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BackgroundDespite long-standing recognition in the significance of mucus overproduction in asthma, its etiology remains poorly understood. Muc5ac is a secretory mucin that has been associated with reduced pulmonary function and asthma exacerbations.ObjectivesWe sought to investigate the immunological pathway that controls Muc5ac expression and allergic airway inflammation in asthma.MethodsCockroach allergen-induced Muc5ac expression and aryl hydrocarbon receptor (AhR) signaling activation was examined in the human bronchial epithelial cells (HBECs) and mouse model of asthma. AhR regulation of Muc5ac expression, mitochondrial ROS (Mito-ROS) generation, and NLRP3 inflammasome was determined by AhR knockdown, the antagonist CH223191, and AhR-/- mice. The role of NLRP3 inflammasome in Muc5ac expression and airway inflammation was also investigated.ResultsCockroach allergen induced Muc5ac overexpression in HBECs and airways of asthma mouse model. Increased expression of AhR and its downstream genes CYP1A1 and CYP1B1 was also observed. Mice with AhR deletion showed increased allergic airway inflammation and MUC5AC expression. Moreover, cockroach allergen induced epithelial NLRP3 inflammasome activation (e.g., NLRP3, Caspase-1, and IL-1β), which was enhanced by AhR knockdown or the antagonist CH223191. Furthermore, AhR deletion in HBECs led to enhanced ROS generation, particularly Mito-ROS, and inhibition of ROS or Mito-ROS subsequently suppressed the inflammasome activation. Importantly, inhibition of the inflammasome with MCC950, a NLRP3-specifc inhibitor, attenuated allergic airway inflammation and Muc5ac expression. IL-1β generated by the activated inflammasomes mediated cockroach allergen-induced Muc5ac expression in HBECs.ConclusionsThese results reveal a previously unidentified functional axis of AhR-ROS-NLRP3 inflammasome in regulating Muc5ac expression and airway inflammation.

Background Cockroach is one of the most important sources of indoor allergens and can lead to IgE sensitization and development of rhinitis and asthma. Objective We sought to perform a cockroach allergen component analysis to determine the allergens and antibody levels and patterns of sensitization associated with asthma and rhinitis. Methods Antibody (IgE, IgG, and IgG4) levels to total cockroach and 8 cockroach allergens were determined in 2 groups of cockroach-sensitized 10-year-old children with (n = 19) or without (n = 28) asthma and rhinitis. Allergen-specific antibody levels were measured in streptavidin ImmunoCAPs loaded with each of the recombinant allergens from groups 1, 2, 4, 5, 6, 7, 9, and 11, and total cockroach-specific IgE levels were measured with the i6 ImmunoCAP. Results IgE antibody levels to cockroach allergens and extract, but not IgG or IgG4 antibody levels, differed between subjects with and without asthma and rhinitis. Specifically, recognition of more cockroach allergens with higher allergen-specific IgE levels was associated with disease. Variable patterns of sensitization with no immunodominant allergens were found in both groups. There was a good correlation between the sum of allergen-specific IgE and total cockroach IgE levels (r = 0.86, P Conclusions Component analysis of 8 cockroach allergens revealed significant differences in IgE reactivity associated with the presence of asthma and rhinitis. Allergen-specific IgE titers and sensitization profiles were associated with asthma and rhinitis.

We here report the case of 2 patients (Pt#1 and Pt#2, both male, 24 and 27 years old, respectively) employed in the production of insect flour made of yellow mealworm larvae (Tenebrio molitor larvae, TML) and black soldier fly larvae (Hermetia illucens larvae, HIL). In order to characterize the patients' allergic profile, we performed: skin prick tests (SPTs) with a standard battery of inhalant and food allergens, specific IgE for TM, Der p10, Dermatophagoides pteronyssinus, Dermatophagoides farinae and Prawn (ImmunoCap Thermo Fisher Scientific Inc) and basophil activation test (BAT) with TML and TMF protein extracts. Immunoblot analyses of both protein extracts and LC-MS/MS analysis followed by protein database screening were performed in order to identify the allergens involved in the TM sensitization

Purpose CpG oligodeoxynucleotide (CpG-ODN), a TLR9 agonist, activates innate immunity and induces Th1 response. Although the immune modulatory effect of CpG-ODN has been extensively studied, its function in cockroach extract-induced allergic asthma has not been studied. Here, we investigated the inhibitory function of CpG-ODN in cockroach extract-induced asthma in mice with different treatment schemes. Methods Scheme 1: BALB/C mice were intra-nasally co-administered by cockroach extract and CpG-ODN twice a week for 3 weeks; Scheme 2: The mice were intra-nasally pre-treated with CpG-ODN at day 0 and cockroach allergen challenge was performed from day 3 as in scheme 1. Scheme 3: Cockroach allergen challenge was performed as in scheme 1 and CpG-ODN was post-treated at day 21. Then, BAL cell count, flow cytometric analysis of alveolar macrophages, regulatory T cells, and lung tissue histology, Th1 and Th2 cytokines, serum IgE, cockroach specific IgE, IgG1/IgG2a ratio, and airway hyper-responsiveness were evaluated. Results Mice with repeated intra-nasal exposure to CpG-ODN showed a dramatic decrease in eosinophilic inflammation, goblet cell hyperplasia, and airway hyper-responsiveness with reduction of IL-13, IL-5, and serum IgE, cockroach specific IgE and IgG1/IgG2a ratio. This inhibitory function might be related to the up-regulation of IL-10 and CD4⁺Foxp3⁺ regulatory T cells in the lung. Interestingly, one-time challenge of CpG-ODN either prior or posterior to cockroach extract exposure could modulate airway inflammation and hyper-responsiveness via increase of Th1 response. Conclusions Collectively, our data suggest that CpG-ODN treatment modulates Th2 inflammation in the lung by induction of regulatory T cells or Th1 response in a cockroach-induced asthma model.

BACKGROUND: Thirdhand smoke (THS) represents the accumulation of secondhand smoke on indoor surfaces and in dust, which, over time, can become more toxic than secondhand smoke. Although it is well known that children of smokers are at increased risk for developing asthma and for exacerbation of that disease if they already have it, how exposure to THS may influence the development or exacerbation of asthma remains unknown. OBJECTIVE: We investigated whether epicutaneous exposure to an important component of THS, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), can influence asthma pathology in a model elicited in mice by repeated intranasal challenge with cockroach antigen (CRA). METHODS: Wild type mice, α7 nicotinic acetylcholine receptor (α7 nAChR)- or mast cell (MC)-deficient mice, and mice with MCs that lacked α7 nAChRs or that were the host’s sole source of α7 nAChRs, were subjected to epicutaneous NNK exposure and/or intranasal CRA challenge, and the severity of features of asthma pathology, including airway hyperreactivity (AHR), airway inflammation and airway remodeling, were assessed. RESULTS: We found that α7 nAChRs were required to observe adverse effects of epicutaneous NNK exposure on multiple features of CRA-induced asthma pathology. Moreover, MC expression of α7 nAChRs significantly contributed to the ability of epicutaneous NNK exposure to exacerbate AHR to methacholine, airway inflammation, and airway remodeling in this model. CONCLUSION: Our results show that skin exposure to NNK, a component of THS, can exacerbate multiple features of a cockroach antigen-induced model of asthma in mice and define MCs as key contributors to these adverse effects of NNK.

Indoor allergens and microbial bio-contaminants play a significant role in asthma symptoms. The aim of the study was to determine levels of house dust mite allergens, bacterial endotoxin, and fungal beta-glucan in homes of 120 asthmatic children in central Taiwan. Dust samples from 120 mattresses (67 double-sided) were analyzed for house dust mite allergens (Der p 1, Der f 1, and Blo t 5), endotoxin, and beta-glucan. Pillows (n = 118) were analyzed for house dust mite allergens only. Kitchen dust samples were analyzed for the cockroach allergen, Bla g 1. Blo t 5 was detected in 9.3% pillows and 82.2% mattresses, Der p 1 in 95.8% pillows and 93.2% mattresses, and Der f 1 in 82.2% pillows and 83.1% mattresses. Geometric mean levels (95% confidence interval) of endotoxin and beta-glucan in mattresses were 108.4 Eu/mg (81.4-144.2) and 25.2 microg/g (22.7-28.0), respectively. House dust mite allergens and endotoxin levels were significantly lower on the bamboo side of 67 mattresses, compared to the inner sprung mattress side. Geometric mean of kitchen Bla g 1 was 0.61 U/g (95% CI: 0.43-0.85). Given the presence of Der p 1, Der f 1 and Blo t 5 in central Taiwan, it is advised to measure allergens of all three house dust mite species to obtain a true index of allergen exposure. Bamboo sides of mattresses had significantly lower house dust mite allergens and endotoxin levels.

The efficacy of residential interventions to reduce cockroach allergens in public housing developments was evaluated over months of follow-up. Repeated measurements were collected from 39 apartments, with longitudinal analyses used to evaluate changes over time. Bla g 1 kitchen concentrations were reduced 71% and bed concentrations 53% (86% and 70% for Bla g 2, respectively) by 6 months post-intervention, after which concentrations began to increase. Apartments with higher concentrations were usually in poorer condition and benefited most from pest management efforts. Intensive interventions can significantly reduce the allergen burden in public housing apartments, but intervention efforts must be sustained.

Asthma morbidity is high in inner-city children in the United States, which may be related in part to increased allergens in poorly maintained housing. This study examined asthma morbidity in relation to mold, cockroach, dust mite, and cat allergens in the homes of 61 low-income Chicago children with asthma. Children exposed to higher levels of Penicillium in the bedroom had more frequent asthma symptoms, whereas those exposed to higher levels of cockroach allergen in the bedroom had a higher number of asthma symptoms. Respiratory infections confounded the association of cockroach allergen with number of asthma symptoms.

Background: Several epidemiology studies have found an increase in the major cockroach allergen Bla g 2 with reported pesticide use. Aims of the study: Our aim was to investigate the effect on the excretion of Bla g 1 and Bla g 2 allergens by cockroaches exposed to sub-lethal doses of the pesticides, boric acid and hydramethylnon gel. Methods: German cockroaches in separate colonies were fed either boric acid or hydramethylnon gel at concentrations of 0.2, 0.1 and 0.01% in their water supply over a 2 week period. Ten colonies were exposed to each treatment concentration. Bla g 1 and Bla g 2 in fecal pellets were measured by ELISA. Results: Cockroaches exposed to boric acid excreted fecal pellets with significantly higher concentrations of Bla g 2 (35 400 U/g) than did controls (12 700 U/g) (P = 0.001). Bla g 1 concentrations were not significantly different. There was no difference in either Bla g 1 or Bla g 2 concentrations between cockroaches that ingested hydramethylnon gel and those in the controls colonies. Conclusions: The application of boric acid, a common pesticide, appears to paradoxically increase the production of Bla g 2, a major allergen, by the surviving cockroaches. This may have important implications in avoidance strategies.

Homes cannot be made allergen free, but exposure to the major indoor allergens can be reduced. All reduction recommendations are based on the principle of reducing or isolating the source, and certain recommendations can be made on the basis of published evidence. House dust mite avoidance measures include fitting allergen-proof mattress and pillow encasings, washing bedding regularly, and reducing humidity. Furred pet avoidance requires removal of the pet form the home, followed by thorough and repeated cleaning; room air cleaners, washing the pet, and isolating the pet from a bedroom are ineffective alternatives. Cockroach allergen avoidance begins with effective pest control, followed by thorough and repeated cleaning; 1 to 2 months are required to eliminate roaches, and an additional 4 to 6 months are required to remove residual allergen. Once allergen levels have been reduced, continued efforts are necessary to maintain the home free of allergen sources.

Background It is known that cockroach allergen exposure is both frequent in inner-city homes and associated with asthma severity in children living in those homes. However, there have been few studies of interventions to reduce exposures in this setting. Objectives To evaluate the effect of short-term professional cockroach control and intensive cleaning on allergen concentrations. Methods Families of children from a school-based asthma treatment program who had skin test results positive to cockroach allergen were enrolled if the home had cockroaches. Forty-nine homes were randomly assigned to receive professional cleaning with bait traps containing insecticide, professional cleaning with bait traps without insecticide, or no cleaning or bait traps. In all homes, dust was collected repeatedly to evaluate cockroach allergen Bla g 2 in the kitchen and bedroom, and cockroaches were trapped and counted repeatedly for more than 11 weeks. Results Median cockroach counts were reduced in the homes treated with insecticide bait traps but not in other groups. There were significant reductions in allergen concentration in the kitchen in homes that received professional cleaning and had higher initial cockroach counts (54), regardless of whether bait traps had insecticide or not. Conclusions We conclude that intensive cleaning can produce significant reductions in cockroach allergen in homes with heavy initial cockroach infestations.

Background: Cockroach allergen is recognized as a causal factor for asthma. However, airborne cockroach allergen has not been detected in undisturbed conditions, and therefore the behavior and properties of airborne cockroach allergen have been poorly characterized. A new aeroallergen sampling method and sensitive system of immunoassay have been used to examine cockroach allergen exposure. Objective: Our purpose was to measure and characterize airborne cockroach allergens during normal domestic exposure in the homes of Sydney, Australia. Methods: Air sampling with Institute of Occupational Medicine, Edinburgh (IOM) samplers was performed in the living rooms of 10 houses during low- and no-disturbance environments. In addition, inhaled particles were collected by each home occupant during low domestic exposure with use of intra-nasal samplers that impact particles onto an adhesive surface. The particles collected on the IOMs and the intra-nasal samplers were immunostained with Bla g 1 monoclonal antibodies. Particle size, morphologic characteristics, and the relative Bla g 1 content of particles were estimated. Reservoir dust samples from the kitchen, living room, and bedroom were assayed by an ELISA. Two forms of repeatability of IOM air sampling were examined. The first measure tested the repeatability of 2 IOM samples collected simultaneously in the same room during low- and no-disturbance activities. The second measure examined the repeatability of IOM sampling over time on 10 consecutive days. Results: Bla g 1 was detected in reservoir dust samples taken from all homes (geometric mean 1.5 U/g, range 0.2-9.4 U/g). Inhaled particles containing Bla g 1 were detected during 1 hour of intra-nasal sampling in 8 of 10 homes during low disturbance. Cockroach particles were detected on all of the IOM samples collected for both 4-hour low-disturbance and overnight no-disturbance sampling environments. Particles containing Bla g 1 collected with the IOM samplers during low disturbance ranged in size from 3 to 350 μm. These particles are amorphous and irregular in shape, and a majority of the large particles were described as flakes (flat, transparent particles) and fibers (threadlike). A relationship was demonstrated between the allergen content of cockroach particles and their particle size. The larger particles elute more Bla g 1. The coefficient of repeatability for measurements made during low and no disturbance was 3.62 and 2.09, respectively. For measurements repeated over time at the same site, the coefficient of repeatability was 2.61. This represents the fold range within which 95% of pairs of measurements made at an interval of 1 day would be expected to lie. Conclusions: Airborne cockroach allergen is present in both undisturbed and low-disturbance environments in homes with relatively low reservoir levels of Bla g 1. In agreement with previous reports, airborne particles containing cockroach allergen (Bla g 1) are mainly associated with particles >10 μm. These particles are amorphous and irregular in shape and can be described as flakes and fibers. (J Allergy Clin Immunol 1999;104:672-80.)

Although cockroach allergen is an important indoor allergen in poor urban environments, no studies on the effectiveness of measures to reduce allergen levels in indoor environments have yet been published.As a model of home extermination, we studied cockroach allergen levels in an urban dormitory that was chronically infested with German cockroaches and that underwent semiannual extermination. Dust samples were collected from 18 bedrooms and 5 kitchens located in the dormitory and were analyzed for Bla g 2 using an immunoassay.We detected allergen in almost every bedroom, with median levels ranging from 3.0 U/g (units/g) in settled dust on the bed, 4.0 U/g on the carpeted floor, and 2.8 U/g in closets. In the kitchen, we found somewhat higher levels, 10.8 U/g on the floor and 2.8 U/g in floor cabinets. Repeated measures of floor dust were similar (median 4.4 and 4.0 U/g) despite weekly vacuum cleaning. In the 2 weeks before extermination, median levels were 5.2 U/g and in the 2 weeks following extermination and regular vacuuming, median levels fell to 0.95 U/g.We concluded that successful allergen abatement could be accomplished in cockroach infested indoor environments using routine extermination and vacuuming.

A sandwich ELISA was developed to measure the concentration of cockroach allergen in the environment. The assay was based on a monospecific rabbit antibody preparation reactive with determinants shared by the important allergens. Per a I and Bla g I, from American and German cockroaches. The sensitivity was 0.2 ng Lowry protein of Per a I equivalents per milliliter, corresponding to 1 ng of Per a I equivalents per gram of dust ( Per a I eq/gm). The assay did not react with noncockroach-allergen sources. Dust samples from 73 households in a cockroach-infested area were assayed. The concentration in these samples varied from below detection to 200,000 ng of Per a eq/gm of dust. Three commercial cockroach-allergen extracts all contained the allergen. The assay will be valuable for studies of the clinically relevant cockroach-allergen exposure levels and for assessment of efficacy of allergen-avoidance measures. Furthermore, the assay could be used for sanitary documentation in bakeries, restaurants, etc.

BackgroundIL12A has been implicated in T-cell development and may thus influence the development of atopy and allergic diseases.MethodsWe tested for association between four linkage disequilibrium (LD)-tagging SNPs (rs2243123, rs2243151, rs668998, and rs17826053) inIL12Aand asthma and allergy-related (serum total and allergen-specific IgE, and skin test reactivity [STR] to two common allergens) phenotypes in two samples: 417 Costa Rican children with asthma and their parents, and 470 families of 503 white children in the Childhood Asthma Management Program (CAMP). The analysis was conducted using the family-based association test (FBAT) statistic implemented in the PBAT program.ResultsAmong Costa Rican children with asthma, homozygosity for the minor allele of each of two SNPs inIL12A(rs2243123 and rs2243151) was associated with increased risks of STR to American cockroach (P ≤ 0.03 for both SNPs), STR to German cockroach (P ≤ 0.01 for both SNPs), and having a positive IgE to German cockroach (P < 0.05 for both SNPs). Among children in CAMP, homozygosity for the minor allele of SNP rs2243151 inIL12Awas inversely associated with STR to German cockroach (P = 0.03) and homozygosity for the minor allele of SNP rs17826053 inIL12Awas associated with increased risks of STR to American cockroach (P = 0.01) and STR to German cockroach (P = 0.007). There was no significant association between any SNP inIL12Aand asthma, STR to dust mite, or total IgE in Costa Rica or CAMP.ConclusionOur findings suggest that variants inIL12Ainfluence cockroach allergy among children with asthma.

The goal of this study was to characterize asthma knowledge in high risk neighborhoods compared to a random sample of residents in the Chicago area. The Chicago Community Asthma Survey-32 (CCAS-32) was administered to 1006 Chicago-area residents and 388 residents in 4 high-risk Chicago inner-city neighborhoods. There was a significant difference in asthma knowledge between groups. The general Chicago-area respondents have an average desirable response rate of 71.6% versus 64.7% for respondents in high-risk communities (p < 0.0001). For some aspects of asthma knowledge, e.g., nocturnal cough, cockroach allergen, and vaporizer use, general knowledge was similarly low. For other aspects, such as the need for asymptomatic asthma visits and chest tightness, there were larger gaps between residents of high risk communities and the general community. High-risk neighborhoods in Chicago had lower asthma knowledge compared to the general Chicago community. This discrepancy may be contributing to the disparities seen in asthma morbidity. Public health efforts to increase asthma knowledge in these high risk minority communities may help reduce these disparities. Important misconceptions exist about asthma triggers, signs and symptoms, especially among lower income African American communities, that should be addressed by physicians.

The ubiquitous existence of cockroaches makes cockroach allergies more prevalent than previously recognized. Massive domestic infestations of the insects produce indoor air contamination, such that cockroach allergens have become an important airborne indoor allergen for patients with allergic airway diseases. Recognition and identification of cockroach allergies is necessary to guide proper management of cockroach-induced atopic diseases. Pest control is the best way of managing cockroach allergies. However, individuals who are unable to rid themselves of exposure to the insects, especially severe asthmatics, may benefit from hyposensitization. Analysis and isolation of major cockroach allergen(s) are important in order to standardize the commercially available stock of diagnostic and therapeutic treatments.

Background In the first 6 months of this previously published, randomized trial, the combined intervention of occupant education, insecticide bait application, and professional cleaning significantly reduced cockroach numbers and Bla g 1 allergen levels in inner-city homes. Objective This continuation study investigated whether the cockroach allergen reductions achieved by month 6 could be maintained through month 12 with insecticide application alone. Methods Because we had agreed to place insecticide bait in control homes at the conclusion of the first study, intervention and control homes were treated with insecticide bait at months 6 and 9. No other intervention was conducted in either arm. Vacuumed dust and swab samples were collected at month 12. Twenty-one of the 31 original homes completed the 12-month study. Results Among the original intervention homes, Bla g 1 concentrations remained essentially unchanged from months 6 to 12. However, among the crossed-over control homes, the geometric mean Bla g 1 concentrations (Units per gram of dust) decreased from 287 to 14.4 for kitchen floors (95% reduction), from 28.8 to 5.6 for living room floors/sofas (81% reduction), from 26.7 to 4.7 for bedroom floors (82% reduction), and from 7.2 to 2.4 for beds (67% reduction). At month 12, Bla g 1 concentrations did not significantly differ between intervention and crossed-over control homes ( P > .64 at each location). Similar results were seen for the allergen Bla g 2. Conclusions Reductions in cockroach allergen concentrations achieved through the combined intervention of occupant education, insecticide application, and professional cleaning can be maintained with continued cockroach control. Surprisingly, and in contrast to other studies, insecticide application alone significantly lowered allergen concentrations in the crossed-over control homes. This unexpected result is being tested further in another randomized trial.

Background Although the importance of cockroach allergen in chronic asthma has now been well defined, little progress has been made in the control of cockroach allergen in infested homes. Objective The objective of this study was to examine the ability of a combination of professional pest extermination and household cleaning using a solution of sodium hypochlorite to reduce cockroach infestation and allergen levels in cockroach infested homes. Methods Seventeen cockroach-infested homes were studied with three homes serving as controls. In the intervention homes, a professional exterminator applied 0.05% abamectin twice at 2-week intervals at study entry and a professional cleaner cleaned the homes before and after the extermination. All washable surfaces were cleaned throughout the study with a solution of 0.5% hypochlorite. Monthly home visits were conducted to inspect the home, interview the homeowner, place passive cockroach traps, and to collect settled dust samples from the kitchen, bedroom, and TV/living room. Results The number of cockroaches in the passive traps decreased rapidly after the initial intervention in most homes. Median Blatella germanica allergen 1 levels in the settled dust samples fell by 91% in the kitchen, 78% in the bedroom, and 77% in the living room over the course of the study in the intervention homes but gradually rose in the control homes. The overall reductions were very similar to those seen in a previous study with a similar protocol except for the use of the sodium hypochlorite. Conclusions Successful extermination is possible in most inner-city homes and cockroach allergen levels can be reduced by 80% to 90%. However, 0.5% sodium hypochlorite did not seem to improve allergen reduction, and in many homes, allergen levels remained above the proposed threshold of 8 U/g of dust throughout the study.

Background: Allergen avoidance has been shown to improve the morbidity and physiology of asthma. Although cockroach allergen has been implicated in chronic asthma, little work has been reported on the feasibility of allergen removal from infested homes. Objective: The objective of this study was to examine the effect of professional pest control and home cleaning on cockroach infestation and allergen concentrations in settled dust samples from the kitchens, bedrooms, and television-living rooms of inner-city homes. Methods: Thirteen homes in inner-city Baltimore, Maryland, received a professional cleaning, with vacuuming and a thorough cleaning in the kitchen. Pest control technicians applied abamectin 0.05% gel to the kitchen and, to a limited extent, to the rest of the home and the cleaning was repeated. Technicians visited monthly from month 2 to month 8 to inspect, collect dust samples, and place passive cockroach traps. Bla g 1 concentrations in dust extract were measured by means of ELISA. Results: The number of cockroaches captured in passive traps decreased rapidly in 11 homes, but complete extermination was achieved in only 7 homes. Bla g 1 concentrations were reduced by 93% in kitchens, 77% in television-living rooms, and 74% in bedrooms. The relative reduction in cockroach allergen was not related to successful extermination or to signs of poor housecleaning. Conclusion: We concluded that cockroach extermination is feasible in inner-city homes but that standard housecleaning procedures are only partially effective in removing residual allergen over 8 months. (J Allergy Clin Immunol 1999;104:842-6.)

To study the asthmatogenic effect of certain airborne elements of the home environment, we studied a group of guinea pigs exposed to aerosolized cockroach allergen (CRa) and side-stream cigarette (S-SC) smoke. Four groups of guinea pigs were exposed to aerosols, either saline or CRa, for 4 weeks, after a sham or S-SC smoke pretreatment. Anaphylactic antibodies were measured by passive cutaneous anaphylaxis (PCA) assay and by skin test. Animals were challenged with aerosol CRa on day 35, and lung function and leukotrienes (LTB4 and LTC4/D4) were measured. Skin tests were positive on days 21 and 29. The antibodies were heat-stable, IgG1a-like antibodies (PCA titers 1:2-18). The CRa challenge caused an immediate reduction in both the maximal expiratory flow rate at 50% of the lung capacity and respiratory compliance. The decreased lung function continued for up to 6 h (p0.0001). LTB4 and LTC4/D4 were elevated (p0.0001) in the sensitized animals at the corresponding times of reduced lung function. S-SC smoke did not affect the CRa sensitization; instead, a protective effect on the CRa-induced bronchospasms was noted. Thus, the study indicates that a simple airborne CRa exposure without an adjuvant sensitizes guinea pigs, and that the animals respond to antigen challenge with CRa-specific airway obstructions.

We have investigated the levels of cat (Fel d I), dog (Can f I), and cockroach (Per a I) allergens in dust from bedrooms, living rooms, kitchens, and bathrooms from 123 homes of asthmatic children in three zones of Sweden with varying climates. Absolute indoor humidity (AIH), relative humidity (RH), rate of ventilation in air changes per hour (ach), and number of airborne particles were also measured. Fel d I, Can f I, and Per a I allergen contents were determined by mab ELISA, and the levels were related to various environmental factors. The major cat allergen. Fel d I, was detected in all homes, and the concentrations varied between 16 ng and 28000 ng/g fine dust. The dog allergen, Can f I, was detected in 85% of the homes, and the levels varied from 60 ng to 866000 ng/g dust. Cockroach allergen was detected in only one home (40 ng/g). Fel d I and Can f I allergens were equally distributed geographically. Dust from living rooms contained significantly higher (P < 0.05) concentrations of both Fel d I and Can f I allergens than dust from bedrooms, kitchens, and bathrooms. The levels tended to be higher in homes with poor ventilation (

The recently published paper in your jour-nal by Gotzsche and Johansen (1) hascaught our attention. We would like to addsome comments.In this newly updated meta-analysis onhouse dust mite control measures forasthma, 44 trials with a total of 3302subjects were included. When comparedwith the last meta-analysis published by thesame authors in 2004 (2), the newly addedstudies were seen to be based on reductionmethods concentrated only on mattressesand bed covers. It has been demonstratedby Frederick in 1997 (3) and more recentlyby Woodcook et al. (4) that house dustmite reduction measures performed only onthe beddings were not able to decrease themite-allergen exposure. Consequently, it isdifficult to state that mite-allergen reduc-tion is not clinically efficient and should notbe recommended as it has been showed thatthese methods are not able to decreasesignificantly the mite-allergen exposure.It is surprising, that the two multifacetedallergen-reduction studies (5, 6) have notbeen taken into consideration for thismeta-analysis as the conclusion of theprevious meta-analysis suggested thatglobal allergen reduction had to be per-formed (2). These two studies, which gath-ered 937 children for the first one (5) and274 for the second one (6), demonstratedthe efficacy of global allergen reduction onallergen exposure and on clinical outcomesin moderate to severe asthma. In the firststudy published by Morgan et al. in 2004(5), the reduction of allergen exposure wasobtained 1 and 2 years after the interven-tion for Dermatophagoides farinae (Der f 1)in the bed and on the bedroom floor andfor Dermatophagoides pteronyssinus (Der p1) and cockroach on the floor. A significantreduction of days with symptoms was alsoobtained when compared with the controlgroup and the reduction of dust mite (Derf 1) and cockroach allergen levels on thebedroom floor was significantly correlatedwith reduced complications of asthma. Inthe second multifaceted study published in2005 by Krieger et al. (6), it was alsodemonstrated that global reduction mea-sures were clinically more efficient thansingle reduction measures.Moreover, these two studies (5, 6)clearly demonstrated the role of indoortechnicians, performing home visits toachieve a global allergen reduction, andconfirmed the results of the French study(7). Brandt et al. (8) underlined also veryrecently the role of indoor techniciansand recommended that public healthprograms should consider the use oftrained field workers such as medicalindoor environment counselors to preventthe progression of allergic asthma andrhinitis.In conclusion, this last meta-analysis byGotzsche and Johansen on house dust mitecontrol measures for asthma clearly dem-onstrated that specific house dust mitecontrol measures for asthma only concen-trated on the bedding were not efficient onallergen exposure and clinical symptoms.So, we think that it is not yet useful toperform every 4 years a new meta-analysisbased on single mite-allergen reductionmeasures for asthma and suggest for thenext meta-analysis to include multi-facetedstudies.F. De Blay, C. Barnig, M. OttDivision of Asthma and Allergy –Department of Chest Diseases UniversityHospital Strasbourg, Strasbourg, France