Bla G2 Research Articles

Ampicillin treated German cockroach extract leads to reduced inflammation in human lung cells and a mouse model of Asthma.

Cockroaches can cause allergic sensitization in humans via contact with their feces or frass. Antibiotics can affect concentration of major allergen and total bacteria production in German cockroaches (Blattella germanica). This study examined the ability of antibiotic-treated German cockroaches to induce allergic airway inflammation and the effect of antibiotics on their lipopolysaccharide and Bla g1, 2, and 5 expression levels. Specifically, we measured the ability of German cockroach extract (with or without prior antibiotic exposure) to induce allergic inflammation in human bronchial epithelial cells and a mouse model of asthma. Bacterial 16S rRNA and lipopolysaccharide levels were lower in ampicillin-treated cockroaches than in the control group. The Bla g1, Bla g2, and Bla g5 expression in ampicillin-treated cockroaches decreased at both the protein and RNA levels. In human bronchial epithelial cell lines BEAS-2B exposed to the ampicillin-treated extract, expression levels of interleukin-6 and interleukin-8 were lower than that in the control group. The total cell count and eosinophil count in bronchoalveolar lavage fluid was also lower in mice exposed to the ampicillin-treated extract than in those exposed to normal cockroach extract. Mouse lung histopathology showed reduced immune cell infiltration and mucus production in the ampicillin group. Our results showed that ampicillin treatment reduced the symbiont bacterial population and major allergen levels in German cockroaches, leading to reduced airway inflammation in mice. These results can facilitate the preparation of protein extracts for immunotherapy or diagnostics applications.

The level of allergens in dust samples collected from selected schools in Shiraz, Iran and its asthma-risk implications

BackgroundBoth home and school are important places where children are exposed to various indoor allergens. This study aimed to identify the profile of indoor allergens in schools and its impact on asthma development. MethodsA total of 104 classrooms from 52 schools were selected for dust collection during the fall of 2017. The levels of indoor allergens including dust mite (Der f1, Der p1), cat (Fel d1), cockroach (Bla g1) and mouse (Mus m1) were measured by enzyme linked immunosorbent assay (ELISA). The diagnosis of asthma was made in all students of the selected classes by the allergist. The collected data were analyzed using SPSS version 21.0. ResultsOut of 2816 students in the selected classes, 180 students were involved with asthma. Students were mostly exposed to Bla g1 (83.1%), followed by Der f1 (51.5%), Mus m 1 (45.5%), Der p1 (8.9%) and Fel d1 (7.9%) in the dust collected from 101 classrooms. Although levels of all studied allergens in the settled dust of the classrooms were low, there was a relationship between Fel d1 in the classroom dust and development of asthma. ConclusionThis study showed considerable levels of cockroach allergens in schools. Exposure to cat allergen in our schools played an important role in asthma development; further school-based investigations require evaluating the role of classroom allergen on asthma development.

Measurement of aeroallergens from furnace filters

BackgroundExposure assessment is an important component of allergic disease diagnosis and management. Analysis for allergen content in vacuumed dust has been used traditionally. ObjectiveTo study allergen levels of dust taken from high-efficiency furnace filters in Midwestern homes. MethodsFurnace 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. ResultsSixty 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 × 107 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. ConclusionAllergens from 5 common aeroallergen species and antigenic material from 4 common fungal taxa can be measured in dust taken from high-efficiency furnace filters.

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 0.15M and 0.3M NaCl to control the electrostatic attraction of the peptide to the chip surface. The apparent KD of HBD3 binding Bla g2 was 5.9±2.1μM and for binding HSA was 4.2±0.7μM, 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.

A comparison of subject room dust with home vacuum dust for evaluation of dust-borne aeroallergens

BackgroundAssessment of indoor allergen is valuable in exposure research and evaluation of allergic individuals. Collection methods range from grab vacuum samples to filtration devices located in the breathing range of an individual. For practical purposes, many research studies use analysis of collected house dust to evaluate allergen reservoirs. ObjectiveTo test the hypothesis that house dust collected from the family vacuum is equivalent to house dust collected by a technician following standard protocol. MethodsHomes from a healthy homes demonstration project (n = 41) were sampled using a specific Department of Housing and Urban Development–suggested protocol in the bedroom of the child with asthma and a simple grab procedure from the family vacuum. Samples were evaluated for the presence of 5 allergens, Bla g2, Can f1, Der f1, and Der p1 combined as total mite, Fel d1, and Mus m1. Samples were also evaluated for total antigenic protein from 4 fungal taxa, including Alternaria, Aspergillus, Cladosporium, and Penicillium. ResultsAll of the allergens and antigens tested showed good correlation between the 2 collection methods. Fungal antigens ranged up to 92,651 nanograms per gram of dust for Aspergillus, and allergens ranged up to 17,928 nanograms per gram of dust for Can f1. The best correlation was for Cladosporium (r = 0.91), and the weakest was for dust mite (r = 0.34). ConclusionAllergens and antigens tested from samples collected by protocol and by grab sampling from the home vacuum were highly positively correlated. Grab samples taken from the family vacuum may be a good surrogate for evaluating home allergen exposure.

Indoor allergens in settled dust from kindergartens in city of Łódź, Poland

The main objective of the study was to determine the levels of house dust mite (Der p1), dog (Can f1), cat (Fel d1) and cockroach (Bla g2) allergens in kindergartens localized in an urban agglomeration. A quantitative analysis of allergens was carried out in settled dust samples collected by vacuuming the floor surface in three kindergartens (N = 84) and children's clothing (N = 36). The samples were collected in spring-summer and autumn-winter periods as well as at the beginning and end of the week. The allergen dust concentration was determined by enzyme-linked immunoenzymatic assay (ELISA). The mean geometric concentrations (±geometric standard deviations) of allergens Der p1, Can f1, Fel d1 and Bla g2 determined in kindergartens were: 0.02 ± 3.21 μg/g of dust; 0.97 ± 4.49 μg/g of dust; 0.30 ± 4.43 μg/g of dust and 0.01 ± 3.08 μg/g of dust, respectively. Younger classrooms (children aged from 3 to 4 years) were characterized by almost twice higher mean concentration of allergen Fel d1, as compared to older classrooms (children aged from 5 to 6 years) (p < 0.05). A significant impact of seasonality on the level of dog allergen Can f1 was found (p < 0.05). No significant weekly variation was found in average concentrations of the allergens. Children who had a dog and/or cat at home were characterized by high concentrations of allergens Can f1 and Fel d1 on their clothes (59.2 ± 5.39 μg Can f1/g of dust; 3.63 ± 1.47 μg Fel d1/g of dust), significantly higher than concentrations of allergens in children who did not have any pets (p < 0.001). Special attention should be paid to keeping the kindergarten rooms tidy and clean and to an appropriate choice of furnishings and fittings which would prevent the proliferation of the house dust mite and accumulation of allergens.

Children’s residential exposure to selected allergens and microbial indicators: endotoxins and (1→3)-β-D-glucans

The study was aimed at assessment of exposure to endotoxins, (1→3)-β-D-glucans and mite, cockroach, cat, dog allergens present in settled dust in premises of children as agents which may be significantly correlated with the occurrence of allergic symptoms and diseases in children. The study covered 50 homes of one-or two-year-old children in Poland. Samples of settled dust were taken from the floor and the child's bed. The levels of (1→3)-β-D-glucans (floor), endotoxins (floor) and allergens of mite, cat, dog and cockroach (floor and bed) were analyzed. Average geometric concentrations (geometric standard deviation) of endotoxins, (1→3)-β-D-glucans, Der p1, Fel d1, Can f1 and Bla g1 in children homes were on the floor 42 166.0 EU/g (3.2), 20 478.4 ng/g (2.38), 93.9 ng/g (6.58), 119.8 ng/g (13.0), 288.9 ng/g (3.4), 0.72 U/g (4.4) and in their beds (only allergens) 597.8 ng/g (14.2), 54.1 ng/g (4.4), 158.6 ng/g (3.1) 0.6 U/g (2.9), respectively. When the floor was covered with the carpet, higher concentrations of endotoxins, (1→3)-β-D-glucans and allergens (each type) were found in the settled dust (p < 0.05). The trend was opposite in case of allergens (except dog) analyzed from bed dust and significantly higher concentrations were found in the rooms with smooth floor (p < 0.05). Among the analyzed factors only the type of floor significantly modified both the level of biological indicators and allergens. The results of this study could be the base for verifying a hypothesis that carpeting may have a protective role against high levels of cockroach, dog and cat allergens.

Characterization of allergens and airborne fungi in low and middle‐income homes of primary school children in Durban, South Africa

The South Durban Health Study (SDHS) is a population-based study that examined the relationship between exposure to ambient air pollutants and respiratory disease among school children with high prevalence of asthma who resided in two purposely selected communities in north and south Durban, KwaZulu-Natal, South Africa. From the SDHS participants, a subgroup of 135 families was selected for investigation of household characteristics potentially related to respiratory health. In these households, a walkthrough investigation was conducted, and settled dust and air samples were collected for allergen and fungal measurements using standardized techniques. Asp f1 allergen was detected in all homes, and Bla g1 allergen was detected in half of the homes. House dust allergens, Der f1 and Der p1 exceeded concentrations associated with risk of sensitization and exacerbation of asthma in 3% and 13%, respectively, of the sampled homes, while Bla g1 exceeded guidance values in 13% of the homes. Although airborne fungal concentrations in sleep areas and indoors were lower than outdoor concentrations, they exceeded 1,000 CFU/m(3) in 29% of the homes. Multivariate analyses identified several home characteristics that were predictors of airborne fungal concentrations, including moisture, ventilation, floor type, and bedding type. Airborne fungal concentrations were similar indoors and outdoors, which likely reduced the significance of housing and indoor factors as determinants of indoor concentrations. Allergen concentrations were highly variable in homes, and a portion of the variability can be attributed to easily recognized conditions.

Sensitization to Cockroach Allergen: Immune Regulation and Genetic Determinants

Asthma is a major public health concern. Cockroach allergen exposure and cockroach allergic sensitization could contribute to the higher prevalence of asthma. However, the underlying immune mechanism and the genetic etiology remain unclear. Recent advances have demonstrated that several receptors (PAR-2, TLRs, CLRs) and their pathways mediate antigen uptake from the environment and induce allergies by signaling T cells to activate an inappropriate immune response. Cockroach-derived protease can disturb airway epithelial integrity via PAR-2 and leads to an increased penetration of cockroach allergen, resulting in activation of innate immune cells (e.g., DCs) via binding to either TLRs or CLRs. The activated DCs can direct cells of the adaptive immune system to facilitate promotion of Th2 cell response and subsequently increase risk of sensitization. Mannose receptor (MR), as a CLR, has been shown to mediate Bla g2 (purified cockroach allergen) uptake by DCs and to determine allergen-induced T cell polarization. Additionally, genetic factors may play an important role in conferring the susceptibility to cockroach sensitization. Several genes have been associated with cockroach sensitization and related phenotypes (HLA-D, TSLP, IL-12A, MBL2). In this review, we have focused on studies on the cockroach allergen induced immunologic responses and genetic basis for cockroach sensitization.

Diesel Exhaust Particulates Exacerbate Asthma-Like Inflammation by Increasing CXC Chemokines

Particulate matter heavily pollutes the urban atmosphere, and several studies show a link between increased ambient particulate air pollution and exacerbation of pre-existing pulmonary diseases, including asthma. We investigated how diesel exhaust particulates (DEPs) aggravate asthma-like pulmonary inflammation in a mouse model of asthma induced by a house dust extract (HDE) containing cockroach allergens and endotoxin. BALB/c mice were exposed to three pulmonary challenges via hypopharyngeal administration of an HDE collected from the home of an asthmatic child. One hour before each pulmonary challenge, mice were exposed to DEP or PBS. Pulmonary inflammation was assessed by histological features, oxidative stress, respiratory physiological features, inflammatory cell recruitment, and local CXC chemokine production. To prove the role of CXC chemokines in the augmented inflammation, CXC chemokine-specific antibodies were delivered to the lungs before DEP exposure. DEP exacerbated HDE-induced airway inflammation, with increased airway mucus production, oxidative stress, inflammatory cell infiltration, bronchoalveolar lavage concentrations of CXC chemokines, and airway hyperreactivity. Neutralization of airway keratinocyte-derived chemokine and macrophage inflammatory protein-2 significantly improves the respiratory function in addition to decreasing the infiltration of neutrophils and eosinophils. Blocking the chemokines also decreased airway mucus production. These results demonstrate that DEP exacerbates airway inflammation induced by allergen through increased pulmonary expression of the CXC chemokines (keratinocyte-derived chemokine and macrophage inflammatory protein-2).

Quantitative measurement of airborne cockroach allergen in New York City apartments.

We designed and tested a sampling and analysis system for quantitative measurement of airborne cockroach allergen with sufficient sensitivity for residential exposure assessment. Integrated 1-week airborne particle samples were collected at 10-15 LPM in 19 New York City apartments in which an asthmatic child who was allergic to cockroach allergen resided. Four simultaneous air samples were collected in each home: at heights of 0.3 and 1 m in the child's bedroom and in the kitchen. Extracts of air samples were analyzed by ELISA for the cockroach allergen Bla g2, modified by amplifying the colorimetric signal generated via use of AMPLI-Q detection system (DAKO Corporation, Carpinteria, CA, USA). Settled dust samples were quantified by conventional ELISA. Of the homes where cockroach allergen was detected in settled dust, Bla g2 also was detected in 87% and 93% of air samples in the bedroom and kitchen, respectively. Airborne Bla g2 levels were highly correlated within and between the bedroom and kitchen locations (P < 0.001). Expressed as picogram per cubic meter, the room average geometric mean for Bla g2 concentrations was 1.9 pg/m³ (95% CI 0.63, 4.57) and 3.8 pg/m³ (95% CI 1.35, 9.25) in bedrooms and kitchens, respectively. This method offers an attractive supplement to settled dust sampling for cockroach allergen exposure health studies. Until now, cockroach allergen exposures have usually been assessed by collection and analysis of settled dust, on the assumption that airborne cockroach allergen cannot be reliably measured. In this study, a sensitive and quantitative method for measuring indoor airborne exposures to cockroach allergens involving a 7-day integrated total suspended particulate (TSP) sample collected at approximately 10-15 l/min was developed. Investigators are now empowered with an alternative exposure assessment method to supplement their studies and the understanding of allergen aerodynamics in the homes of children with asthma. We report airborne cockroach allergen in apartments, suggesting an ongoing burden of inhalation exposure.

Correlation of Airborne Spore Counts and Dust Antigen Levels in Schools

RATIONALE: Children spend between one-third and one-fourth of their time in educational facilities. To investigate aero-allergen exposure in these facilities we conducted the following study.METHODS:: Environmental assessment was carried out at numerous schools in the Kansas City Metropolitan area. Airborne spores were collected using an Allergenco MK3 sampler and enumerated visually. Dust was collected using a HEPA vacuum unit and analyzed for Feld1, Can f1, Mus m1, Der f1, Der p1, Bla g2 using monoclonal antibody based immunoassays. Dust was also analyzed for Alternaria, Aspergillus, Cladosporium and Penicillium whole antigen using polyclonal antibody based immunoassays. Correlation analysis was performed on SPSS statistical software.RESULTS: Total spore counts for the indoor collections varied between 13 and 1000 spores per cubic meter of air. The most prevalent indoor taxa was Cladosporium. The most abundant specific allergen was dust mite and the most abundant fungal antigen was Alternaria. The best correlation between airborne spore types and dust allergen level was for Aspergillus (Cor. = 0.33; p = 0.2). The best correlation between airborne spores and allergen levels was between Alternaria spores and Can f1 allergen (Cor. = 0.99; p < 0.001). Among the allergens Fel d1 correlated with group 1 mite (Cor. = 0.75; p < 0.001) and Can f1 correlated with Bla g2 (Cor. = 0.58; p < 0.001).CONCLUSIONS: Dust borne fungal allergen measurements can be good indicators of exposure to fungi originating indoors but are less indicative when dealing with fungi originating in the outdoor environment. RATIONALE: Children spend between one-third and one-fourth of their time in educational facilities. To investigate aero-allergen exposure in these facilities we conducted the following study. METHODS:: Environmental assessment was carried out at numerous schools in the Kansas City Metropolitan area. Airborne spores were collected using an Allergenco MK3 sampler and enumerated visually. Dust was collected using a HEPA vacuum unit and analyzed for Feld1, Can f1, Mus m1, Der f1, Der p1, Bla g2 using monoclonal antibody based immunoassays. Dust was also analyzed for Alternaria, Aspergillus, Cladosporium and Penicillium whole antigen using polyclonal antibody based immunoassays. Correlation analysis was performed on SPSS statistical software. RESULTS: Total spore counts for the indoor collections varied between 13 and 1000 spores per cubic meter of air. The most prevalent indoor taxa was Cladosporium. The most abundant specific allergen was dust mite and the most abundant fungal antigen was Alternaria. The best correlation between airborne spore types and dust allergen level was for Aspergillus (Cor. = 0.33; p = 0.2). The best correlation between airborne spores and allergen levels was between Alternaria spores and Can f1 allergen (Cor. = 0.99; p < 0.001). Among the allergens Fel d1 correlated with group 1 mite (Cor. = 0.75; p < 0.001) and Can f1 correlated with Bla g2 (Cor. = 0.58; p < 0.001). CONCLUSIONS: Dust borne fungal allergen measurements can be good indicators of exposure to fungi originating indoors but are less indicative when dealing with fungi originating in the outdoor environment.

Nanopore immunosensor for peanut protein Ara h1

A nanopore immunosensor is demonstrated for peanut protein Ara h1, a common food allergen. This biosensor is constructed by immobilizing the antibody to peanut protein Ara h1 within Au-coated pores of commercial nanoporous polycarbonate membranes. Peanut protein Ara h1 is detected as the change in the pore conductivity as the pores are partially obscured by antigen binding. Control experiments with the antibody to cockroach protein Bla g1 demonstrate that the observed effects do not arise from non-specific adsorption. Binding of peanut protein is studied as a function of the pore diameter (15, 30 and 50 nm), and as a function of the concentration of peanut protein. The results show the greatest sensitivity for membranes with the smallest pore diameter, and exhibit mass transfer effects for membranes with larger pore diameters. Approximate calculations of diffusion times for transport of peanut protein Ara h1 through these nanoporous membranes suggest that mass transport effects should not be observed. This discrepancy between experimental observations of mass transfer effects and model predictions suggest that diffusion of peanut protein Ara h1 is anomalously slow in this system.

Resuspension of indoor aeroallergens and relationship to lung inflammation in asthmatic children

Studies have shown links between the concentration of allergens found in homes and asthma. Inhalation of allergens present in settled residential dust can occur when the dust is resuspended via human activity or air currents. Although previous studies have measured allergen concentrations in homes, the focus has been on the presence of the allergens in settled dust samples. However, the actual inhalation exposure is to airborne allergens. The relationship between the settled dust composition and suspended allergens and endotoxin and the effect of exposure of these aeroallergens to asthmatics are not well understood for species typically present indoors. In this study, settled dust and airborne particulate matter samples were collected in the homes and school classrooms of asthmatic children of ages 9 to 16 and analyzed for endotoxin and allergens including dust mite and cockroach allergen, and dog and cat dander (Der p1, Der f1, Bla g1, Can f1, and Fel d1, respectively). Concentrations of cockroach allergen were below detection limit for all samples. Measurements of the settled dust samples show higher dust mite allergen in bedroom samples than in living room samples. Concentrations of airborne endotoxin and indoor allergens were generally higher in the homes than those measured at school. Within the homes, higher concentrations of airborne allergens and endotoxin were observed in the living rooms compared to the bedrooms. Resuspension rates for endotoxin, dust mite allergen, and, cat and dog dander were estimated in this study. Calculated resuspension rates for cat dander (8.1×10−7±3.5×10−7min−1) and dust mite allergen (2.1×10−6±7.6×10−7min−1and 1.4×10−5±4.6×10−6min−1 for Der p 1 and Der f 1, respectively) were found to be higher than those for dog dander (3.1×10−7±1.3×10−7min−1) and endotoxin (3.6×10−7±1.6×10−7min−1). Markers of asthma inflammation including nitrate in exhaled breath condensate (EBC) and exhaled nitric oxide (eNO), were correlated with the concentrations of dust mite allergen (Der p 1) (Spearman r=0.598; p-value=0.068 for EBC and Spearman r=0.819; p-value=0.007 for eNO) and cat dander (Fel d 1) (Spearman r=0.917; p-value=0.0002 for EBC and Spearman r=0.697; p-value=0.054 for eNO) present in PM10 samples.

CXC chemokines modulate IgE secretion and pulmonary inflammation in a model of allergic asthma

The pathophysiology of asthma is influenced by exposure to allergens and endotoxin. Although the role of allergen-induced eosinophilia has been widely studied, neutrophil-mediated responses remain elusive. A role for neutrophils in the asthmatic responses is likely since human neutrophils have been shown to express IgE receptors, as well as receptors for many cytokines and chemokines implicated in the pathogenesis of asthma. In this study we investigated neutrophil involvement in a novel, house dust extract (HDE) induced model of asthma-like pulmonary inflammation. Mice were immunized and challenged with HDE containing high levels of cockroach allergens, 377 U/ml Bla g1 and 6249 ng/ml Bla g2. The biological activity of the murine chemokines KC and MIP-2 was inhibited with specific rabbit antisera. Differential counting of cells recovered from the bronchoalveolar lavage (BAL) fluid showed that neutralization of KC and MIP-2 significantly decreased pulmonary recruitment of neutrophils (reduced 86%) and lymphocytes (reduced 76%). Neutralization of these chemokines also exerted a systemic effect with a significant decrease in plasma IgE levels, 547 ng/ml ± 65 compared to 1314 ng/ml ± 247 for control sera treated animals. This study shows that CXC chemokines play an important role in allergy and asthma both at the level of pulmonary cell recruitment and systemic immune responses.

A multihazard, multistrategy approach to home remediation: Results of a pilot study

Many residential hazards are disproportionately concentrated in older, urban dwellings and share common underlying causes, such as uncorrected moisture problems and inadequate maintenance and cleaning. Comprehensive and affordable approaches to remediation are needed, but the feasibility and efficacy of such approaches has not been well documented. To address this gap, a multihazard, multimethod intervention, addressing deteriorated lead-based paint and lead dust, vermin, mold, and safety hazards was pilot-tested in a sample of 70 pre-1940 dwellings. Dwellings received paint stabilization, dust lead cleaning, integrated pest management (IPM), mold cleaning, and safety devices, as needed. The median remediation cost for labor and materials was $864.66 (range: $120.00–5235.33) per dwelling. Environmental conditions were evaluated prior to, immediately following, and an average of 5 months after remediation. Between the baseline and 5-month follow-up periods, significant reductions were achieved in the number of dwellings with multiple (i.e., three or four) problems (75% vs. 23%, P < 0.0001 ); high levels of dust lead on floors and window sills (67% and 46% declines, P < 0.01 ); evidence of cockroaches or rodents (43% and 36% declines, P < 0.01 ); and fire, electrical and/or fall hazards (between 67% and 88% declines, P < 0.01 ). Significant reductions were also observed in the geometric mean (GM) dust lead levels on floors and window sills (13.3 vs. 5.0 μg/ft 2 and 210.6 vs. 81.0 μg/ft 2, respectively, P < 0.0001 ) and Blatella germanica (Bla g1) levels among dwellings with elevated baseline levels (7.7 vs. 0.09 U/g, P < 0.0001 ). Reductions in mold dust levels were of borderline statistical significance (50% decline, P = 0.07 ). The greatest declines in dust lead and Bla g1 levels occurred in dwellings having the highest baseline levels and, for Bla g1, in dwellings in which occupants attended training sessions. These results indicate that a comprehensive approach to hazard remediation can be highly effective and cost efficient and that overall improvements can be maintained. Further research is needed to clarify the most effective sampling strategies, educational and behavioral interventions, and optimal intervention frequency.

A new and safer method for preserving allergen stability in human vaccines

Rationale Specific allergen immunotherapy is the only treatment that reverses the immunologic imbalance responsible for causing IgE-medicated symptoms. Each allergen vaccine, however, is a mixture of glycoproteins that have varying stabilities in solutions. Currently, human serum albumin (HSA) is widely used as a stabilizing agent in FDA licensed vaccines, which creates a potential risk for the transmission of prion-induced illnesses. We have, therefore, developed a new and safer method of preserving allergen vaccines to eliminate the need for HSA in allergen vaccines. Methods Over a period of 40 weeks, we studied the stability of commercially available vaccines using three methods of preservation: HSA, phosphate buffered saline (PBS), and trehalose. Allergen vaccines were diluted and stored similar to our allergy clinic's routine, and samples studied for specific allergen concentrations using monoclonal reagents. Freezing and thawing effects were also analyzed. The major allergens included in this study were cat (Fel d1), cockroach (Bla g1), and Der f1 from D. farinae. Results Trehalose was comparable to HSA in preserving the antigenicity of both cat and cockroach allergens. Trehalose was superior to both HSA and PBS in stabilizing the mite allergen Der f1. Conclusions These initial studies support the use of trehalose in the stabilization of allergen vaccines intended for human use. The potential transmission of prion proteins to patients who are given allergy injections that contain human serum albumin can thus be totally avoided. Future studies will determine if this patent pending trehalose method proves to be as effective in other commonly used allergen vaccines.

Comprehensive risk assessments of home environments of low-income, non-inner city preschool-aged children with asthma

Rationale Reported prevalence of physician-diagnosed asthma in the Dane County Head Start population was 16%. Comprehensive risk assessments of the indoor environment have not been conducted. Wisconsin Healthy Homes Initiative provides families with comprehensive asthma risk assessments and interventions. Methods Consenting caregivers were administered an asthma screening questionnaire and invited to have their children skin prick tested for relevant indoor allergens. Children were not eligible if they were allergic to cats or dogs and currently living with the animal. In-home assessments included personal interview, visual inspection, vacuum sampling, and continuous humidity monitoring. Results Sixty-six percent of respondents were of an ethnic minority and 33% had at least one family member with asthma. Of the children tested, 72% were allergic to at least 1 allergen. Of the visited homes, 72% were carpeted, 85% had inadequate moisture control measures in the kitchen/bathroom and 30% of families had reported cockroach sightings in the previous year. Evidence of indoor relative humidity higher than 50% was documented in all homes. Mite allergen was predominantly found in the bedroom and Bla g1 in the kitchen. Fifteen percent of bedroom bedding contained mite allergen levels >10ug/g of dust. Conclusions Low-income, non-inner city preschool-aged children have a high prevalence of asthma, indoor allergen sensitivity and exposure. A healthy home for a child with asthma begins with a comprehensive risk assessment.

547 Presence of Bla g2 allergens in store purchansed flour samples

547 Presence of Bla g2 allergens in store purchansed flour samples

Bedroom cockroach allergen (Bla g1) level and Interleukin -5 production in atopic and non atopics 37

Bedroom cockroach allergen (Bla g1) level and Interleukin -5 production in atopic and non atopics 37