Workplace exposure to wood dust and the prevalence of wood-specific sensitization.

Wood is processed worldwide, and occupational exposure to wood dust is affecting millions of workers. Studies have identified wood dust as a risk factor for non-malignant respiratory diseases consistent with both an allergic and a non-allergic origin. This paper summarizes our current knowledge on the importance of specific sensitization among subjects occupationally exposed to wood dust. Specific sensitization to wood dust exists, but is probably of minor importance for most wood species. In order to move the research field forward increased focus on more standardized tools for specific IgE (sIgE) diagnostics is needed and more specific tools are necessary to identify clinical relevant cases of wood dust sensitization. Moreover epidemiological studies on the occurrence of sIgE-mediated sensitization in different populations of woodworkers are needed.

Rare and new occupational inhalant allergens.

Occupational airway diseases induced by the inhalation of allergens at workplaces have become common, but the inducing substances are diverse and their pathomechanisms are not always clear. Only few allergens were studied in detail (like wheat flour dust and natural rubber latex) and most of the occupational airway sensitizers were documented only as case reports. In this review rare and exotic occupational Type I-aeroallergens according to their workplace application area (e.g., production of dough and bakery products, handling with decorative and economic plants, wood processing, fish-, shellfish-processing and fish breeding) are described.

Quantification of protein and latex allergen content of various natural rubber latex products.

INTRODUCTION: The use of natural rubber latex (NRL) products can cause IgE-mediated allergic reactions in exposed people. The aim of this study was to quantify the content of protein and latex allergens of currently available NRL products to estimate the allergenic potential of these products. METHODS: 14 household articles (pacifiers, baby bottle nipples, condoms, household and disposable gloves, toy balloons, and Band-Aids) as well as 18 NRL examination gloves currently used by healthcare workers were investigated. Extracts of the examination gloves were prepared according to the standard method DIN EN 455-3, which contains requirements and testing for biological evaluation of single use medical gloves. The protein content was determined with a modified Lowry method. Latex allergen content was measured using an IgE-inhibition immunoassay with a mix of serum-sensitized patients as detection antibody sources and the latex ImmunoCAP as solid phase. The allergens Hev b 1, 3, 5, and 6.02 were determined using available immunoassays. RESULTS: In 5 out of 18 examination gloves, the protein content was under the detection limit. The other 13 gloves contained protein between 7.1 and 92.3 µg protein/g material. Five glove brands contained protein concentrations above the recommended reference value of 30 µg protein/g material. Latex allergen could be measured in 12 out of 18 NRL gloves. In only 3 gloves could none of the allergens Hev b 1, 3, 5, and 6.02 be detected. Protein and Hev b 1 could be measured in the examined childcare products, while the concentrations of the latex allergens Hev b 3, 5, and 6.02 were mostly under the detection limit. Boiling of childcare products led to a reduction of protein and allergen content. In some of the other daily-used NRL articles, the protein and allergen contents were even higher than in gloves. CONCLUSION: Our study demonstrated that protein, and particularly latex allergens, were detectable in currently available examination gloves as well as in household articles whereby a risk for sensitization and/or induction of allergic symptoms could not be excluded.

Update of the WHO/IUIS Allergen Nomenclature Database based on analysis of allergen sequences.

The IUIS Allergen Nomenclature Sub-Committee, under the auspices of the World Health Organization and the International Union of Immunological Societies, maintains the systematic nomenclature of allergenic proteins and publishes a database of approved allergen names on its Web site, www.allergen.org. In this paper, we summarize updates of allergen names approved at the meetings of the committee in 2011 through 2013. These changes reflect recent progress in identification, cloning, and sequencing of allergens. The goals of this update were to increase consistency in the classification of allergens, isoallergens, and variants and in the incorporation of the evolutionary classification of proteins into allergen nomenclature, while keeping changes of established names to a minimum in the interest of continuity. Allergens for which names have been updated include respiratory allergens from birch and ragweed pollen, midge larvae, and horse dander; food allergens from peanut, cow's milk, and tomato; and cereal grain allergens. The IUIS Allergen Nomenclature Sub-Committee encourages researchers to use these updated allergen names in future publications.

Asthma and exposure to cleaning products - a European Academy of Allergy and Clinical Immunology task force consensus statement.

Professional and domestic cleaning is associated with work-related asthma (WRA). This position paper reviews the literature linking exposure to cleaning products and the risk of asthma and focuses on prevention. Increased risk of asthma has been shown in many epidemiological and surveillance studies, and several case reports describe the relationship between exposure to one or more cleaning agents and WRA. Cleaning sprays, bleach, ammonia, disinfectants, mixing products, and specific job tasks have been identified as specific causes and/or triggers of asthma. Because research conclusions and policy suggestions have remained unheeded by manufactures, vendors, and commercial cleaning companies, it is time for a multifaceted intervention. Possible preventive measures encompass the following: substitution of cleaning sprays, bleach, and ammonia; minimizing the use of disinfectants; avoidance of mixing products; use of respiratory protective devices; and worker education. Moreover, we suggest the education of unions, consumer, and public interest groups to encourage safer products. In addition, information activities for the general population with the purpose of improving the knowledge of professional and domestic cleaners regarding risks and available preventive measures and to promote strict collaboration between scientific communities and safety and health agencies are urgently needed.

Biochemical and immunological analysis of mould skin prick test solution: current status of standardization.

BACKGROUND: Sensitization prevalence to moulds reached from less than 10% in the general population to more than 25% in atopic and/or asthmatic subjects. To diagnose IgE-mediated mould sensitization, skin prick test (SPT) and specific IgE (sIgE) measurement are recommended. However, concordance of SPT and sIgE results is often less than 50% and standardization of the extracts is required to achieve reliable test results. OBJECTIVE: The aim of our study was to analyse mould SPT solutions (SPTs) with respect to quantity and quality of protein, antigen and human IgE-binding content as a prerequisite for further in vivo studies. METHODS: Commercial SPTs of Alternaria alternata, Aspergillus fumigatus, Cladosporium herbarum and Penicillium chrysogenum from six manufacturers as well as two in-house extracts from Aspergillus versicolor were investigated. Protein-, antigen- and IgE-binding contents were quantified by Bradford assay, sandwich ELISA and IgE-ImmunoCAP-inhibition tests. Protein composition and IgE and IgG binding were analysed by SDS-PAGE and immunoblotting, respectively. RESULTS: Median protein concentrations were similar in all mould SPT extracts (90-110 µg/mL). In contrast, antigen contents and IgE-binding capacity showed a high variability with median antigen values from 4 to 118 µg/mL and IgE inhibition results between 30 to 95%. Whereas almost all SPTs of A. alternata and A. versicolor showed complete sIgE inhibition with mean values > 80%, only three extracts for A. fumigatus, two extracts for C. herbarum and none of the tested extracts for P. chrysogenum exceeded 50% sIgE reduction. Quantitative amounts of protein, antigenic and IgE-binding structures were not comparable with the quality of the corresponding protein or immunoblot pattern, with the exception of A. alternata SPTs. CONCLUSIONS AND CLINICAL RELEVANCE: Commercially available mould SPT extracts showed high variability raising the question of comparability and reliability of SPT results. Possible consequences for diagnostic test outcome will be investigated in the next step.

Implementation of non-invasive methods in the diagnosis of diisocyanate-induced asthma.

Diisocyanate-induced asthma is difficult to diagnose since the immunopathological mechanisms and exposure determinants at the workplace are not well defined. The aim of this study was to evaluate the non-invasive methods of nasal lavage fluid (NALF) and induced sputum (IS) to enhance the diagnostic efficiency. Sixty-three diisocyanate-exposed workers with work-related shortness of breath underwent a standardized 4-steps-1-day-whole body exposure test with diisocyanates used at work up to 30 ppb. NALF and IS were collected before, 0.5, and 19 h after the end of exposure. Cellular composition and soluble inflammatory biomarkers were studied in the samples. In addition, ten controls with bronchial hyperresponsiveness, but without prior occupational diisocyanate exposure, were also examined. Twelve out of the 63 subjects (19 %) showed a significant asthmatic reaction (pulmonary responders) after challenge (FEV1 decrease >20 %). NALF samples did not demonstrate significant effects either on cellular composition or on mediator concentrations in the responders, non-responders, or controls at any time point. In contrast, in the IS samples of the pulmonary responders collected 19 h after challenge, the percentage of eosinophils was higher (p = 0.001) compared with baseline before challenge. Eosinophils were also increased 30 min and 19 h after challenge in IS samples of the responders compared with the non-responders or controls. In addition, 19 h after challenge the eosinophilic cationic protein (ECP) concentration was significantly higher in the responders than non-responders (p < 0.04) or controls (p < 0.002). In conclusion, positive asthmatic reactions to diisocyanates are accompanied by an influx of eosinophils into lower airways. Analysis of induced sputum should be implemented in the diagnostic procedure of diisocyanate-related airway diseases.

Occupational allergic respiratory diseases in garbage workers: relevance of molds and actinomycetes.

Exposures to molds and bacteria (especially actinomycetes) at workplaces are common in garbage workers, but allergic respiratory diseases due to these microorganisms have been described rarely. The aim of our study was a detailed analysis of mold or bacteria-associated occupational respiratory diseases in garbage workers. From 2002 to 2011 four cases of occupational respiratory diseases related to garbage handling were identified in our institute (IPA). Hypersensitivity pneumonitis (HP) was diagnosed in three subjects (cases 1-3, one smoker, two non-smokers), occupational asthma (OA) was diagnosed in one subject (case 4, smoker), but could not be excluded completely in case 2. Cases 1 and 2 worked in composting sites, while cases 3 and 4 worked in packaging recycling plants. Exposure periods were 2-4 years. Molds and actinomycetes were identified as allergens in all cases. Specific IgE antibodies to Aspergillus fumigatus were detected exclusively in case 4. Diagnoses of HP were essentially based on symptoms and the detection of specific IgG serum antibodies to molds and actinomycetes. OA was confirmed by bronchial provocation test with Aspergillus fumigatus in case 4. In conclusion, occupational HP and OA due to molds occur rarely in garbage workers. Technical prevention measures are insufficient and the diagnosis of HP is often inconclusive. Therefore, it is recommended to implement the full repertoire of diagnostic tools including bronchoalveolar lavage and high resolution computed tomography in the baseline examination.

Hypersensitivity pneumonitis due to metalworking fluids: how to find the antigens.

Most surveys of outbreaks of hypersensitivity pneumonitis (HP) in subjects with occupational exposure to water-based metalworking fluids (MWFs) were unable to detect a clear link between symptoms and the precise causative agents. We studied the case of a male 41-year-old industrial knife grinder with exposure to water-based MWFs since 12 years. The diagnosis of HP was made by typical work-related symptoms, the demonstration of high lymphocyte numbers in bronchoalveolar lavage and elevated IgG antibody concentrations to various molds in the patient's serum, and complete recovery after early exposure cessation. Whereas an environmental survey showed only low numbers of mold contamination in one sump sample, high antigenic activity was demonstrated in the same sample by antigen-specific IgG inhibition tests. We conclude that the detection of antigenic molds in water-based MWFs by culture methods may be limited. The link between occupational exposure to specific molds in MWFs and hypersensitivity pneumonitis can be established by the demonstration of antigenic activity by antigen-specific IgG inhibition tests.

Evaluation of commercial skin prick test solutions for selected occupational allergens.

BACKGROUND: Skin prick testing (SPT) is an important step in the diagnosis of IgE-mediated occupational allergic diseases. The outcome of SPT is related to the quality of allergen extracts. Thus, the aim of the study was to assess different commercially available SPT solutions for selected occupational allergens. METHODS: SPT was performed in 116 bakers, 47 farmers and 33 subjects exposed to natural rubber latex (NRL), all with work-related allergic symptoms. The SPT solutions from different manufacturers (n = 3-5) for wheat flour, rye flour, soy, cow hair/dander, storage mites (Tyrophagus putrescentiae, Lepidoglyphus destructor, Acarus siro) and NRL were analysed with respect to their protein and antigen contents. SPT was carried out in 16 allergy centres in six European countries using standardized procedures. Specific IgE values were used as the gold standard to calculate the sensitivity and specificity of SPT solutions. The optimal cut-point for each SPT solution was determined by Youden Index. RESULTS: Protein and antigen contents and patterns of the SPT solutions varied remarkably depending on the manufacturer. While SPT solutions for wheat flour and soy reached overall low sensitivities, sensitivities of other tested SPT solutions depended on the manufacturer. As a rule, solutions with higher protein and antigen content showed higher sensitivities and test efficiencies. CONCLUSIONS: There is a wide variability of SPT solutions for occupational allergens, and the sensitivity of several solutions is low. Thus, improvement and standardization of SPT solutions for occupational allergens is essential.

EAACI position paper: skin prick testing in the diagnosis of occupational type I allergies.

Skin prick testing (SPT) in combination with the clinical history of the patient is one important step in the diagnosis of IgE-mediated occupational allergies. However, skin test performance is related to the quality of allergen extracts. The present consensus document was prepared by an EAACI Task Force consisting of an expert panel of allergologists and occupational physicians from Germany, Italy, Spain, France, Austria, and Poland. All members of the panel were also involved in the data collection within the European multicentre study STADOCA (Standard diagnosis for occupational allergy). The aim of this Task Force was the assessment of the quality of commercially available SPT solutions for selected occupational allergens under standardized procedure conditions in different European centres and institutes of Occupational Medicine. The data evaluation shows a wide variability among SPT solutions and also indicates that the sensitivity of several SPT solutions is low. Therefore, improvement and standardization of SPT solutions for occupational allergens is highly recommended. Clinical practitioners should also not presume that their SPT solutions are fully reliable. The main objective of the document is to issue consensus suggestions for the use of SPT with occupational allergens based on the European multicentre study STADOCA, on existing scientific evidence and the expertise of a panel of allergologists.

Comparison of different non-invasive methods for detection of allergic asthma.

Non-invasive methods to assess inflammation of lower airways are induced sputum (IS), exhaled nitric oxide (eNO), and exhaled breath condensate (EBC). Here we focused on the assessment of airway inflammation with a panel of non-invasive methods in health care workers (HCWs) with suspected latex allergy with and without current allergic respiratory symptoms about 10 years after the latex ban in German health care facilities. Seventy-seven non-smoking subjects were examined by skin prick test and specific IgE measurements, eNO, IS, and EBC. Sensitivity, specificity, and positive and negative predicted values for relevant biomarkers were calculated using current asthma symptoms as the gold standard. Twenty-nine subjects (38%) reported ongoing asthmatic symptoms (AS). In these subjects the EBC concentrations of nitrogen oxides (NO(x); p=0.027) and leukotriene B(4) (p=0.025) were significantly higher than in subjects without AS. In addition, in the subjects with AS the numbers of eosinophils (p=0.015) and the concentrations of IL-5 (p= 0.021) in IS samples were significantly higher than in the subjects without AS. A good correlation between several inflammatory markers in IS was detected. The maximum Youden Index was reached for IS total eosinophils ≥3.5·10(4) with a test efficiency of 0.72. In conclusion, non-invasive inflammatory monitoring with EBC and IS may assist the diagnosis of allergic asthma. Self-reported current asthmatic symptoms were reflected by eosinophilic inflammation and the best parameter to support the asthma diagnosis is a total number of eosinophils ≥3.5·10(4) in IS.

[Farmer's lung antigens in Germany]. / Farmerlungen-Antigene in Deutschland.

Recent studies suggest that besides the long-known farmer's lung antigen sources Saccharopolyspora rectivirgula (Micropolyspora faeni), Thermoactinomyces vulgaris, and Aspergillus fumigatus, additionally the mold Absidia (Lichtheimia) corymbifera as well as the bacteria Erwinia herbicola (Pantoea agglomerans) and Streptomyces albus may cause farmer's lung in Germany. In this study the sera of 64 farmers with a suspicion of farmer's lung were examined for the following further antigens: Wallemia sebi, Cladosporium herbarum, Aspergillus versicolor, and Eurotium amstelodami. Our results indicate that these molds are not frequent causes of farmer's lung in Germany.

[Workplace-related respiratory allergies. Current developments]. / Inhalationsallergien am Arbeitsplatz. Aktuelle Entwicklungen.

It is common that the inhalation of occupational allergens induces occupational airway diseases, but the inducers are diverse and complex, and the pathomechanism of the disease is not clear in every case. Only few allergens have been studied in detail (e.g., wheat flour and natural rubber latex), and most of the occupational airway sensitizers have only been documented as case reports. This review describes occupational type I aeroallergens according to their source (plant, animal, microbial, and chemical) and workplace application area. New aspects on the diagnosis and legal preventive regulations for occupational allergic airway diseases are described.

Multiple wheat flour allergens and cross-reactive carbohydrate determinants bind IgE in baker's asthma.

BACKGROUND: Several wheat flour allergens relevant to baker's asthma have been identified in the last 25 years. The aim of this study was to determine the frequency of sensitization to these allergens in German bakers. METHODS: Using recombinant DNA technology, the following wheat flour allergens were cloned, expressed in Escherichia coli and purified: five subunits of the wheat α-amylase inhibitors (WTAI-CM1, WTAI-CM2, WTAI-CM3, WDAI-0.19 and WMAI-0.28), thioredoxin, thiol reductase or 1-cys-peroxiredoxin homologues, triosephosphate-isomerase, αß-gliadin, serpin, glyceraldehyde-3-phosphate-dehydrogenase, a nonspecific lipid transfer protein (nsLTP), dehydrin, profilin and peroxidase. In addition, ImmunoCAPs with the recombinant allergen ω-5-gliadin and two cross-reactive carbohydrate determinants (CCDs), horse radish peroxidase (HRP) and the N-glycan of bromelain (MUXF), were used. Specific IgE was measured in wheat flour-positive sera from 40 German bakers with work-related asthma/rhinitis and 10 controls with pollinosis. RESULTS: Thirty bakers (75%) had IgE to at least one of the 19 single allergens. Most frequent was IgE to WDAI-0.19, HRP and MUXF (25% each), followed by WTAI-CM1 (20%), thiol reductase (16%), WTAI-CM3 (15%), WTAI-CM2 and thioredoxin (12.5%), WMAI-28, triosephosphate-isomerase, αß-gliadin (10%), 1-cys-peroxiredoxin (7.5%), dehydrin, serpin, glyceraldehyde-3-phosphate-dehydrogenase (5%), ω-5-gliadin, nsLTP and profilin (2.5%). Fifteen bakers (38%) had IgE to any α-amylase inhibitor and 12 (30%) to at least one CCD. The controls reacted exclusively to CCDs (80%), profilin (60%), thioredoxin (30%), triosephosphate isomerase and nsLTP (10%). CONCLUSIONS: The single allergen sensitization profiles obtained with 17 recombinant wheat flour allergens and two CCDs revealed no major allergen for German bakers. The highest frequencies were found for α-amylase inhibitors and CCDs.

Allergic asthma after flour inhalation in subjects without occupational exposure to flours: an experimental pilot study.

OBJECTIVE: Cross-reactivity between grass pollen and grain flour allergens is well known, but their significance in apprentice bakers with primary sensitization to grass pollen is not known. METHODS: Twenty-five subjects with mild asthma (most of them with hay fever), but without prior occupational flour exposure, underwent standardized experimental inhalation challenges with placebo and wheat and rye flours in randomized order on three consecutive days. Sensitization to flours and environmental allergens was assessed by skin prick tests and specific IgE antibodies in sera. IgE inhibition experiments were performed with wheat and rye flours as solid phases, and grass and tree pollen as inhibitors. RESULTS: Five subjects experienced a positive reaction after flour inhalation (responders), whereas 20 subjects did not show such a reaction (non-responders). All responders showed sensitizations to flours, whereas only 25% of the non-responders demonstrated the same sensitization. Specific IgE concentrations to flours, but also to grass and tree pollen, were higher in responders. Inhibition experiments demonstrated cross-reactivity between flours and grass or tree pollen, with higher inhibition rates in responders. CONCLUSIONS: Subjects with pronounced sensitizations to grass or tree pollen, but without prior occupational exposure to flours, may experience both sensitization and allergic asthmatic reactions to flours due to cross-reactive grass and tree pollen allergens.

Pulmonary lesions and serum levels of soluble Fas (sCD95) in former hard coal miners.

OBJECTIVE: Fas/APO-1 (CD95) and Fas Ligand (FasL) is a major mediator system that activates programmed cell death (apoptosis) and is most important for pulmonary cellular homeostasis. Another form of Fas, circulating soluble Fas (sCD95), produced by alternative mRNA splicing antagonizes the cell-surface Fas function. It was the aim of the study to test the hypothesis that the Fas/FasL system is implicated in the development of silica-induced pulmonary nodular lesions. MATERIAL AND METHODS: We investigated the serum levels of sCD95 in 55 former hard coal miners. Coal workers' pneumoconiosis (CWP) was assumed when the profusion of small round opacities according to the ILO 2000 classification system was 1/1 or greater. Analyses of sCD95 were performed by a sandwich ELISA. RESULTS: Radiologic CWP was found in 34 of the 55 individuals. The age of subjects with and without CWP was similar (73.5 (SD 7.2) years vs. 73.5 (7.1) years; P = 0.924). sCD95 could be quantified in all samples; significantly higher levels were observed in subjects with radiologic signs of CWP (914 (752-1251) pg/ml vs. 632 (509-804) pg/ml, P < 0.001). However, there was no relationship between sCD95 serum concentrations and the quantity of profusion according to ILO. CONCLUSIONS: The hypothesis of elevated sCD95 concentrations in CWP was corroborated. The usefulness of sCD95 for prevention and diagnosis of CWP and other forms of silica-induced fibrosis needs to be established by epidemiological studies.

[Organic dust at workplaces: measurement of pyrogenic activity]. / Organischer Staub am Arbeitsplatz: Messung der pyrogenen Aktivität.

BACKGROUND: Organic dust is composed of numerous components. Exposed people may have health problems. Respiratory tract complaints may occur at workplaces like those in agriculture or in the waste industry. Therefore methods that determine the composition and activity of dust components are important. They help in the performance of risk estimations and could accompany intervention studies. The aim of our study was to establish a whole blood assay using cryo-preserved blood for characterisation of the pyrogenic activity originating from organic dust samples. METHODS: 30 dust filter extracts from several workplaces as well as E. coli endotoxin, zymosan and Aspergillus versicolor extract were analysed using the whole blood assay. In addition, all workplace samples were analysed by means of the Limulus amoebocyte lysate test (LAL test) with regard to endotoxin activity. The whole blood assay is a two-step assay: Firstly, blood is incubated with the stimulus and, secondly, mediators released in the supernatant were determined (IL1-ß, MCP-1) RESULTS: It was possible to detext pyrogenic activity for all 30 dust filter extracts. IL-1ß release from cryo-preserved blood was in the range of 33 to 500,000 pg/mL. Correlation with the results of the LAL test was r=0.9 (p=5,0E-07). In addition to IL-1ß, measurement of MCP-1 was undertaken. Immunological activity of substances like Aspergillus versicolor extract, which induced no IL-1ß release, could be detected via determination of MCP-1. CONCLUSIONS: Cryo-preserved blood offers the possibility to quantify pyrogenic activity of dust samples by measuring IL-1ß and MCP-1. The whole blood assay can be used as a standardised method for description of the dust load at workplaces.