy treatment are described, which involve modern platform technologies combining immunomodulatory effects at several (immuno-)functional levels.

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 Home Environments in Allergic Disease

Allergic diseases are surprisingly common, chronic health conditions. The primary location where the vast majority of people are exposed to allergens and other substances is in their home. This means it is important to understand home environments and how a home's systems function and interact-and that how we occupy these spaces plays a crucial role in both environmental exposure and management of allergic disease. This review provides an overview of what is understood about home environmental exposure and its impact on our health, and proposes a systematic process for using a patient's environmental history to develop individualized, manageable and cost-effective recommendations. Once occupant-related information has been gathered, a home environmental exposure assessment should be performed focused on identifying the relationships between any identified sources of contaminants and the housing systems, and conditions that may be contributing to exposure. The results and recommendations from this assessment can then be used to guide exposure-reduction efforts by patients and/or their caregivers in an effort to improve disease management. In this review, we'll discuss three different types of home interventions-active, which must be routinely performed by the patient and/or caregiver, passive, which are interventions that work without routine, direct interaction from the homeowner, and behavioral changes in how the home environment is cleaned and maintained for long-term reduction of allergens. In this review, and others evaluated for this discussion, a significant number of home environmental assessment and intervention programs were shown to be cost effective, with the majority of programs showing a net positive return on investment. It is important to recognize that to be cost effective, the level and intensity of services offered through home visit programs need be stratified, based on the estimated health risks of the patient, in order to tailor the assessment and target the interventions to a patient's needs while maximizing cost effectiveness.

Efficacy of indoor air purification in the treatment of Artemisia pollen-allergic rhinitis: A randomised, double-blind, clinical controlled trial

Objectives

To evaluate the clinical efficacy of a high‐efficiency air purifier in patients with allergic rhinitis.

Design

We conducted a randomised, double‐blind, clinical controlled trial with active and inactive versions of an air purifier. Our study included patients with allergic rhinitis who were sensitive to Artemisia pollen and treatment of the indoor environment using air filtration at night. We evaluated the clinical efficacy of indoor air filtration during the Artemisia pollen scattering season in Yulin City in Shanxi Province, China.

Setting

The First Hospital of Yulin (Yulin City, Shanxi Province, China).

Participants

A total of 90 patients with allergic rhinitis who were sensitive to allergens of Artemisia pollen were randomly assigned to one of two groups in equal numbers.

Main outcome measures

The primary outcome measure was the difference in visual analogue scale scores from baseline. Secondary outcomes were changes from baseline in nasal symptoms, allergy symptom scores, responses to the Rhinoconjunctivitis Quality of Life Questionnaire, Epworth Sleepiness Scale scores and tolerability scores for the air purifier.

Results

Based on the allergy symptom score, we found significant differences in rhinitis symptoms between the groups who used the active versus the inactive air purifier.

Conclusions

The results of our investigation demonstrated the health benefits of particle filtration.

Endotoxin clustering with allergens in house dust and asthma outcomes in a U.S. national study

BACKGROUND

Endotoxin is ubiquitous in the environment, but its clustering with indoor allergens is not well characterized. This study examined the clustering patterns of endotoxin with allergens in house dust and their association with asthma outcomes.

METHODS

We analyzed data from 6963 participants of the 2005-2006 National Health and Nutrition Examination Survey. House dust sampled from bedroom floor and bedding was evaluated for endotoxin and allergens from fungi, cockroach, dog, cat, mites, and rodents. Two-step cluster analysis and logistic regressions were performed to identify the clustering patterns and their associations with current asthma and wheeze in the past 12 months, adjusting for covariates.

RESULTS

Of the homes, 17.8% had low endotoxin and allergen levels in house dust (Cluster 1). High endotoxin level clustered with Alternaria and pet allergens in the homes of participants with a high socioeconomic status who own pets (Cluster 2) (48.9%). High endotoxin clustered with Aspergillus, dust mites, cockroach, and rodent allergens in the homes of participants with low socioeconomic status (Cluster 3) (33.3%). Compared to Cluster 1, Cluster 2 was associated with higher asthma prevalence (OR 1.42, 95% CI: 1.06-1.91) and wheeze (OR 1.32, 95% CI: 1.07-1.63). Cluster 3 was positively associated with wheeze only in participants sensitized to inhalant allergens (OR 1.42, 95% CI: 1.06-1.91) or exposed to tobacco smoke (OR 1.72, 95% CI: 1.15-2.60).

CONCLUSIONS

The clustering of endotoxin with allergens in dust from homes with pets or of people with low socioeconomic status is associated with asthma and wheeze.

New Directions in Pediatric Asthma

Childhood asthma affects many children placing them at significant risk for health care utilization and school absences. Several new developments relevant to the field of pediatric asthma have occurred over the last 5 years; yet, there is much more to learn. It is poorly understood how to prevent the disease, optimally address environmental challenges, or effectively manage poor adherence. Moreover, it is not clear how to customize therapy by asthma phenotype, age group, high risk groups, or severity of disease. Highlights of advances in pediatric asthma are reviewed and multiple essential areas for further exploration and research are discussed.

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.

Do Baseline Asthma and Allergic Sensitization Characteristics Predict Responsiveness to Mouse Allergen Reduction?

BACKGROUND

Mouse allergen reduction is associated with improvements in asthma among sensitized and exposed children, but whether clinical characteristics predict responsiveness to allergen reduction is unclear.

OBJECTIVE

To examine the effects of clinical characteristics on relationships between mouse allergen reduction and asthma outcomes.

METHODS

We performed a secondary analysis of data from a randomized clinical trial of a mouse allergen intervention, examining the effects of atopy, demographic characteristics, lung function, asthma control, and asthma severity on relationships between mouse allergen reduction and asthma outcomes.

RESULTS

Participants were predominantly low-income and minority (78% black, 22% Hispanic), and had persistent asthma. Among less atopic participants (<6 positive skin prick test results), each 50% reduction in mouse allergen was associated with fewer symptoms (incidence rate ratio [95% CI]: maximal symptoms: 0.94 [0.92-0.96]). There was little effect of mouse allergen reduction on symptoms among more atopic participants (P > .05). The interactions between atopic status and mouse allergen reduction were statistically significant for all symptom outcomes; however, there was no evidence that atopic status influenced the effect of mouse allergen reduction on exacerbation-related outcomes. Older children (≥9 years) tended to experience greater improvement in some asthma outcomes with reduction in mouse allergen exposure than younger children. There was no evidence that either mouse-specific IgE or lung function influenced the effect of mouse allergen reduction on any asthma outcomes.

CONCLUSIONS

Although there may be variability in the clinical response to mouse allergen reduction among low-income, minority children with asthma, there were no clinical characteristics that clearly identified a subgroup at which the intervention should be targeted.

Acute Severe Asthma in Adolescent and Adult Patients: Current Perspectives on Assessment and Management

Asthma is a chronic airway inflammatory disease that is associated with variable expiratory flow, variable respiratory symptoms, and exacerbations which sometimes require hospitalization or may be fatal. It is not only patients with severe and poorly controlled asthma that are at risk for an acute severe exacerbation, but this has also been observed in patients with otherwise mild or moderate asthma. This review discusses current aspects on the pathogenesis and pathophysiology of acute severe asthma exacerbations and provides the current perspectives on the management of acute severe asthma attacks in the emergency department and the intensive care unit.

Ecological determinants of respiratory health: Examining associations between asthma emergency department visits, diesel particulate matter, and public parks and open space in Los Angeles, California

Los Angeles County (LAC) low-income communities of color experience uneven asthma rates, evidenced by asthma emergency department visits (AEDV). This has partly been attributed to inequitable exposure to diesel particulate matter (DPM). Promisingly, public parks and open space (PPOS) contribute to DPM mitigation. However, low-income communities of color with limited access to PPOS may be deprived of associated public health benefits. Therefore, this novel study investigates the AEDV, DPM, PPOS nexus to address this public health dilemma and inform public policy in at-risk communities. Optimized Hotspot Analysis was used to examine geographic clustering of AEDVs, DPM, and PPOS at the census tract unit of analysis in LAC. Ordinary Least Squares (OLS) regression analysis was used to examine the extent to which DPM and PPOS predict AEDVs. Finally, Geographic Weighted Regression (GWR) was employed to account for spatial dependence in the global OLS model. Optimized Hotspot Analysis confirmed significant clustering of elevated AEDVs and DPM in census tracts with reduced PPOS. After controlling for pertinent demographic characteristics (poverty, children, race/ethnicity), regression analysis confirmed that DPM was significantly positively associated with AEDVs, whereas PPOS was significantly negatively associated with AEDVs. Furthermore, GWR revealed that 71.5% of LACs census tracts would benefit from DPM reductions and 79.4% would benefit from PPOS increases toward redressing AEDVs. This is the first study to identify AEDV reductions in census tracts with higher concentrations of PPOS. Thus, reducing DPM and increasing PPOS may serve to improve asthma outcomes, particularly in low-income communities of color.

The Effects of the Environment on Asthma Disease Activity

Asthma is highly prevalent and causes significant morbidity in children. The development of asthma depends on complex relationships between genetic predisposition and environmental modifiers of immune function. The biological and physical environmental factors include aeroallergens, microbiome, endotoxin, genetics, and pollutants. The psychosocial environment encompasses stress, neighborhood safety, housing, and discrimination. They all have been speculated to influence asthma control and the risk of developing asthma. Control of the factors that contribute to or aggravate symptoms, interventions to eliminate allergen exposure, guidelines-based pharmacologic therapy, and education of children and their caregivers are of paramount importance.

Sirtuin 2 enhances allergic asthmatic inflammation

Allergic eosinophilic asthma is a chronic condition causing airway remodeling resulting in lung dysfunction. We observed that expression of sirtuin 2 (Sirt2), a histone deacetylase, regulates the recruitment of eosinophils after sensitization and challenge with a triple antigen: dust mite, ragweed, and Aspergillus fumigatus (DRA). Our data demonstrate that IL-4 regulates the expression of Sirt2 isoform 3/5. Pharmacological inhibition of Sirt2 by AGK2 resulted in diminished cellular recruitment, decreased CCL17/TARC, and reduced goblet cell hyperplasia. YM1 and Fizz1 expression was reduced in AGK2-treated, IL-4-stimulated lung macrophages in vitro as well as in lung macrophages from AGK2-DRA-challenged mice. Conversely, overexpression of Sirt2 resulted in increased cellular recruitment, CCL17 production, and goblet cell hyperplasia following DRA challenge. Sirt2 isoform 3/5 was upregulated in primary human alveolar macrophages following IL-4 and AGK2 treatment, which resulted in reduced CCL17 and markers of alternative activation. These gain-of-function and loss-of-function studies indicate that Sirt2 could be developed as a treatment for eosinophilic asthma.

Association of food allergy and decreased lung function in children and young adults with asthma

BACKGROUND

Food allergy (FA) appears early in the atopic march, a progression that may lead to the development of asthma. The association between FA and pulmonary function in children with and without asthma remains unknown.

OBJECTIVE

To investigate the association between FA and lung function in children with and without asthma.

METHODS

We enrolled 1,068 children as a part of a family-based FA cohort. We then categorized children as having FA by physician diagnosis, evidence of specific IgE, and typical symptoms within 2 hours of food ingestion. We categorized asthma by physician diagnosis. We used American Thoracic Society criteria for spirometry measurements. We assessed the effects of asthma classification and FA number on lung function using mixed-effect models.

RESULTS

We enrolled 1,068 children: 417 (39%) had asthma, 402 (38%) had at least 1 FA, and 162 (15%) had 2 or more FAs. Unstratified analyses found no significant association between FA number and lung function. In children with asthma, we detected statistically significant differences in predicted forced expiratory flow at 25% to 75% between children with 2 or more FAs compared with those with none (mean [SE] β = -7.5 [3.6]; P = .04). This effect lost significance after adjusting for aeroallergen sensitization. We detected no significant associations between FA number and predicted forced expiratory volume in 1 second, forced vital capacity, and ratio of forced expiratory volume in 1 second to forced vital capacity.

CONCLUSION

Having 2 or more FAs is a potential risk factor for greater small airway airflow obstruction among children with asthma, highlighting the need for close clinical follow-up and improved intervention strategies for these patients.

Cross-Reactivity between Major IgE Epitopes of Family 5 Allergens from Dermatophagoides pteronyssinus and Blomia tropicalis

BACKGROUND

The aim of this work was to understand the molecular features that trigger the cross-reactivity observed between Der p 5 from Dermatophagoides pteronyssinus, Blo t 5 from Blomia tropicalis, and Der f 5 from D. farinae.

METHODS

We collected serum from 60 house dust mite (HDM)-allergic patients residing in the Dellys area of Boumerdès province in northern Algeria. The presence of specific IgE to Der p 5, Der f 5, and Blo t 5 was analyzed. We performed in silico analysis of the structure of the different allergens in order to identify epitopes that can elicit the cross-reactivity of the sera. Synthetic peptides corresponding to the linear epitope sequence of Der p 5, Der f 5, and Blo t 5 were used to evaluate its implication in the cross-reactivity between the allergens. We also modified the sequence of the conformational epitope of Der p 5 by site-directed mutagenesis to mimic Blo t 5.

RESULTS

Several sera of patients allergic to HDM contained specific IgE antibodies to Der p 5 and Blo t 5. We demonstrated that the linear epitope of Der p 5 and Blo t 5 is not involved in the cross-reactivity of the sera. Furthermore, mutations introduced in the sequence of Der p 5 to mimic Blo t 5 could not modulate the cross-reactivity between them.

CONCLUSIONS

The major linear IgE epitopes of Der p 5 and Blo t 5 are involved in species-specific recognition. Our results may be useful for the development of a hypoallergenic vaccine against HDM group 5 allergens.

Impact of eosinophil-peroxidase (EPX) deficiency on eosinophil structure and function in mouse airways

Eosinophil peroxidase (EPX) is a major constituent of the large cytoplasmic granules of both human and mouse eosinophilic leukocytes. Human EPX deficiency is a rare, autosomal-recessive disorder limited to the eosinophil lineage. Our intent was to explore the impact of EPX gene deletion on eosinophil content, structure, and function. In response to repetitive intranasal challenge with a filtrate of the allergen, Alternaria alternata, we found significantly fewer eosinophils peripherally and in the respiratory tracts of EPX^-/- mice compared to wild-type controls; furthermore, both the major population (Gr1^-/lo ) and the smaller population of Gr1^hi eosinophils from EPX^-/- mice displayed lower median fluorescence intensities (MFIs) for Siglec F. Quantitative evaluation of transmission electron micrographs of lung eosinophils confirmed the relative reduction in granule outer matrix volume in cells from the EPX^-/- mice, a finding analogous to that observed in human EPX deficiency. Despite the reduced size of the granule matrix, the cytokine content of eosinophils isolated from allergen-challenged EPX^{-/ -} and wild-type mice were largely comparable to one another, although the EPX^-/- eosinophils contained reduced concentrations of IL-3. Other distinguishing features of lung eosinophils from allergen-challenged EPX^-/- mice included a reduced fraction of surface TLR4⁺ cells and reduced MFI for NOD1. Interestingly, the EPX gene deletion had no impact on eosinophil-mediated clearance of gram-negative Haemophilus influenzae from the airways. As such, although no clinical findings have been associated with human EPX deficiency, our findings suggest that further evaluation for alterations in eosinophil structure and function may be warranted.

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.

Alternaria alternata challenge at the nasal mucosa results in eosinophilic inflammation and increased susceptibility to influenza virus infection

BACKGROUND

Eosinophils in the nasal mucosa are an elemental feature of allergic rhinitis.

OBJECTIVE

Our objective was to explore eosinophilic inflammation and its impact on respiratory virus infection at the nasal mucosa.

METHODS

Inflammation in the nasal mucosae of mice was evaluated in response to repetitive stimulation with strict intranasal volumes of a filtrate of Alternaria alternata. Mice were then challenged with influenza virus.

RESULTS

Repetitive stimulation with A. alternata resulted in eosinophil recruitment to the nasal passages in association with elevated levels of IL-5, IL-13 and eotaxin-1; eosinophil recruitment was diminished in eotaxin-1-/- mice, and abolished in Rag1-/- mice. A. alternata also resulted in elevated levels of nasal wash IgA in both wild-type and eosinophil-deficient ∆dblGATA mice. Interestingly, A. alternata-treated mice responded to an influenza virus infection with profound weight loss and mortality compared to mice that received diluent alone (0% vs 100% survival, ***P < .001); the lethal response was blunted when A. alternata was heat-inactivated. Minimal differences in virus titre were detected, and eosinophils present in the nasal passages at the time of virus inoculation provided no protection against the lethal sequelae. Interestingly, nasal wash fluids from mice treated with A. alternata included more neutrophils and higher levels of pro-inflammatory mediators in response to virus challenge, among these, IL-6, a biomarker for disease severity in human influenza.

CONCLUSIONS AND CLINICAL RELEVANCE

Repetitive administration of A. alternata resulted in inflammation of the nasal mucosae and unanticipated morbidity and mortality in response to subsequent challenge with influenza virus. Interestingly, and in contrast to findings in the lower airways, eosinophils recruited to the nasal passages provided no protection against lethal infection. As increased susceptibility to influenza virus among individuals with rhinitis has been the subject of several clinical reports, this model may be used for further exploration of these observations.

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.

Mechanism for initiation of food allergy: Dependence on skin barrier mutations and environmental allergen costimulation

BACKGROUND

Mechanisms for the development of food allergy in neonates are unknown but clearly linked in patient populations to a genetic predisposition to skin barrier defects. Whether skin barrier defects contribute functionally to development of food allergy is unknown.

OBJECTIVE

The purpose of the study was to determine whether skin barrier mutations, which are primarily heterozygous in patient populations, contribute to the development of food allergy.

METHODS

Mice heterozygous for the filaggrin (Flg)ft and Tmem79ma mutations were skin sensitized with environmental and food allergens. After sensitization, mice received oral challenge with food allergen, and then inflammation, inflammatory mediators, and anaphylaxis were measured.

RESULTS

We define development of inflammation, inflammatory mediators, and food allergen-induced anaphylaxis in neonatal mice with skin barrier mutations after brief concurrent cutaneous exposure to food and environmental allergens. Moreover, neonates of allergic mothers have increased responses to suboptimal sensitization with food allergens. Importantly, responses to food allergens by these neonatal mice were dependent on genetic defects in skin barrier function and on exposure to environmental allergens. ST2 blockade during skin sensitization inhibited the development of anaphylaxis, antigen-specific IgE, and inflammatory mediators. Neonatal anaphylactic responses and antigen-specific IgE were also inhibited by oral pre-exposure to food allergen, but interestingly, this was blunted by concurrent pre-exposure of the skin to environmental allergen.

CONCLUSION

These studies uncover mechanisms for food allergy sensitization and anaphylaxis in neonatal mice that are consistent with features of human early-life exposures and genetics in patients with clinical food allergy and demonstrate that changes in barrier function drive development of anaphylaxis to food allergen.

An update on molecular cat allergens: Fel d 1 and what else? Chapter 1: Fel d 1, the major cat allergen

Background

Cats are the major source of indoor inhalant allergens after house dust mites. The global incidence of cat allergies is rising sharply, posing a major public health problem. Ten cat allergens have been identified. The major allergen responsible for symptoms is Fel d 1, a secretoglobin and not a lipocalin, making the cat a special case among mammals.

Main body

Given its clinical predominance, it is essential to have a good knowledge of this allergenic fraction, including its basic structure, to understand the new exciting diagnostic and therapeutic applications currently in development. The recent arrival of the component-resolved diagnosis, which uses molecular allergens, represents a unique opportunity to improve our understanding of the disease. Recombinant Fel d 1 is now available for in vitro diagnosis by the anti-Fel d 1 specific IgE assay. The first part of the review will seek to describe the recent advances related to Fel d 1 in terms of positive diagnosis and assessment of disease severity. In daily practice, anti-Fel d 1 IgE tend to replace those directed against the overall extract but is this attitude justified? We will look at the most recent arguments to try to answer this question. In parallel, a second revolution is taking place thanks to molecular engineering, which has allowed the development of various forms of recombinant Fel d 1 and which seeks to modify the immunomodulatory properties of the molecule and thus the clinical history of the disease via various modalities of anti-Fel d 1-specific immunotherapy. We will endeavor to give a clear and practical overview of all these trends.

An update on molecular cat allergens: Fel d 1 and what else? Chapter 1: Fel d 1, the major cat allergen

Background

Cats are the major source of indoor inhalant allergens after house dust mites. The global incidence of cat allergies is rising sharply, posing a major public health problem. Ten cat allergens have been identified. The major allergen responsible for symptoms is Fel d 1, a secretoglobin and not a lipocalin, making the cat a special case among mammals.

Main body

Given its clinical predominance, it is essential to have a good knowledge of this allergenic fraction, including its basic structure, to understand the new exciting diagnostic and therapeutic applications currently in development. The recent arrival of the component-resolved diagnosis, which uses molecular allergens, represents a unique opportunity to improve our understanding of the disease. Recombinant Fel d 1 is now available for in vitro diagnosis by the anti-Fel d 1 specific IgE assay. The first part of the review will seek to describe the recent advances related to Fel d 1 in terms of positive diagnosis and assessment of disease severity. In daily practice, anti-Fel d 1 IgE tend to replace those directed against the overall extract but is this attitude justified? We will look at the most recent arguments to try to answer this question. In parallel, a second revolution is taking place thanks to molecular engineering, which has allowed the development of various forms of recombinant Fel d 1 and which seeks to modify the immunomodulatory properties of the molecule and thus the clinical history of the disease via various modalities of anti-Fel d 1-specific immunotherapy. We will endeavor to give a clear and practical overview of all these trends.

The role of the indoor environment: Residential determinants of allergy, asthma and pulmonary function in children from a US-Mexico border community

The El Paso Children's Health Study examined environmental risk factors for allergy and asthma among fourth and fifth grade schoolchildren living in a major United States-Mexico border city. Complete questionnaire information was available for 5210 children, while adequate pulmonary function data were available for a subset of 1874. Herein we studied indoor environmental health risk factors for allergy and asthma. Several indoor environmental risk factors were associated with allergy and asthma. In particular, we found that ant and spider pest problems, pet dogs, fireplace heat, central air conditioning, humidifier use, and cooking with gas stoves were positively associated with both allergy and asthma prevalence. With regards to asthma severity, our analysis indicated that exposure to pet dogs increased monotonically with increasing asthma severity while the lack of any heat source and gas stove use for cooking decreased monotonically with increasing asthma severity. Lung function also decreased among children who lived in homes with reported cockroach pest problem in the past year without concurrent use of pesticides. These effects on pulmonary function were present even after excluding children with a current physician's diagnosis of asthma. Clinicians and public health professionals may need to look closely at the contribution of these indoor risk factors on pulmonary health and quality of life among susceptible populations.