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This Working Group was assembled to review and evaluate methods currently used to estimate work site exposures to biological agents and to present recommendations on suitable measurement strategies. The current state of exposure assessment was evaluated for environments with organic dust including agriculture, composting, sewage and waste treatment processing, peat moss harvesting and handling, cotton and textile processing, greenhouse work, and grass seed processing. Methods for measurement of microbial contaminants in indoor environments were also considered. Important methods are emerging that use quantitative PCR for assessment of microbial agents. Difficulties exist with optimization of extraction to yield contaminant-free DNA without significant DNA loss. Advances in assays for microbial agents (e.g., endotoxin and glucans) as well as allergens have increased the utility of exposure assessment for these agents. A crucial area for further development is international harmonization of methodologies to reduce interlaboratory variability and to facilitate establishment of exposure guidelines. Endotoxin exposure assessment using the Limulus amebocyte lysate method is a high priority for harmonization because of its importance as a pulmonary inflammatory agent in many occupational settings.

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by intense polyclonal production of autoantibodies and circulating immune complexes. Some reports have associated SLE with a Th2 immune response and allergy. In the present study 21 female patients with SLE were investigated for total IgE and IgE antibodies to dust house aeroallergens by an automated enzyme-linked fluorescent assay, and were also evaluated for antinuclear IgE autoantibodies by a modified indirect immunofluorescence test using HEp-2 cells as antigen substrate. Additionally, immunocapture ELISA was used to investigate serum anti-IgE IgG autoantibodies. Serum IgE above 150 IU/ml, ranging from 152 to 609 IU/ml (median = 394 IU IgE/ml), was observed in 7 of 21 SLE patients (33%), 5 of them presenting proteinuria, urinary cellular casts and augmented production of anti-dsDNA antibodies. While only 2 of 21 SLE patients (9.5%) were positive for IgE antibodies to aeroallergens, all 10 patients with respiratory allergy (100%) from the atopic control group (3 males and 7 females), had these immunoglobulins. SLE patients and healthy controls presented similar anti-IgE IgG autoantibody titers (X = 0.37 +/- 0.20 and 0.34 +/- 0.18, respectively), differing from atopic controls (0.94 +/- 0.26). Antinuclear IgE autoantibodies were detected in 17 of 21 (81%) sera from SLE patients, predominating the fine speckled pattern of fluorescence, that was also observed in IgG-ANA. Concluding, SLE patients can present increased IgE levels and antinuclear IgE autoantibodies without specific clinical signs of allergy or production of antiallergen IgE antibodies, excluding a possible association between SLE and allergy.

Research on organic dust during recent years has revealed major clinical effects and some causative agents. Many of the symptoms reported are caused by an inflammation in the airways, characterized by a neutrophil response. This condition can cause a non-allergic asthma. There are also reactions characterized by lymphocyte accumulation and by specific IgE antibody formation. Causative agents identified as bacterial endotoxins, molds, and different allergens.

Background: In healthy adults and children, deep inhalation (DI) is able to reverse induced bronchoconstriction. This ability is impaired in asthma, but the reasons are still to be elucidated., Objectives: This study investigated whether the bronchodilator effect of DI during methacholine-induced bronchoconstriction can be improved by allergen avoidance in asthmatic children, and its relationship with airway inflammation., Methods: The effect of DI on methacholine-induced bronchoconstriction was studied at the beginning and the end of a 3-month allergen avoidance period at high altitude in 14 allergic asthmatic children who had severe asthma attacks. Changes in airway caliber were inferred from the respiratory resistance (Rrs) measured by a forced oscillation technique. Results were related to the percentage of eosinophils in induced sputum and compared with those obtained in 9 age-matched nonasthmatic children., Results: In asthmatic subjects, DI had no significant effect on methacholine-induced increase in Rrs before (P=.62) but significantly reversed it after (P <.01) allergen avoidance. However, the ability of DI to reverse a methacholine-induced increase in Rrs tended to remain less in asthmatic than nonasthmatic children even after allergen avoidance (P=.05). In the asthmatic children, the percentage of eosinophils in induced sputum was decreased at the end of the allergen avoidance period (P <.001), without any significant correlation between sputum eosinophils and airway responsiveness to methacholine or effect of DI., Conclusion: A short period of allergen avoidance may improve the ability of DI to reverse induced bronchoconstriction in some asthmatic children. This effect is associated, yet not correlated, with a reduction in airway inflammation.

Background: Exposure to house dust mite (HDM) allergens can lead to the development of allergic complaints. Mattress covers seem to be an obvious option for lowering allergen exposure in sensitized individuals. Previous studies have shown that Dermatophagoides pteronissinus was the most prevalent HDM species in the Netherlands., Objective: In the present study, we investigated the effect of mattress covers on Der p 1 and Der f 1 concentrations in dust samples in three areas in the Netherlands; Groningen, Utrecht and Rotterdam., Methods: Dust was obtained from mattresses of 277 patients at the beginning of the study and after 12 months of the placebo-controlled intervention. It was analysed for allergen content by immunoassay. The differential effect of the intervention on Der p 1 vs. Der f 1 was analysed in a subgroup with Der p 1+Der f 1>1 microg/g dust (N=161). It was tested whether the intervention caused a significant change in the Der f 1/Der p 1 ratio., Results: At t=0 we found very similar levels of the group 1 allergens of both species. The relatively high prevalence of D. farinae in our study was geographically restricted: the median Der f 1/Der p 1 ratio was 11.1 in the Rotterdam area compared with 1.32 in the Utrecht area and 0.33 in the Groningen area. Analysis of our data showed that the favourable intervention effect found for the combined allergen data (reduction factor=2.9, P<0.001) is essentially due to a favourable effect of the intervention on the Der f 1 levels only (reduction factor=3.6, P<0.001). The effect on the Der p 1 level was remarkably small (reduction factor: 1.2, P=0.48). In the intervention group, the Der f 1/Der p 1 ratio decreased after 12 months by a factor 2.0, whereas in the placebo group it increased (probability of the intervention effect: P<0.005)., Conclusion: Mite-impermeable covers are more effective in reducing the level of Der f 1 than that of Der p 1.

Background: By design, omalizumab binds free IgE in the circulation and prevents its attachment to the surface of mast cells and basophils, thereby preventing them from responding to allergens. Previously, omalizumab rapidly reduced free IgE levels, as well as basophil high-affinity IgE receptors, leading to significant reductions in basophil mediator response to allergen. It is assumed that tissue mast cells are similarly altered in their Fc epsilon RI density and function., Objective: We examined the phenotypic shift of skin mast cells in parallel to that of blood basophils in 3 subjects infused with omalizumab., Methods: Three subjects with allergic rhinitis underwent intradermal skin test titration with house dust mite antigen at days 0, 7, 70, and 196 of omalizumab treatment. As control subjects, 5 untreated subjects with allergic rhinitis were evaluated at similar time points. All subjects underwent skin biopsy 18 to 24 hours later at the site of allergen injection. Biopsy specimens were characterized by means of immunohistochemisty for tryptase and Fc epsilon RI alpha immunoreactivity, as well other markers (CD3, CD45RO, CD68, cutaneous lymphocyte antigen, and major basic protein)., Results: Omalizumab recipients, but not control subjects, demonstrated reductions in Fc epsilon RI alpha immunoreactivity at days 70 and 196 in parallel with reductions in the acute wheal response to allergen. However, no reductions in tryptase-positive cells were noted at these time points., Conclusion: Reductions in free IgE levels by omalizumab leads to a rapid reduction in basophil Fc epsilon RI receptor expression. In contrast, the time course for the decrease of Fc epsilon RI expression in skin mast cells is slower and associated with decreased acute allergen wheal size.

This study presents the results of an investigation of respiratory symptoms, pulmonary function and chest X-ray examinations, and analysis of antibodies to fungi of 197 tussah silk-processing workers and 40 control workers. An industrial hygiene survey and environmental mycological studies were also conducted. The dust concentrations in tussah silk processing workshops were less than 5.1 mg/m(3) on average, with a maximum of 7.8 mg/m(3) below the national health limit of 10 mg/m(3). Most dusts in all tussah silk processing workshops contained less than 1.2% silica. Numbers of isolated fungi in tussah silk processing workshops [755-6,544 cfu/m(3) (colony forming unit/m(3)), were significantly higher than those in control environments (63-472 cfu/m(3)). The prevalences of respiratory symptoms in tussah silk processing workers were higher than those in control workers. The prevalences of respiratory symptoms in exposed male non-smoking workers were 44.4% with chronic cough, and 38.9% with chronic phlegm respectively, which were significantly higher than those (12.5%, 12.5% respectively) in male non-smoking control workers (p<0.05). The prevalences in exposed male smoking workers were 42.9% with dyspnea, and 38.1% with chest tightness respectively, which were significantly higher than those (16.7%, 8.3% respectively) in male smoking control workers (p<0.01). The prevalences of respiratory symptoms in exposed female workers were 25.3% with chronic cough, 38.0% with chronic phlegm, 31.0% with dyspnea, and 29.1% with chest tightness respectively, which were significantly higher than those (10.0%, 10.0%, 10.0%, 5.0% respectively) in female control workers (p<0.01). Fifteen exposed workers often suffered from fever. Five X-rays were abnormal and four cases had nodular or patchy shadows. The prevalences of pulmonary function abnormalities in the exposed female group were significantly higher than those in control groups (p<0.01). The OD(450 nm) values for antibodies to fungi in tussah silk processing workers were significantly higher than those of control workers (p<0.05). The positive rates of anti-fungal antibodies in tussah silk-processing workers were also significantly higher than those of control workers (p<0.01). The results suggested that fungi might be one of the main allergens in respiratory diseases in the tussah silk processing workers.

The morbidity and mortality from asthma in the Western world have increased 75% in the past 20 years. Recent studies have demonstrated that sensitization to cockroach allergens correlates strongly with the increased asthma morbidity for adults and children. We investigated whether dexamethasone administered before or after allergen challenge would inhibit the pulmonary inflammation and airway hyperresponsiveness in a mouse model of asthma induced by a house dust extract with high levels of cockroach allergens. For the prevention experiment, mice were treated with an intraperitoneal injection of dexamethasone 1 h before each pulmonary challenge, and airway hyperresponsiveness was measured 24 h after the last challenge. Mice were killed 48 h after the last challenge. For the reversal study, airway hyperresponsiveness was measured 24 h after the last challenge, and the mice were treated with dexamethasone. Dexamethasone treatment before allergen challenge significantly reduced the pulmonary recruitment of inflammatory cells, myeloperoxidase activity in the lung, airway hyperreactivity, and total serum IgE levels compared with PBS-treated mice. Additionally, dexamethasone treatment could significantly reduce the airway hyperreactivity of an established asthmatic response. These results demonstrate that dexamethasone not only prevents but also halts the asthmatic response induced by house dust containing cockroach allergens. This model exhibits several features of human asthma that may be exploited in the study of pathophysiological mechanisms and potential therapeutic interventions.

Background: It has been suggested that exposure to elevated levels of endotoxin decreases the risk of allergic sensitization., Objective: To examine the associations between current exposure to bacterial endotoxin in house dust and allergic sensitization in adults., Methods: In 1995-1996, we conducted a nested case-control study following a cross-sectional study performed within the European Community Respiratory Health Survey (ECRHS). Data of 350 adults aged 25-50 years was analysed. Allergic sensitization was assessed by measurement of specific immunoglobulin E (IgE) against several inhalant allergens. Living room floor dust samples were taken. The endotoxin content was quantified using a chromogenic kinetic Limulus amoebocyte lysate test., Results: Multiple logistic regression analysis showed a negative association between exposure to house dust endotoxin and severe allergic sensitization. Odds ratios (95% CI) adjusted for place of residence, gender, age, and 'caseness' were 0.80 (0.64-1.00) for sensitization to >/=1 allergen and 0.72 (0.56, 0.92) for sensitization to >/=2 allergens using 3.5 kU/l as a cut-off value for sensitization. With regard to single allergens, the protective effect of endotoxin was strongest for pollen sensitization [aOR (95% CI) = 0.74 (0.58, 0.93)]., Conclusion: Our results indicate that current exposure to higher levels of house dust endotoxin might be associated with a decreased odds of allergic sensitization in adults.

Background: The eczema reaction in the atopy patch test (APT) is proposed to be immunoglobulin (Ig)E mediated, but can take place also in individuals lacking allergen-specific IgE in serum. The purpose of this study was to evaluate the importance of allergen-specific serum IgE for the APT reaction., Methods: Ten patients with reproducible positive APT to extract of Dermatophagoides pteronyssinus, five patients with (group A) and five patients without (group B) detectable serum-IgE to D. pteronyssinus, were tested with extract of D. pteronyssinus on normal skin for 6, 24, 48 and 72 h. Skin biopsies were taken and analysed for cell infiltrates, eosinophils (EG2), IgE, FcepsilonRI, CD1a, CD4, CD8 and metalloproteinase 9 (MMP9)., Results: The number of IgE+, CD4+, EG2+ and MMP9+ cells increased with time in group A. FcepsilonRI+ cells and CD8+ cells increased with time in both groups. A correlation was found between the levels of D. pteronyssinus-specific serum-IgE and the score of dermal cell infiltrates at 72 h. The three patients with the highest values of allergen-specific IgE also had the highest expression of EG2+ cells and the highest APT scores., Conclusions: Our study strengthens the hypothesis that the IgE molecule has a key role, at least as an amplifier, in the APT reaction.

The production of pharmaceutical proteins in plants, particularly in maize (corn), offers solutions to the limited production capacity and flexibility of current cell culture technologies. Implementation of this technology presents unique challenges to industrial hygiene, safety, and occupational medicine, including the handling of pharmaceuticals in the context of agricultural production and the processing of grain for extraction. Protein-related challenges include: (1) widely varying potential for hazard depending upon the activity of the protein and nature and location of the target molecule; (2) limited data related to industrial routes of exposure; and (3) the inability to obtain relevant animal data because of high species-specificity. These challenges necessitate the development of novel approaches to industrial hygiene and safety. Realizing that much remains to be learned, our approach uses conservative assumptions to assure protection of employee health.

Objective: Exposure to endotoxin in early life has been proposed as a factor that may protect against the development of allergic diseases such as eczema. The objective of this study was to examine the relation between endotoxin exposure in early life and eczema in the first year of life in children with parental history of asthma or allergies., Methods: This study used a prospective birth cohort study of 498 children who had a history of allergy or asthma in at least 1 parent and lived in metropolitan Boston. A subset of 401 living rooms had house dust samples adequate for analysis of endotoxin., Results: In multivariate analyses adjusting for gender, income, and season of birth, endotoxin levels in the living room at 2 to 3 months of age was inversely associated with physician- or nurse-diagnosed eczema in the first year of life (odds ratio [OR] for each quartile increment: 0.76; 95% confidence interval [CI]: 0.61-0.96). Exposure to a dog in the home at age 2 to 3 months was also inversely associated with eczema in the first year of life, but the CI widened when endotoxin was included in the multivariate model (OR: 0.54; 95% CI: 0.27-1.09). Other variables associated with eczema in the first year of life included paternal history of eczema (OR: 1.91; 95% CI: 1.03-3.55) and maternal specific immunoglobulin E positivity to > or =1 allergen (OR: 1.61; 95% CI: 1.01-2.56)., Conclusions: Among children with parental history of asthma or allergies, exposure to high levels of endotoxin in early life may be protective against eczema in the first year of life. In these children, paternal history of eczema and maternal sensitization to at least 1 allergen are associated with an increased risk of eczema in the first year of life.

Unlabelled: Recently, cockroaches have been established as the second most Important allergen, producing allergic diseases, especially in low socioeconomic populations. In Thailand, about 44-61% of atopic patients were positive to cockroach extract by a skin-prick test. This study examined cockroach allergen levels in relation to cockroach species and allergic diseases in the houses of cockroach-sensitive patients. Sixty households of allergic patients in the Bangkok metropolitan area were surveyed using open- and closed-ended questionnaires. Cockroaches were collected using commercial cockroach traps, while dust samples were obtained from the bedrooms, kitchens and living rooms of the houses using a vacuum cleaner. The cockroaches were counted and their species Identified. The levels of cockroach allergens were determined by specific monoclonal antibodies using a monoclonal antibody-polyclonal antibody based sandwich ELISA kit. Six cockroach species were Identified: Periplaneta americana (American cockroach, 72.15%), Supella longlpalpa (2.75%, found in only one house), Periplaneta brunnea (0.78%), Periplaneta australaslae (0.78%), Neostylopyga rhombifolla (0.78%), Blattella germanica (German cockroach, 0.39%) and nymphs (22.35%). Allergens of the predominant species, P. americana, were detectable in all homes studied, with the highest levels in the kitchen areas. The range of allergen levels in house dust varied from 0.40-162.00 microg per g of dust. The median and mean allergen levels in kitchen dust were 59.16 microg and 62.80 microg per g of dust, respectively, while the median allergen level in bedroom dust was only 15.90 microg per g of dust. The German cockroach allergen (Bla g 2) was undetectable in any of the houses., In Conclusion: P. americana was the most common cockroach and may be the species causing allergic diseases, especially asthma, in Thailand, which differs from the USA and Europe

Background: Asthma in bakery workers is one of the most frequently occurring forms of occupational asthma in the world. Experience from other countries has shown the prevalence of sensitization (IgE) to bakery-associated allergens (BAAs) (wheat [W], flour dust [FD], alpha-amylase [AA]) in bakery workers to be 5% to 53%, whereas the prevalence in nonoccupationally exposed individuals was estimated to be 1.2% to 6.4%., Objective: To estimate the prevalence of BAA sensitization by measuring BAA specific IgE in the residual serum tubes of volunteer blood donors., Methods: Serum samples from 534 volunteer blood donors were measured for anti-W, anti-FD, and anti-AA specific IgE antibodies (in duplicate) using the AlaSTAT microplate assay. Samples with BAA IgE concentrations of 0.35 kU/L or greater were considered positive., Results: Nineteen of 530 serum samples (3.6%; 95% confidence interval [CI], 3.3%-3.9%) were positive for W (range, 0.38-3.61 kU/L), whereas 31 of 534 (5.8%; 95% CI, 5.3%-6.3%) were positive for FD (range, 0.35-2.34 kU/L) and 5 of 529 (1.0%; 95% CI, 0.9%-1.1%) were positive for AA (range, 0.38-1.59 kU/L). Thirteen serum samples were positive for both W and FD; 1 sample each was positive for W and AA and FD and AA., Conclusions: The prevalence of IgE sensitization in serum samples from a relatively large unselected population of volunteer blood donors is 1.0% for AA, 3.6% for W, and 5.8% for FD, which agrees well with data from other countries for sensitization prevalence rates for nonoccupationally exposed individuals.

Objectives: Air pollutants can affect lung function and also the immune system. In a study about lung function of salt miners in relation to the complex exposure in a salt mine, we also analysed selected immunological parameters and inflammation markers in the blood of miners. Effect of salt dust, diesel exhaust, nitrogen oxides (NOx) and smoking on the biomarkers was analysed., Methods: Blood was drawn from 286 salt miners, and the soluble intercellular adhesion molecule-1 (s-ICAM), monocyte chemotactic protein (MCP-1) and clara cell protein (CC16) were analysed by an immunoassay, blood profile was done and lymphocyte subpopulations (CD3, CD3/CD4, CD3/CD8, CD19, NK-cells, CD3/HLA-DR) were determined by flow cytometry. Salt dust was measured by two-step gravimetry (personal sampling). Diesel exhaust was measured as elemental carbon concentration by coulometry. NOx were determined by an electrochemical cell method. Differences between non-smokers, former smokers and active smokers were analysed by analysis of variance. Linear regression analysis to describe exposure-response relationships was done with regard to confounding factors [smoking, inflammatory diseases, time of blood drawing, respiratory infection and body-mass index (BMI)]., Results: Significant differences between non-smokers and active smokers were found for most of the leukocyte types (e.g. granulocytes P = 0.000, lymphocytes P = 0.002, T-cells P = 0.033) and for some soluble parameters (ICAM P = 0.000, IgM P = 0.007, IgE P = 0.035). Increasing numbers of total lymphocytes, T-cells and HLA-DR positive T-cells in relation to exposure were found by linear regression analysis (e.g. for inhalable dust:total lymphocytes P = 0.011, T-cells P = 0.061, HLA-DR positive T-cells P = 0.007). CONCLUSION. Comparison of immunological markers in non-smokers and active smokers confirms leukocytosis and inflammation following tobacco consumption. The combined exposure of salt dust, diesel exhaust and NOx seems to influence the immune system. Together, the results suggest that the analysis of leukocytes and their subsets can complete other investigations (lung function, questionnaire) to monitor exposure-response relationships in occupational studies investigating the effect of inhaled substances. Longitudinal studies will be necessary to determine the predictive value of the immunological changes., (Copyright 2004 Springer-Verlag)

Background: A few studies have compared indoor allergens and endotoxin levels between urban and rural settings as important determinants for asthma and atopy in children. However, no study was done in the Middle East or investigated refugee camps., Methods: As part of a nested case-control study in Ramallah in 2001, we measured house dust mite and pet allergens, as well as endotoxin in dust collected from 110 children's mattresses and living room floors., Results: Geometric mean (GM) concentrations of Dermatophagoides pteronyssinus (Der p1) antigen were 4.48 microg/g in mattress dust and 1.23 microg/g floor dust. The highest Der p1 levels were seen in refugee camps. Concentrations of Dermatophagoides farinae antigen (Der f1) were much lower (<0.08 microg/g dust). Concentrations of cat allergen (Fel d1) were highest in villages, and those of dog allergen (Can f1) were highest in mattresses from cities and in floor dust from refugee camps. GM of endotoxin levels were 25.7 EU/mg in mattress dust and 49 EU/mg dust in floor dust., Conclusions: Concentrations of Der p1 were high compared to Western European countries, but were lower compared to UK and Australia. Levels of pet allergens were lower than in Western Europe. Endotoxin levels were higher compared to developed countries. Indoor environmental factors such as dampness seemed to be important determinants for allergen and endotoxin, but living habits such as lack of mattress cover appeared unimportant.

Objectives: To evaluate allergic sensitisation to Chrysonilia sitophila, Penicillium glabrum, and Trichoderma longibrachiatum in cork workers with asthma., Methods: Skin prick tests with a battery of common allergens and with the three fungi were performed on ten cork workers with asthma and eight non-exposed asthmatics. Based on serial peak expiratory flow measurements, five were classified as having occupational asthma (AO) and five as having non-occupational asthma (NOA). In exposed patients, specific antibodies for the three fungi were also studied by immunoblotting, Results: Two out of ten patients with occupational exposure and four out of eight of the control group showed positive results for skin prick tests for common allergens. Moreover, two out of five patients with OA and three out of eight controls exhibited sensitisation to storage mites. All exposed patients (with OA or NOA) had negative skin prick test results for the fungal extracts. In patients with asthma and occupational exposure, immunoblotting results confirmed the absence of specific IgE. However, specific IgG4 was present in some cases., Conclusions: Atopy does not seem to characterise occupational asthma in cork workers. Despite their long exposure to moulds, we could not find evidence of IgE sensitisation to the three most prevalent cork fungi in patients with OA, which points to the search for other causative agents, such as cork chemical compounds or contaminants.

Helminthic infections and allergic diseases are highly prevalent in many parts of the world. Although skin reactivity to indoor allergens is decreased in subjects from helminthic endemic areas, the degree of exposure to mite allergens has not yet been investigated in these areas. This study evaluated the association between exposure to dust mites and skin reactivity to mite allergens in subjects with a history of wheezing in the last 12 months selected from a rural endemic area for schistosomiasis (group I, n = 21), and two non-Schistosoma mansoni endemic locale, a rural area (group II, n = 21) and a urban slum area (group III, n = 21). All subjects were evaluated by skin prick tests with mite allergens, and for total and specific immunoglobulin E (IgE) against dust mites, antibodies for S. mansoni, and for intestinal parasites. Dust samples from each subjects' home were quantified for mite allergen and species of the mite identification. Except for S. mansoni infection which was more prevalent in group I than in groups II and III (p < 0.0001), the prevalence of intestinal parasites, and total and specific IgE levels were similar for all groups. Despite the levels of mite allergens and specifically to Der p 1 detected in dust samples of subjects home from all three areas, the frequency of positive skin reactivity to mite antigens was significantly lower (19.0%) in subjects from group I relative to group II (76.2%) and group III (57.1%; p < 0.001). This result suggests that S. mansoni infection could modulate the immediate hypersensitivity skin response to mite allergens in highly exposed subjects.

Dust is an environmental stressor and can become extensive in agricultural production systems. Thirty-six female, Spanish goats (average BW 21.1 kg, SEM = 1.31; age = 4 mo) were randomly assigned to simulated dust events or no dust, with or without tilmicosin phosphate treatment in a 2 x 2 factorial arrangement of treatments to determine effects on performance, rectal temperature, and leukocyte changes. All goats were fed a standard growing diet (13.6% CP) consisting of 37% roughage and 63% concentrate (DM basis). Feed intake was measured daily, and BW (unshrunk) measured individually every 7 d. The tilmicosin-treated group received tilmicosin phosphate (10 mg/kg BW s.c.) before starting the study. Goats exposed to dust were enclosed as a group inside a canvass tent for 4 h each day and ground feed yard manure dust (mean particle size 100 microm) was aerosolized inside the tent to simulate a dust event. There was one single dust event (Phase I) followed by rectal temperature measurement, and heparinized blood collection for complete cell counts at 0 (pretrial), 4, 12, 20, 44, 68, and 210 h after dust exposure. This was followed by 21 d of chronic dust events (Phase II). The sampling procedures for Phase II were exactly the same as in Phase I, except that samples were obtained daily at 0 (before dust application), 4, 8, and 12 h after each dust event. Dust treatment had no effect (P > 0.05) on feed intake or ADG, but the gain:feed (G:F) ratio was lower (P < 0.05) in the control goats than the dust exposed group. Tilmicosin phosphate-treated goats had a higher (P < 0.05) G:F ratio than untreated goats. Dust exposure increased (P < 0.002), but tilmicosin treatment decreased (P < 0.05) rectal temperature at 4 and 8 h. Dust exposure increased (P < 0.02) blood lymphocyte counts compared with controls. These results suggest that simulated dust events altered rectal temperature and leukocyte counts of goats.

Background: Blo t 1 is a cysteine protease-like allergen from Blomia tropicalis. Recombinant Blo t 1 binds up to 90% of IgE from allergic patients and shows limited cross-reactivity to Der p 1. The generation of monoclonal antibodies (mAbs) against Blo t 1 is important for the detection, isolation and characterization of the native form of the allergen., Methods: Mice were immunized intramuscularly with naked plasmid DNA encoding Blo t 1 gene with in vivo electroporation and boosted intraperitoneally with recombinant Blo t 1. mAbs against Blo t 1 were generated using a methylcellulose-based hybridoma cloning kit. The native Blo t 1 was isolated by mAb affinity purification and its allergenicity was determined by ELISA. A two-site ELISA for Blo t 1 was developed using the mAbs generated., Results: A DNA-based immunization protocol induced high titre Blo t 1-specific antibodies in mice. Six stable hybridoma clones secreting mAbs recognizing the native and recombinant Blo t 1 were generated. The native Blo t 1 was affinity-purified from a B. tropicalis extract and its allergenicity was determined at 63% using a panel of Singaporean and Malaysian mite allergic patients' sera. A two-site ELISA was developed, which showed a detection limit of 10 ng/mL of Blot t 1., Conclusion: Six Blo t 1 mAbs were successfully generated by DNA immunization. These mAbs are useful for nBlo t 1 immunoaffinity isolation and quantitative immunoassays for Blo t 1 in mite and environmental dust extracts.

Background: Mites belong to the most frequent and potent allergen sources. Immunotherapy with mite allergen extracts is frequently performed if allergen avoidance is not possible or successful. However, highly controversial results have been reported for mite-specific immunotherapy., Objective: The aim of this study was to develop diagnostic concepts that may contribute to an improved selection of patients for immunotherapy with Der p allergen extracts and that may be used for immunological monitoring of patients undergoing this treatment., Methods: The IgE reactivity profiles to Der p extract were determined in a Middle European mite-allergic population by IgE immunoblotting and by using a panel of seven purified natural or recombinant Der p allergens (nDer p 1, nDer p 4, rDer p 2, rDer p 5, rDer p 7, rDer p 8, rDer p 10). Furthermore, we investigated the sensitization and cross-reactivity to house-dust- and storage-mite allergen extracts by CAP FEIA measurements and by IgE competition studies., Results: More than 95% of the patients could be diagnosed with a combination of nDer p 1 and rDer p 2. With the methods used, we could discriminate mite-allergic patients who were mainly sensitized to the major Der p allergens (Der p 1, Der p 2) from patients with a broad sensitization profile, including highly cross-reactive allergens (e.g. Der p 10: tropomyosin) as well as reactivity to storage mites., Conclusions: Diagnostic tests containing the major mite allergens (i.e. Der p 1, Der p 2) and highly cross-reactive mite allergens (e.g. Der p 10) may improve the diagnostic selection of patients for immunotherapy with Der p extracts. These tests may also be used for the immunological monitoring of patients undergoing immunotherapy.

Your doctor says you're allergic to dust mites, which explains your constant runny nose and watery eyes. You know the best way to prevent your allergy symptoms is to avoid their cause--dust. You've always tried to keep a clean house. What more can you do?

Background: Exposure and sensitization to indoor allergens have been associated with the development of asthma and other allergic diseases in many parts of the world. It is important to establish the degree of exposure, and to evaluate whether allergen control measures are effective in a particular area., Methods: Concentrations of major allergens of mites, cockroach, cat and dog were measured in dust samples from homes of 24 mite-allergic patients living in Ribeirão Preto, Brazil. Allergen concentrations were quantitated by monoclonal antibody-based ELISA. Mite-impermeable mattress and pillow covers were applied to beds in the homes of 19 of the 24 patients, and group 1 mite allergen levels were measured 1 and 6 months following intervention., Results: Patients were exposed to high concentrations of mite allergens in their homes. 87.5% of the homes presented concentrations of group 1 allergens >10 microg/g of dust in at least one site. Cockroach allergen concentrations were low in most samples. Dog allergen concentrations were significantly higher in homes with dogs as compared to those without dogs. Mean concentrations of cat allergen were 0.1 microg/g. Mite allergen concentrations in bedding samples dropped from 24 microg/g at baseline to 0.9 and 1.0 microg/g, respectively, 1 and 6 months following encasement of mattresses and pillows., Conclusions: Significant mite allergen reduction can be achieved in an area of high degree of exposure to mite allergens. Further studies evaluating the effect of this reduction on symptoms and airway inflammation will be necessary to establish the effectiveness of mite avoidance measures in our area., (Copyright 2004 S. Karger AG, Basel)

The results of the determination of the allergenic and immunogenic properties of industrial dust of the cotton factory complex are presented. The antigen of industrial dust consists of, at least, 5 antigenic components. The presence of common antigenic determinants in the antigen of industrial dust and in cotton pollen antigen has been established. The administration of relatively large doses of the allergen according to a shortened schedule has been experimentally shown to enhance the curative effectiveness of specific therapy.

The respiratory health of 230 female and 1,734 male farming students (FS) and 407 male rural controls was analyzed. A significantly increased prevalence of cough (6.9%) was reported among the male FS compared to the controls (2.5%). Measured FEV1 and FVC did not differ between the male FS and the controls, as opposed to significantly higher values among the female FS compared to a random sample of urban females stratified for height. Skin prick test (SPT) to house dust and storage mites was significantly more prevalent among the controls (18.7%) compared to the male FS (12.8%) and the female FS (11.9%). The size of the house dust mite weal and the number of positive skin prick reactions were significantly associated with bronchial hyperreactivity. The difference in lung function among the female FS and the lower prevalence of skin reaction among the male FS and female FS probably reflects a healthy workers selection.

Hypersensitivity pneumonitis or extrinsic allergic alveolitis can be defined as a lung disease caused by a wide group of antigens that reach the lung by inhalation of organic and/or inorganic dust of various sources. The dust of the stored maize corn has been reported as cause of respiratory symptoms. During the storage process, maize corn dust can be contaminated by moulds and thermophilic actinomycetes, which have not been described until now as the causing antigens of these symptoms. We present a case of occupational hypersensitivity pneumonitis in an agricultural worker who cultured and stored maize corn. Clinical findings, precipitating antibodies, and evolution after having removed him from his work, confirmed the diagnosis. In our case, Aspergillus species contaminating the maize corn dust are probably the antigens that caused the disease.

Aim: To evaluate German cockroach (Blattella germanica) allergen levels in house dust and skin reactivity to German cockroach in adult atopic and non-atopic subjects in inland areas of Croatia., Methods: Blattella germanica group 2 (Bla g 2) allergen was measured using the enzyme-linked immunosorbent assay (ELISA) on test strips (Dustscreen(TM) test, Heska AG, Switzerland) in 94 house dust samples collected from living room and bedroom floors, 35 from rural and 59 from urban areas. Skin prick testing with common inhalatory allergens, Blatella germanica, storage mites Lepidoglyphus destructor and Tyrophagus putrescentiae (ALK-Abello, Denmark) was performed in 187 adult outpatients, 131 from urban and 56 from rural areas. Total serum IgE levels were measured using the ELISA method. Subjects with relevant respiratory and/or skin symptoms, at least one positive skin prick test, and/or increased total IgE were considered atopic., Results: Positive skin prick test to cockroach was observed in 18/187 subjects (9.6%). The frequency of skin prick test positive subjects to cockroach was higher in atopic than in non-atopic subjects, but not significantly (12.2% vs. 4.7%; p=0.098). Of 15 atopic subjects with positive skin prick test to cockroach, 14 also had positive skin prick test to storage mites, 8 to house dust mites, 1 to pollens, and none to cockroach only. Positive skin prick test to storage mites was the only factor which significantly increased the risk for having positive skin prick test to cockroach (n=187; odds ratio, 109.82; 95% confidence interval, 2.06- 5853.5; p= 0.020). In all 94 house dust samples, Bla g 2 was not detectable., Conclusions: Our results suggest that there is no relevant exposure to cockroach allergen in house dust samples from inland areas of Croatia. Consequently, positive skin prick test to cockroach is rare in adult subjects, even in atopics. Positive skin prick test to cockroach in atopics is in the majority of cases related to positive skin prick test to storage mites, probably due to cross-reactivity.

Epidemiologic studies report health effects associated with exposure to ambient particulate matter (PM), but underlying biologic mechanisms remain unclear. We evaluated pulmonary and systemic effects in twelve healthy human adult and twelve asthmatic volunteers exposed once for 2 hours in a whole-body chamber to approximately 200 microg/m3 concentrated ambient particles (CAPs) in the fine (< 2.5 microm) size range and once to filtered air. Neither healthy nor asthmatic subjects showed significant changes in symptoms, spirometry, or routine hematologic measurements attributable to CAPs exposure compared with filtered air. Both groups showed CAPs-related (1) decreases of columnar cells in induced sputum after exposure, (2) increases in certain blood mediators of inflammation (ie, soluble intercellular adhesion molecule 1 [ICAM-1] and interleukin [IL] 6 [marginally significant in asthmatic subjects only]), and (3) parasympathetic stimulation of heart rate variability (HRV). In the asthmatic group, systolic blood pressure modestly increased during filtered air exposure and decreased during CAPs exposure, whereas the pattern was reversed in the healthy group. In summary, this study measured a large number and wide range of biologic endpoints on a relatively small number of healthy and asthmatic volunteers and found few biologic endpoints that responded to CAPs and filtered air exposures with significantly different values. However, observed changes in some mediators of inflammation in blood and changes in HRV were consistent with PM-related effects reported from epidemiologic studies. They suggest that exposure to concentrated PM 2.5 pm or smaller in aerodynamic diameter (PM2.5) tends to elicit more systemic than pulmonary effects. This investigation is one of the first to apply concentrator-exposure technology in a high-risk group (subjects with asthma). Further studies of responses to CAPs that involve other biologic endpoints, other PM size modes, and subjects with other risk factors are needed.

The purpose of this study was to assess the impact of short-term exposure to concentrated ambient particles (CAPs*) on lung function and on inflammatory parameters in blood and airways of healthy human subjects. Particles were concentrated from the ambient air in Chapel Hill, North Carolina, using a Harvard/EPA (US Environmental Protection Agency) ambient fine particle concentrator (HAPC). Each of 38 subjects was exposed either to filtered air (n = 8) or to CAPs (n = 30) for two hours, during which all subjects intermittently exercised. Blood was obtained immediately before and 18 hours after exposure. Also at 18 hours after exposure, viable bronchial biopsy tissues and lavage samples were obtained from 10 CAPs-exposed and 7 control subjects by fiberoptic bronchoscopy. To balance these two groups, additional biopsy tissues were obtained from 4 control subjects participating in an identical protocol for another study. For the CAPs-exposed group, the concentration of particulate matter measuring 2.5 microm or less in aerodynamic diameter (PM2.5) in the exposure aerosols varied from 23.1 to 311.1 microg/m3; for the filtered air group, mean particle concentration was 2.9 microg/m3. For comparative analyses, the CAPs-exposed subjects were separated into three tertiles on the basis of the final concentration of particles to which they were exposed. Lung function, assessed by spirometry and plethysmography before and immediately after exposure, was unaffected by CAPs. Of the inflammatory parameters studied in blood, subjects exposed to CAPs showed mean increases in fibrinogen of 40 to 48 mg/dL with no obvious differentiation by dose, whereas subjects exposed to filtered air showed no change; red and white blood cell counts were unaffected by CAPs exposure. In bronchoalveolar lavage fluid from CAPs-exposed subjects, neutrophils showed a dose-dependent increase both when analyzed as an absolute cell count and as a percentage of total lavaged cells. Bronchial biopsy tissues from 10 CAPs-exposed subjects and 11 control subjects did not show any consistent effect of CAPs exposure on cell counts or adhesion molecule expression. We conclude that CAPs induced a modest degree of airway inflammation as judged by lavage, but this effect was not reflected in biopsy tissues from proximal airways. This discrepant finding may mean that the inflammatory effect of CAPs occurs in more distal airways or that the health effects of PM are driven by processes other than those investigated in this study.

Chemokine receptor expression has been shown to be associated with the differentiation of T helper cells. The CCR3, CXCR4 and CCR5 expression on circulating T cells were studied in 30 house dust mite sensitive-patients with allergic diseases and in another 30 healthy controls. The expression was analyzed in CD4, CD8 and double negative (DN) T cells by triple fluorescence staining. In addition, intracellular cytokine staining was performed in the CCR3+ CD4+ T cells. Increased circulating portions of CCR3+ CD4+ T cells and CCR3+ DN T cells were found in these patients (p < 0.01). There was no statistically significant difference in the expression of CXCR4 and CCR5 on T cells. The follow-up data of the patients did not show a statistically significant change in the CCR3 expression. IL-4 was expressed within CCR3+ CD4+ T cells upon activation. The IL-4 secreting CCR3+ type 2 T helper cells may play a pathogenetic role in immune responses of house dust mite-sensitive Chinese patients with allergic diseases.

Up to recently the post-mortem diagnosis of anaphylaxis has been based solely on circumstantial evidence. With the development of assays for mast cell tryptase it is now possible to verify cases of suspected anaphylaxis. Here we present one such case, which initially appeared to be due to sudden death of unknown cause. A 47-year-old farmer was found dead in his bathroom around midnight. Hospital records revealed that he had previously been diagnosed with an allergy to house dust mites. He had also had infrequent episodes of airway symptoms, nausea, hypotension and diarrhoea usually after going to bed. The forensic autopsy did not give any clue to the cause of death. Serum tryptase in post-mortem blood was found to be substantially elevated in two samples (170 and >200 microg/L). Analysis of allergen-specific IgE showed high values for Dermatophagoides pteronyssinus and farinae. High mite allergen levels were found in dust obtained from the patient's mattress. The results of the immunological tests support the assumption that he died of anaphylactic shock. The circumstances and the patient's history of previous attacks after going to bed point to the fact that exposure to mite contaminated food and/or exposure to mite allergens in bed might have caused his death.

Background: Occupational asthma (OA) from iroko wood has been reported primarily in case reports., Objective: To improve understanding of the pathogenesis of OA induced by iroko wood dust., Methods: Three groups of woodworkers were included in this study: 9 workers who had clinically proven OA from iroko; 10 asymptomatic woodworkers; and 10 woodworkers with asthma. All patients underwent the following tests: a skin test with an iroko aqueous extract, specific IgE determination, and an iroko bronchial provocation test (IBPT). An eosinophil count was determined before and after the IBPT, and a methacholine inhalation test was performed after avoidance of exposure to iroko. Patients were asked to monitor their peak expiratory flow rates during a week at work followed by a week's vacation., Results: In all patients with a personal history predictive of OA from iroko, a reduction of the peak expiratory flow rate and positivity to the IBPT while working with iroko were present. The latter test result showed a dual response, with a decrease in forced expiratory volume in 1 second from 25% to 32% at 10 minutes and a further decrease from 35% to 43% at 8 hours; at 24 hours, the eosinophil count was higher (P = .046). In 4 patients, the intradermal test results with iroko extract were positive, whereas the skin prick test result and the specific IgE determination were negative in all patients. The methacholine test result was also positive. In the control groups, all the test results with iroko extract were negative., Conclusions: Our data suggest that OA due to iroko wood may be induced by immunologic mechanisms other than IgE-mediated immediate hypersensitivity reactions.

In this study, we demonstrate that Dermatophagoides farinae (Der f), a major source of airborne allergens, but not OVA, could rapidly activate mast cells in mice. This was indicated by an elevation of serum mouse mast cell protease 1, a mast cell-specific proteinase, as early as 30 min after intratracheal challenge. Administration of sodium cromoglycate (40 mg/kg, i.p., 1 h before Der f instillation), a mast cell stabilizer, not only suppressed acute mouse mast cell protease 1 production but also attenuated the allergic airway inflammation provoked by repetitive Der f challenge in mice (five times at 1-wk interval). Der f induced the expression of mRNA for TNF-alpha, IL-1beta, IL-4, IL-6, IL-9, and IL-13 in mastocytoma P815 cells and stimulated both P815 cells and bone marrow-derived mast cells to produce IL-4, IL-6, and TNF-alpha in a dose- and time-dependent manner. Cycloheximide as well as sodium cromoglycate blocked the Der f-induced IL-4 production, indicating a de novo protein synthesis process. Supernatants of Der f-stimulated mast cells chemoattracted monocytes and T lymphocytes; they up-regulated the expression of costimulatory B7 molecules, eotaxin, RANTES, monocyte chemoattractant protein 1, and IFN-inducible protein 10 mRNA of alveolar macrophages; they supported PHA-induced T cell proliferation; and they promoted Th2 cell development. Our data indicate that mast cells may be an important cell type during the initiation of Der f sensitization in the airway by modulating the function of alveolar macrophages and T cells.

Background: Early in life, natural exposure to microbial components (eg, endotoxin) may mitigate allergy and asthma development in childhood. Bacterial DNA is a potent stimulus for the innate immune system; its immune stimulatory potential in dust is unknown., Objectives: We sought to quantify bacterial DNA and endotoxin content in dust from urban homes, rural homes, farm homes, and farm barns and to determine if dust DNA is immune-stimulatory., Methods: Total DNA, bacterial DNA, and endotoxin were measured in 32 dust samples. To measure bacterial DNA content, a quantitative polymerase chain reaction assay specific for bacterial ribosomal DNA was developed. Peripheral blood mononuclear cells from 5 adults were stimulated with endotoxin-free dust DNA with/without lipopolysaccharide (LPS) from selected dust samples. IL-12p40, IL-10, and tumor necrosis factor-alpha were measured in cell supernatants by enzyme-linked immunosorbent assay., Results: Bacterial DNA in dust correlated with endotoxin (r = 0.56, P <.001) and total DNA content (r = 0.51, P =.003). The highest bacterial DNA levels were measured in farm barns (mean, 22.1 microg/g dust; range, 1.3 to 56.2), followed by rural homes (6.3 microg/g; 0.2 to 20), farm homes (2.2 microg/g; 0.1 to 9.1), and urban homes (0.6 microg/g; 0.1 to 1.2). Farm barn DNA significantly potentiated (P < or =.05) LPS-induced IL-10 and IL-12 p40 but not tumor necrosis factor-alpha release (13-fold, 3-fold, and 1.5-fold increases, respectively). DNA from 6 urban homes did not demonstrate this LPS-potentiating effect., Conclusions: Endotoxin is a marker for bacterial DNA, which is also higher in locales of lower asthma and allergy prevalence. DNA from farm barn dust augments the immune modulatory effects of endotoxin and may combine with exposure to other such naturally occurring microbial components to mitigate allergy and asthma development.

Purpose: To evaluate the response of patients who underwent both skin and in vitro allergy testing, both of which are accepted methods., Data Sources: Retrospective review of the case notes of 100 patients evaluated by both testing methods for allergic disease., Conclusions: A total of 62 patients (62%) tested positive to at least one of the tested allergens via the in vitro method. A total of 65 patients (65%) tested positive to at least one allergen via the skin-testing method. The most frequently elicited allergic response from the in vitro method was to white oak. Indoor mold and dust most frequently elicited response via skin testing., Implications for Practice: Both in vitro and in vivo allergy testing have limitations. Practitioners should be aware of these when establishing a treatment plan based on the results of differing allergy testing methods. Due to differing responses to skin and in vitro testing methods, it may be prudent to perform both tests to obtain a definitive diagnosis for the allergic patient.

Previous studies of mouse allergens and laboratory-animal-worker-related allergy and asthma suggest that quantifying mouse allergen levels in homes could augment our understanding of inner-city asthma. We hypothesized that levels of mouse allergen in inner-city homes would be related to certain household characteristics. Dust samples were collected from the kitchens and beds of 221 mothers enrolled in a prospective birth cohort study, 92 of African American and 129 of Dominican ethnicity. Samples were analyzed for mouse urinary protein. The geometric mean for kitchen samples was 4.6 micro g/g [95% confidence interval (95% CI), 3.2-6.5] and for bed samples was 0.9 micro g/g (95% CI, 0.8-1.1). The variables associated with mouse allergen levels in the home were frequency of mouse sightings, use of traps or pesticides for mice, presence of holes in ceilings or walls, absence of a cat, and living in a building with fewer than eight floors. Statistically significant neighborhood differences in levels of mouse allergen and report of rodents in the home were also observed. In conclusion, mouse allergen was prevalent among inner-city apartments, and the positive predictive value of self-reported frequent mouse sightings was high (90% for kitchens). However, high levels of mouse allergen were also found in many homes where mothers reported never seeing mice.

Objectives: To evaluate the effectiveness of specific immunotherapy (SIT) in patients with severe house dust mite (HDM)-induced perennial allergic rhinitis using diary cards and objective endpoints., Patients and Methods: Thirty-six adult patients were selected with moderate to severe allergic rhinitis due to HDM allergy uncontrolled by regular anti-allergic drugs. Twenty-eight patients completed the study, 22 of these patients also had mild asthma. Subjects were stratified for HDM sensitivity on the basis of their 4-week diary card score and the size of their immediate and late-phase skin reaction to HDM. The groups were well matched for all relevant parameters. Patients were randomized to receive active preparation (Alutard(R)-SQ, ALK, Dermatophagoides pteronyssinus extract) or an identical placebo preparation. Increasing doses were administered until the maintenance dose was reached. This dose was then given once a month for 12 months., Results: Clinical efficacy was evaluated by symptom medication diary cards recorded for 4 weeks after 12 months of continuous treatment and compared with pre-treatment scores. Skin test reactivity was re-measured after 12 months of treatment to HDM, cat dander and codeine phosphate. After 1 year of treatment, the actively treated group showed a 58% reduction in diary card symptom scores (P<0.002) and a 20% reduction in the use of rescue medication. The placebo group had a 32% reduction in symptom scores (P=NS), but no reduction in rescue medication requirements. The active group showed 36% reduction in skin prick test sensitivity to D. pteronyssinus (P=0.006), while the placebo group values were unchanged. Skin reactivity to codeine was unchanged in both groups. No significant adverse reactions to SIT were encountered., Conclusions: One year of SIT for D. pteronyssinus in patients with poorly controlled rhinitis (+/-mild asthma) produced clinically useful improvement as shown by symptom-medication diary cards and reductions in immediate skin reactions compared with placebo treatment.

Background: Treatment of cat allergy normally entails removal of the cat from the household, but cat owners are often unwilling to part with their pets, despite clinically relevant allergies., Objective: To determine whether levels of Fel d 1 can be reduced without removal of the cat and whether this will affect symptoms of cat allergy., Methods: Cat-allergic patients underwent randomization to either a group instructed in environmental control (EC) and a group with unchanged environment (UE). Dust samples were obtained and settled Fel d 1 measured by enzyme-linked immunosorbent assay. Patients recorded daily nasal inspiratory flow rates. At baseline, 3 months, and 8 months, patients underwent symptom evaluation., Results: Eighteen patients were randomized to the EC group and 22 to the UE group; the final number completing the study was 31, 15 in the EC group, and 16 in the UE group. At 8 months, home Fel d 1 levels had diminished to 6.8% of baseline levels in the EC group, whereas no reduction in levels was noted in the UE group. In the EC group, significant improvements were found in nasal inspiratory flow rate and symptoms compared with the UE group. Patients did not have difficulties adhering to EC measures., Conclusion: A decrease in the allergen load was found in the EC group, which had a significant effect on symptoms of nasal allergy.

The study examined the exposure to biological indoor air agents and their possible role for allergies and respiratory tract illnesses of children. It was conducted as a case control study (atopic vs non-atopic children) at the four surveillance public health departments in Baden-Württemberg in the winter season 1999/2000 and included 379 children of the fourth class. The concentrations of the house dust mite antigens Der F1, Der p1, and Der Gr2 as well as cat allergen Fel d1 were determined in the children's bedrooms on the ground and in the mattress. Specific IgE-antibodies against allergens from house dust, mites and cat were determined in the serum of the children. For mite allergens the following medians ( micro g/g) were estimated in floor dust: Der p1 = 0.6, Der f1 = 2.3, Gr2 = 0.1; in mattresses: Der p1 = 1.2, Der f1 = 3.4, Gr2 = 0.3. The median of Fel d1 in floor dust was 0.2 microg/g, in mattresses 0.1 microg/g. Sensitisation to dust mite allergen was found to be more prevalent than sensitisation to cat. The distribution of sensitisation among the cases and controls is different. Among the cases, more subjects were sensitised to dust mites (32.9 %) and cat (13.1 %). Among the controls, 17.1 % were sensitised to dust mites and 4.1 % to cat. The results showed no direct association between the prevalence of allergies or respiratory tract illnesses and the indoor concentrations of the allergens. Possible reasons for these findings are discussed.

Background: Recent increases in the prevalence of asthma and atopy emphasise the need for devising effective methods for primary prevention in children at high risk of atopy., Method: A birth cohort of genetically at risk infants was recruited in 1990 to a randomised controlled study. Allergen avoidance measures were instituted from birth in the prophylactic group (n=58). Infants were either breast fed with mother on a low allergen diet or given an extensively hydrolysed formula. Exposure to house dust mite was reduced by the use of an acaricide and mattress covers. The control group (n=62) followed standard advice as normally given by the health visitors. At age 8, all 120 children completed a questionnaire and 110 (92%) had all assessments (skin prick test, spirometry, and bronchial challenges)., Results: In the prophylactic group eight children (13.8%) had current wheeze compared with 17 (27.4%) in the control group (p=0.08). Respective figures were eight (13.8%) and 20 (32.3%) for nocturnal cough (p=0.02) and 11 of 55 (20.0%) and 29 of 62 (46.8%) for atopy (p=0.003). After adjusting for confounding variables, the prophylactic group was found to be at a significantly reduced risk for current wheeze (odds ratio (OR) 0.26 (95% confidence interval (CI) 0.07 to 0.96)), nocturnal cough (OR 0.22 (95% CI 0.06 to 0.83)), asthma as defined by wheeze and bronchial hyperresponsiveness (OR 0.11 (95% CI 0.01 to 1.02)), and atopy (OR 0.21 (95% CI 0.07 to 0.62))., Conclusion: Strict allergen avoidance in infancy in high risk children reduces the development of allergic sensitisation to house dust mite. Our results suggest that this may prevent some cases of childhood asthma.

Epidemiology, pathogenesis, clinical picture, diagnosis, management, and prognosis of allergic alveolitis are described in this paper.

Background: Indoor dust mite and cat allergens have been related to the risk of atopic conditions. If allergen levels are influenced by modifiable residential characteristics, potential interventions to prevent disease could be deployed., Objective: To evaluate relationships between allergen concentrations in air and dust samples and selected house and household characteristics using a large prospective study with multiple sequential allergen measurements from each residence., Methods: Fel d 1, Der f 1, and Der p 1 were measured in paired air and dust samples collected at intervals throughout 4 years in suburban homes. House and household characteristics were examined for relationships to allergen concentrations in both univariate and multiple variate analyses., Results: The relationships between house and household characteristics and allergen concentrations in both air and dust were complex. When the housing variables were considered in multiple variate analysis, concentrations of Der f 1 in dust increased with increasing number of residents and relative humidity and declined when forced air heating was used. Dust concentrations of Der p 1 were lower in new homes and during forced air heating use but higher with higher relative humidity and in the presence of dogs. The presence of cats was the dominant determinant of Fel d 1 in both air and dust, but when homes without cats were analyzed separately, dust levels of Fel d 1 were inversely related with relative humidity., Conclusions: Air and dust concentrations of Der p 1 and Der f 1 were positively related to relative humidity and the size of the family. Fel d 1 was positively related to the presence of cats. The relationship of other house or household characteristics was inconsistent but different for Der f 1 and Der p 1.

The acaricidal effects of tonka bean, Dipterix odorata, extracts were investigated on Dermatophagoides pteronyssinus, the European house dust mite, and compared with benzyl benzoate as a standard acaricidal compound. A cyclohexane extract was the most effective, with an EC(50) = 0.075 g/m(2) after a 24 h period, as compared with benzyl benzoate (0.025 g/m(2)). Bioassay-guided fractionation of this extract led to the isolation of coumarin (1). Pharmacomodulation of this compound led us to test 20 analogues (2-21), which were either synthesized or purchased.

Background: Equine heaves is a naturally occurring organic dust-induced asthma characterized by airway neutrophilia, mucus hypersecretion and obstructive lung dysfunction. However, the relative role of different dust components in disease severity remains unclear., Objective: This study investigated the relative contribution of inhaled endotoxin and organic dust particulates (mainly mould spores) in inducing heaves in heaves-susceptible horses., Methods: Control and heaves-susceptible horses received inhalation challenges with hay dust suspension (HDS) before and after lipopolysaccharide (LPS) depletion. Heaves-susceptible horses also received inhalation challenge with HDS particulates with and without the addition of LPS and were housed in two separate dusty environments during which mould and endotoxin exposure was measured. The airway inflammatory and functional response to each challenge was measured., Results: Depletion of endotoxin from HDS attenuated the airway neutrophilia and abrogated the airway dysfunction induced in heaves horses by inhaled HDS. The airway response was re-established by adding back LPS to the depleted HDS, confirming that the attenuation in airway response was due specifically to endotoxin depletion. Interestingly, the magnitude of alteration in airway response following endotoxin depletion and add-back was greater than that which could be attributed solely to endotoxin per se, indicating that the LPS activity was enhanced by the other dust components. Consistent with this possibility, washed particulates harvested from HDS enhanced the airway response to inhaled LPS in heaves horses. Heaves horses given two different hay/straw challenges had a significantly different severity of airway inflammation and dysfunction, despite airborne dust and endotoxin concentrations in the horses' breathing zones being similar., Conclusion: Although inhaled endotoxin appears not to be the only determinant of disease severity in heaves, it does contribute significantly to the induction of airway inflammation and dysfunction. This contribution is largely via the synergistic action of inhaled endotoxin and organic dust particulates, although other soluble dust components also contribute to a lesser degree.

Over the last decade, advances in our knowledge of allergens and in methods for determining their structure have given the clinician a molecular rather than macroscopic view of allergy. The prevalence of sensitization to different allergenic molecules is known for the principal pneumallergens. This knowledge is crucial for understanding the cross reactions between respiratory allergens. The main cross reactions are described here for pollen, mites, roaches, and mammals. In addition, the biological function of a certain number of respiratory allergens are known. Allergens with an enzymatic function, allergens with a transport function, allergens implicated in the regulation of muscle contraction, and allergens participating in the protein defense system have been identified. Potential factors underlying the allergenicity of airborne allergens are discussed: physical properties, structures, biological functions. The diversity of biological functions prohibits retaining a single specific function as a prerequisite for allergenicity; certain major allergens do not have a defined function. No structural form appears to be incompatible with the allergenic potential of a protein found in the environment.