Quantitative measurement of airborne cockroach allergen in New York City apartments

German cockroach extract prevents IL-13-induced CCL26 expression in airway epithelial cells through IL-13 degradation

Inhaled aeroallergens can directly activate airway epithelial cells (AECs). Exposure to cockroach allergens is a strong risk factor for asthma. Cockroach allergens mediate some of their effects through their serine protease activity; protease activity is also a major contributor to allergenicity. The Th2 cytokine interleukin-13 (IL-13) induces upregulation of the eosinophil chemotactic factor CCL26. CCL26 induces eosinophil migration in allergic inflammation. In this work, we studied the effect of cockroach proteases on IL-13-induced effects. Immersed cultures of the human bronchial epithelial cell line BEAS-2B and air-liquid interface (ALI) cultures of primary normal human bronchial epithelial (NHBE) cells were stimulated with IL-13, Blattella Germanica cockroach extract (CE), or both. IL-13-induced genes were analyzed with qRT-PCR. IL-13 induced upregulation of CCL26, periostin, and IL-13Rα2 in bronchial epithelial cells which were decreased by CE. CE was heat-inactivated (HICE) or pre-incubated with protease inhibitors. HICE and CE preincubated with serine protease inhibitors did not prevent IL-13-induced CCL26 upregulation. CE-degraded IL-13 and specific cleavage sites were identified. CE also decreased IL-4-induced CCL26 upregulation and degraded IL-4. Other serine proteases such as bovine trypsin and house dust mite (HDM) serine proteases did not have the same effects on IL-13-induced CCL26. We conclude that CE serine proteases antagonize IL-13-induced effects in AECs, and this CE effect is mediated primarily through proteolytic cleavage of IL-13. IL-13 cleavage by cockroach serine proteases may modulate CCL26-mediated effects in allergic airway inflammation by interfering directly with the pro-inflammatory effects of IL-13 in vivo.

Spatial distribution of histamine in bed bug-infested homes

Histamine is a component of the bed bug aggregation pheromone. It was recently identified as an environmental contaminant in homes with active bed bug infestations, posing a potential health risk to humans via skin contact or inhalation. It remains unclear how histamine is distributed in homes and if histamine can become airborne. In the present study, histamine levels in household dust were quantified from multiple locations within bed bug infested and uninfested apartments. Bed bug population levels were quantified using both traps and visual counts. The amount of histamine detected varied significantly with respect to sampling location, with the highest concentration of histamine quantified from bedding material. Infestation severity did not have a significant effect on histamine quantified at any location. Our results indicate that the bedroom should be the primary focus of histamine mitigation efforts, although histamine can be found throughout the home. Histamine quantified from homes without active bed bug infestations suggests that histamine from previous infestations can persist following pest eradication. These findings highlight the importance of histamine as a potential insect allergen and will be important for the development of targeted mitigation strategies of bed bug histamine.

Protozoan Cysts in Faecal Pellets of German Cockroaches (Blattella germanica), with Particular Emphasis on Lophomonas blattarum

Purpose

The aim of this study was to investigate protozoan cysts and oocyts in the faecal pellets of the German cockroach (Blattella germanica), with emphasis on the prevalence of Lophomonas blattarum.

Methods

Thirty adult Blattella germanica (12 males; 18 females) were trapped near Madrid, Spain. Expelled faecal pellets were collected in the laboratory over 5 days in two plastic containers. Protozoan cysts from one container were weighted and those in the other used for morphologically identification.

Results

Protozoan cysts/oocysts per gram of faecal pellet were: Nyctotherus sp. (0.0019/g), Entamoeba (0.0007/g), Balantidium coli (0.0001/g), Lophomonas blattarum (0.00038/g). Observation of 189 protozoan cysts/oocysts indicated the following prevalence: Nyctotherus sp. 65 (34.4%); Gregarina spp. 34 (18%); Entamoeba sp. 24 (12.7%); Cryptosporidium sp. 17 (9%); Coccidia 16 (8.4%); Lophomonas blattarum 13 (6.8%); Balantidium coli 4 (2.1%); and unclassified 16 (8.4%).

Conclusion

Lophomonas blattarum has previously been demonstrated in the gut of cockroaches, but this is the first assessment of the prevalence in Blattella germanica in faecal pellets. The presence of protozoa in faecal pellets provides some evidence for one step in a hypothesised route of respiratory infection whereby protozoa from household insects enter the respiratory tract.

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.

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.

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.

Analysis of 10 Environmental Allergen Components of the American Cockroach in Taiwan

BACKGROUND

Cockroaches are important sources of indoor airborne allergens. The American cockroach (Periplaneta americana) is the second leading inhalant allergen causing allergic airway diseases in Taiwan. We previously reported a difference in pathogenicity of different allergen components from American cockroaches.

OBJECTIVE

To analyze the environmental profile of American cockroach allergen components.

METHODS

Polyclonal antibodies were generated to recombinant American cockroach allergens, Per a 1 through Per a 10. The levels of each allergen in (1) whole-body extracts and feces from American cockroaches and in (2) fresh-frozen 6-month-old and 12-month-old dead American cockroaches were evaluated by immunoblotting and quantified. Levels of allergen components from patients' household dust samples were determined by competition enzyme-linked immunosorbent assay.

RESULTS

Per a 1, 2, and 10 proteins were present predominantly in roach feces, whereas other allergen components were found predominantly in roach bodies. There was a time-dependent decrease in total levels of some allergen proteins. Although levels of Per a 4, 5, 6, and 9 significantly decreased to less 20% of the basal level, there was no significant change in levels of Per a 2, 7, and 10 after 1-year decomposition. The most abundant allergen components in 20 dust samples from patients' houses were Per a 9, Per a 10, and Per a 2.

CONCLUSION

The concentration of 10 American cockroach allergen components differed in the environment. Per a 2 and Per a 10 can be used as markers of long-term environmental cockroach control and Per a 9 as current status of control in patients' houses.

Measurement of aeroallergens from furnace filters

BACKGROUND

Exposure assessment is an important component of allergic disease diagnosis and management. Analysis for allergen content in vacuumed dust has been used traditionally.

OBJECTIVE

To study allergen levels of dust taken from high-efficiency furnace filters in Midwestern homes.

METHODS

Furnace filters used were FQT12 1-inch disposable filters with high-efficiency media placed in homes enrolled in the Kansas City Safe and Healthy Homes Project. Dust was removed from the filters by vacuuming. Fungal culture was used to obtain counts of viable spores. Aeroallergens Fel d1, Can f1, Mus m1, Der f1, Der p1, and Bla g2 and antigenic material from Alternaria, Aspergillus, Cladosporium, and Penicillium species were measured using commercially available immunoassay materials.

RESULTS

Sixty filters were recovered from 56 homes after an average 135 days in situ. Mean weight of dust recovered was 2.43 g and correlated well with the time the filter was in place. Viable spore counts ranged to 4.8 × 10(7) per gram of dust. Mean fungal antigenic material ranged to 42 μg per gram for Cladosporium species. Mean aeroallergen material ranged to 7 μg per gram for Fel d1. Aeroallergen measurements were above the level of detection in 100% of houses for Fel d1 and 89% of houses for Bla g2. Levels of Fel d1 and Can f1 were strongly positively correlated.

CONCLUSION

Allergens from 5 common aeroallergen species and antigenic material from 4 common fungal taxa can be measured in dust taken from high-efficiency furnace filters.

Associations of neighborhood concentrated poverty, neighborhood racial/ethnic composition, and indoor allergen exposures: a cross-sectional analysis of los angeles households, 2006-2008

Although racial/ethnic, socioeconomic, and neighborhood factors have been linked to asthma, and the association between indoor allergens and asthma is well documented, few studies have examined the relationship between these factors and indoor allergens. We examined the frequency of reported indoor allergens and differences by racial/ethnic, socioeconomic, and neighborhood characteristics among a diverse sample of Los Angeles households. Multilevel logistic regression models were used to analyze the data from 723 households from wave 2 of the Los Angeles Family and Neighborhood Survey. The reported presence of rats, mice, cockroaches, mold, pets, and tobacco smoke were the primary outcomes of interest. Hispanic and Asian households had a nearly threefold increase in the odds of reporting cockroaches compared to non-Hispanic Whites (OR, 2.85; 95 % CI 1.38-5.88 and OR, 2.62; 95 % CI 1.02-6.73, respectively) even after adjusting for socioeconomic factors. Primary caregivers who had obtained a high school degree were significantly less likely to report the presence of mice and cockroaches compared to primary caregivers with less than a high school degree (OR, 0.19; 95 % CI 0.08-0.46 and OR, 0.39; 95 % CI 0.23-0.68, respectively). Primary caregivers with more than a high school degree were also less likely to report the presence of rats, mice, and cockroaches within their households, compared to those with less than a high school degree. Compared to renters, home owners were less likely to report the presence of mice, cockroaches, and mold within their households. At the neighborhood level, households located within neighborhoods of high concentrated poverty (where the average poverty rate is at least 50 %) were more likely to report the presence of mice and cockroaches compared to households in low concentrated poverty neighborhoods (average poverty rate is 10 % or less), after adjusting for individual race/ethnicity and socioeconomic characteristics. Our study found evidence in support of neighborhood-level racial/ethnic and socioeconomic influences on indoor allergen exposure, above and beyond individual factors. Future studies should continue to explore individual and neighborhood-level racial/ethnic and socioeconomic differences in household allergen exposures across diverse contexts.

Human β-defensin HBD3 binds to immobilized Bla g2 from the German cockroach (Blattella germanica)

Human β-defensin 3 (HBD3) is a small, well-characterized peptide in mucosal secretions with broad antimicrobial activities and diverse innate immune functions. Among these functions is the ability of HBD3 to bind to antigens. In this study, we hypothesize that HBD3 binds to the allergen Bla g2 from the German cockroach (Blattella germanica). The ability of HBD1 (used as a control β-defensin) and HBD3 to bind to Bla g2 and human serum albumin (HSA, used as a control ligand) was assessed using the SensíQ Pioneer surface plasmon resonance (SPR) spectroscopy biosensor system. HBD1 was observed to bind weakly to Bla g2, while HBD3 demonstrated a stronger affinity for the allergen. HBD3 was assessed under two buffer conditions using 0.15 M and 0.3 M NaCl to control the electrostatic attraction of the peptide to the chip surface. The apparent K(D) of HBD3 binding Bla g2 was 5.9±2.1 μM and for binding HSA was 4.2±0.7 μM, respectively. Thus, HBD3, found in mucosal secretions has the ability to bind to allergens like Bla g2 possibly by electrostatic interaction, and may alter the ability of Bla g2 to induce localized allergic and/or inflammatory mucosal responses.

Environmental assessment and exposure reduction of cockroaches: a practice parameter

This parameter was developed by the Joint Task Force on Practice Parameters, representing the American Academy of Allergy, Asthma & Immunology (AAAAI); the American College of Allergy, Asthma & Immunology (ACAAI); and the Joint Council of Allergy, Asthma & Immunology. The AAAAI and the ACAAI have jointly accepted responsibility for establishing "Environmental assessment and remediation: a practice parameter." This is a complete and comprehensive document at the current time. The medical environment is a changing environment, and not all recommendations will be appropriate for all patients. Because this document incorporated the efforts of many participants, no single person, including those who served on the Joint Task Force, is authorized to provide an official AAAAI or ACAAI interpretation of these practice parameters. Any request for information about or an interpretation of these practice parameters by the AAAAI or ACAAI should be directed to the Executive Offices of the AAAAI, the ACAAI, and the Joint Council of Allergy, Asthma & Immunology. These parameters are not designed for use by pharmaceutical companies in drug promotion. The findings and conclusions in this manuscript are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention (CDC).

Time for new methods for avoidance of house dust mite and other allergens

Asthma is a common disease in which environmental exposures and lifestyle factors play critical roles in expression and symptoms. Recommended methods for reducing exposure to domestic allergens as a component of asthma and rhinitis management have changed little over the last 30 years. The data that implementation of these provides clinical benefit are inconsistent. We contend that current methods are ineffective at reducing chronic personal exposure. More effective strategies can be developed based on understanding when people are exposed, the sources of this exposure and the activities associated with this exposure. Developing new methods should be founded on understanding the aerodynamic behavior of particles, their aerosolization, removal from surfaces, and the complex relationships between exposures and clinical outcomes. It will also require developing better proxy measures of chronic exposure, identifying markers for the sub-set of people who benefit, and integrating this with strategies addressing other domestic exposures and lifestyle factors.

Assessment of environmental cockroach allergen exposure

In the past, cockroach allergen exposure assessment mainly focused on settled dust in homes in low-income urban cities in the United States. That choice was not wrong; without measureable levels of cockroach allergen, it is difficult to show associations with any home characteristics, much less with health outcomes (e.g., allergy, asthma). However, recent studies in other suburban areas, schools, and other countries have elucidated the importance of cockroach allergen in these environments too. In addition, characterizing the underlying factors that give rise to cockroach allergen exposure (or protect against it) can lead to more targeted public health interventions. This review discusses different approaches to sampling indoor environments, interprets recent asthma and allergy studies, compares cockroach allergen levels from past studies with those of recent studies, and describes strategies for decreasing exposures.

Assessment of indoor air pollution in homes with infants

Infants spend most of their indoor time at home; however, residential air quality is poorly understood. We investigated the air quality of infants’ homes in the New England area of the U.S. Participants (N = 53) were parents of infants (0–6 months) who completed telephone surveys to identify potential pollutant sources in their residence. Carbon monoxide (CO), carbon dioxide (CO₂), particulate matter with aerodynamic diameter ≤0.5 µm (PM_0.5), and total volatile organic compounds (TVOCs) were measured in 10 homes over 4–7 days, and levels were compared with health-based guidelines. Pollutant levels varied substantially across homes and within homes with overall levels for some homes up to 20 times higher than for other homes. Average levels were 0.85 ppm, 663.2 ppm, 18.7 µg/m³, and 1626 µg/m³ for CO, CO₂, PM_0.5, and TVOCs, respectively. CO₂, TVOCs, and PM_0.5 levels exceeded health-based indoor air quality guidelines. Survey results suggest that nursery renovations and related potential pollutant sources may be associated with differences in urbanicity, income, and presence of older children with respiratory ailments, which could potentially confound health studies. While there are no standards for indoor residential air quality, our findings suggest that additional research is needed to assess indoor pollution exposure for infants, which may be a vulnerable population.