Occupational respiratory allergy to lettuce in lettuce farmers

BACKGROUND

Lettuce-associated respiratory allergy has never been reported before. The aim of this study was to clarify the clinical condition of lettuce-associated respiratory allergy and to identify the lettuce antigen which induces allergic symptoms.

METHODS

We distributed questionnaires to 1168 lettuce farmers and performed medical examinations in those who exhibited respiratory symptoms related to occupational exposure to lettuce. We analysed specific IgE-binding proteins in the sera of patients through immunoblotting analysis and determined molecular characterization of the IgE-binding bands using liquid chromatography-mass spectrometry.

RESULTS

A total of 932 farmers (80%) responded to the questionnaire. Of those, 7% exhibited lettuce-associated respiratory symptoms, during harvesting and packaging. Thirteen patients were diagnosed with allergy to lettuce and agreed to undergo further examinations. The percentage of activated basophils in these patients was significantly higher compared with that reported in negative controls (P < .05). Lettuce-specific IgE (ImmunoCAP® ) and skin prick testing was positive in 46% and 62% of patients, respectively. Notably, occupational lettuce-allergic asthma was detected in one patient through specific bronchial provocation testing. The IgE-binding bands recognized in the sera of >50% of patients were identified as epidermis-specific secreted glycoprotein EP1-like (51 kDa).

CONCLUSION

The present analysis identified a novel lettuce allergen. This allergen may have clinically useful applications, such as specific IgE testing and allergen-specific immunotherapy.

High Prevalence of Pollinosis Symptoms among the Farmers Cultivating Japanese Pears

In a district of Japanese pear cultivators, a questionnaire survey and an IgE antibody survey were conducted on the pollinosis. A high prevalence of 36.3 % of the farmers complained of pollinosis symptoms. By the IgE antibody survey, the symptoms were found to be related to the airborne pollens in the orchard.

Effect of pesticide exposure on immunological, hematological and biochemical parameters in thai orchid farmers- a cross-sectional study

Various studies have found that many Thai orchid farmers used excessive amounts of pesticides without proper protective gear, but no toxicological study has been made. This cross-sectional study aimed to evaluate the immunological, hematological and biochemical statuses of these farmers. Sixty four orchid farmers and 60 controls were studied. Plasma cholinesterase activity, the percentage and absolute number of B lymphocytes (CD19+) were significantly lower in the farmers group (3966.32±1165.48 U/L, 11.61±4.09% and 312.26±164.83 cells/mm3, respectively) as compared to those of controls (5048.85±1139.40 U/L, 14.32±4.23%, 420.34±195.18 cells/mm3, respectively). There was a statistically significant higher level of serum IgE among the orchid farmers (0.031±0.011 mg/dL vs. 0.018±0.007 mg/dL) but not IgG, IgA and IgM, levels. Serum lysozyme level, lymphocyte proliferative responses to mitogens, hematological parameters and kidney function test, were not significantly different between the two groups. The liver function profiles showed significantly lower levels of albumin and serum protein in the farmer group. Thus frequent pesticide exposure resulted in subtle changes of some biological parameters. These changes, though may not be clinically significant, strongly indicated that caution in handing pesticides by these farmers is warranted.

Glyphosate-rich air samples induce IL-33, TSLP and generate IL-13 dependent airway inflammation

Several low weight molecules have often been implicated in the induction of occupational asthma. Glyphosate, a small molecule herbicide, is widely used in the world. There is a controversy regarding a role of glyphosate in developing asthma and rhinitis among farmers, the mechanism of which is unexplored. The aim of this study was to explore the mechanisms of glyphosate induced pulmonary pathology by utilizing murine models and real environmental samples. C57BL/6, TLR4-/-, and IL-13-/- mice inhaled extracts of glyphosate-rich air samples collected on farms during spraying of herbicides or inhaled different doses of glyphosate and ovalbumin. The cellular response, humoral response, and lung function of exposed mice were evaluated. Exposure to glyphosate-rich air samples as well as glyphosate alone to the lungs increased: eosinophil and neutrophil counts, mast cell degranulation, and production of IL-33, TSLP, IL-13, and IL-5. In contrast, in vivo systemic IL-4 production was not increased. Co-administration of ovalbumin with glyphosate did not substantially change the inflammatory immune response. However, IL-13-deficiency resulted in diminished inflammatory response but did not have a significant effect on airway resistance upon methacholine challenge after 7 or 21 days of glyphosate exposure. Glyphosate-rich farm air samples as well as glyphosate alone were found to induce pulmonary IL-13-dependent inflammation and promote Th2 type cytokines, but not IL-4 for glyphosate alone. This study, for the first time, provides evidence for the mechanism of glyphosate-induced occupational lung disease.

Avian influenza H9N2 seroprevalence among poultry workers in Pune, India, 2010

Avian influenza (AI) H9N2 has been reported from poultry in India. A seroepidemiological study was undertaken among poultry workers to understand the prevalence of antibodies against AI H9N2 in Pune, Maharashtra, India. A total of 338 poultry workers were sampled. Serum samples were tested for presence of antibodies against AI H9N2 virus by hemagglutination inhibition (HI) and microneutralization (MN) assays. A total of 249 baseline sera from general population from Pune were tested for antibodies against AI H9N2 and were negative by HI assay using ≥40 cut-off antibody titre. Overall 21 subjects (21/338 = 6.2%) were positive for antibodies against AI H9N2 by either HI or MN assays using ≥40 cut-off antibody titre. A total of 4.7% and 3.8% poultry workers were positive for antibodies against AI H9N2 by HI and MN assay respectively using 40 as cut-off antibody titre. This is the first report of seroprevalence of antibodies against AI H9N2 among poultry workers in India.

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.

Frequency of seropositivity for Coxiella burnetii immunoglobulins in livestock and abattoir workers in Trinidad

Coxiella burnetii is a zoonotic, rickettsial pathogen which causes mild and severe diseases often referred to as Q-fever in humans, particularly those occupationally exposed. This study determined the seropositivity for Coxiella burnetii IgM immunoglobulins using the enzyme immunoassay (EIA) in livestock and abattoir workers in Trinidad and related to selected personal characteristics to seroprevalence. Overall, of the 455 humans whose serum samples were tested, 20 (4.4%) were seropositive for C. burnetii IgM immunoglobulin, comprising 13 (4.6%) out of 283 livestock workers, 4 (4.7%) out of 85 abattoir workers and 3 (3.4%) out of 87 office workers (P>0.05; Chi 2). The age, sex and race of workers were not significantly associated with the occurrence of acute Q-fever (P>0.05; Chi 2). This is considered the first documentation of Q-fever in the human population in Trinidad. It is difficult to assess the impact of the disease in the country since the disease is not routinely tested for in the local hospitals or diagnostic laboratories.

Occupational allergy to bell pepper pollen in greenhouses in the Netherlands, an 8-year follow-up study

BACKGROUND

Pollen from bell pepper plants cultivated in greenhouses are known to cause occupational allergic disease. A cross-sectional study among 472 bell pepper employees in 1999 estimated prevalences for sensitization to bell pepper pollen of 28% and for work-related allergic symptoms of 54%. There is scarce information on the incidence of work-related allergy and its risk factors. Aims of the present study were to estimate the cumulative incidence of work-related symptoms and sensitization to bell pepper pollen, and to determine risk factors for the onset of these symptoms and sensitization.

METHODS

Bell pepper employees who participated in a cross-sectional survey in 1999 were asked to take part in a follow-up study in 2007. Information on demographic characteristics, job characteristics and allergic symptoms was gathered by means of a questionnaire. Furthermore, skin tests were performed with a.o. bell pepper pollen.

RESULTS

In total, 280 of 472 employees were available for questionnaires and in 250 employees allergy tests were performed. During the 8-year follow-up, the cumulative incidence of sensitization to bell pepper pollen was 9% and of work-related rhinitis 19%. Atopy [odds ratio (OR) 5.60] and smoking (OR 3.53) were significantly associated with development of rhinitis. The cumulative incidence of work-related asthma symptoms was 8%. Again atopy (OR 5.03) and smoking (OR 11.85) were significant risk factors.

CONCLUSION

Cumulative incidences for sensitization to bell pepper pollen, work-related rhinitis and asthma symptoms were 9%, 19% and 8%, respectively. Atopy and smoking are risk factors for developing work-related symptoms among workers in bell pepper horticulture.

Usefulness of the QuantiFERON-TB-Gold in tube in a population at risk of bovine tubercular infection

The effectiveness of the QuantiFERON-TB-Gold in tube was compared with PPD to detect tuberculosis infection in the staff of cattle-farms, as a consequence of an outbreak of bovine tuberculosis in livestock. The data revealed the advantage of the immunological test for the specific detection of subjects infected by Mycobacterium tuberculosis complex.

[Hypersensitivity pneumonitis induced by Hypsizigus marumoreus]

We present the case of a 53-year-old woman who was employed at a mushroom (Pleurotus eryngii and Hypsizigus marumoreus) cultivation factory for 15 years. She was admitted to our hospital because of fever and dry cough. Chest radiography and CT scanning revealed diffuse ground glass opacity and centrilobular nodules in both lung fields. Serum KL-6 was elevated. In the bronchoalveolar lavage fluid, the CD4/CD8 ratio was reduced, and the lymphocyte fraction was very high. Transbronchial lung biopsy specimens showed lymphocyte alveolitis. After admission, the patient's symptoms improved rapidly without medication. Although these findings are compatible with hypersensitivity pneumonitis, it was difficult to identify a causative antigen. Serum antibody against Trichosporon was positive. A lymphocyte stimulation test of the peripheral blood was positive against extracts of P. eryngii and H. marumoreus. Furthermore, precipitins against the extracts of H. marumoreus were detected by a double immunodiffusion test. Therefore, we decided to conduct a challenge test using H. marumoreus. As an inhalation provocation test with H. marumoreus conducted in a sickroom caused the same clinical symptoms and signs as experienced in the workplace, we diagnosed hypersensitivity pneumonitis caused by H. marumoreus. A provocation test, in which antigen exposure is limited using a closed space, such as a sickroom, was simple, safe and effective for determining the antigen causing hypersensitivity pneumonitis.

Cord Blood-Derived Plasma Factor (CBPF) Potentiates the Low Cytokinetic and Immunokinetic Profile of Bone Marrow Cells in Pesticide Victims Suffering from Acquired Aplastic Anaemia (AAA): An in vitro Correlate

Cases of Acquired Aplastic Anaemia (AAA) in patients with a long history of pesticide exposure from agricultural fields have been investigated in our laboratory using an immunological approach. These patients showed moderate to severe degrees of bone marrow aplasia as a result of 9-12 years protracted exposure to pesticides which were mainly comprised of organophosphorous and organochloride compounds. The bone marrow aspirate culture was found to be severely deficient both in terms of differentiation and proliferation, and cell mediated immune function (CMI). We attempted ex vivo manipulation of the bone marrow population of patients in two different protocols: in one, stem cell factor (SCF), interleukin-3 (IL-3), and granulocyte-colony stimulating factor (G-CSF) were administered and, in the second set, cord blood-derived plasma factors (CBPF) were supplemented to evaluate the effects, if any. Simultaneously, two control groups including one for healthy normal control (N) and the second, for non-pesticide induced aplastic anaemia group of patients (NPAA) was also investigated for all the above parameters. Active colony formation and improved cellular immune activity (CMI) was observed more frequently in the CBPF treated group rather than that in the cytokine treated group. Surprisingly, administration of cytokines in the first set and CBPF in the second set triggered CD34 (+) cell generation as revealed through flow cytometric analysis (FACS). The effect was more pronounced in the second set. Investigations carried out with NPAA showed relatively insignificant effects with both cytokine and CBPF set up. The investigations indicated that AAA as induced by pesticides could be therapeutically manipulated by exogenous cytokines and growth factors and, more efficiently, by CBPF by way of immunopotentiation through microenvironmental supplementation.

Cathelicidin LL-37, granzymes, TGF-beta1 and cytokines levels in induced sputum from farmers with and without COPD

The cathelicidin LL-37 is an antimicrobial and lipopolysaccharide neutralizing peptide, possessing pro-inflammatory, tissue repair and remodeling activities. Recent reports indicate that the progression of COPD might be connected with increased levels of LL-37. The numerous experimental data show the potential role of LL-37 in the response to the exposure to organic dust (containing lipopolysaccharide and microorganisms) which is one of the major COPD causative factors. This work strives to further prove the role of LL-37 in the development of COPD. A cross-sectional study was conducted in 30 farmers in the early stages of COPD according to GOLD, 36 healthy farmers and 16 healthy urban dwellers. Collection of induced-sputum samples and lung function testing were conducted before and after work. The quantification of the LL-37 in sputum samples was performed by mass spectrometry and radioisotope techniques. Levels of granzymes A and B, IL-8, IFN-gamma and TGF-beta1 in sputum were measured by ELISA technique. Statistical analysis was conducted by Kruskal-Wallis and Mann-Whitney U tests. Significantly higher levels of LL-37 were observed in sputum samples from farmers with COPD compared to healthy individuals. The concentration of LL-37 in sputum from farmers was significantly higher compared to urban dwellers. The same was true for both granzymes A and B. The results of this study suggest that LL-37 and granzymes A and B may add to the development of COPD. The results suggest also their role in an organism's response to organic dust exposure.

Educational intervention in farmers with occupational asthma: long-term effect on exhaled nitric oxide

BACKGROUND

The fraction of exhaled nitric oxide (FE(NO)) has been found reduced 4 to 6 weeks after an educational intervention in farmers with occupational asthma.

OBJECTIVE

To reveal whether long-term changes in FE(NO) would still be detectable a year after the intervention.

METHODS

We evaluated airway inflammation and obstruction at baseline and after 1 year in animal farmers with occupational asthma (n = 43, 16 women, mean [SD] age, 46.5 [8.9] years) who participated in a 1-day educational program, and in a control group of farmers without intervention (n = 15, 3 women, mean age, 44.1 [10.7] years). FE(NO), spirometry results, and questionnaire data were compared between measurements and between the intervention and control group.

RESULTS

In the intervention group, geometric mean (SEM) FE(NO) decreased from 31.5 (1.1) to 25.0 (1.1) parts per billion (ppb) (P = .001), whereas in the control group there was a slight but not statistically significant increase from 27.2 (1.2) to 30.7 (1.2) ppb. Spirometric values remained unchanged in both groups.

CONCLUSIONS

We found that FE(NO) was still decreased 1 year after an educational intervention in farmers with occupational asthma. It would thus seem that FE(NO), a noninvasive marker of airway inflammation that can be easily assessed in occupational field work, may be suitable for the evaluation of both short-term and long-term effects of preventive measures in occupational asthma.

Risk of occupational allergy to stored grain arthropods and false pest-risk perception in Czech grain stores

Arthropods are a documented cause of occupational allergy in cereal stores. Since the current allergenic risk of various arthropods in grain stores is not known, we evaluated its extent using data from the Czech Republic (CZ). We surveyed 514 grain storage units for pest composition and density. Recalculating literature data we established 4 density dependent classes of pooled mite "allergy-risk level" (ARL) in stored grain: (i) safe-ARL: 0 mites.g(-1) grain, (ii) low-ARL: up to 1 mite.g(-1) grain, (iii) high-ARL: from 1 to 5 mites.g(-1) grain, (iv) danger-acute asthma-ARL: higher than 5 mites.g(-1) grain. Farmers (15) were questioned for pest taxon-related pesticide treatments. Mites constituted the largest group of collected pests (92%) followed by psocids (5%), beetles (3%) and moths (0%). 60% of mites belonged to known allergen producing species; the most abundant were Acarus siro, A. faris, Tyrophagus putrescentiae and Lepidoglyphus destructor. Grain samples belonged to the established ARL classes as follows: (i) safe-ARL: 37% (ii) low-ARL: 53%; (iii) high-ARL: 6%; (iv) danger-acute asthma-ARL: 4%. The enquiry among farmers revealed that almost no pesticides were targeted solely to control mites. This study suggests that mites represent, due to their allergenic potential, density and frequency, the most serious source of allergens in stored grain in CZ. However, the medical aspect of pest control--such as allergy avoidance strategy--is overlooked since grain feeding insects were mostly chemically controlled, regardless of their relatively low density and allergen production in comparison with mites.

Allergenic pollens and spores in the working environment of Japanese pear farmers

Occupational allergies such as pollinosis are reported in several agricultural works in Japan. Many pollens and spores were observed in Japanese pear orchard during the artificial pollination season. By the study on daily symptoms in an allergic farmer, we confirmed that the pollinosis symptoms were most common and most severe during the artificial pollination. These results suggest that the exposure to allergenic pollens and spores induces allergic symptoms. Thus, caution should be paid for the avoidance of the exposure to these allergenic pollens and spores to prevent the allergy.

Risk factors for allergy due to the two-spotted spider mite (Tetranychus urticae) among table grape farm workers

BACKGROUND

Recent studies have reported an increased prevalence of respiratory symptoms among farm workers. The aim of this study was to identify risk factors associated with spider mite allergy among table grape farm workers.

METHODS

A cross-sectional study of 207 workers in table grape farms was conducted. Skin prick tests used extracts of 8 common aeroallergens, grape mould (Botrytis cinerea) and Tetranychus urticae. Specific IgE to T. urticae was quantified using ImmunoCAP (Phadia). Erythrocyte cholinesterase levels were determined using the Test-mate ChE Cholinesterase Test System (model 460).

RESULTS

The average duration of employment of workers was 10 years and 12% were pesticide crop sprayers. Work-related wheeze (26%), ocular-nasal (24%) and urticaria/skin symptoms (14%) were more prevalent in the orchards. The prevalence of sensitization (skin prick test) was highest to T. urticae (22%) followed by house dust mite (16%), with 25% being atopic. The prevalence of allergy to T. urticae (skin reactivity and work-related symptoms) was 9.5%, with respiratory allergy (6%) more common than skin allergy (3%). Work-related ocular-nasal (OR = 4.9) and skin (OR = 3.7) symptoms were more commonly reported by pesticide crop sprayers. Workers with T. urticae-allergic rhino-conjunctivitis and probable asthma were more likely to be atopic, spray pesticides and have low (<30 U/g hemoglobin) erythrocyte cholinesterase levels.

CONCLUSIONS

This study demonstrated that spider mite, T. urticae, is an important outdoor allergen among table grape farm workers. The increased risk of spider mite allergy appears to be related to high pesticide exposure among crop sprayers.

An occupational respiratory allergy caused by Sinapis alba pollen in olive farmers

BACKGROUND

Sinapis alba (white mustard) is a entomophilic species included in the Brassicaceae family. To date it has not been related to allergic sensitization or clinical respiratory disease.

METHODS

Twelve olive orchard workers had a history of rhinitis and/or bronchial asthma that occurred during control weed management and/or harvest, from January to March. They underwent skin prick tests (SPT) with S. alba pollen extract and a standard battery of aeroallergens. Sinapis alba pollen extract was prepared for performing quantitative skin tests, enzyme allergosorbent test and nasal challenge test (NCT). A portable monitoring station and an urban volumetric Hirst-type spore trap were used for the aerobiological study.

RESULTS

Eleven patients suffered from rhinitis and bronchial asthma and one had only from rhinitis. All patients were sensitized to S. alba pollen extract, and they showed a positive NCT response. In the urban aerobiologic monitoring station the amount of S. alba pollen only exceptionally reached peaks of 21 grains/m(3), whereas in the work environment peaks of 1801 grains/m(3) were detected between 15 February and 7 April.

CONCLUSIONS

We demonstrate the existence of a new occupational allergen for olive farmers: S. alba pollen. We point out the importance of perform aerobiological sampling within the occupational environment for the detection and quantification of the allergenic source.

What characterizes house dust mite sensitive individuals in a house dust mite free community in Reykjavik, Iceland?

BACKGROUND

Previous studies show that 6-9% of young adults in Reykjavik are sensitised to the house dust mite (HDM) Dermatophagoides pteronyssinus (D. pteronyssinus). However, only negligible amounts of HDM and HDM allergens were detected in their homes. The study investigates what characterizes these individuals.

METHODS

We investigated all participants in the European Community Respiratory Health Surveys I and II (ECRHS I and II) with D. pteronyssinus specific IgE, in the years 1991-92. A grass positive but D. pteronyssinus negative control group was recruited from the same cohort. A detailed questionnaire was administered and the specific IgE (Pharmacia CAP system) against six D. pteronyssinus cross-reactive allergens was measured.

RESULTS

Of 601 ECRHS I participants with available IgE results, 88% returned for ECRHS II, 8.4 years later. Of 49 individuals with D. pteronyssinus specific IgE in ECRHS I, 24 had become negative in ECRHS II. Compared with controls, HDM sensitive subjects were more often men who had lived on farms or kept aquaria fish in childhood. Of those with specific IgE against D. pteronyssinus in ECRHS I and II, 75% had detectable IgE antibodies (>or=0.35 kU/l) to cross-reactive allergens compared with none in the control group (p<0.0001): Lepidoglyphus destructor (L. destructor) (67%), shrimp (58%), cockroach (33%), mosquito (17%), tropomyosin (17%) and blood worm (4%).

CONCLUSIONS

Icelanders with specific IgE to D. pteronyssinus are more often men who spent time on farms in childhood and today have high prevalence of IgE antibodies cross-reactive to D. pteronyssinus.

Respiratory allergy in agriculture

Allergic respiratory diseases in farmers may be caused by exposures to many organic substances. Potentially inhalable particulate material of biologic origin are referred to collectively as organic dust, whose composition includes also molds and other microorganisms. Organic dust may evoke immuno-allergic reactions and cause rhinitis, asthma and extrinsic allergic alveolitis. The agricultural work environment represents a risk factor for these diseases, whose occupational origins are often overlooked by clinicians. Prevalence studies of respiratory allergic diseases among agricultural workers are advocated for the development of prevention strategies.

Toxicity Study of the Volatile Constituents of Myoga Utilizing Acute Dermal Irritation Assays and the Guinea‐Pig Maximization Test

Myoga is a fragrant plant which is the special product of Japan and is cultivated throughout Japan. According to our earlier investigation (unpublished data) of myoga cultivators in Japan, 8 of 35 cultivators experienced contact dermatitis in the harvest season. The purpose of this study was to assess the allergenicity of myoga and its major volatile components. The volatile components of myoga were analyzed by gas chromatograph (GC). They included a-pinene, beta-pinene and R-(+)-limonene. We performed a toxicity study of each of the major fragrant components of myoga using acute dermal irritation assays and the Guinea-Pig Maximization test (GPMT) in order to probe the mechanism of allergic contact dermatitis. In acute dermal irritation assays, alpha-pinene, beta-pinene and limonene showed positive responses at concentrations of 4%; limonene oxide at 20% and myoga showed a positive response at concentrations of 100%. From the results of the GPMT, according to Kligman scores, limonene oxide was identified as an extreme skin sensitizer and myoga as a mild skin sensitizer. The results of the present study show that R-(+)-limonene is the most important allergen amongst the chemical components of myoga, and we consider it to be the reason why myoga cultivators experience allergic contact dermatitis.

Exercise-induced bronchoconstriction in textile and agricultural workers and in bakers

To assess the prevalence and the characteristics of exercise-induced bronchoconstriction (EIB) in subjects occupationally exposed to organic dusts we performed a cross-sectional study including 152 exposed subjects (67 textile workers, 42 agricultural workers, and 43 bakers) and 72 unexposed controls. Evaluation of exposed and unexposed subjects included a questionnaire, skin prick tests to common inhalant allergens, spirometry, and exercise challenge tests (ECT). The EIB prevalence found in textile workers was 8.9 %, in agricultural workers 7.1 %, in bakers 6.9 %, and in office workers 5.5 %. The highest bronchial reaction to exercise was found in ECT-positive agricultural workers (26.1+/-6.9), followed by textile workers (25.2+/-7.4), bakers (23.0+/-5.8), and office workers (21.8+/-4.4). EIB was significantly associated with atopy and positive family history of asthma in all exposed groups. EIB was significantly associated with smoking duration in textile workers (P=0.039) and agricultural workers (P=0.027). Bronchial reaction to exercise was significantly greater in smoking than in non-smoking textile (P=0.045) and agricultural workers (P=0.032). Our data suggest that the combination of daily smoking and workplace exposure to certain types of organic dusts could contribute to EIB development and severity.

Immunological exposures in Norwegian agriculture and pre-eclampsia

Immune system perturbations are involved in pre-eclampsia pathophysiology. We hypothesised that immunomodulating substances, such as mycotoxins, endotoxins or pesticides, affect pre-eclampsia risk. Associations between indicators of immunomodulating exposures in agriculture and pre-eclampsia are reported. In a Norwegian family cohort based on participants in agricultural censuses conducted by Statistics Norway 1969-89, 183 313 pregnancies to farmers were identified in the Medical Birth Registry of Norway. Cases notified as pre-eclampsia as well as pregnancies indicated by hypertension in combination with proteinuria were included. Data on farm production and meteorologically based fungal forecasts 1973-90 (a marker of temperate and humid climatic conditions known to favour fungal growth and mycotoxin formation in grain) were obtained and allocated to each farm. Pre-eclampsia prevalence rates were studied in strata of exposure indicators using Poisson regression models. Adjusted rate ratios (RR) and 95% confidence intervals [CI] were computed. We identified 4912 cases, equivalent to 26.8 pre-eclampsia cases per 1000 pregnancies [95% CI 26.1, 27.6]. Pre-eclampsia showed moderate associations with animal farming, RR 1.14, [95% CI 1.07, 1.22] and moderate negative associations with grain production, RR 0.93, [95% CI 0.86, 1.01], and two or more fungal forecasts appearing in any year 1973-90, RR 0.90 [95% CI 0.84, 0.97], using no years with two or more forecasts as reference. Exposure to immunomodulating substances as indicated by grain farming, animal farming and fungal warnings could possibly have moderate effects on pre-eclampsia risk, thus supporting the study hypothesis. The use of exposure indicators as surrogates for real exposures may introduce a non-differential misclassification of the exposure that would attenuate any true exposure-outcome association. The use of exposure proxies warrants that inferences from the study should be made with caution.

Pattern of sensitization to honeybee venom in beekeepers: a 5-year prospective study

Beekeepers are at increased risk for honeybee (Hb) venom allergy and they represent a unique population for Hymenoptera venom studies. The aim of this was to prospectively examine the pattern of Hb venom sensitization over a 5-year period in new beekeepers and define possible predisposing factors. Thirty-five beekeepers were tested every 6 months for 5 years with in vivo and in vitro methods to detect the possible development of sensitization to Hb and common wasp (Cw) venom. Inclusion criteria included the lack of previous beekeeping activity and absence of sensitization or reported reaction to Hymenoptera stings. Subjects with both in vivo and in vitro tests that were definitely positive or with one definitely positive and the other doubtful were considered sensitized. Ten of 35 new beekeepers (28.6%) and 3 of 36 controls (8.3%) developed sensitivity to Hb venom during the 5-year period. The risk ratio in incidence studies was calculated at 3.43 (SE of log risk ratio = 0.61; 95% CI of risk ratio = 1.03-11.42). All sensitized beekeepers were detected within the first 18 months of occupational exposure; 8 of 10 (80%) beekeepers were detected during the initial 12 months and the 2 remaining beekeepers were detected between 12 and 18 months. One of 35 (2.9%) beekeepers and 1 of 36 controls (2.8%) were sensitized to Cw venom. The number of stings per year and atopy had no effect on sensitization rate. Although predisposing factors to sensitization or anaphylaxis could not be identified, beekeepers developed sensitization to bee venom in <18 months.

Airways inflammation among workers in poultry houses

OBJECTIVES

Previous studies have demonstrated that persons working with poultry have an increased incidence of chest symptoms and decreased lung function. A study was undertaken to evaluate the usefulness of airway responsiveness measurements to diagnose the presence of airways inflammation and relate this to the workplace exposure.

METHODS

The group studied comprised of 42 non-smoking poultry workers and 40 controls not exposed to organic dusts. The presence of symptoms was evaluated using a standardized questionnaire for organic dust exposures. Airway responsiveness was measured using the methacholine challenge test. The concentrations of airborne endotoxin and (1-->3)-beta-D-glucan were measured.

RESULTS AND CONCLUSIONS

Exposure levels were in excess of those expected to cause effects in the airways. There was significantly higher airway responsiveness among the workers compared to controls (decrease 9.5 SD 7.5 vs 3.4, SD 3.3). Poultry workers had a higher prevalence of toxic pneumonitis, airways inflammation and chronic bronchitis compared to controls. Endotoxin levels in the poultry buildings exceeded those earlier suggested as the threshold value for airways inflammation.

[Occupational allergy caused by ornamental plants]

The problem of allergy to decorative plants is still poorly known. Reports on occupational allergy to flowers are scarce and usually concern gardeners, greenhouse workers and florists. The handling, smelling and caring of flowers may cause rhinoconjunctivitis, asthma, urticaria and also contact dermatitis. Plants of the Compositae family that includes many different species have been frequently described. Chrysanthemum flowers, the strongest sensitizer among ornamental Compositae plants, especially contribute to the development of contact dermatitis. Allergy to Liliaceae, mostly to tulips, hyacinths, lilies and crocuses has quite often been reported as well as sensitization to rose pollen in rose planters. Occupational sensitization to flowers of other families, among which spathe flowers, primulas, weeping fig or Stephanotis floribunda should be mentioned, is less frequent. Exposure to ornamental flowers is common in the general population. Persons occupationally involved in cultivation of flowers and who demonstrate allergic symptoms are often forced to change their jobs. Candidates to these occupations with diagnosed atopy should be informed about the risk of developing allergy to flowers, which could make them unable to perform the job.

[Comparison of two types of diagnostic test detecting antibodies against Borrelia burgdorferi: EIA based on one genospecies antigens and ELISA based on recombinant antigens]

The aim of the study was to compare the results of ELISA diagnostic kit detecting antibodies against B. burgdorferi based on combination of three genospecies recombinant and EIA kits based on one of three genospecies. Sera of 351 forest workers were evaluated with ELISA kit (Recombinant antigen, IgG). Seropositive samples were tested with EIA kits based on B. burgdorferi s.s., B. garinii, B. afzelii antigens. Diagnostic kits based on combination of antigens of three genospecies more often detect antibodies against B. burgdorferi and are more usefull as screening tests, in comparison with those based on one genospecies. Among diagnostic kits based on one genospecies, the most sesnitive in detection of antibodies against B. burgdorferi are those based on B. afzelii.

Hypersensitivity pneumonitis induced by spores of Penicillium citrinum in a worker cultivating Enoki mushroom

A 47-year-old Japanese woman was admitted to our hospital with a 2-week history of dry cough and shortness of breath. She had been engaged in Enoki mushroom production for 22 years. Chest X-ray and chest computed tomography (CT) scan showed bilateral fine-nodular shadows and ground glass opacity. Bronchoalveolar lavage fluid demonstrated an increase of total cell counts with predominant lymphocytosis. Pathological specimens obtained by video-assisted thoracoscopic surgery revealed alveolitis and noncaseating granuloma with giant cells. Lymphocyte stimulation test showed positive responses with Enoki mushroom, culture medium, and Penicillium citrinum. On double immunodiffusion test, a precipitation line was observed between patient's serum and Penicillium citrinum antigen. She was found to have hypersensitivity pneumonitis caused by Penicillium citrinum. This is the first report of mushroom worker's lung caused by Penicillium citrinum.

Effect of farming environment on sensitisation to allergens continues after childhood

AIMS

The farming environment in childhood has been reported to decrease the risk of sensitisation to allergens. The purpose of the present study was to explore whether later exposure to a farming environment also could affect this sensitisation.

METHODS

A population based sample of 202 women who did not live on a farm and 231 who did. The subjects filled in a questionnaire and underwent skin prick tests for several common and farming related allergens.

RESULTS

The prevalence of sensitisation to any of the allergens was similar in the two groups (37.1 v 34.6% (p = NS). However, compared with women who did not live on a farm, the women who lived on a dairy farm showed a low prevalence of sensitisation to pollens (4.4 v 17.3%, p = 0.01) and cats (3.5 v 10.4%, p = 0.047). The risk of sensitisation to pollens and pets was lowest among women with both a childhood and adulthood farming environment and was dose dependently associated with current contact with farm animals. However, this contact increased the risk of sensitisation to bovine dander.

CONCLUSION

The farming environment may reduce sensitisation to common allergens also after early childhood. However, it may also increase sensitisation to farm allergens.

Tumor necrosis factor-alpha hyper-responsiveness to endotoxin in whole blood is associated with chronic bronchitis in farmers

Many farmers experience chronic bronchitis, airflow obstruction, and asthma. It is thought that these respiratory problems may be related to workplace inhalation of organic dust containing endotoxin. The purpose of this study was to determine whether whole blood cytokine responsiveness to endotoxin is associated with airflow disorders (i.e., airflow obstruction, chronic bronchitis, and doctor-diagnosed asthma). Farmers (N = 95) were recruited from a rural cohort study and completed a respiratory symptom and history questionnaire, spirometry, and blood sampling. Blood was incubated 24 hours in the presence and absence of endotoxin and supernatants were analyzed for TNF-alpha, IL-1beta, IL-6, and IL-8. Hypo- or hyper-responsiveness to endotoxin was based on whether cytokine values were in the lower or upper 10% of the group range, respectively. A significant association existed between TNF-alpha hyper-responsiveness and chronic bronchitis. These results indicate that the whole blood cytokine assay may be useful to identify individual responsiveness to endotoxin, and may provide an additional diagnostic tool to evaluate persons potentially at risk for developing chronic bronchitis following exposure to organic dust in the workplace.

Activation of eosinophils by rice-husk dust exposure: a possible mechanism for the aggravation of asthma during rice harvest

Grain dust and other irritants affect the airway of allergic patients in rice-growing area during the harvest. The aim of this study was to elucidate the mechanism of airway hypersensitivity in rice-growing areas during the harvest. Firstly, the effect of rice-husk dust on eosinophil activation was studied. Secondary, the concentration of lipopolysaccharides (LPS), a potent activator of inflammatory cells, in rice-husk dust was measured. Since it is possible for LPS, a component of gram-negative bacterial cell wall, to adhere to the particle of smoke generated from rice-husk dust, LPS contained in the smoke was also measured. Furthermore, chemical irritants contained in the smoke generated from the rice-husk dust were analyzed. Microscopically, the dust contained fine thorns dropped off from the outer sheath of the rice, and irritated the skin, throat and eyes. The grain dust extract increased the expressions of eosinophil activation markers. These up-regulatory effects were largely dependent on LPS. The smoke contained LPS and several chemical irritants such as formaldehyde and acetaldehyde. Rice-husk dust and its smoke, hazardous air pollutants, probably play a major role in the aggravation of airway diseases in agricultural areas.

Respiratory allergy in agricultural workers: recent developments

PURPOSE OF REVIEW

To review recent evidence on the relationship between occupational exposure to allergens and asthmagens, and risk for developing allergy and asthma and the role of modifying factors in farmers and farm workers.

RECENT FINDINGS

Recent studies identified agents that have not been associated with allergy or asthma in farming populations before. The most intriguing findings, however, are those that suggest that the development of atopy and asthma might be influenced by exposure to pathogen associated molecular patterns (PAMPs), including endotoxin.

SUMMARY

The adverse and potentially protective effects of microbial exposures in the farm environment are discussed. Recent findings indicate that it is very likely that the protective effect of exposure to PAMPs such as endotoxin is not limited to childhood age. The protective effects that probably developed during childhood can still be observed at adult age. Furthermore, it even seems likely that exposures at adult age (in occupational environments), which stimulate the innate immune system, have an effect on allergy, independently of childhood exposure. It is hypothesized that reversal of atopy might occur as a result of high exposure to endotoxins and other PAMPs.

Allergen-specific sensitization in asthma and allergic diseases in children: the study on farmers' and non-farmers' children

BACKGROUND

Farmers' children are less frequently sensitized to common allergens than the non-farmers' children, but less is known about their sensitization to other allergens and its association with clinical diseases.

OBJECTIVE

To examine the association of farm environment with atopic sensitization, allergic diseases, expression of allergen-induced symptoms, and the importance of specific sensitization against 'common' (timothy, dog, cat, birch, Dermatophagoides pteronyssimus, mugwort) and 'other' (cockroach, horse, Lepidoglyphus destructor, cow) allergens for asthma and allergic diseases in children.

METHODS

A cross-sectional study including 344 farmers' and 366 non-farmers' children aged 6-13 years in eastern Finland, using a self-administered written questionnaire and skin prick tests against the above-mentioned allergens.

RESULTS

Farmers' children had less asthma and allergic diseases and were less often sensitized against common allergens than the non-farmers' children. However, little difference was observed in sensitization against the other allergens between the farmers' (17.2%) and non-farmers (14.5%) children [adjusted odds ratios (aOR) 1.11 (0.71-1.72)]. Being sensitized against only other allergens, without sensitization against common allergens, was unrelated to asthma or allergic diseases. Among the single allergens, sensitization against pets or pollen, or against horse or cow, had the strongest association with asthma, hayfever, and atopic eczema; no such association was seen in D. pteronyssimus, mugwort, cockroach, or L. destructor. Farmers' children had significantly less often symptoms of allergic rhinitis in contact with dog (aOR 0.32%, 95% confidence interval (CI) 0.15-0.67), cat (aOR 0.45, 0.22-0.88), or pollen (aOR 0.58%, 95% CI 0.37-0.90) than the non-farmers' children.

CONCLUSION

Farm environment reduces the occurrence of asthma, allergic diseases, and atopic sensitization in children, and also the occurrence of allergen-induced rhinitis. Remarkable differences were observed between single allergens in their association with allergic disease, stressing the importance of allergen selection when defining atopy in epidemiological studies.

Natural history of Hymenoptera venom allergy in Eastern Spain

INTRODUCTION

The natural history of stings, the clinical reaction of the patient and in vivo and in vitro tests are necessary parameters to assess before initiating Hymenoptera venom immunotherapy. In the decision to initiate immunotherapy with Hymenoptera venom, it is not usual to evaluate the natural history of the disease, which seems to be self-limiting and therefore of variable clinical significance.

OBJECTIVES

Our aim was to determine the natural history of Hymenoptera hypersensitivity over 4 consecutive years in a rural Mediterranean population.

METHODS

An epidemiological study of Hymenoptera sting reactions and possible sensitivity was carried out in 145 randomly selected subjects out of a rural Mediterranean population of 600. Seventy-two subjects, including those with a history of anaphylaxis, completed the 4-year study. The nature of their clinical reactions, age, sex, history of atopy, profession, family history of reactions to Hymenoptera insects, time elapsed since the last sting, number of stings and specific IgE and IgG were determined (the latter, to the three most important insects in the area: Apis mellifera, Polistes dominulus, and Vespula germanica).

RESULTS

Of the 72 subjects, four subjects had systemic reactions (SR), 23 had large local reaction (LLR) and all the others (117) was minor local reactions. None who had experienced an SR had a repeat SR when re-stung over the 4-year study. Of those with LLR, 12 subjects had the same type of reaction and 11 experienced more mild local reactions when re-stung. In the SR and local reaction groups, IgE to honey bee (Hb) increased significantly during the study period, whereas in those with only LLR, specific IgE to wasp (Polistes) decreased. Specific IgG to Polistes and Vespula (wasps) decreased significantly, whereas there was no change in the specific IgG to Hb in any of the groups. The number of stings per year decreased at the end of the study in all groups, but positive-specific IgG was higher in subjects with the greatest number of stings. On multivariate analysis using logistic regression, the existence of specific IgE to bee venom, male sex, being an agricultural worker, age of over 16 years and more than five stings per year are seen as individual or co-factors for developing SR or LLR.

CONCLUSIONS

The prevalence of SR was 2.8% in our Mediterranean population. The evolution of IgE and IgG throughout the 4-year study differed depending on the Hymenoptera studied. Adult male agricultural workers are at greater risk of having SR or LLR, especially when they have specific IgE to Hb and suffer from more than five stings every 4 years.

Endotoxin exposure and atopic sensitization in adult pig farmers

BACKGROUND

Recent studies have reported a low prevalence of atopic sensitization and respiratory allergy in children growing up on farms.

OBJECTIVES

We sought to evaluate the dose-response relationship between endotoxin and atopic sensitization in adult farmers and to assess the effect on respiratory health outcomes.

METHODS

Data on endotoxin exposure and serum IgE levels were available for 162 pig farmers from a cross-sectional case-control study, with case selection on the basis of respiratory symptoms. Exposure to endotoxin was modeled in detail, and respiratory health effects were assessed during a medical examination. Exploratory analysis was done by using nonparametric modeling and was followed by classical parametric regression.

RESULTS

IgE to one or more common allergens was detected in sera from 28 (17%) farmers. The average (geometric mean) total serum IgE levels was 37 IU/mL (geometric SD, 4 IU/mL). A strong inverse relationship was found between endotoxin and sensitization to common allergens for exposures of 75 ng/m 3 or less, with an odds ratio of 0.03 (95% CI, 0.0-0.34) for a 2-fold increase in endotoxin. For endotoxin exposure of greater than 75 ng/m 3 , the association was weak (odds ratio, 1.2 [95% CI, 0.38-3.6]). No association was found between endotoxin exposure and total serum IgE levels. Endotoxin was associated with increased airway hyperresponsiveness to histamine and lower lung function in sensitized farmers, without evidence of a nonlinear relationship.

CONCLUSIONS

The prevalence of atopic sensitization in adult pig farmers is low. Endotoxin or related exposures might protect from sensitization, even in an adult working population exposed to high levels of endotoxin, but is a risk factor for increased airway hyperresponsiveness and low lung function.

HLA class II DPB1, DQA1, DQB1, and DRB1 genotypic associations with occupational allergic cough to Bunashimeji mushroom

We previously reported that two-third of workers in a Bunashimeji mushroom (Hypsizigus marmoreus) farm complained of respiratory allergic symptoms, but one-third workers did not suffer from such symptoms even when working for a long period. CD4+ T-helper (Th) cells increased, and Th2/Th1 ratio increased in the allergic workers. To address these immunological backgrounds, we have investigated whether there is any relationship between mushroom allergy and human leukocyte antigen (HLA) class II alleles of DPB1, DQA1, DQB1, and DRB1 by using the polymerase chain reaction-restriction fragment length polymorphism (RFLP) and sequencing-based typing methods. We observed that the allele frequencies of DQA1*0103, DQB1*0601, and DRB1*0803 were significantly higher in the workers having no allergic symptoms than allergic workers (DQA1*0103: 57 vs 25%, DQB1*0601: 49 vs 14%, and DRB1*0803: 29 vs 0%). However, this phenomenon was not seen in workers producing another kind of mushroom, Honshimeji (Lyophyllum aggregatum). The HLA-DRB1*0803 allele alone, the DRB1*0803, DQA1*0103, DQB1*0601 haplotype, or both were negatively associated with allergy to Bunashimeji, and these alleles might be involved in the prevention of Bunashimeji mushroom-specific respiratory allergy.

Hypersensitivity Pneumonitis Associated with Mushroom Worker’s Lung: An Update on the Clinical Significance of the Importation of Exotic Mushroom Varieties

Hypersensitivity pneumonitis remains an important industrial disease in mushroom workers. It has a significant morbidity, and early diagnosis and removal from exposure to the antigen are critically important in its management. Recently, several new allergens have been described, particularly those from mushroom species originating in the Far East, which are of clinical significance to workers occupationally exposed to such allergens in cultivation, picking, and packing of commercial mushroom crops. Importing of exotic mushrooms including Shiitake is common in EU countries, and some of the exotic species of mushrooms are cultivated for local markets. This practice may contribute to an increase in clinical cases of mushroom hypersensitivity pneumonitis. This update reviews the recent literature and examines changing trends of mushroom worker's lung, with increased movement of commercial product and labour markets worldwide.

Health effects of exposure to herb dust in valerian growing farmers

The aim of the present study was to determine the health status of farmers cultivating valerian (Valeriana officinalis L.) and occupationally exposed to dust from this plant. A group of 75 valerian growing farmers were examined. As a reference group, 50 urban dwellers, not exposed to any kind of organic dust were examined. All people were interviewed for the presence of work-related symptoms and subjected to physical and spirometric examinations. Skin prick tests were conducted with 4 microbial antigens associated with organic dust and 3 herbal extracts, precipitin tests with 12 microbial antigens and 4 herbal extracts and tests for specific inhibition of leukocyte migration with 4 microbial antigens. 30.7 % of the valerian farmers reported occurrence of work-related symptoms. No significant differences were found between the spirometric values in the group of valerian farmers and the reference group. Valerian farmers showed a low frequency of positive skin reactions to all tested antigens (0-4.0 %), not significantly greater compared to reference group. The frequency of positive precipitin reactions to the antigen of Gram-negative bacterium Pantoea agglomerans was very high in valerian farmers (45.5 %) with 3-fold concentrated sera and significantly greater compared to the reference group (p < 0.001). The positive precipitin response of valerian farmers to other microbial and herbal antigens was much lower or absent and did not show any difference compared to reference group. In the test for specific inhibition of leukocyte migration, the highest frequencies of positive reactions in valerian farmers were noted with Pantoea agglomerans and Saccharopolyspora rectivirgula (15.0 % each), in both cases significantly greater compared to reference group (p < 0.05). In conclusion, the farmers growing valerian showed a moderate frequency of work-related symptoms and low reactivity to most microbial and herbal allergens. They exhibited an increased immunologic response to Gram-negative bacterium Pantoea agglomerans which appears to be the most important risk factor associated with valerian dust.

Immunoblot and radioallergosorbent test inhibition studies of allergenic cross-reactivity of the predatory mite Amblyseius cucumeris with the house dust mite Dermatophagoides pteronyssinus

BACKGROUND

In 1999, an extensive study among bell pepper growers showed that a predatory mite, Amblyseius cucumeris, is a potentially relevant source of occupational allergens because 23% of the population had positive skin prick test reactions.

OBJECTIVE

To investigate whether cross-reactivity between A. cucumeris and Dermatophagoides pteronyssinus is responsible for the cosensitization to both mite species found in 58.7% of A. cucumeris-sensitized greenhouse workers.

METHODS

Fifteen serum samples from greenhouse workers with work-related inhalant allergy and a positive radioallergosorbent test (RAST) reaction to A. cucumeris or D. pteronyssinus were selected for immunoblot analysis using extracts of both mites. A subselection (n = 5) was used for RAST and immunoblot inhibition to investigate potential cross-reactivity.

RESULTS

On immunoblot, 2 distinct patterns were observed: one pattern showed common protein bands in A. cucumeris and D. pteronyssinus blots suggestive of cross-reactivity between A. cucumeris and D. pteronyssinus and the other pattern showed no shared protein bands. Dermatophagoides pteronyssinus RAST inhibition with A. cucumeris extract was low in 4 serum samples (<25% inhibition) and nearly absent in 1 serum sample; A. cucumeris RAST inhibition with D. pteronyssinus extract was high in 1 serum sample (75% inhibition), low in 2 serum samples (35% and <15% inhibition), and absent in 2 serum samples. These results were confirmed by immunoblot inhibition experiments.

CONCLUSIONS

Amblyseius cucumeris, a new occupational allergen, has species-specific antigens and common antigens that are cross-reactive with the house dust mite D. pteronyssinus.

Atopic and non-atopic asthma in a farming and a general population

BACKGROUND

In a previous study inverse associations between asthma and exposure to fungal spores and endotoxins in atopic farmers and positive associations with the same factors in non-atopic farmers were documented. No external reference population had been included. We, therefore, compared this farming population with the general population from an adjacent region.

METHODS

Random samples of a farming (n=2,106) and a rural (n=351) and urban (n=727) general population were selected. Atopy was assessed by serum IgE and asthma by questionnaires.

RESULTS

The asthma prevalence was 4.0% among farmers, 5.7% in the rural, and 7.6% in the urban population. Atopy was similar (9-10%). Most asthmatics were not atopic, 67-75%. Farmers had asthma less often than the general population OR 0.52 (95% CI 0.36-0.75); both atopic (OR 0.33 (95% CI 0.15-0.69)) and non-atopic asthma (OR 0.60 (95% CI 0.39-0.93)).

CONCLUSION

This may indicate a protective effect of the farm environment on asthma but a healthy worker effect may also play a role.

Occupational asthma in greenhouse workers

PURPOSE OF REVIEW

A prevalence of asthma over 5% has been reported in flower farmers,and work inside greenhouses has emerged as an additional risk factor. Workplace determinants behind this high prevalence has been examined, and a prevalence of sensitization to workplace allergens over 30% has been reported being pollens, moulds, and Tetranychus urticae allergens the main sensitizers. Bronchial challenge tests in the workplace have demonstrated occupational asthma in more than 20% of the sensitized greenhouse growers.

RECENT FINDINGS

Air contamination inside greenhouses is mainly related to moulds, and is facilitated by the high indoor temperature and humidity. Cladosporium, Penicillium, Aspergillus, and Alternaria and a wide range of flower pollens are able to sensitize the greenhouse worker and cause occupational asthma. Tetranychus urticae have allergens shared with other mites, but the low prevalence of cross-sensitization between them confirm that Tetranychus urticae contains species-specific allergens that may cause respiratory symptoms. Additionally, working inside greenhouses has been related to an increase in the prevalence of chronic bronchitis in nonsmokers.

SUMMARY

The cultivation of greenhouse crops may cause occupational asthma through sensitization to workplace pollens, moulds, and Tetranychus urticae allergens. In greenhouse flower growers, skin testing identifies sensitization to these allergens in one third of the growers, and more than one fifth of the sensitized workers will develop occupational asthma. Greenhouse work has also been related to chronic bronchitis in nonsmokers, suggesting a causal effect of greenhouse air contaminants on this disease as well.

Successful treatment of hypersensitivity pneumonitis caused by Grifola frondosa (Maitake) mushroom using a HFA-BDP extra-fine aerosol

We successfully treated a patient with occupational hypersensitivity pneumonitis (HP) caused by Grifola frondosa (Maitake) mushroom spore with an extra-fine aerosol corticosteroid; beclomethasone dipropionate (BDP) dissolved in hydrofluoroalkane-134a (HFA). A 49-year-old woman developed respiratory symptoms 3 months after beginning work on a mushroom farm. She was diagnosed as HP based on radiological and serological findings. Oral prednisolone therapy improved her HP and she returned to the same farm. Her HP relapsed after 5 months, and daily 400 microg of HFA-BDP was administered with gradual improvement. An extra-fine particle inhaled corticosteroid might reach appropriate alveoli to be effective therapy for mild HP.

Respiratory allergy to peach leaves and lipid-transfer proteins

BACKGROUND

Several lipid-transfer proteins (LTPs) have been identified as important food allergens, especially in fruits of the Rosaceae family. The major peach (Prunus persica) allergen has been identified, sequenced and designated Pru p 3.

OBJECTIVE

To present Pru p 3 as an aeroallergen able to induce occupational asthma.

METHODS

A thorough investigation was performed in a fruit grower with occupational asthma. Skin prick-prick tests with peach leaves and prick tests with perennial respiratory allergens and pollens, fruits and peach leaf extracts were done. Serum-specific IgE was tested for peach leaf, peach fruit, peach skin and respiratory allergens that were positive in skin prick tests. Specific bronchial provocation tests (BPTs) with extracts of peach leaf were also done. Before and 24 h after the BPT, BPTs with methacholine and sputum induction were done. The IgE reactivity pattern to peach leaf and fruit extracts and to Pru p 3 was identified by using SDS-PAGE and immunoblotting. Blotting inhibition of peach leaf extract by Pru p 3 was also performed. The putative allergen was quantified in leaf and fruit skin extracts with ELISA based on an anti-Pru p 3 antibody.

RESULTS

Skin tests were positive for peach leaf and fruit. The BPT was positive, with immediate and delayed response. This test induced a decrease in PD20 (dose of agonist that induces a 20% fall in FEV1) methacholine and an increase in eosinophils and eosinophil cationic protein in sputum. Peach leaf extract contained concentrations of Pru p 3 similar to those found in peach skin. Specific IgE immunodetection showed that patient's sera reacted with Pru p 3, and with a single major band from the peach leaf extract fully inhibited by Pru p 3.

CONCLUSION

Pru p 3 from peach leaves can act as a respiratory allergen and cause occupational rhinoconjunctivitis and asthma.

Occupational asthma due to grain pests Eurygaster and Ephestia

BACKGROUND

Workers occupationally exposed to grain dust have a high prevalence of asthma. The pathogenesis of their respiratory symptoms remains obscure when sensitization to cereal allergens has not been proved. Given the ubiquity of arthropods in stored vegetable products, we have studied the allergenic potential of two very prevalent grain pests, Eurygaster and Ephestia, as a cause of occupational asthma. We have also studied the allergenic relationship between Anisakis simplex (AS) and these pests.

METHODS

We selected 15 asthmatic workers exposed to cereal dust, in whom sensitization to cereal allergens was not clear. As controls, we selected a patient who suffered from anaphylaxis after the ingestion of cereals, 6 patients sensitized to different arthropods, 1 patient who suffered from asthma after inhaling fish flour contaminated with AS, and a pool of 40 asthmatic patients with different ethiologies not due to arthropods or cereals. We performed prick tests with these pests, AS, and pure and parasitized flours, bronchial challenges, specific IgE determination, and RAST inhibition.

RESULTS

All of the 15 cereal-exposed workers were sensitized to Eurygaster and Ephestia. Only 2 had detectable levels of serum IgE to these pests, but 13 presented a positive prick test result and IgE to AS without problems after eating fish. Bronchial challenges were positive to Eurygaster in 7 patients and to Ephestia in 2 patients. Twelve patients had positive prick tests to parasitized flour but not to pure flour. The patient with cereal anaplylaxis presented sensitization to both flours but not to AS. In the control group, the patient who suffered from asthma after the inhalation of AS-parasitized fish flour presented a positive prick test result and high levels of specific IgE to these pests. The RAST inhibition showed cross-reactivity between Eurygaster and AS in this patient, but the inhibition was not as evident with the sera of other workers. The same tests in the group of 40 asthmatic patients were negative.

CONCLUSIONS

The clinical importance of pests as a cause of baker's asthma should not be underestimated. Sensitization to Eurygaster and Ephestia could be important in the asthma episodes suffered by our patients, and the parasitized wheat was found to have a higher allergenic potential than pure cereal flour.

Mushroom plant workers experience a shift towards a T helper type 2 dominant state: contribution of innate immunity to spore antigen

Contemporary mushroom factories are places where there is a substantial risk of the occurrence of respiratory allergy. The aims of this investigation were to estimate its causative agents and to evaluate the contribution of innate immune response in mushroom workers who cultivate Hypsizigus marmoreus (Bunashimeji). Cross-sectional and follow-up studies were performed in the factory. We investigated CD1b, CD3, CD4, CD8, CD14, CD45RO, CD62L and CD161 expression in peripheral blood mononuclear cells (PBMC) by flow cytometry, and serum levels of interleukin (IL-2), IL-4, granulocyte-macrophage colony stimulating factor (GM-CSF), IL-13 and interferon (IFN)-gamma by enzyme-linked immunosorbent assay (ELISA). Co-culture experiments of PBMC with spore extracts were also performed. Percentages of CD1b+ monocytes, natural killer (NK), NK T and CD4+ T cells were increased in the workers compared with controls. Increases in Th2 type cells, Th2/Th1 ratio and serum IL-13 and decreased IFN-gamma were detected, indicating a Th2-biased status of the workers. The follow-up study showed that monocytes and NK cells increased soon after employment while CD4+ T, Th2 and NK T cells increased gradually as employment time lengthened. Serum precipitating antibody to the mushroom antigen could be detected at a later stage. Co-cultivation of PBMC with the spore extracts induced much higher CD1b expression, and suppressed secretion of Th1 cytokine in culture supernatants. These results indicate that the mushroom antigen contains highly immunogenic substances which stimulate PBMC into a Th2-biased in vivo status, and innate immune cells might also play a critical role in developing respiratory allergy in mushroom workers.

Immunologic reactivity to work-related airborne allergens in people occupationally exposed to dust from herbs

A group of 150 people occupationally exposed to dust from herbs were examined. The examined group consisted of 47 thyme farmers, 32 chamomile farmers, 31 sage farmers and 40 workers of herbs processing industry. As a reference group, 50 urban dwellers, not exposed to any kind of organic dust, were examined. Skin prick tests and precipitin tests were conducted with, respectively, 4 and 11 microbial antigens associated with organic dust. Both skin and precipitin tests were also conducted with herbal extracts of chamomile and sage. Precipitin tests were carried out with sera not concentrated and sera 3-fold concentrated. Tests for inhibition of leukocyte migration (MIF) were also conducted with 4 microbial antigens. People occupationally exposed to dust from herbs showed a higher frequency of positive skin reactions to microbial antigens compared to the reference group. The results of precipitin test also revealed greater reactivity to the environmental microbial antigens in the examined group, compared to the reference group. The highest frequency of positive results was noted with the antigen of Pantoea agglomerans (30.6 % with sera not concentrated and 48.3 % with sera 3-fold concentrated) - the difference compared to the reference group (12.0 %) was highly significant (p < 0.01). The frequencies of positive results of MIF test in the examined group were high with all antigens tested: Arthrobacter globiformis (12.6 %), Pantoea agglomerans (11.1 %), Saccharopolyspora rectivirgula (17.0 %), Aspergillus fumigatus (13.3 %), and, compared to the reference group with no positive result for any antigen, all the differences were significant (p < 0.05). In conclusion, the frequency of positive allergological reactions to airborne microorganisms was high in people occupationally exposed to dust from herbs and suggests a potential role of microbial allergens in the pathogenesis of work-related health disorders among herb workers. The risk of sensitization seems to be greatest among thyme farmers, who showed the highest positive response. The results confirmed the particular allergenic importance of Gram-negative bacterium Pantoea agglomerans.

Hypersensitivity pneumonitis due to occupational inhalation of fungi-contaminated corn dust

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