Endotyping asthma related to 3 different work exposures.

BACKGROUND: Work exposures play a significant role in adult-onset asthma, but the mechanisms of work-related asthma are not fully elucidated. OBJECTIVE: We aimed to reveal the molecular mechanisms of work-related asthma associated with exposure to flour (flour asthma), isocyanate (isocyanate asthma), or welding fumes (welding asthma) and identify potential biomarkers that distinguish these groups from each other. METHODS: We used a combination of clinical tests, transcriptomic analysis, and associated pathway analyses to investigate the underlying disease mechanisms of the blood immune cells and the airway epithelium of 61 men. RESULTS: Compared with the healthy controls, the welding asthma patients had more differentially expressed genes than the flour asthma and isocyanate asthma patients, both in the airway epithelia and in the blood immune cells. In the airway epithelia, active inflammation was detected only in welding asthma patients. In contrast, many differentially expressed genes were detected in blood cells in all 3 asthma groups. Disease-related immune functions in blood cells, including leukocyte migration and inflammatory responses, and decreased expression of upstream cytokines such as TNF and IFN-γ were suppressed in all the asthma groups. In transcriptome-phenotype correlations, hyperresponsiveness (R ∼ |0.6|) had the highest clinical relevance and was associated with a set of exposure group-specific genes. Finally, biomarker subsets of only 5 genes specifically distinguished each of the asthma exposure groups. CONCLUSIONS: This study provides novel data on the molecular mechanisms underlying work-related asthma. We identified a set of 5 promising biomarkers in asthma related to flour, isocyanate, and welding fume exposure to be tested and clinically validated in future studies.

Prunus persica 9, a new occupational allergen from peach tree pollen involved in rhinitis and asthma.

OBJECTIVES: Several studies have described peach tree (PT) as an occupational allergen. The aim of this work was to assess the effect of Prunus persica 9 (Pru p 9), a recently identified allergen from PT pollen, in exposed workers. METHODS: The study included people who reported respiratory symptoms after handling PT in orchards during the flowering period (Blanca village, Murcia region, south-east Spain). After completing a detailed questionnaire, participants underwent skin prick test (SPT) and nasal provocation test (NPT). The IgE response was analysed by SDS-PAGE and immunoblotting assays. RESULTS: A total of 21 cases were included (mean age 45 years; 57% women). Most were polysensitised to common pollens, although one person was sensitised only to PT pollen. All cases had a positive SPT to this pollen, and 43% also to Pru p 9. All participants reported having rhinitis, and six participants reported having also asthma. Immunoblotting showed a heterogeneous IgE pattern for several proteins, with Pru p 9 recognised in nine cases. Most participants sensitised to PT pollen and Pru p 9 had positive NPTs, while those who were not sensitised to Pru p 9 tested negative. CONCLUSIONS: We demonstrate for the first time that Pru p 9, an allergen from PT pollen, can induce respiratory symptoms following occupational exposure. This must be considered a relevant allergen when people working with PT cultivars develop respiratory symptoms.

Exposure to additives or multigrain flour is associated with high risk of work-related allergic symptoms among bakers.

OBJECTIVES: Wheat flour exposure in bakers can elicit respiratory and skin symptoms. Scarce data are available on the prevalence of such conditions in bakers. We investigated the prevalence of work-related rhinitis, asthma-like symptoms and dermatitis in bakers according to job task and type of allergens involved. METHODS: Of the 229 traditional bakeries in Verona area who were invited to participate in a cross-sectional survey, 211 (92%) accepted; 727 employees in these bakeries answered a modified version of a questionnaire on job tasks; allergen exposure within the bakery; and work-related nasal, asthma-like and skin symptoms during 2010-2014. Determinants of work-related nasal, asthma-like or skin disorders were separately evaluated using different logistic models. RESULTS: The prevalence of work-related nasal and asthma-like symptoms was, respectively, 15.1% and 4.2% in bakery shop assistants, increasing to 25.7% and 9.5% in bakers using only wheat flour, and further to 31.8% and 13.6% in bakers using flour and additives, and then to 34.1% and 18.2% in bakers using flour with additives and multigrain (p<0.001). The risk of work-related asthma-like symptoms was more than doubled in bakers using additives without or with multigrain than in shop assistants (OR 2.3, 95% CI 1.0 to 5.5 and OR 3.4, 95% CI 1.1 to 10.8, respectively). Making bread with additives alone or with multigrain significantly increased the risk of work-related nasal symptoms in shop assistants, while the risk of skin symptoms was not significantly affected. CONCLUSIONS: Bakers using additives alone or with multigrain are at a high risk of experiencing nasal and asthma-like symptoms.

Baker's asthma in bread factory workers.

Background: Baker's asthma (BA) is one of the most common causes of occupational asthma. Prevalence of BA varies from 3 to 24% in various studies; however, in our country, there are not enough data on its prevalence. Objective: The aim of this study was to evaluate wheat flour sensitivity and to determine the rate of BA in workers at a large bread factory in Ankara. Methods: All steps of the study were carried out in the workplace by the research team who made regular visits to the bread factory. A questionnaire was used to determine the presence of respiratory symptoms and its relation with the occupation. Skin-prick tests and specific immunoglobulin E measurements were performed. Pulmonary function tests and specific inhalation challenges (SIC) were performed to confirm the BA diagnosis. Results: A total of 162 workers (women/men, 3/159; mean ±standard error age, 38.25 ± 7.8 years) were included in the study. Of the 99 workers who described symptoms, 88 (88.8%) had nasal and 57 (57.5%) had lower respiratory symptoms. Sensitivity to wheat flour was present in 23 of the workers (14.2%) among all the workers. Among all the workers, seven (4.32%) were diagnosed with BA and SICs were positive in four (2.46%). Conclusion: Wheat sensitivity was high among the bakers who were exposed to wheat flour; however, the prevalence of BA was quite lower than the previous data in the literature.

Assessing the health impact of interventions for baker's allergy and asthma in supermarket bakeries: a group randomised trial.

PURPOSE: To assess the impact of an intervention for baker's allergy and asthma in supermarket bakeries. METHODS: A group randomised trial conducted in 31 bakeries (n = 337 bakers) that were randomly assigned to one of two intervention groups (n = 244 bakers) and a control group (n = 93 bakers). Health data collected prior to and 1-year after the intervention included information obtained from an ECRHS questionnaire; tests for atopy and serum-specific IgE to cereal flours; fractional exhaled nitric oxide (FeNO). Data from the two intervention groups were combined to form one intervention group for purposes of the statistical analysis. RESULTS: At 1 year of follow-up, the incidence and level of decline of work-related ocular-nasal and chest symptoms, sensitisation status and elevated FeNO (FeNO > 25 ppb) was similar in both intervention and control groups. The mean FeNO difference was also similar across both groups (2.2 ppb vs 1.7 ppb, p = 0.86). In those with FeNO > 25 ppb at baseline, the decline was greater in the intervention compared to control group (16.9 ppb vs 7.7 ppb, p = 0.24). Multivariate logistic regression models (adjusting for smoking, baseline sensitisation to cereal flour, baseline FeNO > 25 ppb) did not demonstrate an appreciable FeNO decline (≥ 10%) in the intervention compared to control group. However, stratification by the presence of work-related ocular-nasal symptoms in bakers at baseline demonstrated a significant FeNO decline (≥ 10%) in the intervention compared to the control group (OR 3.73, CI 1.22-11.42). CONCLUSION: This study demonstrates some evidence of an intervention effect on FeNO 1 year after an intervention, particularly in bakers with work-related ocular-nasal symptoms.

Nasal protein profiles in work-related asthma caused by different exposures.

BACKGROUND: The mechanisms of work-related asthma (WRA) are incompletely delineated. Nasal cell samples may be informative about processes in the lower airways. Our aim was to determine the nasal protein expression profiles of WRA caused by different kind of exposures. METHODS: We collected nasal brush samples from 82 nonsmoking participants, including healthy controls and WRA patients exposed to (i) protein allergens, (ii) isocyanates and (iii) welding fumes the day after relevant exposure. The proteome changes in samples were analysed by two-dimensional difference gel electrophoresis, and the differentially regulated proteins found were identified by mass spectrometry. Immunological comparison was carried out using Western blot. RESULTS: We detected an average of 2500 spots per protein gel. Altogether, 228 protein spots were chosen for identification, yielding 77 different proteins. Compared to the controls, exposure to protein allergens had the largest effects on the proteome. Hierarchical clustering revealed that protein allergen- and isocyanate-related asthma had similar profiles, whereas asthma related to welding fumes differed. The highly overrepresented functional categories in the asthma groups were defence response, protease inhibitor activity, inflammatory and calcium signalling, complement activation and cellular response to oxidative stress. Immunological analysis confirmed the found abundance differences in galectin 10 and protein S100-A9 between the groups. CONCLUSIONS: Work-related asthma patients exposed to protein allergens and isocyanates elicit similar nasal proteome responses and the profiles of welders and healthy controls were alike. Revealed biological activities of the protein expression changes are associated with allergic inflammation and asthma.

Assessment of eosinophilic airway inflammation as a contribution to the diagnosis of occupational asthma.

BACKGROUND: Ascertaining the presence of asthma through the assessment of nonspecific bronchial hyperresponsiveness (NSBH) is a key step in the diagnosis of occupational asthma (OA). We aimed at investigating whether indices of airway inflammation including fractional exhaled nitric oxide (FeNO) and sputum eosinophils would be useful adjuncts to the measurement of NSBH in diagnosing OA defined as a positive specific inhalation challenge (SIC). METHODS: The study included 240 consecutive subjects with a suspicion of OA who completed a SIC, of whom 133 showed a positive response. The sensitivity, specificity, and predictive values of NSBH, and FeNO, as well as sputum eosinophil counts assessed at baseline of the SIC were determined. RESULTS: A concentration of histamine inducing a 20% decline in FEV1 (PC20 ) ≤16 mg/mL showed a sensitivity of 87% and a specificity of 36%. A FeNO level ≥25 ppb and a sputum eosinophil count ≥2% provided lower sensitivity rates (47% and 39%, respectively) than the PC20 value. Eight of the 17 subjects without baseline NSBH despite a positive SIC showed a sputum eosinophil count ≥2%, a FeNO level ≥25 ppb, or both outcomes. Combining either a PC20 value ≤16 mg/mL or a FeNO ≥25 ppb increased the sensitivity to 91%. Using either a PC20 ≤16 mg/mL or a sputum eosinophil count ≥1% increased the sensitivity to 94%. CONCLUSION: Adding the assessment of FeNO level and sputum eosinophils to NSBH improves the identification of subjects who may have OA and require further objective testing before excluding the possibility of OA.

Baker's Asthma: Is the Ratio of Rye Flour-Specific IgE to Total IgE More Suitable to Predict the Outcome of Challenge Test Than Specific IgE Alone.

Usually the diagnosis of baker's asthma is based on specific inhalation challenge with flours. To a certain extent the concentration of specific IgE to flour predicts the outcome of challenge test in bakers. The aim of this study was to evaluate whether the ratio of specific IgE (sIgE) to total IgE (tIgE) improves challenge test prediction in comparison to sIgE alone. Ninety-five bakers with work-related respiratory symptoms were challenged with rye flour. Total IgE, sIgE, and the sIgE/tIgE ratio were determined. Receiver operator characteristic (ROC) plots including the area under the curve (AUC) were calculated using the challenge test as gold-standard. Total IgE and sIgE concentrations, and their ratio were significantly higher in bakers with a positive challenge test than in those with a negative one (p < 0.0001, p < 0.0001, and p = 0.023, respectively). In ROC analysis, AUC was 0.83 for sIgE alone, 0.79 for tIgE, and 0.64 for the ratio. At optimal cut-offs, tIgE, sIgE, and the ratio reached a positive predicted value (PPV) of 95%, 84% and 77%, respectively. In conclusion, calculating the ratio of rye flour-sIgE to tIgE failed to improve the challenge test prediction in our study group.

Integrated innate mechanisms involved in airway allergic inflammation to the serine protease subtilisin.

Proteases are recognized environmental allergens, but little is known about the mechanisms responsible for sensing enzyme activity and initiating the development of allergic inflammation. Because usage of the serine protease subtilisin in the detergent industry resulted in an outbreak of occupational asthma in workers, we sought to develop an experimental model of allergic lung inflammation to subtilisin and to determine the immunological mechanisms involved in type 2 responses. By using a mouse model of allergic airway disease, we have defined in this study that s.c. or intranasal sensitization followed by airway challenge to subtilisin induces prototypic allergic lung inflammation, characterized by airway eosinophilia, type 2 cytokine release, mucus production, high levels of serum IgE, and airway reactivity. These allergic responses were dependent on subtilisin protease activity, protease-activated receptor-2, IL-33R ST2, and MyD88 signaling. Also, subtilisin stimulated the expression of the proallergic cytokines IL-1α, IL-33, thymic stromal lymphopoietin, and the growth factor amphiregulin in a human bronchial epithelial cell line. Notably, acute administration of subtilisin into the airways increased lung IL-5-producing type 2 innate lymphoid cells, which required protease-activated receptor-2 expression. Finally, subtilisin activity acted as a Th2 adjuvant to an unrelated airborne Ag-promoting allergic inflammation to inhaled OVA. Therefore, we established a murine model of occupational asthma to a serine protease and characterized the main molecular pathways involved in allergic sensitization to subtilisin that potentially contribute to initiate allergic airway disease.

[New in vitro allergological diagnostic tool and its application in professional disease.] / Nuova diagnostica allergologica in vitro e sua applicazione nelle allergopatie professionali.

OBJECTIVES: Molecular diagnostic is a new therapeutic approach that - allows to valuate sensitization towards a single molecule in a allergenic source and to obtain relevant information on clinical features: sensitization towards molecules as alfa amylase of wheat or lipocalins of pets, Alt a 1 of alternaria spores and Hev b 6 of latex correlates with the risk to develop asthma - has a greater sensitivity in the serum IgE identification than the whole source.

[Diagnostic approach to occupational allergic respiratory diseases.] / Approccio diagnostico alle patologie respiratorie allergiche professionali.

OBJECTIVES: An accurate diagnosis of occupational allergic respiratory diseases is crucial because they are related to disability, loss of work and worsening of psychosocial and economic status of workers. Early diagnosis is therefore essential to prevent the progression of allergic respiratory diseases and to implement preventive measures. The most frequent occupational allergic respiratory diseases are asthma (OA) and rhinitis (OR), less frequently hypersensitivity pneumonia (HP) and non-asthmatic eosinophilic bronchitis (NAEB). METHODS: The diagnosis is based on the objective evidence of the disease, on a clear correlation with the work activity and the identification of a specific sensitizing agent in the workplace. RESULTS: Reference standard methods are available, such as Specific Inhalation Challenge in the laboratory or in the workplace. CONCLUSIONS: A multidisciplinary approach in highly-specialized centres is always recommended for diagnostic confirmation, as it is accompanied by greater diagnostic sensitivity and specificity.

The role of allergen components for the diagnosis of latex-induced occupational asthma.

BACKGROUND: Recombinant Hevea brasiliensis (rHev b) natural rubber latex (NRL) allergen components have been developed to assess the patients' allergen sensitization profile and to improve the diagnosis of NRL allergy. OBJECTIVE: To examine whether the determination of specific IgE (sIgE) reactivity to a panel of recombinant allergen components would be helpful for diagnosing NRL-induced occupational asthma (OA) in predicting the outcome of a specific inhalation test. METHODS: sIgE levels to NRL extract and 12 recombinant NRL allergen components were assessed in 82 subjects with OA ascertained by a positive specific inhalation challenge (SIC) with NRL gloves and in 25 symptomatic subjects with a negative challenge. RESULTS: The sensitivity, specificity, positive predictive value, and negative predictive value of a NRL-sIgE level ≥0.35 kUA /l as compared to the result of SICs were 94%, 48%, 86%, and 71%, respectively. The positive predictive value increased above 95% when increasing the cutoff value to 5.41 kUA /l. Subjects with a positive SIC showed a significantly higher rate of sIgE reactivity to rHev b 5, 6.01, 6.02, and 11 than those with a negative SIC. A sIgE sum score against rHev b 5 plus 6.01/6.02 ≥ 1.46 kUA /l provided a positive predictive value >95% with a higher sensitivity (79%) and diagnostic efficiency (Youden index: 0.67) as compared with a NRL-sIgE ≥5.41 kUA /l (49% and 0.41, respectively). CONCLUSION: In suspected OA, high levels of sIgE against rHev b 5 combined with rHev b 6.01 or 6.02 are the most efficient predictors of a bronchial response to NRL.

Developing a framework for assessing chemical respiratory sensitization: A workshop report.

Respiratory tract sensitization can have significant acute and chronic health implications. While induction of respiratory sensitization is widely recognized for some chemicals, validated standard methods or frameworks for identifying and characterizing the hazard are not available. A workshop on assessment of respiratory sensitization was held to discuss the current state of science for identification and characterization of respiratory sensitizer hazard, identify information facilitating development of validated standard methods and frameworks, and consider the regulatory and practical risk management needs. Participants agreed on a predominant Th2 immunological mechanism and several steps in respiratory sensitization. Some overlapping cellular events in respiratory and skin sensitization are well understood, but full mechanism(s) remain unavailable. Progress on non-animal approaches to skin sensitization testing, ranging from in vitro systems, -omics, in silico profiling, and structural profiling were acknowledged. Addressing both induction and elicitation phases remains challenging. Participants identified lack of a unifying dose metric as increasing the difficulty of interpreting dosimetry across exposures. A number of research needs were identified, including an agreed list of respiratory sensitizers and other asthmagens, distinguishing between adverse effects from immune-mediated versus non-immunological mechanisms. A number of themes emerged from the discussion regarding future testing strategies, particularly the need for a tiered framework respiratory sensitizer assessment. These workshop present a basis for moving towards a weight-of-evidence assessment.

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.

The influence of diisocyanate antigen preparation methodology on monoclonal and serum antibody recognition.

Exposure to diisocyanates (dNCOs), such as methylene diphenyl diisocyanate (MDI) can cause occupational asthma (OA). Currently, lab tests for dNCO specific IgE are specific, but not sensitive, which limits their utility in diagnosing dNCO asthma. This may be due to variable preparation and poor characterization of the standard antigens utilized in these assays. The aim of this study was to produce and characterize a panel of antigens prepared using three different commonly employed methods and one novel method. The conjugates were examined for recognition by anti-MDI monoclonal antibodies (mAbs) in varying enzyme linked immunosorbant assay (ELISA) formats, extent of crosslinking, total amount of MDI, the sites of MDI conjugation, relative shape/charge, and reactivity with human serum with antibodies from sensitized, exposed workers. Results indicate that while there are minimal differences in the total amount of MDI conjugated, the extent of crosslinking, and the conjugation sites, there are significant differences in the recognition of differently prepared conjugates by mAbs. Native and denaturing polyacrylamide gel electrophoresis demonstrate differences in the mobility of different conjugates, indicative of structural changes that are likely important for antigenicity. While mAbs exhibited differential binding to different conjugates, polyclonal serum antibodies from MDI exposed workers exhibited equivalent binding to different conjugates by ELISA. While differences in the recognition of the different conjugates exist by mAb detection, differences in antigenicity could not be detected using human serum from MDI-sensitized individuals. Thus, although dNCO conjugate preparation can, depending on the immunoassay platform, influence binding of specific antibody clones, serologic detection of the dNCO-exposure-induced polyclonal antibody response may be less sensitive to these differences.

Occupational asthma in a fruit and vegetables vendor.

BACKGROUND: This study presents a case report of a woman running a fruit and vegetables market stall, occupationally exposed to mushroom spores, who developed asthmatic symptoms. Basidiospores are allergens that can give rise to sensitization and subsequently trigger an allergic reaction, such as contact dermatitis, rhino-conjunctivitis, asthma and hypersensitivity pneumonitis. METHODS: A 40-year-old atopic woman, who had worked at a market stall selling fruit and vegetables for the past 26 years in a small town market in southern Italy, came to our attention at the Occupational Medicine Unit, complaining of a 3-year history of dyspnoea, cough, and wheezing during autumn and winter. RESULTS: Spirometry showed a severe mixed type respiratory deficit with a significant bronchodilator response obtained with salbutamol administration. Skin prick tests to common aeroallergens were negative. Prick-to-prick test with fresh Pleurotus ostreatus was positive. We evaluated the size of the skin wheals and compared them to the positive control according to the Skin Index. An on-the-spot inspection of her store was performed and environmental conditions were identified that did not allow a satisfactory air exchange. CONCLUSIONS: The clinical history and the results of the allergologic investigations, plus an on-the-spot inspection, permitted us to ascertain that this subject had developed occupational asthma due to Pleurotus ostreatus spores. We advised her to stop handling and selling mushrooms, and she has no longer suffered asthmatic symptoms, over seven years of follow-up, and regularly continued to work without needing to take anti-asthma drugs.

Biomarkers of systemic inflammation in pathogenesis of syntropic occupational bronchial asthma and metabolic syndrome.

In search of inflammatory molecular markers helpful in detection of increased risk and prognosis of severity of syntropic occupational bronchial asthma and metabolic syndrome, the authors conducted a study covering 140 examinees with confirmed occupational bronchial asthma. According to IDF criteria (2005), the patients were assigned into a group with combined occupational bronchial asthma and metabolic syndrome, and a group of occupational bronchial asthma without metabolic syndrome. All the examinees underwent studies of inflammation markers - biochemical (C-reactive protein, leptine) and molecular-genetic ( polymorphism of Gln223Arg gene of leptine receptor (LEPR), polymorphism of C174G gene of interleukin-6 (IL-6), polymorphism of G308A gene of (TNF-a) tumor necrosis factor alpha). Evidences are that the patients with combined bronchial asthma and metabolic syndrome demonstrate higher activity of inflammatory processes (higher level of C-reactive protein, leptine) - that manifests in clinically more severe course of bronchopulmonary disease. Moleculary-genetic markers revealed are associated with higher activity of inflammation and therefore with increased risk of occupational bronchial asthma associated with metabolic syndrome and diabetess mellitus 2 type (polymorphisms of LEPR gene, IL-6 gene).

Neutrophils mediate airway hyperresponsiveness after chlorine-induced airway injury in the mouse.

Chlorine gas (Cl2) inhalation causes oxidative stress, airway epithelial damage, airway hyperresponsiveness (AHR), and neutrophilia. We evaluated the effect of neutrophil depletion on Cl2-induced AHR and its effect on the endogenous antioxidant response, and if eosinophils or macrophages influence Cl2-induced AHR. We exposed male Balb/C mice to 100 ppm Cl2 for 5 minutes. We quantified inflammatory cell populations in bronchoalveolar lavage (BAL), the antioxidant response in lung tissue by quantitative PCR, and nuclear factor (erythroid-derived 2)-like 2 (NRF2) nuclear translocation by immunofluorescence. In vitro, NRF2 nuclear translocation in response to exogenous hypochlorite was assessed using a luciferase assay. Anti-granulocyte receptor-1 antibody or anti-Ly6G was used to deplete neutrophils. The effects of neutrophil depletion on IL-13 and IL-17 were measured by ELISA. Eosinophils and macrophages were depleted using TRFK5 or clodronate-loaded liposomes, respectively. AHR was evaluated with the constant-phase model in response to inhaled aerosolized methacholine. Our results show that Cl2 exposure induced neutrophilia and increased expression of NRF2 mRNA, superoxide dismutase-1, and heme-oxygenase 1. Neutrophil depletion abolished Cl2-induced AHR in large conducting airways and prevented increases in antioxidant gene expression and NRF2 nuclear translocation. Exogenous hypochlorite administration resulted in increased NRF2 nuclear translocation in vitro. After Cl2 exposure, neutrophils occupied 22 ± 7% of the luminal space in large airways. IL-17 in BAL was increased after Cl2, although this effect was not prevented by neutrophil depletion. Neither depletion of eosinophils nor macrophages prevented Cl2-induced AHR. Our data suggest the ability of neutrophils to promote Cl2-induced AHR is dependent on increases in oxidative stress and occupation of luminal space in large airways.

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.

Serum S100A8 and S100A9 Enhance Innate Immune Responses in the Pathogenesis of Baker's Asthma.

BACKGROUND: S100A8 and S100A9 can be produced by lipopolysaccharide-stimulated granulocytes and provoke an innate immune-mediated airway inflammation. Involvement of S100A8 and S100A9 has been implicated in asthma. To further understand the role of S100A8 and S100A9 during innate immune responses in baker's asthma, we investigated the associations of serum S100A8 and S100A9 with exposure to bakery allergens and polymorphisms of the Toll-like receptor 4 (TLR4) gene. METHODS: Totally, 381 bakery workers and 100 unexposed healthy controls were recruited. Skin prick tests for bakery allergens were performed. Serum levels of S100A8, S100A9, myeloperoxidase (MPO), tumor necrosis factor (TNF)-α, and interleukin (IL)-8 were measured using ELISA. Predictive values of serum S100A8 and S100A9 in bakery workers were evaluated by receiver-operating characteristic (ROC) curves. Polymorphisms of TLR4 -2027Ax2192;G and -1608Tx2192;C were genotyped. RESULTS: Higher serum levels of S100A8 and S100A9 were noted in bakery workers compared to the normal controls (p < 0.001); however, no significant differences were noted according to work-related symptoms. The area under the ROC curve of serum S100A8 was 0.886 for occupational exposure (p < 0.001). The TLR4 -1608CC genotype was significantly associated with a higher serum S100A8 level (p = 0.025). Serum S100A8 and S100A9 levels were correlated with serum levels of MPO (r = 0.396 and 0.189, respectively), TNF-α (r = 0.536 and 0.280, respectively), and IL-8 (r = 0.540 and 0.205, respectively; p < 0.001 for all). CONCLUSION: S100A8 and S100A9 are involved in innate immune responses under the regulation of TLR4 polymorphisms in baker's asthma pathogenesis. Serum S100A8 could be a potential biomarker for predicting occupational exposure to wheat flour in bakery workers.