Allergen component analysis as a tool in the diagnosis of occupational allergy

EAACI Molecular Allergology User's Guide 2.0

Since the discovery of immunoglobulin E (IgE) as a mediator of allergic diseases in 1967, our knowledge about the immunological mechanisms of IgE-mediated allergies has remarkably increased. In addition to understanding the immune response and clinical symptoms, allergy diagnosis and management depend strongly on the precise identification of the elicitors of the IgE-mediated allergic reaction. In the past four decades, innovations in bioscience and technology have facilitated the identification and production of well-defined, highly pure molecules for component-resolved diagnosis (CRD), allowing a personalized diagnosis and management of the allergic disease for individual patients. The first edition of the "EAACI Molecular Allergology User's Guide" (MAUG) in 2016 rapidly became a key reference for clinicians, scientists, and interested readers with a background in allergology, immunology, biology, and medicine. Nevertheless, the field of molecular allergology is moving fast, and after 6 years, a new EAACI Taskforce was established to provide an updated document. The Molecular Allergology User's Guide 2.0 summarizes state-of-the-art information on allergen molecules, their clinical relevance, and their application in diagnostic algorithms for clinical practice. It is designed for both, clinicians and scientists, guiding health care professionals through the overwhelming list of different allergen molecules available for testing. Further, it provides diagnostic algorithms on the clinical relevance of allergenic molecules and gives an overview of their biology, the basic mechanisms of test formats, and the application of tests to measure allergen exposure.

Update on latex allergy: New insights into an old problem

Despite the efforts made to mitigate the consequences of this disease, natural rubber latex allergy (NRLA) continues to be a global health problem and is still considered one of the main worries in the working environment in many countries throughout the world. Due to thousands of products containing latex, it is not surprising that the current statistics suggest that prevalence remains high among healthcare workers and susceptible patients. In developed countries, reduction in the prevalence of IgE-mediated allergy to latex proteins from gloves may lead to lax attention by health care personnel. On the other hand, this situation is different in developing countries where there is a lack of epidemiological data associated with a deficit in education and awareness of this issue. The aim of this review is to provide an update of the current knowledge and practical recommendations regarding NRLA by allergologists from different parts of the world with experience in this field.

Current state of occupational latex allergy

PURPOSE OF REVIEW

During the 1980s, natural rubber latex (NRL) emerged as a major cause of occupational allergy and asthma, especially in healthcare workers using powdered NRL gloves. Increased recognition of NRL allergies and transfer of research findings into prevention strategies resulted into an almost elimination of this health problem. Here, the current knowledge on allergens, their use in diagnostics, prevalence data of occupational NRL allergy and the status of prevention strategy are summarized.

RECENT FINDINGS

While the current studies conducted in high-income countries show that prevention measures have reduced NRL allergy, this does not yet apply worldwide. For latex allergy diagnosis, it is important that recombinant allergens as reliable tools are available, because in several European countries and the United States, NRL skin prick test extracts and powdered latex gloves for bronchial challenge test are no longer commercially available, leading to a deficit in diagnostic tools. Due to the fact that latex is suitable with good properties as a raw material for gloves, alternatives with significantly lower protein content and without cross-reactive structures to latex proteins are sought.

SUMMARY

Awareness of the sensitization risk associated with the use of latex gloves should still be present in all occupational settings.

[New allergens for occupational dermatology?]

BACKGROUND

The environment is continuously subject to change. Exposures in the work environment and therefore the importance of occupational type I and type IV allergens may change.

OBJECTIVES

The most important trends concerning occupational allergens, new occupational allergens/allergen exposures, the diagnostic procedure to detect new allergens in practice and regulatory developments are presented.

MATERIALS AND METHODS

Building on known relevant allergen exposures in occupational dermatology, published trends from clinical cohorts are evaluated and a systematic literature search (PubMed 2016-2021) for new occupational allergens is also performed RESULTS: Occupations with the highest incidence of occupational allergic contact urticaria and/or protein contact dermatitis include bakers, farmers and farm workers, veterinary technicians, veterinarians, cooks, dairy and livestock workers, gardeners, and hairdressers. The highest risk of developing occupational contact dermatitis is in health care, agriculture, metalworking occupations and machine operators, the food sector, service industries, and construction occupations. The search strategy "new occupational allerg*" yielded 603 hits and "novel occupational allerg*" 158 hits. A total of 25 papers included results relevant to the research question and were processed. New protein-based immediate-type allergens, as well as contact allergens (haptens) relevant for occupational dermatology, are presented.

CONCLUSIONS

Current trends on known occupational allergens and new occupational allergens in the period 2016-2021 can be identified. Only a thorough individual workplace history and testing of patients' own materials can identify new allergens in occupational dermatology.

Occupational asthma and rhinitis due to wheat flour: sublingual specific immunotherapy treatment

BACKGROUND

There are several potential sensitizers in the bakery environment and wheat flour appears to be the dominant sensitizer in most bakeries. Apart from traditional drug therapy or a change in profession, there are no effective therapies for workers who develop serious respiratory symptoms in the workplace.

OBJECTIVES

To describe clinical and laboratory findings in workers with asthma and/or rhinitis induced by wheat flour who underwent sublingual specific immunotherapy (SLIT).

METHODS

Since drug therapy and prevention strategies were not effective, five bakers were elected to undergo SLIT. A three-year study was led by administering a sublingual wheat flour extract. Questionnaires, allergy and respiratory tests were performed before and after SLIT.

RESULTS

After SLIT an improvement in symptoms is observed in every patient: Asthma Control Test and a quality-of-life questionnaire show higher scores and as a result, workers have reduced the use of drug therapy. We observed significantly reduced exhaled nitric oxide (FeNO) and eosinophil cationic protein (ECP) levels after SLIT, hypothesizing that these parameters may be used to monitor the effectiveness of immunotherapy. The improvement of FEV1 (forced expiratory volume in 1second) and responsiveness to bronchoprovocative tests with methacholine denotes a possible role of SLIT in treating patients with low-respiratory tract involvement, even though more data are needed.

DISCUSSIONS

This is the first report in the literature on the use of SLIT for baker's asthma and rhinitis. SLIT for occupational wheat flour allergy should be possible and efficient, saving vocational training, professionalism, and avoiding job loss.

A WAO - ARIA - GA2LEN consensus document on molecular-based allergy diagnosis (PAMD@): Update 2020

Precision allergy molecular diagnostic applications (PAMD@) is increasingly entering routine care. Currently, more than 130 allergenic molecules from more than 50 allergy sources are commercially available for in vitro specific immunoglobulin E (sIgE) testing. Since the last publication of this consensus document, a great deal of new information has become available regarding this topic, with over 100 publications in the last year alone. It thus seems quite reasonable to publish an update. It is imperative that clinicians and immunologists specifically trained in allergology keep abreast of the new and rapidly evolving evidence available for PAMD@.

PAMD@ may initially appear complex to interpret; however, with increasing experience, the information gained provides relevant information for the allergist. This is especially true for food allergy, Hymenoptera allergy, and for the selection of allergen immunotherapy. Nevertheless, all sIgE tests, including PAMD@, should be evaluated within the framework of a patient's clinical history, because allergen sensitization does not necessarily imply clinical relevant allergies.

An Official American Thoracic Society Workshop Report: Presentations and Discussion of the Sixth Jack Pepys Workshop on Asthma in the Workplace

The Sixth Jack Pepys Workshop on Asthma in the Workplace focused on six key themes regarding the recognition and assessment of work-related asthma and airway diseases: (1) cleaning agents and disinfectants (including in swimming pools) as irritants and sensitizers: how to evaluate types of bronchial reactions and reduce risks; (2) population-based studies of occupational obstructive diseases: use of databanks, advantages and pitfalls, what strategies to deal with biases and confounding?; (3) damp environments, dilapidated buildings, recycling processes, and molds, an increasing problem: mechanisms, how to assess causality and diagnosis; (4) diagnosis of occupational asthma and rhinitis: how useful are recombinant allergens (component-resolved diagnosis), metabolomics, and other new tests?; (5) how does exposure to gas, dust, and fumes enhance sensitization and asthma?; and (6) how to determine probability of occupational causality in chronic obstructive pulmonary disease: epidemiological and clinical, confirmation, and compensation aspects. A summary of the presentations and discussion is provided in this proceedings document. Increased knowledge has been gained in each topic over the past few years, but there remain aspects of controversy and uncertainty requiring further research.

Allergen component analysis as a tool in the diagnosis and management of occupational allergy

We are now in the epoch of "molecular allergology" and numerous clinically relevant allergenic molecules are available improving the performance of in vitro allergen tests and allergen detection methods. This review is focusing on characterized occupational allergens and their implementation into the in vitro diagnosis for occupational allergy and in allergen detection methods. More than 400 occupational agents are identified and documented as being 'respiratory sensitizers', but currently only a limited number of them are characterized on the molecular level and available for routine diagnosis as native or recombinant allergens. One exception, however, is natural rubber latex (NRL) from Hevea brasiliensis still remaining an important occupational allergen source. Characterization of 15 NRL allergens led to the development of assays for the determination of allergen content of NRL materials and the implementation of component-resolved diagnosis (CRD) for specific IgE antibody measurement. Microarray or singleplex using recombinant or native allergens are reliable tools for NRL allergy diagnosis. In addition, NRL allergy is an excellent model for improving extract-based specific IgE measurement by amplification of NRL extract preparation with stable recombinant major allergen rHev b 5. Despite the many efforts to characterize the occupationally relevant wheat allergens for baker's asthma, the most frequently occurring forms of occupational asthma, the results are highly diverse. Wheat sensitization profiles of bakers showed great interindividual variability and no wheat allergen could be classified as the major allergen. For diagnosis of baker's asthma, a whole wheat extract is still the best option for specific IgE determination. But single wheat allergens might help to discriminate between wheat-induced food allergy, grass pollen allergy and baker's asthma. For workplace-related allergens like coffee, wood, soybean, seafood and moulds allergens are characterized and few of them are available, but their relevance for occupational sensitization routes should be verified in the further studies.

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.

Pre- and perioperative aspects of dermatosurgery

Dermatosurgery occupies an exceptional position among all surgical disciplines. Above all, this includes the fact that, with very few exceptions, the vast majority of surgical interventions can be performed under local or regional anesthesia, usually in smaller procedure rooms that are spatially separated from larger operating suites. Thus, peri- and postinterventional patient monitoring is the responsibility of the dermatosurgeon and his team. Though inherently smaller, this team still has to observe numerous perioperative requirements that - in larger surgical specialties - would be attended to by a host of various specialists working in concert. Said requirements include hygienic aspects, knowledge concerning pre- and intraoperative patient monitoring, managing surgical site infections, adequate postsurgical pain management, as well as detailed pharmacological knowledge with respect to common local anesthetics and the toxic and allergic reactions associated therewith. Not only does this require interdisciplinary collaboration and shared responsibility for the patient. It also necessitates the development and implementation of quality-oriented and evidence-based guidelines that, in the dermatosurgical setting, usually extend far beyond the scope of the specialty per se. The objective of the present CME article is the condensed presentation of interdisciplinary aspects relating to the most important perioperative issues.

Prä- und perioperative Aspekte der Versorgung dermatochirurgischer Patienten

Die Dermatochirurgie nimmt hinsichtlich vieler Punkte eine Sonderstellung unter den operativen Fächern ein. Hierzu gehört in erster Linie die Tatsache, dass bis auf wenige Ausnahmen fast alle Eingriffe traditionell in Lokal- bzw. Regionalanästhesie und oft auch in räumlich-infrastruktureller Trennung von den großen Zentral-Operationssälen stattfinden können. Die peri- und postoperative Überwachung obliegt dabei dem dermatochirurgischen Operationsteam. Das sui generis kleinere OP-Team hat somit eine ganze Reihe perioperativer Notwendigkeiten zu beachten, um die sich in den "großen" chirurgischen Fächern eine Vielzahl verschiedener beteiligter Fachgruppen gemeinsam kümmern. Hierzu gehören neben Hygieneaspekten, Kenntnissen in der Überwachung der Patienten sowie dem Aspekt der surgical site infections auch Fragen zur postoperativen Schmerztherapie sowie detailliertes pharmakologisches Wissen über die zur Anwendung kommenden Lokalanästhetika und das Handling der damit assoziierten toxischen und allergischen Reaktionen. Eine interdisziplinäre Zusammenarbeit und Verantwortung für den Patienten ist notwendig und erfordert die Erarbeitung und Umsetzung qualitätsorientierter und evidenzbasierter Handlungsanweisungen, die im dermatochirurgischen OP-Setting meist weit über das eigentliche Fach hinausgehen. Ziel dieses Weiterbildungsartikels soll die komprimierte Darstellung der genannten fachübergreifenden Standpunkte bezüglich der wichtigsten perioperativen Aspekte sein.

Occupational Allergy

An estimated 11 million workers in the USA are potentially exposed to agents that can become a cause of allergic diseases such as occupational asthma and allergic contact dermatitis, which can adversely affect health and well-being. Hundreds of chemicals (e.g. metals, epoxy and acrylic resins, rubber additives, and chemical intermediates) and proteins (e.g. natural rubber latex, plant proteins, mould, animal dander) present in virtually every industry have been identified as causes of allergic disease. In general, allergens can be classified as low molecular weight (chemical) allergens and high molecular weight (protein) allergens. These agents are capable of inducing immunological responses that are both immunoglobulin E and non-immunoglobulin E-mediated. Interestingly, the same chemical can induce diverse immune responses in different individuals. As new hazards continue to emerge, it is critical to understand the immunological mechanisms of occupational allergic disease. Specific understanding of these mechanisms has direct implications in hazard identification, hazard communication, and risk assessment. Such efforts will ultimately assist in the development of risk management strategies capable of controlling workplace exposures to allergens to prevent the induction of sensitisation in naïve individuals and inhibit elicitation of allergic responses. The purpose of this short review is to give a brief synopsis of the incidence, agents, mechanisms, and research needs related to occupational allergy.

New developments in work-related asthma

INTRODUCTION

Work-related asthma includes two subtypes: occupational asthma or asthma caused by specific agents (sensitizers or irritants) in the workplace, and work-exacerbated asthma or pre-existing asthma worsened by workplace exposures. Areas covered: This review provides an update on the definitions and the clinical features of the different work-related asthma subtypes as well as new insights into their etiology and the pathophysiological mechanisms involved. The diagnosis of work-related asthma should be made on objective basis using a constellation of clinical, physiologic and allergologic tests. Specific inhalation challenge with the suspected occupational agent(s) remains as the reference standard for diagnosis. A literature search was performed using the following terms: work-related asthma, occupational asthma, work-exacerbated asthma, irritant-induced asthma and etiological agents. Expert commentary: Studies focusing on the biological effects and mechanisms of environmental exposures in the development of sensitizer-induced or irritant-induced asthma in various workplace settings are of greatest interest. An integrative approach that combines clinical parameters with component-resolved diagnosis as well as inflammatory biomarkers appears to be very promising. Occupational allergy provides a good opportunity to understand the complex relationships between exposure to allergens in the workplace, interaction with genes and the co-exposures to other factors in the working environment.