Respiratory allergy in apprentice bakers: do occupational allergies follow the allergic march?

Comparison of high- and low-molecular-weight sensitizing agents causing occupational asthma: an evidence-based insight

INTRODUCTION

The many substances used at the workplace that can cause sensitizer-induced occupational asthma are conventionally categorized into high-molecular-weight (HMW) agents and low-molecular-weight (LMW) agents, implying implicitly that these two categories of agents are associated with distinct phenotypic profiles and pathophysiological mechanisms.

AREAS COVERED

The authors conducted an evidence-based review of available data in order to identify the similarities and differences between HMW and LMW sensitizing agents.

EXPERT OPINION

Compared with LMW agents, HMW agents are associated with a few distinct clinical features (i.e. concomitant work-related rhinitis, incidence of immediate asthmatic reactions and increase in fractional exhaled nitric oxide upon exposure) and risk factors (i.e. atopy and smoking). However, some LMW agents may exhibit 'HMW-like' phenotypic characteristics, indicating that LMW agents are a heterogeneous group of agents and that pooling them into a single group may be misleading. Regardless of the presence of detectable specific IgE antibodies, both HMW and LMW agents are associated with a mixed Th1/Th2 immune response and a predominantly eosinophilic pattern of airway inflammation. Large-scale multicenter studies are needed that use objective diagnostic criteria and assessment of airway inflammatory biomarkers to identify the pathobiological pathways involved in OA caused by the various non-protein agents.

The Identification of Potential Immunogenic Antigens in Particular Active Developmental Stages of the Rice Weevil (Sitophilus oryzae)

BACKGROUND

The rice weevil (Sitophilus oryzae) originates from subtropical and tropical areas of Asia and Africa, but it also appears on other continents, mostly as a result of trade in rice. It may occur in grain fields as well as in storage facilities, and cause allergenic reactions. The aim of this study was to identify the potential antigens in all developmental stages of S. oryzae, which may cause an allergic response in humans.

METHODS

Sera of 30 patients were tested for the presence of IgE antibodies to antigens from three life stages of the rice weevil. To identify protein fractions containing potential allergens, proteins collected from larvae, pupae, and adults separated by sex of S. oryzae were fractionated by SDS-PAGE. Then, they were probed with anti-human, anti-IgE monoclonal antibodies, fractionated by SDS-PAGE and detected by Western blotting.

RESULTS

In total, 26 protein fractions of males and 22 fractions of other life stages of S. oryzae (larvae, pupae, and females) positively reacted with the examined sera.

CONCLUSIONS

The conducted study showed that S. oryzae may be a source of many antigens which may cause the potential allergic reactions in humans.

Work-Related Upper-Airway Disorders

Work-related rhinitis and laryngeal disorders are common and can significantly contribute to work absences and presenteeism. Each can cause respiratory symptoms that may be misdiagnosed as asthma symptoms, and each may occur as an isolated disorder or may also accompany asthma. Suspicion of these disorders and correct management require a careful medical and occupational history. Investigations for work-related rhinitis include examination of the nose, allergy skin tests, and in some cases, monitoring of peak inspiratory nasal flows at work and off work, or specific challenge tests. Work-related laryngeal disorders require assistance from an otolaryngologist and speech language pathologist.

Occupational Rhinitis

There is convincing evidence that tight relationships between the upper and lower airways also apply to the workplace context. Most patients with occupational asthma (OA) also suffer from occupational rhinitis (OR), although OR is 2 to 3 times more common than OA. OR most often precedes the development of OA, especially when high-molecular-weight protein agents are involved, and longitudinal cohort studies have confirmed that OR is associated with an increased risk for the development of OA. The level of exposure to sensitizing agents at the workplace is the most important determinant for the development of IgE-mediated sensitization and OR. Atopy is a risk factor for the development of IgE-mediated sensitization only to high-molecular-weight agents. In workers with work-related rhinitis symptoms, documentation of IgE-mediated sensitization to a workplace agent via skin prick testing or serum specific IgE confirms a diagnosis of probable OR, whereas specific nasal provocation testing in the laboratory remains the reference method to establish a definite diagnosis of OR. Complete avoidance of exposure to the causal agent is the most effective therapeutic option for controlling work-related nasal symptoms and preventing the development of OA. If complete elimination of exposure is expected to induce meaningful adverse socioeconomic consequences, reduction of exposure can be considered as an alternative approach, but it is important to consider the individual risk factors for the development of OA to implement a more personalized management of OR.

Wheat Consumption Aggravates Colitis in Mice via Amylase Trypsin Inhibitor-mediated Dysbiosis

BACKGROUND & AIMS

Wheat has become the world's major staple and its consumption correlates with prevalence of noncommunicable disorders such as inflammatory bowel diseases. Amylase trypsin inhibitors (ATIs), a component of wheat, activate the intestine's innate immune response via toll-like receptor 4 (TLR4). We investigated the effects of wheat and ATIs on severity of colitis and fecal microbiota in mice.

METHODS

C57BL/6 wild-type and Tlr4^-/- mice were fed wheat- or ATI-containing diets or a wheat-free (control) diet and then given dextran sodium sulfate to induce colitis; we also studied Il10^-/- mice, which develop spontaneous colitis. Changes in fecal bacteria were assessed by taxa-specific quantitative polymerase chain reaction and 16S ribosomal RNA metagenomic sequencing. Feces were collected from mice on wheat-containing, ATI-containing, control diets and transplanted to intestines of mice with and without colitis on control or on ATI-containing diets. Intestinal tissues were collected and analyzed by histology, immunohistochemistry, and flow cytometry. Bacteria with reported immunomodulatory effects were incubated with ATIs and analyzed in radial diffusion assays.

RESULTS

The wheat- or ATI-containing diets equally increased inflammation in intestinal tissues of C57BL/6 mice with colitis, compared with mice on control diets. The ATI-containing diet promoted expansion of taxa associated with development of colitis comparable to the wheat-containing diet. ATIs inhibited proliferation of specific human commensal bacteria in radial diffusion assays. Transplantation of microbiota from feces of mice fed the wheat- or ATI-containing diets to intestines of mice on control diets increased the severity of colitis in these mice. The ATI-containing diet did not increase the severity of colitis in Tlr4^-/- mice.

CONCLUSIONS

Consumption of wheat or wheat ATIs increases intestinal inflammation in mice with colitis, via TLR4, and alters their fecal microbiota. Wheat-based, ATI-containing diets therefore activate TLR4 signaling and promote intestinal dysbiosis.

Predicting occupational allergy in culinary and hairdressing apprentices

Background

Apprentices are usually exposed to the same workplace agents as qualified professionals. There is therefore a risk of the development of occupational allergy in apprentices exposed to high (HMW-A) and low molecular inhalant allergens (LMW-A).

Aims

To evaluate and compare the occurrence of work-related allergy-like symptoms in apprentices exposed to HMW-A and LMW-A in a culinary and hairdressing school during the first and second year of vocational training.

Methods

We asked culinary and hairdressing apprentices in their first and second year of vocational training to complete a questionnaire about work-related allergy-like symptoms. In first-year apprentices, we undertook spirometry, skin prick tests for occupational allergens and blood tests for allergen-specific Immunoglobulin E (IgE) antibodies.

Results

Hypersensitivity to occupational allergens was more frequent in first-year apprentices exposed to HMW-A compared to LMW-A (P < 0.05). Apprentices exposed to LMW-A reported increasing occurrence of skin disorders and upper respiratory tract symptoms between the first and second years of training. First-year apprentices exposed to HMW-A more frequently reported rhino-conjunctivitis and dyspnoea (approximately P < 0.001 and P < 0.05) and those exposed to LMW-A more often reported skin symptoms (P < 0.05).

Conclusions

Periodic skin and respiratory health surveillance for apprentices exposed to LMW-A or HMW-A might help with early identification and management of occupational allergy.

Occupational Safety and Health Among Young Workers in the Nordic Countries: A Systematic Literature Review

This review aimed to identify risk factors for occupational accidents and illnesses among young workers in the Nordic countries and to attain knowledge on specific vulnerable groups within the young working force that may need special attention. We conducted a systematic review from 1994 to 2014 using five online databases. Of the 12,528 retrieved articles, 54 met the review criteria and were quality assessed, in which data were extracted focusing on identifying occupational safety, health risk factors, and vulnerable groups among the young workers. The review shows that mechanical factors such as heavy lifting, psychosocial factors such as low control over work pace, and organizational factors such as safety climate are all associated with increased injury risk for young Nordic workers. Results show that exposures to chemical substances were associated with skin reactions, e.g., hand eczema. Heavy lifting and awkward postures were risk factors for low back pain, and high job demands were risk factors for mental health outcomes. The review identified young unskilled workers including school drop-out workers as particularly vulnerable groups when it comes to occupational accidents. In addition, apprentices and young skilled workers were found to be vulnerable to work-related illnesses. It is essential to avoid stereotyping young Nordic workers into one group using only age as a factor, as young workers are a heterogeneous group and their vulnerabilities to occupational safety and health risks are contextual. Politicians, researchers, and practitioners should account for this complexity in the education, training and organization of work, and workplace health and safety culture.

Occupational rhinitis and occupational asthma: Association or progression?

BACKGROUND

Occupational asthma is the most frequently reported occupational respiratory disease in registries, and is often co-diagnosed with occupational rhinitis. We undertook a systematic review of the English-language epidemiologic literature linking these two conditions, with emphasis on progression from occupational rhinitis to occupational asthma.

METHODS

PubMed and Embase were queried in a series of structured searches designed to identify studies comparing occupational asthma and occupational rhinitis incidence or prevalence in occupationally exposed individuals.

RESULTS

The searches yielded a total of 109 unique citations, 15 of which yielded inferential data on the occupational rhinitis-asthma relationship. Nine of fifteen studies showed statistically significant associations between the occurrence of occupational rhinitis and occupational asthma among individual workers.

CONCLUSIONS

Limited data support the notion that occupational rhinitis precedes the development of occupational asthma, particularly when high-molecular-weight (HMW) agents are involved. The relationship between the two conditions could not be evaluated in many relevant studies due to a lack of cross-tabulation of individual cases.

Nutritional Wheat Amylase-Trypsin Inhibitors Promote Intestinal Inflammation via Activation of Myeloid Cells

BACKGROUND & AIMS

Wheat amylase-trypsin inhibitors (ATIs) are nutritional activators of innate immunity, via activation of the toll-like receptor 4 (TLR4) on myeloid cells. We aimed to characterize the biologic activity of ATIs in various foods and their effect on intestinal inflammation.

METHODS

We selected 38 different gluten-containing and gluten-free products, either unprocessed (such as wheat, rye, barley, quinoa, amaranth, soya, lentils, and rice) or processed (such as pizza, pasta, bread, and biscuits). ATIs were extracted and their biological activities determined in TLR4-responsive mouse and human cell lines. Effects of oral ATIs on intestinal inflammation were determined in healthy C57BL/6 mice on a gluten-free or ATI-free diet and in mice given low-level polyinosinic:polycytidylic acid or dextran sodium sulfate to induce colitis. Parameters of innate and adaptive immune activation were determined in duodenum, ileum, colon, and mesenteric lymph nodes.

RESULTS

Modern gluten-containing staples had levels of TLR4-activating ATIs that were as much as 100-fold higher than in most gluten-free foods. Processed or baked foods retained ATI bioactivity. Most older wheat variants (such as Emmer or Einkorn) had lower bioactivity than modern (hexaploid) wheat. ATI species CM3 and 0.19 were the most prevalent activators of TLR4 in modern wheat and were highly resistant to intestinal proteolysis. Their ingestion induced modest intestinal myeloid cell infiltration and activation, and release of inflammatory mediators-mostly in the colon, then in the ileum, and then in the duodenum. Dendritic cells became prominently activated in mesenteric lymph nodes. Concentrations of ATIs found in a normal daily gluten-containing diet increased low-level intestinal inflammation.

CONCLUSIONS

Gluten-containing cereals have by far the highest concentrations of ATIs that activate TLR4. Orally ingested ATIs are largely resistant to proteases and heat, and increase intestinal inflammation by activating gut and mesenteric lymph node myeloid cells.

Career Advice for Young Allergy Patients

BACKGROUND

One-third of all young persons entering the work force have a history of atopic disease. Occupationally induced allergy and asthma generally arise in the first few months on the job, while pre-existing symptoms tend to worsen. Young persons with a history of an atopic disease should receive evidence-based advice before choosing a career.

METHODS

We systematically searched PubMed for cohort studies investigating the new onset of asthma, rhinitis, or hand eczema among job trainees from before the start of training and onward into the first few years on the job. The search revealed 514 articles; we read their abstracts and selected 85 full-text articles for further analysis. 24 of these met the inclusion criteria.

RESULTS

According to present evidence, atopy and a history of allergic disease (allergic rhinitis, atopic dermatitis) are the main risk factors for occupationally induced disease. The predictive value of a personal history of allergic diseases for the later development of an occupationally induced disease varies from 9% to 64% in the studies we analyzed. It follows that only young people with severe asthma or severe atopic eczema should be advised against choosing a job that is associated with a high risk of allergy, e.g., hairdressing or working with laboratory animals. Young people with a history of other atopic diseases should be counseled about their individual risk profile.

CONCLUSION

In view of the relatively poor predictive value of pre-existing atopic disease, secondary prevention is particularly important. This includes frequent medical follow-up of the course of symptoms over the first few years on the job. If sensitization or allergic symptoms arise, it should be carefully considered whether exposure reduction will enable the apprentice to stay on the job.

Work-Related Asthma

OBJECTIVE

Summarize developed evidence-based diagnostic and treatment guidelines for work-related asthma (WRA).

METHODS

Comprehensive literature reviews conducted with article critiquing and grading. Guidelines developed by a multidisciplinary expert panel and peer-reviewed.

RESULTS

Evidence supports spirometric testing as an essential early test. Serial peak expiratory flow rates measurement is moderately recommended for employees diagnosed with asthma to establish work-relatedness. Bronchial provocation testing is moderately recommended. IgE and skin prick testing for specific high-molecular weight (HMW) antigens are highly recommended. IgG testing for HMW antigens, IgE testing for low-molecular weight antigens, and nitric oxide testing for diagnosis are not recommended. Removal from exposure is associated with the highest probability of improvement, but may not lead to complete recovery.

CONCLUSION

Quality evidence supports these clinical practice recommendations. The guidelines may be useful to providers who diagnose and/or treat WRA.

Bread and Other Edible Agents of Mental Disease

Perhaps because gastroenterology, immunology, toxicology, and the nutrition and agricultural sciences are outside of their competence and responsibility, psychologists and psychiatrists typically fail to appreciate the impact that food can have on their patients' condition. Here we attempt to help correct this situation by reviewing, in non-technical, plain English, how cereal grains-the world's most abundant food source-can affect human behavior and mental health. We present the implications for the psychological sciences of the findings that, in all of us, bread (1) makes the gut more permeable and can thus encourage the migration of food particles to sites where they are not expected, prompting the immune system to attack both these particles and brain-relevant substances that resemble them, and (2) releases opioid-like compounds, capable of causing mental derangement if they make it to the brain. A grain-free diet, although difficult to maintain (especially for those that need it the most), could improve the mental health of many and be a complete cure for others.

A Grounded Guide to Gluten: How Modern Genotypes and Processing Impact Wheat Sensitivity

The role of wheat, and particularly of gluten protein, in our diet has recently been scrutinized. This article provides a summary of the main pathologies related to wheat in the human body, including celiac disease, wheat allergy, nonceliac wheat sensitivity, fructose malabsorption, and irritable bowel syndrome. Differences in reactivity are discussed for ancient, heritage, and modern wheats. Due to large variability among species and genotypes, it might be feasible to select wheat varieties with lower amounts and fewer types of reactive prolamins and fructans. Einkorn is promising for producing fewer immunotoxic effects in a number of celiac research studies. Additionally, the impact of wheat processing methods on wheat sensitivity is reviewed. Research indicates that germination and fermentation technologies can effectively alter certain immunoreactive components. For individuals with wheat sensitivity, less-reactive wheat products can slow down disease development and improve quality of life. While research has not proven causation in the increase in wheat sensitivity over the last decades, modern wheat processing may have increased exposure to immunoreactive compounds. More research is necessary to understand the influence of modern wheat cultivars on epidemiological change.

Prevalence and risk factors for allergic rhinitis in bakers in Douala, Cameroon

OBJECTIVE

To determine the prevalence and risk factors of allergic rhinitis among bakers in Douala.

DESIGN

A cross-sectional study; the logistic regression model was use to find the risk factors of allergic rhinitis.

SETTING

The study was conducted in 42 bakeries randomly selected among a total of 151 bakeries in the city of Douala.

PARTICIPANTS

All bakers who consented to participate in the study between 1 May and 31 July 2013.

OUTCOME MEASURES

Allergic rhinitis was the outcome of interest. It was defined as the presence of the following symptoms: itchy nose, rhinorrhea, nasal obstruction and sneezing.

RESULTS

During the study period, a total of 273 bakers were invited and 229 finally agreed to participate in this study. Males were the most represented gender with 222 (96.9%) participants. The mean age of the participants was 36.29±8.9 years. Smoking was found in 55 participants (24.5%). The symptoms of allergic rhinitis were observed in 24.5% of participants. Work related nasal symptoms were present in 15% of participants. Sensitisation to wheat flour and α-amylase was found in 16.6% and 8.3% of participants, respectively. The Prick test was positive for mites in 12.2% of participants. After multivariate analysis, sensitisation to flour (OR 3.95, 95% CI 1.85 to 8.47) and storage mites (OR 3.44, 95% CI 1.45 to 8.18) were the factors independently associated with symptoms of allergic rhinitis.

CONCLUSIONS

Allergic rhinitis is frequent among bakers in Cameroon. Implementation of preventive measures against inhalation of airborne allergens in bakeries and clinical monitoring of bakers sensitised to wheat flour and mites could help to reduce the prevalence of allergic rhinitis among bakers.

An official American Thoracic Society proceedings: work-related asthma and airway diseases. Presentations and discussion from the Fourth Jack Pepys Workshop on Asthma in the Workplace

Work-related asthma is a common occupational lung disease. The scope of the Fourth Jack Pepys Workshop that was held in May 2010 went beyond asthma to include discussion of other occupational airway diseases, in particular occupationally related chronic obstructive pulmonary disease (COPD) and bronchiolitis. Aspects explored included public health considerations, environmental aspects, outcome after diagnosis, prevention and surveillance, and other work-related obstructive airway diseases. Consistent methods are needed to accurately estimate the comparative burden of occupation-related airway diseases among different countries. Challenges to accomplishing this include variability in health care delivery, compensation systems, cultural contexts, and social structures. These factors can affect disease estimates, while heterogeneity in occupations and workplace exposures can affect the underlying true prevalence of morbidity. Consideration of the working environment included discussion of practical methods of limiting exposure to respiratory sensitizers, methods to predict new sensitizers before introduction into workplaces, the role of legislated exposure limits, and models to estimate relative validity of various ameliorative measures when complete avoidance of the sensitizer is not feasible. Other strategies discussed included medical surveillance measures and education, especially for young individuals with asthma and new workers about to enter the workforce. Medical outcomes after development of sensitizer-induced occupational asthma are best following earlier diagnosis and removal from further exposure, but a subset may be able to continue working safely provided that exposure is reduced under close follow-up monitoring. It was recognized that occupationally related COPD is common but underappreciated, deserving further study and prevention efforts.

Diagnosis of occupational asthma: an update

Work-related asthma (WRA) includes patients with sensitizer- and/or irritant-induced asthma in the workplace, as well as patients with preexisting asthma that is worsened by work factors. WRA is underdiagnosed; thus, the diagnosis is critical to prevent disease progression and its potential for morbidity and mortality. The interview is the first diagnostic tool to be used by physicians, and the question, "Does asthma improve away from work?" is of the highest sensitivity. However, history can show numerous false positives, and the relationships between asthma worsening and work should be confirmed by objective methods such as peak expiratory flow (PEF) at and away from work. PEF sensitivity and specificity can be enhanced in combination with nonspecific bronchial hyperresponsiveness to histamine/methacholine (NSBP) before and after 2 weeks at work and a similar period off work. Immunologic testing, especially skin prick test (SPT) or specific IgE, is useful for high molecular weight allergens and some low molecular weight agents. Other immunologic tests, as well as induced sputum, measurement of exhaled nitric oxide, exhaled breath condensate, and specific inhalation challenge (SIC) are methods that contribute to the diagnosis and are typically performed at specialized facilities. A diagnosis of occupational asthma (OA) should no longer be based on a compatible history only but should be confirmed by means of objective testing. SIC is the diagnostic gold standard. When SIC is not available, the combination of PEF measurement, NSBP test , a specific SPT, or specific IgE may be an appropriate alternative in diagnosing OA.

Mould sensitisation among bakers and farmers with work-related respiratory symptoms

Fungi belong to common allergens, which can be found both in occupational and non-occupational environment. The aim of the study was to determine the frequency and factors associated with mould allergy among bakers and farmers reporting work-related respiratory symptoms. The study group comprised 117 bakers and 83 farmers reporting work-related respiratory symptoms. Skin prick tests (SPT) with common, fungal and occupational allergens, estimation of serum total IgE level, spirometry, histamine test and specific inhalative challenge test with occupational allergens were performed in all subjects. The prevalence of hypersensitivity to fungal species was higher among farmers (32.5%) than bakers (16.2%). Positive SPT with mould allergens were found among 10.8% farmers and 6.8% bakers with occupational allergy. The fungi allergens giving positive SPT results most frequently were Candida albicans, Levures mélanges, Aspergillus mix. and Charbons cerealiers in both groups. Among mould allergens, hypersensitivity to Aspergillus genus was the most common in farmers and bakers group, while among Saccharomyces - Candida albicans sensitization was the most frequently detected. Mould hypersensitivity is related to occupational respiratory allergy, especially to asthma and rhinitis in farmers, and occupational asthma in bakers. Although sensitization to Saccharomyces was more frequent, similar correlation was not observed.

Spectrum of gluten-related disorders: consensus on new nomenclature and classification

A decade ago celiac disease was considered extremely rare outside Europe and, therefore, was almost completely ignored by health care professionals. In only 10 years, key milestones have moved celiac disease from obscurity into the popular spotlight worldwide. Now we are observing another interesting phenomenon that is generating great confusion among health care professionals. The number of individuals embracing a gluten-free diet (GFD) appears much higher than the projected number of celiac disease patients, fueling a global market of gluten-free products approaching $2.5 billion (US) in global sales in 2010. This trend is supported by the notion that, along with celiac disease, other conditions related to the ingestion of gluten have emerged as health care concerns. This review will summarize our current knowledge about the three main forms of gluten reactions: allergic (wheat allergy), autoimmune (celiac disease, dermatitis herpetiformis and gluten ataxia) and possibly immune-mediated (gluten sensitivity), and also outline pathogenic, clinical and epidemiological differences and propose new nomenclature and classifications.

Occupational rhinitis

Work-related rhinitis, which includes work-exacerbated rhinitis and occupational rhinoconjunctivitis (OR), is two to three times more common than occupational asthma. High molecular weight proteins and low molecular weight chemicals have been implicated as causes of OR. The diagnosis of work-related rhinitis is established based on occupational history and documentation of immunoglobulin E (IgE) mediated sensitization to the causative agent if possible. Management of work-related rhinitis is similar to that of other causes of rhinitis and includes elimination or reduction of exposure to causative agents combined with pharmacotherapy. If allergens are commercially available, allergen immunotherapy can be considered.

EAACI position paper: prevention of work-related respiratory allergies among pre-apprentices or apprentices and young workers

Apprenticeship is a period of increased risk of developing work-related respiratory allergic diseases. There is a need for documents to provide appropriate professional advice to young adults aiming to reduce unsuitable job choices and prevent impairment from their careers. The present document is the result of a consensus reached by a panel of experts from European and non-European countries addressed to allergologists, pneumologists, occupational physicians, primary care physicians, and other specialists interested in this field, which aims to reduce work-related respiratory allergies (rhinoconjunctivitis and asthma) among allergic or nonallergic apprentices and other young adults entering the workforce. The main objective of the document is to issue consensus suggestions for good clinical practice based on existing scientific evidence and the expertise of a panel of physicians.

Industrial fungal enzymes: an occupational allergen perspective

Occupational exposure to high-molecular-weight allergens is a risk factor for the development and pathogenesis of IgE-mediated respiratory disease. In some occupational environments, workers are at an increased risk of exposure to fungal enzymes used in industrial production. Fungal enzymes have been associated with adverse health effects in the work place, in particular in baking occupations. Exposure-response relationships have been demonstrated, and atopic workers directly handling fungal enzymes are at an increased risk for IgE-mediated disease and occupational asthma. The utilization of new and emerging fungal enzymes in industrial production will present new occupational exposures. The production of antibody-based immunoassays is necessary for the assessment of occupational exposure and the development of threshold limit values. Allergen avoidance strategies including personal protective equipment, engineering controls, protein encapsulation, and reduction of airborne enzyme concentrations are required to mitigate occupational exposure to fungal enzymes.

Effect of Toll-like receptor 4 gene polymorphisms on work-related respiratory symptoms and sensitization to wheat flour in bakery workers

BACKGROUND

Bakery workers are exposed to flour allergens and endotoxins, which interact to induce allergic responses and respiratory symptoms. We hypothesized that Toll-like receptor 4 (TLR4) may be involved in the development of work-related respiratory symptoms and sensitization to wheat flour.

OBJECTIVE

To investigate the genetic contribution of TLR4 to respiratory symptoms and sensitization to wheat flour in bakery workers, we performed a genetic association study of TLR4 in Korean bakery workers.

METHODS

A total of 381 workers completed a questionnaire regarding work-related symptoms. Skin prick tests with common and occupational allergens were done, and specific antibodies to wheat flour were measured by enzyme-linked immunosorbent assay. Two single-nucleotide polymorphisms (SNPs) of the TLR4 gene (-2027A>G and -1608T>C) were genotyped, and the functional effects of the polymorphisms were analyzed using the luciferase reporter and electrophoretic mobility shift assay.

RESULTS

Homozygotes for the -2027G and -1608C alleles exhibited a lower prevalence of work-related lower respiratory symptoms than carriers of the -2027AA/AG (P = .007) and -1608TT/TC (P =.021) genotypes. Furthermore, haplotype analysis indicated that workers with the haplotype 2, ht2 [GC], had fewer work-related lower respiratory symptoms (P = .021). The ht2 [GC] construct showed lower promoter activity than the haplotype 1, ht1[AT], in both BEAS-2B (P = .001) and U937 cells (P = .007).

CONCLUSION

Bakery workers carrying the TLR4 variants are at lower risk of developing work-related chest symptoms. This finding suggests that the TLR4 gene may be involved in allergic sensitization to wheat flour as well as endotoxin-induced respiratory symptoms in endotoxin-allergen-exposed workers and that carriers of TLR4 variants are less affected by environmental exposure.

Prevention of occupational asthma

Prevention of occupational asthma related to a work-sensitizing agent ideally would be achieved by avoidance of exposures that cause immunologic sensitization and subsequent asthma. There are a few examples in which a sensitizing agent has been removed from a work process and others in which exposure has been significantly changed or reduced with associated reduced rates of sensitization and disease. Additional measures include containment, use of robots, ventilation measures, exposure monitoring, and use of respiratory protective devices. Secondary prevention includes medical surveillance, which may involve periodic respiratory questionnaires, spirometry, and immunologic tests aiming to detect sensitization or disease early to allow intervention and improve outcomes. Education measures for workers to understand the meaning of work-related respiratory symptoms and appropriate workplace safety measures have not been formally evaluated but may also be expected to enhance protective measures and lead to earlier diagnosis. Tertiary prevention includes medical management and workers' compensation.

Occupational rhinitis

Work-related rhinitis, which includes work-exacerbated rhinitis and occupational rhinitis, may be two to three times more common than occupational asthma. Both high molecular weight proteins and low molecular weight chemicals have been implicated as causes of occupational rhinitis. A diagnosis is established based on occupational history and, if appropriate, documentation of IgE-mediated sensitization to the causative agent. Management of work-related rhinitis is similar to that of non-work-related rhinitis and includes elimination or reduction of exposure to offending agents combined with pharmacotherapy. If treatment allergens are commercially available, allergen immunotherapy may also be considered if appropriate.

The impact of food allergy on asthma

Food allergy is a potentially severe immune response to a food or food additive. Although a majority of children will outgrow their food allergies, some may have lifelong issues. Food allergies and other atopic conditions, such as asthma, are increasing in prevalence in Western countries. As such, it is not uncommon to note the co-existence of food allergy and asthma in the same patient. As part of the atopic march, many food allergic patients may develop asthma later in life. Each can adversely affect the other. Food allergic patients with asthma have a higher risk of developing life-threatening food-induced reactions. Although food allergy is not typically an etiology of asthma, an asthmatic patient with food allergy may have higher rates of morbidity and mortality associated with the asthma. Asthma is rarely a manifestation of food allergy alone, but the symptoms can be seen with allergic reactions to foods. There may be evidence to suggest that early childhood environmental factors, such as the mother's and child's diets, factor in the development of asthma; however, the evidence continues to be conflicting. All food allergic patients and their families should be counseled on the management of food allergy and the risk of developing co-morbid asthma.

[Occupational rhinitis]

Occupational rhinitis (OR) is an inflammatory disease of the nose, which is characterized by intermittent or persistent symptoms, arising out of causes and conditions attributable to a particular work environment and not to stimuli encountered outside the workplace. Its clinical symptoms (nasal congestion, sneezing, rhinorrhea, itching, nasal airflow limitation) are very similar with the symptoms of the allergic rhinitis caused by other (classical) agents. According to the 27/1996 NM Departmental Order, OR in Hungary is a notifiable disease. Despite, between year 1997 and 2009, not even a single case was reported in Hungary. In the last 20 years the only Hungarian reference in this field was published in 2004, in the Textbook of Occupational Medicine, edited by Ungváry. This disease is not unknown in other European countries. It can be produced by both high and low molecular weight agents. For example, according to the publications, its prevalence among bakers can be 18-29%, and among workers with diisocyanates (painters, urethane mould workers) 36-42%. Risk factors are atopy, high concentration and multiple irritant agents in the air of workplace. Atopy has been associated with an increased risk of specific sensitization to a variety of HMW agents. Beside of the clinical and occupational history, objective investigations have to be used as well, for the diagnosis of OR. The gold standard for confirming the diagnosis of OR is the nasal provocation test. Objective methods that can be used for assessing nasal patency during the investigation of OR include rhinomanometry, acoustic rhinometry, peak nasal inspiratory flow, and gravimetry of the nasal secret. The management of the OR needs environmental interventions. These are: increasing the ventilation, decreasing the time of exposure, substitution of the irritant agent, investigation of possible asthma in all workers with OR. Medical treatments are: oral antihistamines, local (nasal) corticosteroids, combined (antihistamine+membrane-stabilizer) eyedrops.

Exposure to respirable dust and crystalline silica in bricklaying education at Dutch vocational training centers

BACKGROUND

Construction workers are educated at vocational training centers before they begin their working lives. Future bricklayers and their instructors are exposed to respirable dust and possibly to hazardous respirable crystalline silica from trial mortar.

METHODS

Thirty-six personal air samples were collected at six training centers to estimate exposure to respirable dust for both students and teachers. A selection of 22 samples was analyzed for crystalline silica.

RESULTS

Average respirable dust exposures ranged from 0.59 mg/m(3) for teachers to 1.45 mg/m(3) for students performing recycling and cleaning tasks. In 45% of the analyzed samples, respirable crystalline silica was detected. Exposure to silica remained below the Dutch OEL (75 microg/m(3)). Exposure was significantly less for teachers than for students. This effect was found in both types of vocational training centers present in the Netherlands. Dry sweeping, as performed at all locations in this study, contributed considerably to the exposure to respirable dust. A first step in reducing exposure to dust and silica at training centers would therefore be to avoid dry sweeping. The presence of a dust extraction system, although not optimally designed, also significantly lowered exposure.

CONCLUSIONS

To assess a construction worker's lifetime exposure to respirable dust and crystalline silica, the vocational training period should also be taken into account. Several epidemiological studies have shown that time since first exposure can be an important risk factor for chronic health effects.

Increase in exhaled nitric oxide is associated with bronchial hyperresponsiveness among apprentices

RATIONALE

Airway inflammation is a hallmark of asthma. Several studies have validated the use of the fractional concentration of exhaled nitric oxide (Fe(NO)) as a surrogate marker of airway inflammation in asthma.

OBJECTIVES

We examined how the change in Fe(NO) levels, since the beginning of occupational exposure, could be associated with the incidence of bronchial hyperresponsiveness (BHR) among baker, pastry maker, and hairdresser apprentices during their 2-year training.

METHODS

A standardized questionnaire was administered; skin prick tests for common and specific occupational allergens were done; methacholine challenge and measurement of Fe(NO) were performed 6, 12, and 15 months after the first examination.

MEASUREMENTS AND MAIN RESULTS

Of 441 apprentices initially included, 351 completed the study. The increase in Fe(NO), since the beginning of exposure, was associated with the incidence of BHR (odds ratio, 2.00 [95% confidence interval, 1.21-3.32] per unit increase in log parts per billion) both in atopic and nonatopic subjects. The average increase in Fe(NO) was similar in atopic and nonatopic subjects and was unrelated to past or current smoking habits, sex, or training track. Atopy in bakers/pastry makers and sensitization to alkaline persulfates in hairdressers were also independently associated with the incidence of BHR. BHR occurred sooner among bakers/pastry makers than among hairdressers, but its incidence leveled off later.

CONCLUSIONS

Our results suggest that measurement of Fe(NO), a simple and reproducible test, could be useful in the screening of BHR in workers newly exposed to agents known to cause occupational asthma.

Thaumatin-like protein and baker's respiratory allergy

BACKGROUND

Baker's asthma and rhinitis are among the most common occupational diseases. Inhaled cereal flours, such as wheat, especially cause this disease.

OBJECTIVE

To identify and test in vivo clinically important wheat allergens in baker's respiratory allergy in a Finnish population.

METHODS

Potential wheat allergens were purified using chromatographic methods from salt-soluble protein extracts of wheat flour and were used in skin prick tests with serial 10-fold dilutions (0.5-0.005 mg/mL). Twenty patients with baker's rhinitis, asthma, or both participated in this study. All the patients had positive skin prick test reactions and specific IgE antibodies to wheat flour. The control group consisted of 10 healthy individuals. Molecular identities of purified wheat allergens were characterized using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and tandem mass spectrometry.

RESULTS

Allergen concentrations of 0.3-0.5 mg/mL revealed that 12 patients reacted to a-amylase inhibitor (alpha-AI), 9 to peroxidase I (PI), 9 to thaumatin-like protein (TLP), and 6 to lipid transfer protein 2G (LTP2G). Conversely, with allergen concentrations of 0.05 mg/mL, 5 patients responded to alpha-AI, 3 to PI, 4 to LTP2G, and 6 to TLP. Of these, TLP and LTP2G are now observed to be new allergens associated with baker's asthma.

CONCLUSIONS

In addition to the earlier-described alpha-AI and PI, TLP and LTP2G are important in vivo wheat allergens in baker's allergies in Finland. Further studies are needed to elucidate the role of these novel wheat allergens in respiratory disorders.

Occupational and environmental lung disease: occupational asthma

Occupational exposures cause 10-15% of new-onset asthma in adults, and that represents a considerable health and economic burden. Exposure to many causative agents is now well controlled but workplace practices are constantly evolving and new hazards being introduced. Overall, there is no good evidence that the incidence of occupational asthma is decreasing. Evidence-based guidelines such as those published by the British Occupational Health research Foundation and Standards of Care documents should help raise awareness of the problem and improve management. Key targets include the control of occupational exposures, a high index of suspicion in any adult with new onset asthma, and early detailed investigation.

[Rhinitis and asthma related to cotton dust exposure in apprentices in the clothing industry]

OBJECTIVE

Respiratory allergies are the most common occupational diseases in the world. The aim of this study was to determine the prevalence of rhinitis and asthma among apprentices exposed to cotton dust in the clothing industry and to describe their epidemiologic and clinical profiles.

SUBJECTS AND METHODS

We carried out a descriptive study of 600 apprentices in a textile and clothing vocational training centre in the Monastir area. The investigation comprised a questionnaire exploring risk factors and symptoms appearing during their training. Subjects who developed allergic respiratory symptoms at the work-place underwent a clinical examination, rhinomanometry and investigation of their allergic status and respiratory function.

RESULTS

One hundred twenty apprentices (20%) developed allergic respiratory reactions due to exposure to textile dust (exclusively cotton) during their training, with a positive withdrawal-re-exposure test. Conjunctivitis (14.3%) and rhinitis (8.5%) were the most frequent allergic symptoms. Twenty eight apprentices (4.6%) presented symptoms of asthma. Rhinitis was associated with asthma in 45% of cases. Two cases of asthma were diagnosed clinically at the work-place following their exposure to textile dust. The prick test performed in 120 symptomatic apprentices was positive in 41.6% of cases. There was sensitization to pollens in 29 cases and to dermatophagoides in 13 cases. Cotton and wool allergy was noted in two cases. Allergic symptoms developing during the training were significantly more frequent in the atopic group, and they varied according to the intensity of textile dust exposure.

CONCLUSION

In the textile and clothing industry the frequency of respiratory disorders caused by allergens remains high, especially in atopic apprentices who constitute a population at high risk.

Early markers of airways inflammation and occupational asthma: rationale, study design and follow-up rates among bakery, pastry and hairdressing apprentices

Background

Occupational asthma is a common type of asthma caused by a specific agent in the workplace. The basic alteration of occupational asthma is airways inflammation. Although most patients with occupational asthma are mature adults, there is evidence that airways inflammation starts soon after inception of exposure, including during apprenticeship. Airways hyper responsiveness to methacholine is a valid surrogate marker of airways inflammation, which has proved useful in occupational epidemiology. But it is time-consuming, requires active subject's cooperation and is not readily feasible. Other non-invasive and potentially more useful tests include the forced oscillation technique, measurement of fraction exhaled nitric oxide, and eosinophils count in nasal lavage fluid.

Methods and design

This study aims to investigate early development of airways inflammation and asthma-like symptoms in apprentice bakers, pastry-makers and hairdressers, three populations at risk of occupational asthma whose work-related exposures involve agents of different nature. The objectives are to (i) examine the performance of the non-invasive tests cited above in detecting early airways inflammation that might eventually develop into occupational asthma; and (ii) evaluate whether, and how, constitutional (e.g. atopy) and behavioural (e.g. smoking) risk factors for occupational asthma modulate the effects of allergenic and/or irritative substances involved in these occupations. This paper presents the study rationale and detailed protocol.

Discussion

Among 441 volunteers included at the first visit, 354 attended the fourth one. Drop outs were investigated and showed unrelated to the study outcome. Sample size and follow-up participation rates suggest that the data collected in this study will allow it to meet its objectives.

EAACI position paper on occupational rhinitis

The present document is the result of a consensus reached by a panel of experts from European and non-European countries on Occupational Rhinitis (OR), a disease of emerging relevance which has received little attention in comparison to occupational asthma. The document covers the main items of OR including epidemiology, diagnosis, management, socio-economic impact, preventive strategies and medicolegal issues. An operational definition and classification of OR tailored on that of occupational asthma, as well as a diagnostic algorithm based on steps allowing for different levels of diagnostic evidence are proposed. The needs for future research are pointed out. Key messages are issued for each item.

Wheat

Wheat is the dominant crop in temperate countries being used for human food and livestock feed. Its success depends partly on its adaptability and high yield potential but also on the gluten protein fraction which confers the viscoelastic properties that allow dough to be processed into bread, pasta, noodles, and other food products. Wheat also contributes essential amino acids, minerals, and vitamins, and beneficial phytochemicals and dietary fibre components to the human diet, and these are particularly enriched in whole-grain products. However, wheat products are also known or suggested to be responsible for a number of adverse reactions in humans, including intolerances (notably coeliac disease) and allergies (respiratory and food). Current and future concerns include sustaining wheat production and quality with reduced inputs of agrochemicals and developing lines with enhanced quality for specific end-uses, notably for biofuels and human nutrition.

IL-18 levels in nasal lavage after inhalatory challenge test with flour in bakers diagnosed with occupational asthma

OBJECTIVES

The authors discuss the outcomes of a study on IL-18 concentration in nasal washings after the inhalatory challenge test with flour allergens (ICHT-F) in bakers with flour-induced occupational airway allergy (OAA).

METHODS

We measured IL-18 concentration using ELISA kit and assessed morphological changes in nasal lavage fluid (NLF) before, and 4 h and 24 h after ICHT-F in three groups of subjects: Group A - 9 patients with diagnosed OAA (occupational asthma and rhinitis), Group B - 10 patients with atopic asthma and rhinitis, and Group C - 9 healthy volunteers.

RESULTS

In Group A, significant differences in the basophil proportion in NLF were noted only 24 h after ICHT-F. Both the basophil proportion and total eosinophil count were higher in Group A than in Group C at this time-point. Group A also showed a statistically significant increase in IL-18 levels 4 h after the challenge. A significant relationship was noted between the proportion of basophils 4 h after ICHT-F and IL-18 level at 24 h after the test.

CONCLUSIONS

This is the first study demonstrating an increased expression of IL-18 in nasal washings of subjects diagnosed with OAA to flour allergens. The observed higher concentrations of IL-18 in nasal washings after ICHT as well as the increase in the proportion of basophils provide evidence for the important role of IL-18 in persistent allergic inflammation.

Chronic cough – occupational considerations

Chronic cough is a common symptom in a wide range of respiratory conditions, and may also occur as a result of upper airway or gastro-esophageal problems. Whilst chronic cough of any cause may be exacerbated by work, in some cases it has a direct occupational cause, resulting from a harmful acute or chronic workplace exposure. Such occupational conditions may only be suspected by taking a detailed occupational history, and directly asking employed patients whether their cough improves away from work. Early and accurate diagnosis, linked with tailored drug therapy, modification of workplace exposures, and expert compensation advice is likely to offer the best outcome for this group of patients.

Occupational rhinitis

The present document is the result of a consensus reached by a panel of experts from European and nonEuropean countries on Occupational Rhinitis (OR), a disease of emerging relevance, which has received little attention in comparison to occupational asthma. The document covers the main items of OR including epidemiology, diagnosis, management, socio-economic impact, preventive strategies and medicolegal issues. An operational definition and classification of OR tailored to that of occupational asthma, as well as a diagnostic algorithm based on steps allowing different levels of diagnostic evidence, are proposed. The needs for future research are pointed out. Key messages are issued for each item.

Making the diagnosis of occupational asthma: when to suspect it and what to do

Although most adult patients seen by a clinician are employed, medical school curricula and residency training rarely cover occupational exposures and resultant diseases, even common ones that are encountered in a typical medical practice. This primer on occupational asthma is intended for the primary care clinician to provide the essential tools to diagnose and treat airways disease in the workplace. Using a case vignette format, we review the basic approach to suspecting and establishing a diagnosis of occupational asthma and address the thornier question of what to do about it. After reviewing this primer, the reader will be able to routinely include occupational asthma as part of the differential diagnoses in the adult patient with new or worsened asthma.

Common characteristics of upper and lower airways in rhinitis and asthma: ARIA update, in collaboration with GA(2)LEN

This update aimed to review the new evidence available to support or refute prior Allergic Rhinitis and its Impact on Asthma (ARIA) statements. A Medline search of publications between 2000 and 2005 was conducted, with articles selected by experts. New evidence supports previous ARIA statements, such as: (i) allergic rhinitis (AR) is a risk factor for asthma; (ii) patients with persistent rhinitis should be evaluated for asthma; (iii) most patients with asthma have rhinitis; (iv) a combined strategy should be used to treat the airways and (v) in low- to middle-income countries, a different strategy may be needed. The increased risk of asthma has also been found among sufferers from non-AR. Recent reports show AR is a global problem. Many studies demonstrated parallel increasing prevalence of asthma and rhinitis, but in regions of highest prevalence, it may be reaching a plateau. Factors associated with a reduced risk of asthma and AR have been identified, confirming previous findings of protection related to exposure to infections. Treatment of rhinitis with intranasal glucocorticosteroids, antihistamines, leukotriene antagonists or immunotherapy may reduce morbidity because of asthma. To take advantage of the paradigm of unified airways, there is a need to rationalize diagnosis and treatment to optimize management.

Long-term outcomes in a prospective cohort of apprentices exposed to high-molecular-weight agents

RATIONALE

We conducted a long-term (8-yr) follow-up of 408 apprentices entering programs involving exposure to high-molecular-weight allergens.

OBJECTIVES

The objectives were to assess the frequency of new and persisting sensitization, symptoms, and bronchial hyperresponsiveness in relation with job history after ending apprenticeship and to examine characteristics significantly associated with the incidence and remission of these occupational outcomes.

METHODS

A respiratory symptom questionnaire, skin prick tests with work-related allergens (laboratory animals, flour, and latex), spirometry, and methacholine challenge were administered. The association between incidence or remission of these outcomes and individual characteristics at baseline and end of apprenticeship was examined.

MEASUREMENTS AND MAIN RESULTS

In subjects who at any time during follow-up held a job related to their training (78%), the incidence of sensitization, rhinoconjunctival and chest symptoms, and bronchial hyperresponsiveness at follow-up was 1.3, 1.7, 0.7, and 2.0 per 100 person-years, respectively. The remission of these outcomes acquired during apprenticeship was 18.5, 9.6, 9.6, and 12.4 per 100 person-years, respectively, in subjects no longer in a job related to training. Several clinical, immunological, and functional characteristics at baseline and acquired during apprenticeship were found to be significantly associated with the incidence and remission of the outcomes.

CONCLUSIONS

The incidence of sensitization, symptoms, and bronchial hyperresponsiveness was lower while at work than during the apprenticeship period. A high proportion of subjects in a job not related to training experienced remission of symptoms acquired during apprenticeship.

Exposure of bakery and pastry apprentices to airborne flour dust using PM2.5 and PM10 personal samplers

Background

This study describes exposure levels of bakery and pastry apprentices to flour dust, a known risk factor of occupational asthma.

Methods

Questionnaires on work activity were completed by 286 students. Among them, 34 performed a series of two personal exposure measurements using a PM_2.5 and PM₁₀ personal sampler during a complete work shift, one during a cold ("winter") period, and the other during a hot ("summer") period.

Results

Bakery apprentices experience greater average PM_2.5 and PM₁₀ exposures than pastry apprentices (p < 0.006). Exposure values for both particulate fractions are greater in winter (average PM₁₀ values among bakers = 1.10 mg.m^-3 [standard deviation: 0.83]) than in summer (0.63 mg.m^-3 [0.36]). While complying with current European occupational limit values, these exposures exceed the ACGIH recommendations set to prevent sensitization to flour dust (0.5 mg.m^-3). Over half the facilities had no ventilation system.

Conclusion

Young bakery apprentices incur substantial exposure to known airways allergens, a situation that might elicit early induction of airways inflammation.

Optimized methods for fungal ?-amylase airborne exposure assessment in bakeries and mills

BACKGROUND

In order to enable reproducible and comparable exposure measurements of fungal alpha-amylase (alpha-amylase) in different laboratories and countries, the entire procedure from sampling of airborne dust to measuring extracted samples (including standards and the used enzyme) immunoassays must be standardized. The aim of this study was to establish optimal elution and assay conditions.

METHODS

A parallel sampler was used for simultaneous collection of 10 samples of inhalable dust in bakeries and mills in Germany, England, the Netherlands and Spain. Three enzyme-immunoassays (EIAs) for detection of fungal alpha-amylase based on monoclonal antibodies or polyclonal antibodies were used for the measurement of the parallel-sampled filters (n=432) extracted using several methods. The results were analysed by regression analysis of variance. Additional filters (n=54) were extracted and analysed using two EIAs to investigate the storage stability of the extracts.

RESULTS

Although alpha-amylase concentrations correlated well (r> or =0.88), differences were found between the EIAs in the sensitivity and nominal values (up to a mean factor 5.8). The best elution medium for airborne filters (phosphate-buffered saline 'PBS' with 0.05% Tween-20) led to 1.2 to two times higher alpha-amylase allergen yields than extraction in PBS only, while higher Tween-20 concentrations decreased the extracted alpha-amylase yield. During storage of frozen dust/filter extracts for 3-4 months at -20 degrees C, a loss of approximately 40% of measurable alpha-amylase was observed, which could be partially prevented by addition of 0.1% casein to the medium directly after extraction.

CONCLUSION

Although the effects of only a few of many possible causes of variation were investigated, for these factors a clear choice could be made with regard to optimal elution conditions and the use of validated EIAs with calibrated standards, thus making significant progress towards a completely standardized procedure for airborne alpha-amylase measurements.