Maternal Exposure to Occupational Asthmagens During Pregnancy and Autism Spectrum Disorder in the Study to Explore Early Development

Maternal immune activity has been linked to children with autism spectrum disorder (ASD). We examined maternal occupational exposure to asthma-causing agents during pregnancy in relation to ASD risk. Our sample included 463 ASD cases and 710 general population controls from the Study to Explore Early Development whose mothers reported at least one job during pregnancy. Asthmagen exposure was estimated from a published job-exposure matrix. The adjusted odds ratio for ASD comparing asthmagen-exposed to unexposed was 1.39 (95 % CI 0.96-2.02). Maternal workplace asthmagen exposure was not associated with ASD risk in this study, but this result does not exclude some involvement of maternal exposure to asthma-causing agents in ASD.

Granulometry, microbial composition and biological activity of dusts collected in French dairy farms

BACKGROUND

Dairy working increases the prevalence of lower airway respiratory diseases, especially COPD and asthma. Epidemiological studies have reported that chronic inhalation of organic dusts released during specific daily tasks could represent a major risk factor for development of these pathologies in dairy workers. Knowledge on size, nature and biological activity of such organic dusts remain however limited.

OBJECTIVE

To compare size distribution, microbial composition and cellular effects of dusts liberated by the spreading of straw bedding in five French dairy farms located in Brittany.

RESULTS

Mechanized distribution of straw bedding generated a cloud of inhalable dusts in the five dairy farms' barns. Thoracic particles having a 3-7.5µm size constituted 58.9-68.3% of these dusts. Analyses of thoracic dusts by next generation sequencing showed that the microbial dust composition differed between the five French farms, although Actinobacteria, Bacteroidetes, Firmicutes and Proteobacteria represent more than 97.5% of the bacterial phyla detected in each sample. Several bacteria genera comprising of human pathogenic species, such as Pseudomonas, Staphylococcus, Thermoactinomyces or Saccharopolyspora were identified. Cladosporium and Alternaria fungal genera, which are potent environmental determinants of respiratory symptoms, were detected in dusts collected in the five farms and their levels reached 15.5-51.1% and 9-24.7% of assignable fungal sequences in each sample, respectively. Finally, all dust samples significantly and strongly increased the expression of the pro-inflammatory TNF-α, IL-1β, IL-6 and IL-8 cytokines at both mRNA and protein levels in human monocyte-derived macrophages. Their effects were dose-dependent and detectable from 1µg/ml. The intensity of the macrophage responses however differed according to the samples.

CONCLUSIONS

Our results strengthen the hypothesis that organic dusts released during the distribution of straw bedding are mainly constituted of thoracic particles which are small enough to deposit on lower bronchial epithelium of dairy farmers and induce inflammation.

Influence of 5 different caging types and the use of cage-changing stations on mouse allergen exposure

Animal allergens constitute a serious health risk in laboratory animal facilities. To assess possibilities for allergen reduction by technical and organizational measures, we studied personnel exposure to mouse urinary aeroallergens in an animal facility with a holding capacity of 30,000 cages. Short-term (2 h) and intermediate-term (12 h) stationary samples (n = 107) and short-term (2 h) personnel samples (n = 119) were collected on polytetrafluorethylene filters by using air pumps. Long-term (14 d) stationary dust samples containing airborne allergens (n = 165) were collected with electrostatic dust fall collectors (EDC). Mouse allergens were quantified by ELISA. Personnel samples were collected during bedding disposal and refilling of clean cages as well as during cage changing with and without use of cage-changing station. Animal rooms were equipped with either open cages, cages with a soft filter top, cages with a rigid filter top (static microisolation caging), or with individually ventilated cages (IVC) with either a sealed or nonsealed lid, each in positive- or negative-pressure mode. Highest personnel allergen exposure was detected during cage change and emptying of soiled cages. Allergen concentrations were lowest in rooms with sealed IVC under positive or negative pressure, with unsealed IVC under negative pressure, and with static microisolation caging. The use of cage-changing stations and a vacuum bedding-disposal system reduced median personnel exposures 14- to 25-fold, respectively. Using sealed IVC and changing stations minimized allergen exposure, indicating that state-of-the-art equipment reduces exposure to mouse allergens and decreases health risks among animal facility personnel.

Evaluation of the sensitisation to grains and its pulmonary impact in employees of the port of Brest silos

BACKGROUND

Evaluation of the sensitisation and levels of exposure to grains and its pulmonary impact ina population of Brest port silo employees.

MATERIALS AND METHODS

We included exposed workers. The study consisted of clinical examination witha standardised questionnaire, blood samples, prick-tests, and spirometry tests. The atmospheric concentrationof total dust in the workplace was also associated.

RESULTS

Eight workers were included in the study. No case of occupational asthma was found, but 3 casesof occupational rhinitis were noted and occupational prick-tests were positive in 4 cases. The mean totaldust concentration in the three atmospheric samples was 4.87 mg/m3 for 8 hours but it was under thedetection limits for alveolar fractions.

CONCLUSIONS

Port silo workers are exposed to total dust concentrations below the French legal limit (10 mg/m3) but higher than Canadian and American recommendations. Levels of exposure in our studyare similar to other studies developed in port silos. Symptoms developed by workers may be due to highexposure to dust with an irritant effect rather than an allergic effect. Despite this fact, a specific medicalsurvey is needed, and ventilation and respiratory masks have to be promoted for prevention.

Immunotoxicology of arc welding fume: worker and experimental animal studies

Arc welding processes generate complex aerosols composed of potentially hazardous metal fumes and gases. Millions of workers worldwide are exposed to welding aerosols daily. A health effect of welding that is of concern to the occupational health community is the development of immune system dysfunction. Increased severity, frequency, and duration of upper and lower respiratory tract infections have been reported among welders. Specifically, multiple studies have observed an excess mortality from pneumonia in welders and workers exposed to metal fumes. Although several welder cohort and experimental animal studies investigating the adverse effects of welding fume exposure on immune function have been performed, the potential mechanisms responsible for these effects are limited. The objective of this report was to review both human and animal studies that have examined the effect of welding fume pulmonary exposure on local and systemic immune responses.

Immune functions of the garment workers

BACKGROUND

Occupational exposure to cotton dust, fibers, metal fumes and different chemicals used in the aparrel manufacturing industries cause a wide range of physical and psychological health problems in the garment workers that may also affect their immune function.

OBJECTIVE

To assess the immune system function in garment workers.

METHODS

A total of 45 workers of a garment factory, and 41 control subjects, not exposed to the garment working environment were enrolled in this study. In the study subjects, the complement system function was assessed as bactericidal activity on Escherichia coli DH5α cells using the standard plate count method. Serum complement components C3 and C4 were measured by immunoprecipitation, and IgG was measured by immunonephelometry.

RESULTS

The bactericidal activity of serum complement in the garment workers (range: 93.5%-99.9%) was significantly (p<0.01) lower than that in the controls (range: 98.6%-100%). The heat-inactivated serum of the workers showed a significantly enhanced bactericidal activity. In the garment workers, the mean levels of complement C3, and C4 were 1.75 and 0.26 g/L, respectively that were close to those of the controls. The mean IgG level in the garment workers was 13.5 g/L that was significantly (p<0.001) higher than that in the controls.

CONCLUSION

Working in a garment factory may affect the immune system.

Symptoms, spirometry, and serum antibody concentrations among compost workers exposed to organic dust

Work-related symptoms and diseases of 190 currently exposed compost workers, 59 former compost workers, and 38 nonexposed control subjects were investigated in a cross-sectional study. Using a standardized questionnaire, participants were asked for work-related symptoms, exposures to bioaerosols, atopic diseases, and smoking habits. The subjects underwent a physical examination and a lung function test. In addition, total immunoglobulin (Ig) E, IgE specific to environmental allergens and moulds, and IgG specific to molds and actinomycetes were quantified. Compared to controls, compost workers suffered more often from cough and irritation of the eyes in terms of mucosal membrane irritation (MMI). Former compost workers reported similar work-related complaints, but most MMI symptoms had improved after termination of bioaerosol exposure. In contrast, cough and dyspnea persisted, indicating a chronic process. Lung function parameters of compost workers were within the reference ranges. Nevertheless, forced vital capacity (FVC) was significantly lower than for controls. Specific IgE to environmental allergens and molds was positive in 25.3% and 7.4%, respectively, of currently exposed compost workers. There were no marked differences in IgE and IgG concentrations among the three groups. Compost workers suffered with a higher frequency from cough and MMI symptoms. The findings that MMI symptoms improved in former compost workers after leaving the job confirmed the association with bioaerosol exposure. Further, the reduced FVC may be produced by this exposure. There was no higher frequency of mold sensitization in the group of compost workers compared to controls, which may be an indication of a healthy worker survivor effect.

Induced sputum evaluation in restorers and conservators of cultural heritage

The objective of this study was to examine induced sputum (IS) cells profile from restorers/conservators of cultural heritage (restorers) with no lower airway symptoms and normal ventilatory lung function. The study involved 22 restorers and 48 control workers. Medical interview, physical examination, spirometry, skin prick testing to inhalatory allergens, and IS collection were performed. Compared with control workers, restorers demonstrated higher percentage of neutrophils (34% vs 15.5%; p = .004). This pattern was found only in male workers. They had almost 9 times greater chance to have increased proportion of sputum neutrophils than male controls (odds ratio [OR] 8.98, 95% confidence interval [CI] 1.98-40.7). The mobilization of eosinophils or macrophages into the airways was not established regardless of workers sex. Additional gender difference in sputum cells distribution was found for occupationally unexposed subjects, with higher proportion of sputum neutrophils in women.

Occupational exposure to airborne fungi in two Croatian sawmills and atopy in exposed workers

Airborne fungi were collected over a one year period at 2-month intervals at 2 sawmills in Croatia (SM 1 and SM 2) processing mainly beech wood and oak wood. A questionnaire concerning respiratory symptoms and skin prick test (SPT) with common inhalatory allergens and moulds Cladosporium herbarum, Alternaria alternata, Aspergillus niger, Penicillium notatum, and Rhizopus nigricans were performed in 96 workers from the same sawmills. Average concentrations of airborne fungi were 1,696-7,316 cfu/m(3) in SM 1 and 1,706-4,819 cfu/m(3) in SM 2, respectively. Health hazardous levels of airborne fungi (above 10 4 /m(3)) were present only in SM 1. These levels were related to saw working sites and were season-dependent, i.e. present only during the summer. Penicillium (50-100%), Paecilomyces (43-100%) and Chrysonilia (33-100%) dominated among 17 fungal genera identified in both sawmills. Symptoms of rhinitis, asthma, and dry cough were most frequently recorded among analysed workers. SPT to moulds was negative in all tested workers, except one positive to R. nigricans, indicating that moderate airborne fungi levels found in the analysed sawmills were not related to IgE-mediated sensitization to moulds in exposed workers, even in atopics. Atopy was present among woodworkers in similar proportions to the general population of Croatia, suggesting that the wood-processing industry is not selective for atopic workers.

Exposure to formaldehyde and its potential human health hazards

A widely used chemical, formaldehyde is normally present in both indoor and outdoor air. The rapid growth of formaldehyde-related industries in the past two decades reflects the result of its increased use in building materials and other commercial sectors. Consequently, formaldehyde is encountered almost every day from large segments of society due to its various sources. Many governments and agencies around the world have thus issued a series of standards to regulate its exposure in homes, office buildings, workshops, public places, and food. In light of the deleterious properties of formaldehyde, this article provides an overview of its market, regulation standards, and human health effects.

Occupational rhinitis in bell pepper greenhouse workers: determinants of leaving work and the effects of subsequent allergen avoidance on health-related quality of life

BACKGROUND

Avoidance of occupational allergens or reduction in exposure has been advocated as the mainstay of the management of occupational rhinitis. Sparse data to the effect of allergen avoidance are available.

OBJECTIVE

To identify factors that may lead to leaving work and to address the effect of subsequent allergen avoidance on quality of life.

METHODS

A survey to the prevalence of occupational allergy to bell pepper performed in 1999 comprised 472 employees, of which 254 had work-related rhinitis and 228 completed the Rhinitis-related Quality of Life Questionnaire. After 8-year follow-up in 2007, 91 workers with rhinitis in 1999 were available to fill out the questionnaire again and were used to evaluate the course of nasal disease in terms of perceived severity and impact on daily life.

RESULTS

Workers with rhinitis at baseline were more likely to leave their job in bell pepper cultivation for another job (OR = 1.62, 95% CI 0.95-2.75). Among the 91 workers, 58 subjects were still at work, whereas 33 subjects had left work. The subjects who left jobs reported substantial improvement in quality of life. The magnitude of the changes ranged from -0.31 to -1. The effect of quitting work on the mean quality of life score amounted -0.76 ± 0.15.

CONCLUSIONS

The current study is the first large longitudinal studies showing that leaving work and subsequent occupational allergen avoidance have a beneficial effect on rhinitis-related quality of life. The study suggests that occupational rhinitis can be a reason to leave work.

[Evaluation of occupational allergic diseases of the respiratory tract]

The paper presents the basic etiological and pathogenetic aspects of occupational allergic diseases of the respiratory tract, discusses the clinical course, diagnosis, and priorities of the prevention of allergic diseases of the upper airways and bronchopulmonary apparatus from the action of industrial allergens.

Occupational mouse allergen exposure among non-mouse handlers

This study assessed mouse allergen exposure across a range of jobs, including non-mouse handling jobs, at a mouse facility. Baseline data from 220 new employees enrolled in the Jackson Laboratory (JAXCohort) were analyzed. The baseline assessment included a questionnaire, allergy skin testing, and spirometry. Exposure assessments consisted of collection of two full-shift breathing zone air samples during a 1-week period. Air samples were analyzed for mouse allergen content, and the mean concentration of the two shifts represented mouse allergen exposure for that employee. The mean age of the 220 participants was 33 years. Ten percent reported current asthma and 56% were atopic. Thirty-eight percent were animal caretakers, 20% scientists, 20% administrative/support personnel, 10% materials/supplies handlers, and 9% laboratory technicians. Sixty percent of the population handled mice. Eighty-two percent of study participants had detectable breathing zone mouse allergen, and breathing zone mouse allergen concentrations were 1.02 ng/m³ (0.13-6.91) (median [interquartile range (IQR)]. Although mouse handlers had significantly higher concentrations of breathing zone mouse allergen than non-handlers (median [IQR]: 4.13 ng/m³ [0.69-12.12] and 0.21 ng/m³ [below detection (BD)-0.63], respectively; p < 0.001), 66% of non-handlers had detectable breathing zone mouse allergen. Mouse allergen concentrations among administrative/support personnel and materials/supplies handlers, jobs that generally do not entail handling mice, were median [IQR]: 0.23 ng/m³ [BD-0.59] and 0.63 ng/m³ [BD-18.91], respectively. Seventy-one percent of administrative/support personnel, and 68% of materials/supplies handlers had detectable breathing zone mouse allergen. As many as half of non-mouse handlers may have levels of exposure that are similar to levels observed among mouse handlers.

[Health effects of occupational endotoxin exposure: a review and relevance to veterinary practice]

Endotoxins are cell-wall components of Gram-negative bacteria that are commonly present in plants and plant products and in faecal matter. This review presents an overview of endotoxin exposure levels, associated health effects, and relevance regarding veterinary practice. Exposure to airborne endotoxin is especially high in the agricultural sector and among veterinarians, and in particular among those working with horses or farm animals. Inhalation of endotoxins may cause acute airway inflammation and respiratory symptoms that can lead to (non-allergic) asthma and chronic obstructive pulmonary disease in individuals with prolonged exposure to high levels of endotoxins. Interestingly, recent studies have shown that individuals exposed to high levels of endotoxin also have a lower risk of allergic conditions such as hay fever. Although endotoxin may protect against allergies, it is essential to reduce exposure levels in the agricultural sector in order to prevent workers from developing chronic non-allergic respiratory disorders.

A reconsideration of acute Beryllium disease

CONTEXT

Although chronic beryllium disease (CBD) is clearly an immune-mediated granulomatous reaction to beryllium, acute beryllium disease (ABD) is commonly considered an irritative chemical phenomenon related to high exposures. Given reported new cases of ABD and projected increased demand for beryllium, we aimed to reevaluate the patho physiologic associations between ABD and CBD using two cases identified from a survey of beryllium production facility workers.

CASE PRESENTATION

Within weeks after exposure to beryllium fluoride began, two workers had systemic illness characterized by dermal and respiratory symptoms and precipitous declines in pulmonary function. Symptoms and pulmonary function abnormalities improved with cessation of exposure and, in one worker, recurred with repeat exposure. Bronchoalveolar lavage fluid analyses and blood beryllium lymphocyte proliferation tests revealed lymphocytic alveolitis and cellular immune recognition of beryllium. None of the measured air samples exceeded 100 microg/m(3), and most were < 10 microg/m(3), lower than usually described. In both cases, lung biopsy about 18 months after acute illness revealed noncaseating granulomas. Years after first exposure, the workers left employment because of CBD.

DISCUSSION

Contrary to common understanding, these cases suggest that ABD and CBD represent a continuum of disease, and both involve hypersensitivity reactions to beryllium. Differences in disease presentation and progression are likely influenced by the solubility of the beryllium compound involved.

RELEVANCE TO PRACTICE

ABD may occur after exposures lower than the high concentrations commonly described. Prudence dictates limitation of further beryllium exposure in both ABD and CBD.

Leukotrienes and 8-isoprostane in exhaled breath condensate in bronchoprovocation tests with occupational allergens

Exhaled breath condensate (EBC) contains many substances, which could help in diagnosis of occupational asthma. The aim of the study is to monitor leukotrienes (LT) and 8-isoprostane from EBC in bronchoprovocation tests with allergens in 47 patients with suspected occupational asthma. Forty-one patients were tested negative. In negative bronchoprovocation tests, no significant differences (P<0.05) were seen between the five measurements during and after the test. In control measurements (without provocation), significant differences were found among four measurements done within 24h for 8-isoprostane (P=0.0138). The relationship between the log transformed ratios of the EBC parameters and FEV(1) was never significant at the 5% level in control measurements, while in negative tests, statistical significance was recorded for LTB(4) (P=0.0299) before and 5h after the test. Six of 47 patients were tested positive. Such a small number of patients did not allow proper statistical analysis and therefore, the results are described separately for each patient.

Issues in diisocyanate antibody testing

Diisocyanates are used to produce a wide variety of polyurethane products; they are also recognized as an important cause of occupational asthma. Their chemical reactivity presents challenges to toxicologists and clinicians alike seeking to understand the mechanisms underlying diisocyanate asthma. In this article, we review the literature on immunoassay detection of IgE and IgG binding to diisocyanate-protein conjugates and assess the utility of such testing as a diagnostic tool and exposure indicator. Data from 29 studies of occupational exposure to diisocyanates revealed considerable variability in assay methodology and heterogeneity in the prevalence of positive antibody responses across laboratories. In studies that included both confirmed diisocyanate asthma subjects and exposed nonasthmatics, positive IgE responses identified cases with low sensitivity (18-27%), but high specificity (96-98%). Detection of IgG binding to diisocyanate conjugates is an indirect, qualitative indicator of disease status and past diisocyanate exposure. The utility of these assays is limited, however, due to a lack of (1) method standardization, (2) population norms to guide interpretation of results, and (3) demonstration that the assays improve either on disease prediction or on exposure confirmation beyond that of other indicators. Sources of assay heterogeneity are discussed and suggestions are offered for improving test performance and interpretability.

Symptoms and immunologic markers among vulcanization workers in rubber industries in southern Sweden

OBJECTIVES

The aim of this study was to estimate the risk of symptoms and the possible derangement of levels of immunologic markers for contemporary Swedish rubber workers. Furthermore, the relation between exposure and these biomarkers of response was examined using urinary levels of 2-thiothiazolidine-4-carboxylic acid (TTCA), which reflect the exposure.

METHODS

Included in the study were 166 exposed workers and 117 controls. Medical and occupational histories were obtained in structured interviews. Symptoms were recorded, and immunologic markers were analyzed in blood. Urinary levels of TTCA were determined by liquid chromatography tandem mass spectrometry.

RESULTS

Compared with the controls, the exposed workers had increased risks of eye symptoms [odds ratio (OR) 3.0], nose bleeds (OR 4.0), burning and dry throat (OR 3.0), hoarseness (OR 2.4), severe dry cough (OR 3.8), nausea (OR 4.3), and headache (OR 2.5). When the exposed workers were divided into three groups according to the TTCA levels, the highest risks were observed among the exposed workers with intermediate TTCA levels. Furthermore, the exposed workers in all of the TTCA subgroups had elevated concentrations of total immunoglobulin G when compared with the controls. Elevated concentrations of leukocytes, neutrophils, and eosinophils were observed in the group with high TTCA levels.

CONCLUSIONS

This work shows an increased risk of several symptoms and elevated levels of some immunologic markers among exposed workers in Swedish rubber industries. In addition, relationships between urinary levels of TTCA and some biomarkers of response were reported.

Diisocyanate conjugate and immunoassay characteristics influence detection of specific antibodies in HDI-exposed workers

BACKGROUND

The structural characteristics of diisocyanate chemical protein antigens vary depending upon the methods of production, and may influence diisocyanate antigen immunoassays. The impact of different antigen preparation methods on immunoassay sensitivity, specificity, and predictive value for identifying workers with diisocyanate asthma (DA) has not been systematically evaluated.

OBJECTIVE

Evaluate the influence of preparation methodology of hexamethylene diisocyanate human serum albumin (HDI-HSA) conjugates on the performance of specific antibody assays for identifying workers with confirmed HDI asthma.

METHODS

Asthmatic reactions to HDI exposure were assessed in 80 autobody shop workers by specific inhalation challenge (SIC). HDI-specific IgE and IgG in serum were measured by RAST and ELISA with seven different HDI-HSA conjugates prepared in liquid phase with monomeric or polymeric HDI, or vapour-phase monomeric HDI. The HDI : HSA substitution ratios were determined by mass spectrometry.

RESULTS

DA was confirmed by SIC in 23 subjects. The maximal sensitivity for detecting specific IgE among workers with positive SIC results was higher with RAST and with polymeric vs. monomeric HDI-albumin conjugates (21.7% vs. 8.7%) with a generally high specificity (>or=95%). HDI-HSA specific IgG antibody was also detected in 22-43% of HDI asthmatics depending upon the conjugate used. The specificity of specific IgG varied from 88% to 96%, and it was higher for monomeric (vs. polymeric) HDI-albumin conjugates with low (vs. high) substitution ratios.

CONCLUSION

The test performance of specific IgE and IgG immunoassays for identifying a positive SIC response varied with different HDI-HSA conjugates. Standard test antigens and common immunoassays must be used to minimize inter-laboratory variability.

Specific sensitization in wheat flour and contributing factors in traditional bakers

Skin prick tests (SPTs) play an important role in the diagnosis of bakers asthma and epidemiological field studies on frequencies of sensitization to wheat or rye flour. In many epidemiological studies the investigators have tried to reveal the determinants of specific sensitization, and atopy appears to be a very strong determinant for sensitization to flour allergens. Age and gender have not reported to be determinants of sensitization. Only one study found that sensitization in wheat flour with skin prick test was significantly associated with cigarette smoking. Few data are available on sensitization to wheat flour in populations without occupational exposure to bakery allergens. The aim of this study was to investigate the sensitization of wheat flour and other baking allergens (oat, barley, and rye flour) in traditional bakers and in cleaners in a big hospital in the same area. In addition the correlation of atopy with specific sensitization and the correlation of specific sensitization with age, sex, working hours, working years, smoking status and pack/years with use of skin prick tests.

Airborne exposure to wheat allergens: measurement by human immunoglobulin G4 and rabbit immunoglobulin G immunoassays

BACKGROUND

Exposure to airborne wheat allergens in the bakery trade is associated with a high risk of occupational allergy and asthma. Control and reduction of allergen exposure require relatively simple but reliable monitoring techniques. We developed new rabbit IgG-based enzyme immunoassays (EIA) for wheat allergens, which might be a convenient alternative for the thus far used human IgG4 inhibition assay.

METHODS

The reactivity and specificity of rabbit antibodies were assessed by EIA and immunoblotting, and compared with those of IgE from wheat-sensitized bakers, and with the antibodies used in the IgG4 inhibition EIA. An IgG inhibition and a sandwich EIA were developed for analysis of airborne dust samples.

RESULTS

Human IgG4 and rabbit IgG inhibition EIAs had comparable sensitivities, with limits of detection (LOD) between 18 and 88 ng/mL, while the sandwich EIA was much more sensitive (LOD<0.2 ng/mL). Human IgG4 and rabbit IgG reacted in immunoblotting with most of the IgE-binding wheat proteins, although with quantitative differences. All three assays showed a strong reaction with wheat proteins, and some cross-reactivity with rye and barley, but were further highly specific for cereal flour proteins. Concentrations measured with the three EIAs in 432 airborne dust samples were highly correlated (r>0.95) and their absolute values showed less than 10-20% differences.

CONCLUSION

The rabbit IgG EIAs are valid substitutes for the human IgG4 inhibition EIA, with important practical advantages. The inhibition EIA is recommended for routine wheat allergen measurements. The sandwich EIA may be used to measure low allergen levels, as in short task-related exposure measurements or in subfractions of airborne dust samples.

Smoking and occupational asthma

Cigarette smoking is a known risk factor for many chronic illnesses such as coronary heart and chronic obstructive pulmonary diseases. Smoking is often described as a risk factor for occupational asthma even though its effect on the development of asthma is still under debate and the links between smoking and occupational asthma, occupational rhinitis or occupational sensitization are elusive, controversial and contradictory. This review describes these relationships in a wide range of occupations, from laboratory, farm, brewery and hospital workers, to bakers, printers, cleaners, fish processors and others as observed in cross-sectional, cohort, and case-control studies published over the past thirty-five years i.e. from 1970 to 2005. Surprisingly, the data show there is little to support the view that the risk of occupational asthma is increased in workers who are smokers. However, evidence emerges of an increased risk of occupational sensitization in smoking workers exposed to several high and low molecular weight agents. This in-depth review confirms the relationship between smoking and occupational asthma is complex and contradictory. It deserves more attention and further studies, which need to be conducted without being influenced by selection bias or by the justifiable prejudice against smoking.

Mouse allergen-specific immunoglobulin G4 and risk of mouse skin test sensitivity

BACKGROUND

High serum levels of cat-specific IgG and IgG4 are associated with protection against allergic sensitization to cat, but whether this association applies to other animal allergens remains unclear.

OBJECTIVE

To determine if high levels of mouse-specific IgG and IgG4 are associated with a decreased risk of mouse skin test sensitivity.

METHODS

Two hundred and sixty workers of a mouse facility underwent skin prick testing and completed a questionnaire. Serum levels of mouse-specific IgG and IgG4 were quantified by solid-phase antigen binding assays. Room air samples were collected and airborne Mus m 1 was quantified by ELISA.

RESULTS

Forty-nine participants had a positive skin prick test to mouse. Mouse-specific IgG was detected in 219 (84%) participants and IgG4 was detected in 72 (28%) participants. A detectable mouse-specific IgG4 level was associated with an increased risk of mouse skin test sensitivity (odds ratios (OR) 6.4, 95% confidence intervals (CI) 3.3-12.4). Mouse-specific IgG and IgG4 were both positively correlated with mouse allergen exposure (r(s)=0.31, P=0.0001, and r(s)=0.27, P=0.0006, respectively). The odds of skin test sensitivity peaked at moderate levels of IgG4, but decreased at the highest levels of mouse-specific IgG4. In contrast, the odds of skin test sensitivity increased monotonically with IgG levels.

CONCLUSIONS

A detectable level of mouse-specific IgG4 is associated with an increased risk of skin test sensitivity to mouse. However, the highest IgG4 levels appear to be associated with an attenuated risk of mouse skin test sensitivity, suggesting that induction of high levels of IgG4 through natural exposure may protect against the development of allergic sensitization.

Occupational rhinoconjunctivitis and bronchial asthma due to Acalypha wilkesiana allergy

BACKGROUND

Acalypha wilkesiana, or copperleaf, is a plant of the Euphorbiaceae family. Although it is widely known as an outdoor ornamental plant, no cases of A. wilkesiana allergy have been reported to date.

OBJECTIVE

To describe a patient with occupational respiratory allergy to A. wilkesiana.

METHODS

Extracts from A. wilkesiana leaves and flowers were used for skin prick testing, specific conjunctival and bronchial challenge tests, and in vitro studies. These studies range from A. wilkesiana specific IgE determination to sodium dodecyl sulfate-polyacrylamide gel electrophoresis immunodetection of A. wilkesiana protein bands in patient serum samples and immunoblot inhibition by preincubation with Salsola kali and Chenopodium album pollen extracts.

RESULTS

Our patient had positive skin prick test reactions to A. wilkesiana leaf and flower extracts; negative reactions were found in a control group of 20 atopic patients. On immunodetection of A. wilkesiana extracts in patient serum samples, as many as 9 different IgE-binding proteins, with apparent molecular weights of 16 to 86 kDa, were revealed. Preincubation with S. kali and C. album pollen extracts completely inhibited IgE binding to the A. wilkesiana extract. Specific bronchial challenge resulted in a spirometric 30% decline in forced expiratory volume in 1 second with respect to baseline 1 minute after 1:100 (vol/vol) A. wilkesiana extract solution inhalation; 2 atopic controls had negative bronchial challenge test results.

CONCLUSION

Acalypha wilkesiana is a new etiologic agent for IgE-mediated occupational respiratory allergy.

Mouse allergen-specific immunoglobulin G and immunoglobulin G4 and allergic symptoms in immunoglobulin E-sensitized laboratory animal workers

BACKGROUND

High levels of allergen-specific IgG have been associated with clinical efficacy in immunotherapy studies, but whether this antibody isotype is associated with clinical tolerance in the setting of environmental exposure remains unclear.

OBJECTIVE

To determine if mouse allergen-specific IgG (mIgG) and IgG4 (mIgG4) levels are associated with mouse-related symptoms among IgE-sensitized laboratory workers.

METHODS

Fifty-eight workers with either skin test or serologic evidence of IgE-mediated mouse sensitization were studied. Symptom data were obtained by a questionnaire. Serum levels of mouse-specific IgG, IgG4, and IgE were quantified by a solid-phase antigen-binding assay (IgG) and RAST (IgG4 and IgE), and the relationships between mouse-specific serologic responses and mouse-related symptoms were analysed.

RESULTS

Twenty-three (39.7%) participants reported mouse-related symptoms. Mouse-specific IgG and IgG4 levels were not associated with mouse-related symptoms among the study population as a whole. Among the 29 (50%) participants with detectable mouse-specific IgE (mIgE), higher mouse-specific IgG and IgG4 levels were associated with a decreased risk of symptoms, after adjusting for mIgE level (odds ratio (OR) 0.3, 95% confidence interval (CI): 0.1-1.4, and OR 0.3, 95% CI: 0.04-2.6, respectively). Higher levels of mIgG and mIgG4 remained associated with a decreased risk of symptoms after additional adjustment for sex and handling of mice (OR 0.1, 95% CI: 0.02-0.7, and OR 0.2, 95% CI: 0.02-2.1, respectively). Higher mIgG : IgE and mIgG4 : IgE ratios were also associated with a decreased risk of symptoms after adjusting for these confounders (OR 0.1, 95% CI: 0.02-0.7, and OR 0.2, 95% CI: 0.02-0.92, respectively).

CONCLUSION

Among workers with detectable mIgE, higher mIgG and mIgG4 levels are associated with a decreased risk of mouse-related symptoms. High serum levels of mIgG or mIgG4 may be markers for clinical tolerance among laboratory mouse workers with detectable mIgE, but these findings need to be confirmed in larger, prospective studies.

Occupational rhinitis: diagnostic criteria, relation to lower airway symptoms and IgE sensitization in bakery workers

CONCLUSIONS

The use of different diagnostic criteria has considerable consequences for the prevalence estimates of occupational rhinitis. There is a strong relationship between occupational rhinitis and lower airway symptoms. Storage mites appear to be important occupational allergens in Norwegian bakeries.

OBJECTIVES

To study the consequences of various diagnostic criteria on the prevalence of occupational rhinitis, assess the prevalence of IgE sensitization and explore the relationships between upper and lower airway symptoms and between symptoms and IgE sensitization.

MATERIAL AND METHODS

A total of 197 employees in 6 bakeries were interviewed and completed a questionnaire. A skin prick test was performed, total and specific IgE were determined and a histamine release test was performed for relevant allergens. The criteria for the diagnosis of occupational rhinitis were based on the 1994 International Consensus Report on Rhinitis.

RESULTS

The prevalence of occupational rhinitis varied between 23% and 50%, depending on the criteria used. The occurrence of nasal symptoms was found to precede the development of lower airway symptoms. Occupational rhinitis, both IgE- and non-IgE-mediated, was associated with asthma symptoms. The most frequent causes of sensitization (20%) were different species of storage mites. Storage mite sensitization was related to occupational rhinitis and work exposure.

IgE-mediated sensitisation, rhinitis and asthma from occupational exposures. Smoking as a model for airborne adjuvants?

OBJECTIVE

Airborne pollutants with adjuvant effect, called airborne adjuvants, may promote IgE-sensitisation and development of allergic airway diseases. Smoking and occupational allergen exposures were reviewed to establish a general and verified framework for hazard identification and risk assessment of adjuvant effects of airborne pollutions.

METHODS

The relative risks and the attributable risks of adjuvant effect of smoking were determined for co-exposures with green coffee and castor beans, ispaghula, senna, psyllium, flour and grain dust, latex, laboratory animals, seafood, enzymes, platinum salts, organic anhydrides, or reactive dyes.

RESULTS

Adjuvant effects of smoking depended on the types of allergen, but not on whether sensitisation or allergy was promoted by atopy-the hereditarily increased ability to increase IgE formation.

CONCLUSION

Promotion of IgE sensitisation in humans and in animals may serve for hazard identification of adjuvant effects. Risk assessment has been based mainly on epidemiological studies, which are sensitive to confounding factors. This highlights the need to develop appropriate animal models for risk assessment.

[Specific immunotherapy in inhalative allergy to rat epithelium]

BACKGROUND

The only causal treatment that can be offered to allergic patients apart from allergen avoidance is specific immunotherapy. Its efficacy depends on the specific allergen the patient is allergic to, the quality of the extract, the total amount of allergen administered to the patient and the administration schedule.

METHODS AND PATIENT

Our patient suffered from inhalative allergy to rat epithelium with severe rhinoconjunctivitis and bronchial asthma. She regularly worked with laboratory rats as a biologist. A job-shift was impossible for the patient, and so was allergen avoidance. We therefore decided to treat the patient with specific immunotherapy. Treatment was performed as in-patient procedure with Rush-Immunotherapy in dosage increase phase. Maintenance injections were administered as out-patient.

RESULTS

As early as some months after induction of the therapy, the patient felt subjective symptom relief, blood samples taken revealed decrease of total IgE and specific IgE towards rat epithelium. Therapy was continued for 18 months, specific IgE against rat epithelium could not be detected any more. The patient does not claim any allergy symptoms when working in the rat laboratory any more.

CONCLUSIONS

Even in unusual allergies, specific immunotherapy can be indicated. In our patient, specific immunotherapy to rat epithelium lead to complete symptom relief and enabled the patient to practise her profession without restraints.

Exposure to bioaerosols: allergic reactions and respiratory function in Polish hop growers

BACKGROUND

The aim of the study was to assess the prevalence of work-related symptoms in hop growers and their relation to bioaerosols exposure. The study group comprised 69 hop growers and 58 office workers as controls. The examination included: physician-administrated questionnaire, PEF measurements, skin prick test, agar-gel precipitation test, and migration inhibition test. Microbiological air sampling was performed on all farms.

RESULTS

The concentrations of total airborne microflora ranged from 2.08 to 129.6 x 10(3) CFU/m3. Airborne endotoxin and dust concentrations ranged from 26 to 6250 ng/m3 and 0.2-31.7 mg/m3, respectively. Altogether 52.2% of farmers complained of work-related symptoms. Positive skin reactions to microbial allergens were significantly more frequent in a group of hop growers with work-related respiratory symptoms compared to the rest of the farmers (18% vs 2%, P <0.05). Positive reactions in agar-gel precipitation test and in the leukocyte migration inhibition test were not correlated with the occurrence of work-related symptoms. The mean daily PEF values in farmers were lower compared to controls (469.7 +/- 127.5 vs 562.9 +/- 123.8; P <0.001). PEF (amp%mean) was higher in farmers compared to controls (9.3% vs 8.1%; P <0.05).

CONCLUSION

Despite relatively lower exposure to bioaerosols, compared to farmers in other branches of agriculture, over 50% of hop growers complained of work-related symptoms. This may be partly due to the effects of microbial allergens and toxins and partly to the irritant or allergic properties of hop plant itself.

Mouse allergen exposure and immunologic responses: IgE-mediated mouse sensitization and mouse specific IgG and IgG4 levels

BACKGROUND

Although there is evidence that contact with mice is associated with IgE-mediated mouse sensitization and mouse specific antibody responses, the exposure-response relationships remain unclear.

OBJECTIVE

To determine whether IgE-mediated mouse sensitization and mouse specific IgG (mIgG) and mIgG4 levels increase with increasing Mus m 1 exposure.

METHODS

One hundred fifty-one workers at a mouse research and production facility were studied. Exposure assignments were made by linking participants to airborne Mus m 1 concentrations in their respective work areas. Cumulative exposure was estimated by multiplying airborne Mus m 1 concentration by duration of employment. Serum mIgG and mIgG4 levels were quantified by antigen-binding assays, and IgE-mediated mouse sensitization was evaluated by skin prick testing (SPT).

RESULTS

Prevalence rates of mouse SPT sensitivity and of high levels of mIgG and mIgG4 were increasingly higher by quintiles of increasing cumulative exposure (P < .01 for SPT, mIgG, and mIgG4). After adjusting for age, sex, and atopy, the log odds ratio (OR) of having positive mouse SPT results was linearly related to cumulative exposure (r2 = 0.87), as was the log OR of having a high mIgG level (r2 = 0.86). Quintile of cumulative exposure was an independent predictor of both SPT sensitivity (OR, 1.7; 95% confidence interval, 1.2-2.5) and a high mIgG level (OR, 1.7; 95% confidence interval, 1.2-2.4).

CONCLUSIONS

IgE-mediated mouse sensitization and mIgG and mIgG4 levels were related to cumulative exposure in a dose-dependent manner. Thus, strategies to prevent allergy to mice should remain focused on reducing mouse allergen exposure.

Immunological biomarkers in salt miners exposed to salt dust, diesel exhaust and nitrogen oxides

OBJECTIVES

Air pollutants can affect lung function and also the immune system. In a study about lung function of salt miners in relation to the complex exposure in a salt mine, we also analysed selected immunological parameters and inflammation markers in the blood of miners. Effect of salt dust, diesel exhaust, nitrogen oxides (NOx) and smoking on the biomarkers was analysed.

METHODS

Blood was drawn from 286 salt miners, and the soluble intercellular adhesion molecule-1 (s-ICAM), monocyte chemotactic protein (MCP-1) and clara cell protein (CC16) were analysed by an immunoassay, blood profile was done and lymphocyte subpopulations (CD3, CD3/CD4, CD3/CD8, CD19, NK-cells, CD3/HLA-DR) were determined by flow cytometry. Salt dust was measured by two-step gravimetry (personal sampling). Diesel exhaust was measured as elemental carbon concentration by coulometry. NOx were determined by an electrochemical cell method. Differences between non-smokers, former smokers and active smokers were analysed by analysis of variance. Linear regression analysis to describe exposure-response relationships was done with regard to confounding factors [smoking, inflammatory diseases, time of blood drawing, respiratory infection and body-mass index (BMI)].

RESULTS

Significant differences between non-smokers and active smokers were found for most of the leukocyte types (e.g. granulocytes P = 0.000, lymphocytes P = 0.002, T-cells P = 0.033) and for some soluble parameters (ICAM P = 0.000, IgM P = 0.007, IgE P = 0.035). Increasing numbers of total lymphocytes, T-cells and HLA-DR positive T-cells in relation to exposure were found by linear regression analysis (e.g. for inhalable dust:total lymphocytes P = 0.011, T-cells P = 0.061, HLA-DR positive T-cells P = 0.007). CONCLUSION. Comparison of immunological markers in non-smokers and active smokers confirms leukocytosis and inflammation following tobacco consumption. The combined exposure of salt dust, diesel exhaust and NOx seems to influence the immune system. Together, the results suggest that the analysis of leukocytes and their subsets can complete other investigations (lung function, questionnaire) to monitor exposure-response relationships in occupational studies investigating the effect of inhaled substances. Longitudinal studies will be necessary to determine the predictive value of the immunological changes.

[Allergenic and immunogenic properties of industrial dust of the cotton factory]

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

Occupational asthma due to exposure to iroko wood dust

BACKGROUND

Occupational asthma (OA) from iroko wood has been reported primarily in case reports.

OBJECTIVE

To improve understanding of the pathogenesis of OA induced by iroko wood dust.

METHODS

Three groups of woodworkers were included in this study: 9 workers who had clinically proven OA from iroko; 10 asymptomatic woodworkers; and 10 woodworkers with asthma. All patients underwent the following tests: a skin test with an iroko aqueous extract, specific IgE determination, and an iroko bronchial provocation test (IBPT). An eosinophil count was determined before and after the IBPT, and a methacholine inhalation test was performed after avoidance of exposure to iroko. Patients were asked to monitor their peak expiratory flow rates during a week at work followed by a week's vacation.

RESULTS

In all patients with a personal history predictive of OA from iroko, a reduction of the peak expiratory flow rate and positivity to the IBPT while working with iroko were present. The latter test result showed a dual response, with a decrease in forced expiratory volume in 1 second from 25% to 32% at 10 minutes and a further decrease from 35% to 43% at 8 hours; at 24 hours, the eosinophil count was higher (P = .046). In 4 patients, the intradermal test results with iroko extract were positive, whereas the skin prick test result and the specific IgE determination were negative in all patients. The methacholine test result was also positive. In the control groups, all the test results with iroko extract were negative.

CONCLUSIONS

Our data suggest that OA due to iroko wood may be induced by immunologic mechanisms other than IgE-mediated immediate hypersensitivity reactions.

Airborne endotoxin predicts symptoms in non-mouse-sensitized technicians and research scientists exposed to laboratory mice

Research scientists, laboratory technicians, and animal handlers who work with animals frequently report respiratory and skin symptoms from exposure to laboratory animals (LA). However, on the basis of prick skin tests or RASTs, only half are sensitized to LA. We hypothesized that aerosolized endotoxin from mouse work is responsible for symptoms in nonsensitized workers. We performed a cross-sectional study of 269/310 (87%) workers at a research institution. Subjects completed a questionnaire and underwent prick skin tests (n = 254) or RASTs (n = 16) for environmental and LA allergens. We measured airborne mouse allergen and endotoxin in the animal facility and in research laboratories. Of 212 workers not sensitized to mice, 34 (16%) reported symptoms compared with 26 (46%) of mouse-sensitized workers (p < 0.001). Symptomatic workers were more likely to be atopic, regardless of mouse sensitization status. Symptomatic non-mouse-sensitized workers spent more time performing animal experiments in the animal facility (p = 0.0001) and in their own laboratories (p < 0.0001) and had higher daily endotoxin exposure (p = 0.008) compared with asymptomatic coworkers. In a multivariate model, daily endotoxin exposure most strongly predicted symptoms to mice in non-mouse-sensitized workers (odds ratio = 30.8, p = 0.003). We conclude that airborne endotoxin is associated with respiratory symptoms to mice in non-mouse-sensitized scientists and technicians.

Chemical allergy: considerations for the practical application of cytokine profiling

Chemical respiratory allergy is an important occupational health problem, but there are currently available no validated methods for hazard identification. This is due in part to the fact that the relevant cellular and molecular mechanisms of sensitization of the respiratory tract have been unclear, with particular controversy regarding the role of IgE. There is now increasing evidence that respiratory sensitization is associated with the preferential activation of type 2 T lymphocytes and the expression of type 2 cytokines interleukin (IL)-4, IL-5, IL-10, and IL-13. Type 2 cell products favor immediate type hypersensitivity reactions, serving as growth and differentiation factors for mast cells and eosinophils, the cellular effectors of the clinical manifestations of the allergic responses, and promoting IgE antibody production. There has been considerable interest in the application of cytokine profiling for the characterization of chemical allergens, with cytokine phenotypes analyzed in freshly isolated tissue, or following culture in the presence or absence of mitogen at the level of protein secretion or mRNA expression. Experience to date suggests that the measurement of induced cytokine secretion profiles shows promise for the hazard identification and characterization of chemical respiratory allergens. The purpose of this brief review article is to consider the approaches available and to highlight key procedural issues.

Advances in molecular immunotoxicology of occupational asthma induced by low molecular weight chemicals

The paper reviews the literature reports on low molecular weight (LMW) sensitizers that are commonly encountered in the work environment as well as on the major mechanisms responsible for their effect on the immune cells of the respiratory tract. Current studies have focused on: LMW-antigens; the role of airway epithelial and dendritic cells (DCs); activation of naive helper T (Th) cells by DCs; naive B cell-effector Th2 cell interactions; and activation of mast cells by LMW asthmogens. A better understanding of the pathogenesis of occupational asthma due to LMW asthmogens should facilitate the development of better diagnostics and the improvement of strategies for disease surveillance and intervention.

Cotton fluffs as latex allergen carriers in a glove factory

BACKGROUND

Latex allergens released from gloves and bound to airborne cornstarch powder have been shown to cause respiratory allergy in health care workers.

OBJECTIVE

Cornstarch from powdered latex gloves is a well-known carrier of airborne allergens. It should be investigated whether cotton fluffs used to lubricate household and industrial gloves also function as airborne carriers for latex allergens.

METHODS

Latex gloves, cotton fluffs with or without latex glove contact, dipping water from the glove cooling tank, a dust sample from the floor, and 10 samples from area dust samplers were analyzed for their allergen content by using a CAP inhibition method. Furthermore, 84% (119/142) of the working group participated in a cross-sectional study involving a questionnaire and measurement of latex-specific IgE by means of CAP inhibition.

RESULTS

Latex gloves, area dust samples from latex glove production sites, and the floor dust sample contained high concentrations of latex allergens. Cotton fluffs were free of allergens before being in contact with gloves but showed considerable allergen concentrations after their removal from gloves. The dipping water of the cooling tank also contained latex allergens. Of the examined employees, 12.6% had IgE-mediated sensitization, and a third of the sensitized subjects (ie, 4% of the total group) reported work-related hypersensitivity reactions.

CONCLUSIONS

Cotton fluffs bind latex allergens and behave like cornstarch as airborne allergen carriers causing conjunctivitis and allergic respiratory disorders.

Diisocyanate-exposed auto body shop workers: a one-year follow-up

BACKGROUND

Diisocyanates currently are the most commonly identified cause of occupational asthma in industrialized countries. Auto body shops, a common hexamethylene diisocyanate (HDI) exposure setting, are difficult to study due to their small size and episodic exposures.

OBJECTIVES

A 1-year follow-up was undertaken as an adjunct to the cross-sectional SPRAY study (Survey of Painters & Repairers of Auto bodies by Yale) to investigate the effects of HDI on auto body shop workers over time and whether or not the healthy worker effect may exist in this industry.

METHODS AND RESULTS

Forty-eight workers from seven shops were re-contacted. Thirty-four subjects who stayed at the same shop and 11 who left their original shop participated. No statistically significant changes in physiology, symptoms, and immunologic responses from baseline to follow-up were noted. However, significant differences between those who left the shops and those who stayed were noted. Those who left were younger, less experienced in the industry, and more likely to have a history of asthma (23 vs. 3%; P < 0.05), bronchial hyper-responsiveness (23 vs. 9%), HDI-specific IgG (64 vs. 29%; P < 0.05), and HDI-specific proliferation (S.I. 2.0 vs. 1.3; P < 0.05).

CONCLUSIONS

The differences in workers who stayed at their shop compared to those who left, combined with the low asthma prevalence and high job turnover rate, all suggest that a healthy worker effect may exist in the auto body industry, and may in part account for the low prevalence of asthma noted in SPRAY and other cross-sectional studies of diisocyante workers.

Neopterin as a marker of immunostimulation: an investigation in anaesthetic workplaces

Personnel working in operating theatres and recovery rooms are exposed to a variety of noxious substances. The results of studies of the effects of occupational exposure on immune parameters are conflicting. Neopterin is an acknowledged marker of immunostimulation. Urinary neopterin levels of 58 anaesthetists and anaesthetic nurses were measured over a 3-week period. Neopterin analyses were performed using high performance liquid chromatography. Neopterin levels were within the normal range for all subjects. Younger subjects (aged < or = 35 years) had significantly higher urinary neopterin concentrations than older subjects (aged > 35 years). The present study is the first to investigate the influence of anaesthetic exposure on neopterin levels. No evidence of immunostimulation was found.

Allergic and latex-specific sensitization: route, frequency, and amount of exposure that are required to initiate IgE production

Quantitative data that documents human exposure-response relationships for IgE sensitization to allergens are limited. Although seemingly straightforward, documentation of exposure-response relationships can be difficult. Issues that are related to study design, allergen standardization, exposure assessment, and evaluation for sensitization can impact greatly on study results. Despite these issues, exposure-response relationships for sensitization to protein allergens have been documented in several occupational groups, which include enzyme-detergent workers, bakers, and laboratory animal workers. In general, atopy acts as an effect modifier in these settings, steepening the exposure-response relationship. Several studies suggest that the greatest risk for sensitization is within the first several years of exposure. For 1 allergen, the protease subtilisin, a short-term exposure limit of 60 ng/m(3) has been recommended by the American Council of Governmental Industrial Hygienists. With regard to natural rubber latex, exposure-related factors such as number of operations have been shown to be risk factors for sensitization of children with spina bifida. By contrast, fewer studies show exposure-response relationships for IgE sensitization of health care workers to natural rubber latex, and the area remains controversial. However, a recent cohort study that evaluated incident sensitization in dental hygiene students suggests strongly that, with sufficient exposure, employment in health care can lead to an increased risk of IgE sensitization to natural rubber latex.

Effect of respiratory protective devices on development of antibody and occupational asthma to an acid anhydride

STUDY OBJECTIVES

To determine whether the use of respiratory protective equipment would reduce the incidence of occupational asthma due to exposure to hexahydrophthalic anhydride (HHPA).

DESIGN

Prospective cohort study.

SETTING

A facility that makes an epoxy resin product requiring HHPA for its manufacture.

PARTICIPANTS

Sixty-six individuals newly hired at a facility that makes an epoxy resin product requiring HHPA for its manufacture.

INTERVENTION

Employees who wished to use respiratory protective equipment could choose from three types of masks: dust mask, half-face organic vapor respirator, or full-face organic vapor respirator.

MEASUREMENTS

Workers were evaluated annually for development of positive antibody to HHPA and occupational, immunologic respiratory disease, including occupational asthma.

RESULTS

With use of respiratory protective equipment, the rate of developing an occupational immunologic respiratory disease was reduced from approximately 10 to 2% per year. Occupational asthma developed in only three individuals, and they were all in the higher exposure category. Statistically, one respirator was not superior to the others.

CONCLUSION

Respiratory protective equipment can reduce the incidence of occupational immunologic respiratory disease, including occupational asthma, in employees exposed to HHPA.

Prevalence of occupational allergy to bell pepper pollen in greenhouses in the Netherlands

BACKGROUND

An increasing number of allergic complaints appear to have occurred among bell pepper greenhouse employees.

OBJECTIVE

The aim of this study was to estimate the prevalence of work-related allergic symptoms and the prevalence of sensitization to specific occupational allergens and its determinants.

METHODS

We studied 472 employees who were invited to answer an extensive questionnaire and to be tested on location with inhalant allergens and home-made extracts of the bell pepper plant. In addition, peak expiratory flow monitoring and RASTs were performed.

RESULTS

Work-related symptoms were reported in 53.8% of all cases. Sensitization to the bell pepper plant was found in 35.4%. Positive reactions to leaf, stem and/or juice, however, were associated in nearly 90% with sensitization to pollen, which appeared to be most important allergen of the plant. Sensitization to the bell pepper plant and inhalant atopy were considered the most important risk factors for the occurrence of work-related symptoms of the upper airways (PRR 2.63, CI 2.11-3.25 and PRR 2.25, CI 1.82-2.79) as well as of the lower airways (PRR 4.08, CI 2.38-7.00 and PRR 3.16, CI 1.87-5.33).

CONCLUSION

There is a surprisingly high prevalence of work-related respiratory symptoms (53.8%) in bell pepper horticulture. In two-thirds of the employees, symptoms at work were associated with an IgE-mediated allergy due to the high and chronic exposure to bell pepper pollen. Complaints at work without specific sensitization to bell pepper pollen can be caused by non-specific hyper-reactivity or atopy to other occupational allergens. The extent of this occupational allergy has important consequences for the health care of this large, still growing occupational group.

Induced changes in total serum IgE concentration in the Brown Norway rat: potential for identification of chemical respiratory allergens

A variety of chemicals can cause sensitization of the respiratory tract and occupational asthma that may be associated with IgE antibody production. Topical exposure to chemical respiratory allergens such as trimellitic anhydride (TMA) has been shown previously to induce increases in the total serum concentration of IgE in BALB/c strain mice. Contact allergens such as 2,4-dinitrochlorobenzene (DNCB), which apparently lack respiratory sensitizing potential, fail to provoke similar changes. However, it became apparent with time that there was some inter-animal variation in constitutive and inducible IgE levels. We have now examined the influence of topical exposure to TMA and DNCB on serum IgE levels in the Brown Norway (BN) rat. Such animals can be bled serially and thus it is possible to perform longitudinal analyses of changes in serum IgE concentration. The kinetics of IgE responses therefore can be followed on an individual animal basis, allowing discrimination between transient and sustained increases in serum IgE concentration. Rats (n = 5) were exposed on shaved flanks to 50% TMA, to 1% DNCB (concentrations that elicit comparable immune activation with respect to draining lymph node cellularity and proliferation) or to vehicle alone. Total IgE was measured by enzyme-linked immunosorbent assay in serum samples taken prior to and 14-42 days following initial exposure. Those animals having high pre-existing IgE levels (>1.0 microg ml(-1)) were excluded from subsequent analyses. The levels of serum IgE in the majority of rats exposed to DNCB or vehicle alone remained relatively stable throughout the duration of all the experiments conducted, although some animals displayed transient increases in serum IgE. Only TMA treatment was associated with a significant and sustained increase in the level of serum IgE in the majority of experiments. The elevated concentrations of IgE induced by topical exposure to TMA are persistent, the results reported here demonstrating that induced changes in IgE are maximal or near maximal at approximately 35 days, with a significant increase in IgE demonstrable for at least 42 days following the initiation of exposure. Interestingly, although TMA and DNCB at the test concentrations used were found to be of comparable overall immunogenicity with regard to lymph node activation and the induction of lymph node cell proliferation, there were apparent differences in humoral immune responses. Thus, not only did exposure to TMA stimulate increases in total serum IgE concentration and the production of specific IgE antibody, but also a more vigorous IgG antibody response was provoked by TMA compared with DNCB. These data suggest that the measurement of induced changes in serum IgE concentration in the BN strain of rat is able to differentiate between different classes of chemical allergen. Given the inter-animal variation in IgE production, it would be prudent to incorporate a concurrent assessment of responses induced by treatment with TMA as a positive control against which to assess the activity of other test materials.

Occupational asthma caused by grass pea used in the industrial processing of parquet

BACKGROUND

although grass pea belongs to the leguminoseae family, allergic reactions to its flour have rarely been described. Clinical and immunological studies were performed to confirm a type I hypersensitivity mechanism in a case of occupational asthma to grass pea flour exposure, used in the industrial processing of parquet.

METHODS

occupational asthma was diagnosed according to patient history, PEFR monitoring and a specific bronchial challenge test. Skin prick test with an aqueous grass pea flour extract, specific IgE determinations (CAP assay) and IgE immunoblot tests were performed.

RESULTS

skin prick test with the extract showed a positive immediate response, and negative response in controls. Specific IgE to grass pea was positive (9.57 KU/l). Immunoblotting demonstrated the presence of specific serum IgE that recognized 3 proteins in the extract (MW 46, 32 and 28 kDa). PEFR monitoring showed positive results. Bronchial challenge test with the extract elicited an isolated immediate response.

CONCLUSIONS

as far as we know this is the first time that IgE mediated occupational asthma caused by grass pea is reported and it is also the first time that its allergens are characterized. Grass pea flour might constitute a relevant occupational allergen in this unreported source of exposure in parquet manufacturers.

Subclinical immunologic and physiologic responses in hexamethylene diisocyanate-exposed auto body shop workers

BACKGROUND

Diisocyanates are potent sensitizing agents and currently the most commonly identified cause of occupational asthma in industrialized countries. However, diisocyanate asthma is difficult to diagnose and exposure and host risk factors are unclear. Auto body shops, one of the most common hexamethylene diisocyanate (HDI) exposure settings, are particularly difficult to study due to their small size and episodic exposures. Surveillance studies of such workers are limited.

OBJECTIVES

We have initiated a cross-sectional field epidemiologic study, Survey of Painters and Repairers of Auto bodies by Yale (SPRAY), to characterize the effects of diisocyanate exposures on actively employed auto body shop workers. Methods and Results We present here questionnaire, physiologic, immunologic, and exposure data on 75 subjects enrolled in the study. No overt cases of clinically apparent diisocyanate asthma were identified based on spirometry, methacholine challenge, peak flows, and symptoms. HDI-specific lymphocyte proliferation was present in 30% of HDI-exposed workers and HDI-specific IgG in 34% of HDI-exposed workers, but they were not associated. HDI-specific IgE was detected in two workers. HDI-specific lymphocyte proliferation, increased methacholine responsiveness, and symptoms of chest tightness and shortness of breath were more common in the most heavily HDI-exposed workers, the painters. More long-term follow-up of this cohort should clarify the significance of these HDI-specific immunologic responses, physiologic changes, and symptoms.

CONCLUSIONS

These findings demonstrate the presence of HDI-specific immune responses in a large proportion of healthy HDI-exposed workers.

Response of sawmill workers to work-related airborne allergens

The aim of this work was to determine the reactivity of sawmill workers to biological allergens associated with wood dust. Allergological examinations by skin and precipitin tests were performed in 43 workers employed in a sawmill processing coniferous wood (pine), in 90 workers employed in two sawmills processing deciduous wood (oak), and in 32 healthy urban dwellers not exposed to organic dusts (referents). The skin test was performed by the intradermal method with the saline extracts of wood dust and of the cultures of three microbial species (Rahnella sp., Brevibacterium linens and Penicillium citrinum) isolated from the air polluted with wood dust. Sawdust from pine was used for testing of the pine processing workers and referents while sawdust from oak was used for testing of the oak processing workers. Skin reactions were recorded after 20 minutes, 8 hours and 24 hours. The agar-gel test for the presence of precipitins in serum was performed with the extract of pine wood dust and extracts of 17 microbial isolates. The workers processing pine showed a very high frequency of positive skin reactions to the extract of wood dust at all time intervals, significantly greater compared to the workers processing oak and referents (p < 0.001). The early skin reactions to the extracts of dust-borne bacteria and fungi were very common among sawmills workers and showed a significant relationship with the degree of exposure. The frequency of reactions to Gram-negative bacterium Rahnella sp. was significantly greater in the pine processing workers than in the oak processing workers and referents (p < 0.001). By contrast, the oak processing workers reacted significantly more frequently to Penicillium citrinum, compared to the pine processing workers and referents (p < 0.01). These results conform to the prior study of airborne microflora in which the dominancy of Gram-negative bacteria was stated in the pine processing sawmill while mould fungi were most common in the oak processing sawmills. The antibody response of sawmill workers to work-related antigens was much weaker compared to skin reactions. As many as 41 sawmill workers reported the occurrence of work-related symptoms. A significant relationship was found between the occurrence of symptoms and frequency of allergic reactions, but only with a limited number of antigens. The obtained results suggest that early allergic reactions to coniferous wood and to microorganisms associated with wood dust are common among sawmill workers, posing a potential risk of work-related disease in this occupational group.

Passive dispersion of latex aeroallergen in a healthcare facility

BACKGROUND

Prompted by worsening asthma in a dental assistant with latex allergy and occupational asthma while under personal latex precautions, we confirmed continuing latex aeroallergen exposure.

OBJECTIVES

To determine the source of latex aeroallergen and ascertain the effects of site-wide substitution of nonpowdered low allergen latex glove in a health care site.

METHODS

Using a volumetric sampler, baseline latex aeroallergen levels were measured in rooms where she worked and nearby rooms, as well as shared X-ray, laboratory, and waiting rooms. Allergen levels were measured in upholstery fabric samples, ventilation duct dust, and latex gloves. Alterations in aeroallergen levels following change of glove types were prospectively determined.

RESULTS

Baseline latex aeroallergen levels ranged from 6 to 25 ng/m3 in the patient's work areas and in other rooms from 29 to 90 ng/m3 during work hours. Latex antigen was found in three brands of powdered latex gloves (chi = 1,156 microg/g) used in the nearby opertories and the hygiene room, and in upholstery fabric, carpet dust, but not ventilation duct dust. In the absence of any other control measures, airborne latex became undetectable (<5 ng/m3) with exclusive use of nonpowdered latex gloves.

DISCUSSION

Latex aeroallergen is primarily generated by active glove use; carpeting and fabric upholstery can serve as important aeroallergen repositories. Site-wide substitution of nonpowdered latex gloves eliminates detectable latex aeroallergen.

Exposure to formaldehyde and phenol during an anatomy dissecting course: sensitizing potency of formaldehyde in medical students

BACKGROUND

The sensitizing potency of formaldehyde and phenol during anatomy dissecting was investigated. The objective was to determine whether exposure induces specific IgE or IgG against formaldehyde-albumin or phenol-albumin.

METHODS

In 27 medical students, specific IgE against formaldehyde-albumin by RAST plus ELISA and specific IgE against phenol-albumin by ELISA were assessed. In addition, specific IgG against formaldehyde-albumin was assessed in 23 students. Symptoms before and during dissecting were assessed, and indoor formaldehyde and phenol were measured.

RESULTS

Mean indoor formaldehyde was 0.265 +/- 0.07 mg/m3, and mean indoor phenol was 4.65 +/- 2.96 mg/m3. Specific IgE/IgG against formaldehyde-albumin was not found at the beginning. Four students developed specific IgE against formaldehyde-albumin (RAST classes of > or =2.0), and all four also had specific IgE in the ELISA, but IgG against formaldehyde-albumin was not found. Specific IgE against phenol-albumin was not seen. Itch and paresthesia of the hands (P<0.00001), dizziness (P<0.008), burning eyes (P<0.01), headache, sneezing, epistaxis, gingival bleeding, oral or pharyngeal itch, and shortness of breath were experienced.

CONCLUSIONS

Formaldehyde exposure during dissecting may induce specific IgE, but not IgG, against formaldehyde-albumin. Sensitization did not correlate with symptoms.