Progress in Occupational Asthma

Occupational asthma (OA) represents one of the major public health problems due to its high prevalence, important social and economic burden. The aim of this review is to summarize current data about clinical phenotypes, biomarkers, diagnosis and management of OA, a subtype of work-related asthma. Most studies have identified two phenotypes of OA. One is sensitizer-induced asthma, occuring after a latency period and caused by hypersensitivity to high- or low-molecular weight agents. The other is irritant-induced asthma, which can occur after one or more exposures to high concentrations of irritants without latency period. More than 400 agents causing OA have been identified and its list is growing fast. The best diagnostic approach for OA is a combination of clinical history and objective tests. An important tool is a specific inhalation challenge. Additional tests include assessments of bronchial hyperresponsiveness to methacholine/histamine in patients without airflow limitations, monitoring peak expiratory flow at- and off-work, sputum eosinophil count, exhaled nitric oxide measurement, skin prick tests with occupational allergens and serum specific IgE. Treatment of OA implies avoidance of exposure, pharmacotherapy and education. OA is a heterogeneous disease. Mechanisms of its different phenotypes, their diagnosis, role of new biomarkers and treatment require further investigation.

[Occupational allergic asthma in a laboratory animal keeper with COPD]

This is a case report of a 63-year-old woman, who had worked as a laboratory animal keeper for 23 years. She developed increasing symptoms of rhinitis, coughing and shortness of breath and was diagnosed and treated for COPD based on her smoking history and spirometry results. She went on sick leave due to dyspnoea, and after testing she was diagnosed with occupational allergic asthma from rodents. Her lung function was at this point significantly reduced. Occupational asthma is common, and occupational causes of respiratory symptoms should always be taken into consideration when assessing patients in the working population.

Occupational asthma and rhinitis: Do we think about it as soon as possible?

Occupational asthma and allergic diseases of the upper airway play an important role in occupational diseases. The most frequent allergens, which causes occupational respiratory diseases in the Czech Republic, are isocyanates and wheat and rye flour. Isocyanates are the substances used in car industry during production of polyurethanes, they are in colours and glues. Occupational allergic asthma and rhinitis are diagnosed using specific challenge tests with substances from the workplace. These tests can be done in a special exposure box in a lab with substances taken by hygiene specialists from the patient´s workplace or using direct exposure at the workplace. Spirometry and anterior active rhinomanometry are used as objective methods during these tests. For prognosis the early diagnosis and withdrawal from the occupational allergen exposure are essential. Keywords: allergic asthma, allergic rhinitis, irritant-induced asthma, irritant-induced rhinitis, isocyanate, occupational disease, specific inhalation challenge.

Serum Periostin Levels: A Potential Serologic Marker for Toluene Diisocyanate-Induced Occupational Asthma

PURPOSE

Toluene diisocyanate (TDI) is a leading cause of occupational asthma (OA). Periostin is a matricellular protein implicated in type 2 immunity-driven asthma. Its pathogenic role in TDI-OA has not been completely elucidated. The present study was performed to investigate the role of periostin in TDI-OA.

MATERIALS AND METHODS

Serum periostin levels were measured in subjects with TDI-OA, asymptomatic TDI-exposure controls (AECs), non-occupational asthmatics (NAs), and unexposed normal controls (NCs). To understand the mechanism by which TDI induces periostin production, primary small airway epithelial cells (SAECs) were cultured under stimulation of TDI and neutrophils from asthmatic patients.

RESULTS

Fifty-three subjects with TDI-OA, 71 AECs, 67 NAs, and 83 NCs were enrolled. Serum periostin levels were significantly higher in TDI-OA subjects than in AECs (p=0.001), NAs (p<0.001), and NCs (p<0.001). In TDI-exposed subjects (TDI-OA and AEC), the PC₂₀ methacholine levels were significantly lower in subjects with a higher periostin level than in those with a lower periostin level. TDI exposure did not increase periostin production directly by SAECs; however, periostin production increased significantly after co-culture with TDI and neutrophils, which was suppressed by an antioxidant. In addition, increased release of TGF-β1 was noted from SAECs when exposed to TDI and neutrophils, which was also suppressed by an antioxidant.

CONCLUSION

These results suggest that an increased periostin level may contribute to the progression of airway inflammation to remodeling in TDI-exposed workers. A high serum periostin level is a potential serologic marker of the phenotype of TDI-OA.

[Characteristics of asthma cases reported as a suspected occupational disease in Navarra. Period 2010-2015]

OBJECTIVE

Although, occupational asthma (OA) causes great work disability, due to its diagnostic complexity, it is difficult to have it recognized by the official registration systems. To improve its detection, suspected systems have been developed. After years of experience in Navarre, we set out to characterize the suspected cases and compare them with those declared as an occupational disease (OD).

METHODS

We identified the cases of OA reported as sentinel events in the Epidemiological Surveillance Program in Occupational Health in Navarra from January 2010 to December 2015 and the cases declared as OD (asthma). The population under study was the Navarra employed population (357,200 on average). In the cases with consent, the clinical and labor characteristics were compared with those of OD. Using the SPSS Statistics® 20v computer program, mean differences were calculated by the T test for independent samples and distribution percentage differences by Chi-square test, Fisher's exact test and nonparametric tests when application conditions were not satisfied. As an indicator of notification, the accumulated incidence per 100,000 workers was calculated for each year of program monitoring.

RESULTS

In the period, 79 sentinel events were reported (in 22 the investigation was concluded) and 50 cases of OD (24% relapses). We did not find statistically significant differences in age (41 vs. 40 years), nor gender (40.9% women vs. 44.7%), nor proportion that caused sick leave (45% and 36.8%), nor size, activity of the company or occupation of the worker. Where differences are found was in the meantime of exposure before the recognition/notification, significantly higher in the OD than in the sentinel (94.1 vs. 22.2 months), 72 months longer.

CONCLUSIONS

The cases detected by both systems are similar but, due to the diagnostic complexity, the recognition is delayed as OD, which demonstrates the usefulness of a more agile system for reporting suspicions of this work pathology.

Addressing Molecular Diagnosis of Occupational Allergies

PURPOSE OF REVIEW

Numerous clinically relevant allergenic molecules enhance the performance of specific (s) IgE tests and improve the specificity of allergy diagnosis. This review aimed to summarize our current knowledge of the high-molecular-weight allergens involved in the development of occupational asthma and rhinitis and to critically analyze the contribution of component-resolved diagnosis in the management of these conditions.

RECENT FINDINGS

There is a lack of standardization and validation for most available extracts of occupational agents, and assessment of sIgE reactivity to occupational allergen components has been poorly investigated, with the notable exception of natural rubber latex (NRL) and wheat flour. In the case of NRL, the application of recombinant single allergens and amplification of natural extracts with stable recombinant allergens improved the test sensitivity. IgE-sensitization profile in patients with baker's asthma showed great interindividual variation, and extract-based diagnostic is still recommended. For other occupational allergens, it remains necessary to evaluate the relevance of single allergen molecules for the sensitization induced by occupational exposure. Progress has been made to characterize occupational allergens especially NRL and wheat, although there is still an unmet need to increase the knowledge of occupational allergens, to include standardized tools into routine diagnostic, and to evaluate their usefulness in clinical practice.

[New in vitro allergological diagnostic tool and its application in professional disease.]

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

[Diagnostic approach to occupational allergic respiratory diseases.]

OBJECTIVES

An accurate diagnosis of occupational allergic respiratory diseases is crucial because they are related to disability, loss of work and worsening of psychosocial and economic status of workers. Early diagnosis is therefore essential to prevent the progression of allergic respiratory diseases and to implement preventive measures. The most frequent occupational allergic respiratory diseases are asthma (OA) and rhinitis (OR), less frequently hypersensitivity pneumonia (HP) and non-asthmatic eosinophilic bronchitis (NAEB).

METHODS

The diagnosis is based on the objective evidence of the disease, on a clear correlation with the work activity and the identification of a specific sensitizing agent in the workplace.

RESULTS

Reference standard methods are available, such as Specific Inhalation Challenge in the laboratory or in the workplace.

CONCLUSIONS

A multidisciplinary approach in highly-specialized centres is always recommended for diagnostic confirmation, as it is accompanied by greater diagnostic sensitivity and specificity.

Recommendations for a Clinical Decision Support System for Work-Related Asthma in Primary Care Settings

OBJECTIVE

The aim of this study was to describe a recommended clinical decision support (CDS) approach for work-related asthma for incorporation in electronic health records (EHRs) for primary care health care providers.

METHODS

Subject matter experts convened by the American Thoracic Society reviewed available guidelines and published literature to develop specific recommendations.

RESULTS

It is important to recognize possible work-related asthma among persons with new-onset or worsening asthma. The work group recommends incorporating three simple questions about temporal relations between asthma symptoms and work in EHR systems and identified specific clinical conditions to trigger this intervention. Patients with positive responses to the three questions should have the asthma diagnosis documented and have further evaluation, education, and possible referral.

CONCLUSION

An effective CDS system for improving recognition of work-related asthma may help reduce morbidity and mortality of asthma in adults.

[Work-related asthma in an orthopaedic surgeon]

An orthopaedic surgeon with no history of lung disease developed cough and dyspnoea. The patient was diagnosed with asthma by spirometry and bronchial provocation test with methacholine. A clear correlation between symptoms and work was established meriting a referral to a centre for occupational health. The patient was diagnosed with work-related disease, which was recognized by the industrial injury board. The cause was methyl methacrylate, a known airway irritant, which is an important component of bone cement. Previously, no cases of work-related asthma in orthopaedic surgeons have been reported.

Work-related asthma among professional cleaning women

The job of cleaning has developed dynamically as a working service, and women constitute the majority of all professional cleaning workers. Cleaners are at an increased risk of work-related asthma (WRA). This study characterizes work-related respiratory symptoms reported by female cleaners, evaluates any associated factors of WRA, and shows diagnostic management of medical certification. The study group comprised 50 professional cleaning women referred to our Occupational Diseases Department due to suspicion of occupational asthma (OA). A questionnaire, skin prick tests, serum specific IgE antibodies, and specific inhalant challenge were performed in all of the participants. Work-related asthma was recognized in 46% of symptomatic cleaners, of whom 15 were considered as having work-exacerbated asthma (WEA) and 8 as having OA. Sensitization to latex and disinfectants played an important role as a causative agent in OA of cleaners.

[Occupational asthma]

Occupational asthma is the most common occupational respiratory disease. It mainly affects young workers with significant socio-economic consequences. Early recognition improves its prognosis. A rigorous investigative approach while the worker is still exposed at work and appropriate medical care require a multi-disciplinary collaboration. Prevention is the key element in the management of professional asthma.

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

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

Occupational and Environmental Contributions to Chronic Cough in Adults: Chest Expert Panel Report

BACKGROUND

In response to occupational and environmental exposures, cough can be an isolated symptom reflecting exposure to an irritant with little physiological consequence, or it can be a manifestation of more significant disease. This document reviews occupational and environmental contributions to chronic cough in adults, focusing on aspects not previously covered in the 2006 ACCP Cough Guideline or our more recent systematic review, and suggests an approach to investigation of these factors when suspected.

METHODS

MEDLINE and TOXLINE literature searches were supplemented by articles identified by the cough panel occupational and environmental subgroup members, to identify occupational and environmental aspects of chronic cough not previously covered in the 2006 ACCP Cough Guideline. Based on the literature reviews and the Delphi methodology, the cough panel occupational and environmental subgroup developed guideline suggestions that were approved after review and voting by the full cough panel.

RESULTS

The literature review identified relevant articles regarding: mechanisms; allergic environmental causes; chronic cough and the recreational and involuntary inhalation of tobacco and marijuana smoke; nonallergic environmental triggers; laryngeal syndromes; and occupational diseases and exposures. Consensus-based statements were developed for the approach to diagnosis due to a lack of strong evidence from published literature.

CONCLUSIONS

Despite increased understanding of cough related to occupational and environmental triggers, there remains a gap between the recommended assessment of occupational and environmental causes of cough and the reported systematic assessment of these factors. There is a need for further documentation of occupational and environmental causes of cough in the future.

Determination of albumin adducts of 4,4'-methylenediphenyl diisocyanate after specific inhalative challenge tests in workers

4,4'-Methylenediphenyl diisocyanate (MDI) is the most important isocyanate used in the industry. Lung sensitization with bronchial asthma is the main disorder in exposed workers. Albumin adducts of MDI might be involved in specific immunological reactions. MDI adducts with lysine (MDI-Lys) of albumin have been found in MDI-workers and construction workers. MDI-Lys is an isocyanate-specific adduct of MDI with albumin. In the present study, we report MDI-adducts in workers undergoing diagnostic MDI challenge tests. The workers were exposed for 2h to 5ppb of MDI. The adduct levels increase significantly after the exposure to MDI in the challenge chamber. About 0.6% of the dose was bound to albumin. So far, only urinary metabolites of MDI were measured to monitor isocyanate workers. However, such urinary metabolites are not isocyanate specific. Therefore, we propose to measure albumin adducts for monitoring MDI exposed subjects.

[Specific bronchial and nasal provocations with work-related allergens]

Specific inhalation challenge (SIC) is the golden standard for identifying specific causes of work-related asthma and rhinoconjunctivitis. Few centres offer SIC as it requires experience, resources and acute treatment facilities. Prior to SIC treatment should be carefully reduced. A control challenge is performed on a separate day. Many new asthma causes have been identified with SIC. SIC provides the basis for optimal treatment and advice.

Occupational asthma in a fruit and vegetables vendor

BACKGROUND

This study presents a case report of a woman running a fruit and vegetables market stall, occupationally exposed to mushroom spores, who developed asthmatic symptoms. Basidiospores are allergens that can give rise to sensitization and subsequently trigger an allergic reaction, such as contact dermatitis, rhino-conjunctivitis, asthma and hypersensitivity pneumonitis.

METHODS

A 40-year-old atopic woman, who had worked at a market stall selling fruit and vegetables for the past 26 years in a small town market in southern Italy, came to our attention at the Occupational Medicine Unit, complaining of a 3-year history of dyspnoea, cough, and wheezing during autumn and winter.

RESULTS

Spirometry showed a severe mixed type respiratory deficit with a significant bronchodilator response obtained with salbutamol administration. Skin prick tests to common aeroallergens were negative. Prick-to-prick test with fresh Pleurotus ostreatus was positive. We evaluated the size of the skin wheals and compared them to the positive control according to the Skin Index. An on-the-spot inspection of her store was performed and environmental conditions were identified that did not allow a satisfactory air exchange.

CONCLUSIONS

The clinical history and the results of the allergologic investigations, plus an on-the-spot inspection, permitted us to ascertain that this subject had developed occupational asthma due to Pleurotus ostreatus spores. We advised her to stop handling and selling mushrooms, and she has no longer suffered asthmatic symptoms, over seven years of follow-up, and regularly continued to work without needing to take anti-asthma drugs.

[Clinical, biochemical and allergological indices characterizing occupational diseases of the bronchial and pulmonary system in employees at aluminium production]

There are many harmful factors that possess a damaging impact on the body of employees at aluminum production. It leads to the development of bronchial asthma (BA), chronic nonobstructive bronchitis (CNB) and chronic obstructive pulmonary disease (COPD). The pathogenesis of these disorders, as well as sensitizing effect offluorine in the aluminum production is not fully understood. The purpose of this work was to study the characteristics of laboratory indices in patients with occupational diseases of the respiratory system. In workers of aluminum production with the diagnosis of occupational diseases of respiratory system (15 patients with a diagnosis of asthma, 30 CNB cases, 20 COPD patients) we evaluated the content of total protein, total cholesterol, high density lipoprotein cholesterol (HDLC), total calcium, phosphorus, ceruloplasmin, hematological indices and performed emigration of leukocytes braking test (TTEEL). Clinical and biochemical profile ofpersons with occupational asthma was characterized by a low level of total calcium and ceruloplasmin, a high concentration of phosphorus in the blood serum and inhibition of leukocyte emigration in the test with sodium fluoride. For aluminum production CNB workers characteristic active proatherogenic process was pronounced by a decrease in the HDLC level and an increase in atherogenic index; higher hematocrit value and concentration of erythrocytes, and more than 50% of cases of sensitization to the presence of sodium fluoride. COPD cases had occupational lower average concentration of hemoglobin in the erythrocyte, total protein in serum, as well as polymorphic variant response to sodium fluoride in the form of a depression and activation of leucocytes emigration.