Standardisation of allergen products: 4. Validation of a candidate European Pharmacopoeia standard method for quantification of major grass pollen allergen Phl p 5.

BACKGROUND: The aim of the BSP090 project is the establishment of European Pharmacopoeia Chemical Reference Substances (CRSs) in combination with corresponding standard ELISA methods for quantification of major allergens in allergen products. Here, we present data of a Phl p 5-specific sandwich ELISA that proved suitable for the quantification of Phl p 5, one of the major Timothy grass (Phleum pratense) pollen allergens. METHODS: A Phl p 5-specific ELISA system was assessed with respect to accuracy, precision, inter-assay (within laboratory) and inter-laboratory variations, in a ring trial including 14 laboratories in Europe and the USA. Model samples containing recombinant Phl p 5a CRS as well as native grass pollen extracts were analysed. Each participant was instructed to perform at least one preliminary assay to familiarise with the protocol, followed by three independent assays. RESULTS: The candidate standard ELISA proved suitable to quantify recombinant and native Phl p 5 with satisfactory precision (93% of results within ±30% acceptance range). Inter-assay variation (max. GCV 24%) and especially inter-laboratory variation (max. GCV 13%) showed conclusive results. When assessing accuracy by means of recovery of recombinant spikes from a grass pollen extract matrix, similarly satisfactory spike recovery results were observed for the two spikes with higher concentrations (all within ±30% acceptance range), whereas recovery of the lowest concentration spike was slightly poorer with mean results of six laboratories exceeding acceptance range. CONCLUSIONS: Based on the collaborative study results, the assessed Phl p 5-specific immunoassay is appropriate to be proposed as European Pharmacopoeia standard method.

Comparing the concentration levels of allergens and endotoxins in employees' homes and offices.

OBJECTIVE: The aim of the study was to find out whether allergen and endotoxin concentrations in offices differ from those measured at the homes of employees, and identify the parameters that influence exposure. METHODS: Electrostatic dust collectors (EDCs) were placed in five office buildings (68 rooms, 436 EDCs), as well as the homes of the office workers (145 rooms, 405 EDCs) for 14 days, four times a year. In addition, surface samples were collected from the offices four times a year by vacuuming the carpeted floors. Domestic mite (DM), and the major cat and dog allergens (Fel d 1 and Can f 1) were quantified in all samples using fluorescence enzyme immunoassays. Endotoxin was measured in the EDC samples, using the Limulus amoebocyte lysate assay. The allergen and endotoxin concentrations were log transformed and analysed with multilevel models. RESULTS: Endotoxin concentrations were significantly higher in personal homes compared to levels measured in the offices, and depended on the number of persons living in each household, as well as the presence of a dog. DM allergens were significantly higher in households than in offices, and were significantly higher in bedrooms compared to living rooms. Offices occupied by cat owners had significantly higher Fel d 1 concentrations than offices or homes without. Additionally, Can f 1 concentrations were significantly higher in offices occupied by dog owners compared to those without. CONCLUSIONS: Pet owners appear to transfer cat and dog allergens to their offices. Therefore, in case of allergy complaints at the office, employers and physicians might consider possible contamination by cat and dog allergens.

Skin symptoms in veterinary assistant staff and veterinarians: A cross-sectional study.

BACKGROUND: Veterinary assistants and veterinarians are at an increased risk of developing an occupational skin disease, for example, irritant/allergic contact dermatitis, contact urticaria and hand eczema (HE). OBJECTIVES: We aimed to investigate the prevalence of skin problems and the influence of predisposing factors especially among veterinary assistants. METHODS: We conducted a cross-sectional study among veterinary assistant staff (n = 103) and veterinarians (n = 19). A questionnaire, specific IgE determination and photographs of hands were evaluated for skin symptoms. Logistic regression models assessed predisposing factors. RESULTS: Over 50% (n = 62/122) of our study population reported hand eczema (HE) in the last 12 months (1-year prevalence). Twenty-seven subjects reported redness and contact urticaria directly after animal contact, 35 had a positive history of allergic contact dermatitis. HE was associated with (i) increased frequency of hand washing (11-15 times per day; OR 4.15, confidence interval [CI] 95% 1.18-14.6, p = 0.027, univariate model) and (ii) unprotected contact to fluids and tensides >5 times per day (OR 4.56, CI 95% 1.53-13.6, multivariate model). CONCLUSIONS: We observed a high prevalence of self-reported HE among staff in veterinary practices. Excessive hand washing, unprotected contact with irritants and long-term glove use should be avoided.

Occupational allergy to phytase: case series of eight production workers exposed to animal feed additives.

BACKGROUND: In agricultural meat production, adding enzymes such as phytase to animal feed is widespread, but there is little awareness of the allergenic potential and health risks of these fungal enzymes. PATIENTS AND METHODS: We report on eight patients working in a plant producing phytase granulates. All patients complained about work-related rhinitis occurring within six months of the onset of exposure to phytase dust. Asthmatic symptoms and contact urticaria also occurred. To detect sensitizations to phytase, skin prick-, patch-, and basophil activation test were carried out with the factory product. Levels of IgE and IgG against phytase were also measured. RESULTS: There was a positive reaction to phytase with skin prick testing in seven of the eight patients. IgE specific to phytase was detectable in four of the eight patients, and IgG specific to phytase was detectable in six of the eight patients. The basophil activation test was positive in four out of seven patients tested, but the patch test was negative in all patients tested. Transfer to a different workplace with no exposure to phytase completely eliminated the symptoms. CONCLUSIONS: Mold enzymes such as phytase are highly potent occupational allergens. Occupational safety measures must be strictly implemented in order to protect the health of workers.

Occupational generalized urticaria and anaphylaxis after inhalation of cefuroxime in a nurse.

We present the case of a 53 years old nonatopic female nurse who experienced repeated anaphylactic reactions at work without involvement in drug-specific tasks such as crushing of tablets or preparation of injections. The causal allergen was not identified until a further severe anaphylactic reaction occurred after oral use of cefuroxime during a respiratory infection. Sensitization to cefuroxime was demonstrated by specific IgE, basophil activation test and skin prick test. An inhalation challenge with a dosimeter induced generalized urticaria after a cumulative dose of about 10 µg of the drug, but no asthmatic reaction. Complete exposure cessation was initiated and a 1-year follow-up was without further allergic reactions. We conclude that work-related systemic allergic reactions to ß-lactam antibiotics may occur in nurses after inhalation of low doses and without perceived association with drug-specific tasks like handling of antibiotics.

A recombinant polypeptide of the megakaryocyte potentiating factor is a potential biomarker in plasma for the detection of mesothelioma.

Malignant mesothelioma (MM) is a fatal disease mostly associated with asbestos exposure and difficult to detect by non-invasive methods. This study aimed to use recombinant fragments of the megakaryocyte potentiating factor (MPF) for the development of cost-effective MPF ELISAs. Three polypeptides spanning the MPF region (MPF1-148, MPF 34-288, MPF/MSLN254-400) were produced in E.coli as maltose-binding protein hybrids. After isolation, Factor Xa digest, and purification, the polypeptides were used for the generation of rabbit antibodies and development of ELISAs. Forty-one MM patients with known histological subtype before tumor-specific treatment and 70 asbestos-exposed individuals free of any cancer were matched according to age, gender, and smoking. Plasma of all subjects was tested with the three newly developed polyclonal antibody-based ELISAs and a commercial mesothelin assay (MESOMARK™). The latter differentiated patients (median concentration 1.95 nM) from controls (median 1.07 nM, p < 0.0001) and showed an area under curve (AUC) of 0.77 in receiver operating characteristics (ROC) analysis. Of the MPF variants, exclusively the ELISA based on antibodies against the MPF34-288 fragment displayed significantly (p = 0.0002) higher values in patients than in controls (median 1.61 nM versus 0.88 nM; AUC = 0.72). The combination of the MPF34-288 and mesothelin displayed an improved ROC performance (AUC = 0.80). The MPF34-288 ELISA could be a cost-effective and minimal-invasive contribution to support a diagnosis of mesothelioma, especially in regions with a limited medical care.

Medical surveillance and long-term prognosis of occupational allergy due to platinum salts.

PURPOSE: Medical surveillance of workers in precious metals refineries and catalyst production plants is well established in many countries as a measure to prevent occupational asthma due to platinum (Pt) salts. It was the aim of this study to evaluate the impact of medical surveillance and to define prognostic factors with an emphasis on exposure determinants. METHODS: As part of an observational longitudinal study, 96 workers from German precious metals refineries and catalyst production plants with Pt salt allergy underwent a second examination several years (median 67 months) after the initial diagnosis was made. RESULTS: When the second examination was conducted, 92 subjects (96 %) had already been transferred to jobs with very low or no exposure to Pt salts. The number of subjects with sensitization to Pt salt as assessed by skin prick test (SPTPt) decreased from 86 to 52 %, and there was a clear improvement for rhinitis, conjunctivitis and contact urticaria between both examinations. Although the number of subjects with asthma symptoms decreased significantly, at the second examination 74 subjects (77 %) continued to suffer from asthma and 51 subjects (53 %) received asthma medication. Airway obstruction or bronchial hyperresponsiveness persisted in 83 subjects (86 %). CONCLUSIONS: Secondary prevention in subjects with occupational exposure to Pt salts, as practiced for over 25 years in Germany could not avoid persistent asthma in the majority of cases, although improvements occurred. This study reveals the limitations of the concept that removal from exposure after the occurrence of respiratory symptoms may prevent chronic asthma. It is recommended that removal from exposure should be done immediately after the occurrence of a positive SPTPt, irrespective of symptoms.

Allergen quantification in surface dust samples from German day care centers.

Indoor allergens are among the main causes of allergic rhinitis and asthma. Allergen exposure is not limited to private homes. Mite, cat, and dog allergens were measured in day care centers to determine whether these concentrations detected might exert significant influence on human health. In 20 day care centers across North Rhine-Westphalia, Germany, the surfaces of 171 rooms were vacuumed 4 times a year to collect dust (1340 samples in total). In all samples, domestic mite antigens (DM) and the main allergens of cats (Fel d 1) and dogs (Can f 1) were quantified using enzyme immunoassays. Provisional threshold limits (PTL) for increased risks of sensitization and allergic symptoms were estimated according to published values and conversion factors. The influence of room characteristics on allergen concentrations was analyzed in mixed linear models, also considering values below the limit of detection (LOD). Nearly all samples contained allergens (99% DM, 96% Fel d 1, and 96% Can f 1). The concentrations rarely exceeded levels that were previously found to induce symptoms in home environments, but were frequently higher than estimates for enhanced sensitization risk (13% DM, 43% Fel d 1, and 27% Can f 1). Upholstered furnishings had the highest dust and allergen loads, followed by carpets and smooth floors. Allergen concentrations on different surface types that were sampled in the same room at the same time were significantly correlated and analyzed in separate models. The highest DM concentrations were present in bedrooms and in autumn. Further, DM loads on floors decreased significantly in rooms that were renovated within the last 5 years. If there were no records that furnishings were vacuumed, there were then significantly higher Can f 1 loads. Sweeping floors elevated DM and cat allergen concentrations. In addition to mite allergens, cat and dog allergens were detected in nearly all samples from day care centers. Overall, the present results indicate that allergen concentrations may be reduced by renovation and appropriate cleaning procedures.

Allergen Quantification by Use of Electrostatic Dust Collectors (EDCs): Influence of Deployment Time, Extraction Buffer, and Storage Conditions on the Results.

Sampling of endotoxin, beta-glucan, or allergens on electrostatic dust collectors (EDCs) is a convenient method for exposure assessment. However, especially for allergens few experiments on validation of this method concerning deployment time or storage and extraction procedure have been performed. The aim of study was to optimize the EDC procedure for sampling of allergens in indoor environments. EDCs were placed in households or day-care centers and after extraction, allergens were quantified by six immunoassays detecting mite antigens (Domestic mites DM, Dermatophagoides pteronyssinus Dp, Tyrophagus putrescentiae Tp) or the main allergens from cat (Fel d 1), dog (Can f 1) and mouse (Mus m 1). For 20 EDC holders, deployment times of cloths were varied between 7 and 28 days, 36 EDCs were used to test reproducibility, and for 28 EDCs extraction buffers were varied (with or without 0.05% Tween 20, borate, or phosphate buffer). The influence of storage of cloths at room temperature (2-629 days) or extracts at -80°C (7-639 days), and variation of extract storage temperature (-20°C and -80°C) for long time storage (1.5 years) on the outcome of allergen quantification were tested for about 150 EDCs. The allergens on EDC cloths increased proportionally with deployment time, and allergen loads on parallel sampled tissues were significantly correlated (P < 0.0001, Pearson of log-transformed values 0.91-0.99). Extraction without Tween reduced all results (P < 0.0001, -51% DM, -85% Dp, -60% Tp, -99% Fel d 1, -86% Can f 1, -52% Mus m 1), and borate buffer resulted in lower yields of Mus m 1 (-53%), DP (-45%), and Tp (-27%) than phosphate buffer. Storage of cloths at room temperature significantly decreased Can f 1 levels (P < 0.0001, -4.8% loss for every 30 days), whereas storage of extracts at -80°C decreased DM results (P < 0.0001, -1.2% loss for every 30 days). Extracts stored at -20°C gave at mean 12% higher DM results compared to extracts stored at -80°C for 1.5 years. Several mammalian allergens and also DM antigens could be quantified reproducibly on EDCs from indoor environments. Allergen levels on EDC cloths increased proportionally with deployment time in a period of 4 weeks. Allergen yields are strongly influenced by the extraction procedure; the use of detergent Tween 20 and phosphate buffer is recommended.

Triticale allergy in a farmer.

We present the case of a 29-year-old farmer with hay fever and atopic dermatitis since adolescence who had developed work-related asthma about 5 years earlier. He was sensitized to grass pollen, wheat and rye flour, dust from the floors of the animal facilities (cows and pigs) and grain barn, and a battery of animal feed from his farm. Work-relatedness of his asthma was demonstrated by serial measurements of spirometry and fractional exhaled nitric oxide at work and during a holiday. Immunoblot analyses revealed dominant IgE-binding to grass pollen and triticale (a hybrid of rye and wheat). IgE inhibition experiments demonstrated that sensitization to triticale was not due to cross-reactivity to grass pollen. Testing of specific IgE-antibodies to recombinant wheat allergens showed sensitizations to profilin, peroxidase, and nonspecific lipid transfer proteins type I subfamily 9.1 and 9.7. We conclude that triticale allergy may occur as a distinct allergy in farmers. Am. J. Ind. Med. 59:501-505, 2016. © 2016 Wiley Periodicals, Inc.

Component-resolved diagnosis of baker's allergy based on specific IgE to recombinant wheat flour proteins.

BACKGROUND: Sensitization to wheat flour plays an important role in the development and diagnosis of baker's asthma. OBJECTIVES: We evaluated wheat allergen components as sensitizers for bakers with work-related complaints, with consideration of cross-reactivity to grass pollen. METHODS: Nineteen recombinant wheat flour proteins and 2 cross-reactive carbohydrate determinants were tested by using CAP-FEIA in sera of 101 bakers with wheat flour allergy (40 German, 37 Dutch, and 24 Spanish) and 29 pollen-sensitized control subjects with wheat-specific IgE but without occupational exposure. IgE binding to the single components was inhibited with wheat flour, rye flour, and grass pollen. The diagnostic efficiencies of IgE tests with single allergens and combinations were evaluated by assessing their ability to discriminate between patients with baker's allergy and control subjects based on receiver operating characteristic analyses. RESULTS: Eighty percent of bakers had specific IgE levels of 0.35 kUA/L or greater and 91% had specific IgE levels of 0.1 kUA/L or greater to at least one of the 21 allergens. The highest frequencies of IgE binding were found for thiol reductase (Tri a 27) and the wheat dimeric α-amylase inhibitor 0.19 (Tri a 28). Cross-reactivity to grass pollen was proved for 9 components, and cross-reactivity to rye flour was proved for 18 components. A combination of IgE tests to 5 components, Tri a 27, Tri a 28, tetrameric α-amylase inhibitor CM2 (Tri a 29.02), serine protease inhibitor-like allergen (Tri a 39), and 1-cys-peroxiredoxin (Tri a 32), produced the maximal area under the curve (AUC = 0.84) in receiver operating characteristic analyses, but this was still lower than the AUC for wheat- or rye flour-specific IgE (AUC = 0.89 or 0.88, respectively). CONCLUSIONS: Component-resolved diagnostics help to distinguish between sensitization caused by occupational flour exposure and wheat seropositivity based on cross-reactivity to grass pollen. For routine diagnosis of baker's allergy, however, allergen-specific IgE tests with whole wheat and rye flour extracts remain mandatory because of superior diagnostic sensitivity.

Allergen Levels in the Hair of Different Cattle Breeds.

BACKGROUND: Cattle are well-known sources of respiratory allergens in agricultural environments. Breed-specific differences in Bos d 2 (a major bovine allergen) levels in cattle hair have been previously suggested but not fully characterized. Therefore, the aim of the current study was to determine whether hair from common cattle breeds differs in protein and allergen content. METHODS: In total, 80 hair samples from 16 different cattle breeds were analyzed. The protein concentration was determined using the Bradford assay. The allergen content was measured using a sandwich ELISA based on polyclonal antibodies against a bovine hair protein extract and a commercial immunoassay based on monoclonal antibodies against Bos d 2. Results are given in micrograms per gram of hair. Statistical analysis was performed using the Kruskal-Wallis test and Spearman's rank correlation. RESULTS: A wide variability in all 3 tested parameters was observed between the individual samples. The protein content differed by about 35-fold (0.3-12 mg/g), the bovine hair allergen content differed by about 500-fold (37-18,553 µg/g), and the Bos d 2 content differed by about 1,200-fold (5-6,323 µg/g). Protein, bovine hair allergen, and Bod d 2 values correlated strongly and significantly with one another. The median Bos d 2/bovine hair allergen ratio was 0.28. No significant differences were found between the most common breeds in Germany (Simmental, Holstein, and Braunvieh) and a group of rare breeds or between female and male animals. CONCLUSIONS: The results confirm a high variability in allergen levels between individual animals but also indicate that allergen production is related neither to the breed nor to gender.

IgE sensitization to lupine in bakers - cross-reactivity or co-sensitization to wheat flour?

BACKGROUND: Food allergy to lupine has frequently been reported in patients allergic to peanut or soy, and cross-reactivity between these legumes is known. Moreover, respiratory allergy to lupine has been described after inhalation, mostly at workplaces. Our aim was to study the frequency of lupine sensitization in European bakers with suspected bakers' allergy. Furthermore, associations between sensitizations to lupine and other plant allergens were investigated. METHODS: One hundred and sixteen bakers with work-related allergic symptoms but without known food allergies were examined. Specific IgE (sIgE) antibodies to wheat flour, rye flour, lupine, peanut, soy and the recombinant single birch protein rBet v 1 were quantified. Selected sera were tested for cross-reactivity using ImmunoCAP inhibition and ISAC microarrays. RESULTS: Whereas 67% of bakers were sensitized to wheat and/or rye flour, 35% showed sIgE to peanut and 33% to lupine. All lupine-positive bakers also had sIgE to either wheat flour (89%) and/or peanut (92%), and lupine sIgE correlated significantly with sIgE to peanut, soy, wheat and rye flour. Used as an inhibitor, wheat flour inhibited IgE binding to lupine in 4 out of 8 sera, indicating cross-reactivity. In microarrays, these sera showed IgE binding to lipid transfer proteins, profilins and/or cross-reactive carbohydrate determinants. Further inhibition experiments suggest that these single allergens are involved in cross-reactivity. CONCLUSION: One third of 116 symptomatic bakers showed sIgE to lupine. At least some of these sensitizations were based on cross-reactivity between lupine and wheat flour. However, the considerable sensitization rate could also be a sign that the use of lupine flour in bakeries may be of occupational relevance.

Eosinophilic airway disease in a patient with a negative skin prick test, but a positive patch test with platinum salts--implications for medical surveillance.

We present the case of a 52-year-old woman with a topic dermatitis since adolescence who developed work-related hand eczema, cough and runny nose 12 years after she had started working as a laboratory technician at a precious metals refinery. While skin prick test with sodium hexachloroplatinate (SPTPt ) was negative, patch testing with ammonium tetrachloroplatinate was positive after 24, 48, 72, and 96 hr. Inhalation challenge with sodium hexachloroplatinate yielded cough, mild shortness of breath, and a maximal decrease of FEV1 of 8% from baseline 24 hr after the challenge. Significant increases of bronchial hyperresponsiveness, exhaled nitric monoxide and sputum eosinophils were documented after the challenge. We conclude that eosinophilic airway disease due to platinum salts may occur in SPTPt negative subjects. Both, patch testing and inhalation challenge with platinum salts should be considered in SPT negative subjects with occupational exposure to precious metal salts and work-related allergic symptoms.

Serial measurements of exhaled nitric oxide at work and at home: a new tool for the diagnosis of occupational asthma.

Whereas serial measurements of lung function at work and at home are a well-known diagnostic tool for the diagnosis of occupational asthma (OA), little is known about the serial measurements of non-invasive parameters such as exhaled nitric oxide (eNO). A 51-year-old baker with variable shortness of breath without relation to work was examined for suspected OA. Skin prick test showed weak sensitizations to wheat and rye flour (without sensitizations to environmental allergens) that were corroborated by in vitro testing (CAP class 3). Baseline FEV1 of 58% predicted and a decrease of forced expiratory volume in 1 s (FEV1) after placebo (sugar powder) of 17% did not allow inhalational challenge testing. The patient performed daily measurements of FEV1 and eNO for about a month during a holiday at home and at work. Whereas symptoms and FEV1 did not show differences between holidays and work periods, eNO showed a clear increase from below 10 ppb to a maximum of 75 ppb. A diagnosis of baker's asthma was made, and the patient quit his job immediately after medical advice. A year afterwards, the patient was still taking asthma medication, but his symptoms had improved, FEV1 had increased to 73% predicted, and eNO was 25 ppb. We conclude that serial measurements of eNO at home and at work may be a useful tool for the diagnosis of OA.

Effectiveness of interventions to reduce flour dust exposures in supermarket bakeries in South Africa.

RATIONALE: A recent study of supermarket bakery workers in South Africa demonstrated that 25% of workers were sensitised to flour allergens and 13% had baker's asthma. Evidence on exposure reduction strategies using specifically designed interventions aimed at reducing the risk of baker's asthma is scarce. OBJECTIVES: The aim of this study was to evaluate the effectiveness of different control measures to reduce airborne flour dust exposure using a randomised design. METHODS: A group-randomised study design was used to assign 30 bakeries of a large supermarket chain store to two intervention groups and a control group, of which 15 bakeries were studied. Full-shift environmental personal samples were used to characterise exposure to flour dust and wheat and rye allergens levels pre-intervention (n=176) and post-intervention (n=208). RESULTS: The overall intervention effect revealed a 50% decrease in mean flour dust, wheat and rye allergen exposure. The reduction in exposure was highest for managers (67%) and bakers (47%), and lowest for counterhands (23%). For bakers, the greatest reduction in flour dust was associated with control measures such as the use of the mixer lid (67%), divider oil (63%) or focused training (54%). However, the greatest reduction (80%) was observed when using a combination of all control measures. CONCLUSIONS: A specially designed intervention strategy reduced both flour dust and allergen levels. Best results were observed when combining both engineering controls and training. Further studies will investigate the long-term health impact of these interventions on reducing the disease burden among this group of bakers.

Concentration of bioaerosols in composting plants using different quantification methods.

BACKGROUND: Bioaerosols (organic dusts) containing viable and non-viable microorganisms and their metabolic products can lead to adverse health effects in exposed workers. Standard quantification methods of airborne microorganisms are mainly based on cultivation, which often underestimates the microbial burden. The aim of the study was to determine the microbial load in German composting plants with different, mainly cultivation-independent, methods. Second purpose was to evaluate which working areas are associated with higher or lower bioaerosol concentrations. METHODS: A total of 124 inhalable dust samples were collected at different workplaces in 31 composting plants. Besides the determination of inhalable dust, particles, and total cell numbers, antigen quantification for moulds (Aspergillus fumigatus, Aspergillus versicolor, Penicillium chrysogenum, and Cladosporium spp.) and mites was performed. Concentrations of ß-glucans as well as endotoxin and pyrogenic activities were also measured. The number of colony forming units (cfu) was determined by cultivation of moulds and actinomycetes in 36 additional dust samples. RESULTS: With the exception of particle numbers, concentrations of all determined parameters showed significant correlations (P < 0.0001; r Spearman: 0.40-0.80), indicating a close association between these exposure markers. Colony numbers of mesophilic moulds and actinomycetes correlated also significantly with data of cultivation-independent methods. Exposure levels showed generally large variations. However, all parameters were measured highest in dusty working areas like next to the shredder and during processing with the exception of Cladosporium antigens that were found in the highest concentrations in the delivery area. The lowest concentrations of dust, particles, antigens, and pyrogenic activity were determined in wheel loader cabins (WLCs), which were equipped with an air filtration system. CONCLUSION: It was possible to assess the microbial load of air in composting plants with different quantification methods. Since allergic and toxic reactions may be also caused by nonliving microorganisms, cultivation-independent methods may provide additional information about bioaerosol composition. In general, air filtration reduced the bioaerosol exposure shown in WLCs. Due to the fact that the mechanical processing of compost material, e.g. by shredding or sieving is associated with the generation of high bioaerosol concentrations, there is still a need of improved risk assessment and state-of-the-art protective measures in composting plants.

Animal exposure, sensitization, and allergic symptoms in first-year veterinary medicine students.

The AllergoVet study longitudinally examines the influence of animal exposure on the development of sensitization and allergic diseases among veterinary medicine students. In this group, contact to animals usually existed long before the study began. Therefore, the aim of this analysis was to investigate lifelong animal species-specific exposure and the prevalence of sensitizations and allergic symptoms already existing before the start of the study. Questionnaire data, including exposure history, were summarized to determine the duration and intensity of animal-related exposure as well as the prevalence of allergic symptoms to animals. Serologically, specific IgE was determined against ubiquitous inhalant allergens (atopy screen sx1) and against animal allergens using ImmunoCAP. The association between animal-specific sensitization, allergic symptoms, and exposure was analyzed using Fisher's exact test or Cochran-Armitage trend test. All study participants (n = 313) had previous contact with animals, with dogs mentioned most frequently (91.1%) followed by cats (89.5%) and horses (72.2%). Sensitization to ubiquitous allergens (positive sx1 value) was detected in 38.4% of subjects. Approximately 11%, 7%, and 5% were sensitized to cats, dogs, and horses, respectively. Only a small proportion of these sensitizations were associated with self-reported symptoms (41% for cat, 9% for dog, and 13% for horse). While no significant association between animal-specific exposure and sensitization was found for cats and horses, a clear trend emerged for dogs. With increasing duration of exposure to dogs, the number of dog-specific sensitizations decreased significantly (p = 0.0069). Furthermore, a decreasing trend in sx1 sensitization was noted with increasing cat (p = 0.0288) and dog (p = 0.0107) exposure. None of the subjects who grew up on a farm (n = 40) had any sensitization to animals. The sensitization prevalence determined among first-year students in veterinary medicine roughly corresponds to that in the general population. Most animal sensitizations were not clinically relevant. In this collective, a protective effect of increasing exposure to animals in childhood and adolescence was found on sensitization, which was particularly pronounced during contact with dogs.

Exposure levels of animal allergens, endotoxin, and ß-(1,3)-glucan on a university campus of veterinary medicine.

OBJECTIVES: The study aimed to determine the allergen, endotoxin and ß-(1,3)-glucan concentrations at various areas on a university campus of veterinary medicine. METHODS: Dust samples were collected four times a year for three years using electrostatic dust collectors (EDC) at 25 different locations on a campus of veterinary medicine and in laboratories of inorganic chemistry as a control area representing animal-free environment. Major animal allergens from dog, cat, horse, cattle and mouse, domestic mite (DM) allergens, and ß-(1,3)-glucan were measured using enzyme immunoassays and endotoxin using the limulus amoebocyte lysate (LAL) assay. Seasonal, annual and local influences on exposure levels were analyzed using Bayesian mixed models. RESULTS: With the exception of mouse allergens, all other determinants were found in almost all locations on the campus and in the control area, but in up to 10.000-fold variable concentrations. By far the highest levels of feline, canine, equine and bovine allergens were detected in buildings where the respective species were examined. The highest levels of mouse and DM allergens, ß-(1,3)-glucan and endotoxin occurred together and were associated with locations where large animals were present. In buildings without animals, allergen levels were considerably lower but still elevated at several locations compared to the control area, especially for dog and horse allergens, and ß-(1,3)-glucan. Significant seasonal effects were observed for dog, cat, horse and DM allergens, and ß-(1,3)-glucan. Variations between years were less apparent than between seasons (except for ß-(1,3)-glucan). CONCLUSIONS: The strongest influencing factor on the concentration of mammalian allergens was the presence of the corresponding animal at the collection site. Seasonal influence on allergen concentrations was observed, while the overall exposure remained constant over the years. At locations with horses, elevated levels of mite allergens, endotoxin, and ß-(1,3)-glucan can be expected, probably due to passive transfer from stable environment.