Immunological treatments for occupational allergy

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.

Potential of molecular based diagnostics and its impact on allergen immunotherapy

Molecular based in vitro technologies greatly changed the diagnostic approaches in allergy. At present, sensitization profiles can be dissected according to IgE subsets, which are specific for genuine or cross-reacting components and potentially dangerous or virtually harmless components. The identification of IgE in components with specific characteristics has a direct impact on the accuracy of the diagnosis (indeed, it is possible at present to not only identify the allergen derived from a given allergen source but also the family of molecules to which the patient is sensitized), on the prognosis of the patient’s allergy, and on the prevention activities to be implemented. More interestingly, during the last few years, and thanks to the tools of molecular diagnostics, the indications for Allergen Immunotherapy (AIT) have also be modified, and novel strategies for the selection of the allergens to be administered have been better defined. Indeed, protocols indicating how Molecular Based Diagnosis (MBD) can be used to identify the best AIT approach have been recently published. In this review, the rationale for the use of MBD tools is discussed, and the recent strategies for the choice of allergens to be used in AIT are reported.

Orphan immunotherapies for allergic diseases

OBJECTIVE

As confirmed by systematic reviews and meta-analyses, allergen immunotherapy is clinically effective in the treatment of allergic diseases. In particular, subcutaneous immunotherapy is a pivotal treatment in patients with severe reactions to Hymenoptera venom, whereas subcutaneous immunotherapy and sublingual immunotherapy are indicated in the treatment of allergic rhinitis and asthma by inhalant allergens. Other allergies related to animal dander (other than cat, which is the most studied), such as dog, molds, occupational allergens, and insects, have also been recognized. For these allergens, immunotherapy is poorly studied and often unavailable. Thus, use of the term orphan immunotherapies is appropriate.

DATA SOURCES

We used MEDLINE to search the medical literature for English-language articles.

STUDY SELECTION

Randomized, controlled, masked studies for orphan immunotherapies were selected. In the remaining cases, the available reports were described.

RESULTS

The literature on food desensitization is abundant, but for other orphan allergens, such as mosquito, Argas reflexus, dog, or occupational allergens, there are only a few studies, and most are small studies or case reports.

CONCLUSION

Orphan immunotherapy is associated with insufficient evidence of efficacy from controlled trials, an erroneous belief of the limited importance of some allergen sources, and the unlikelihood for producers to have a profit in making commercially available extracts (with an expensive process for registration) to be used in few patients. It should be taken into consideration that adequate preparations should be available also for orphan allergens.

Wheat allergy: diagnosis and management

Triticum aestivum (bread wheat) is the most widely grown crop worldwide. In genetically predisposed individuals, wheat can cause specific immune responses. A food allergy to wheat is characterized by T helper type 2 activation which can result in immunoglobulin E (IgE) and non-IgE mediated reactions. IgE mediated reactions are immediate, are characterized by the presence of wheat-specific IgE antibodies, and can be life-threatening. Non-IgE mediated reactions are characterized by chronic eosinophilic and lymphocytic infiltration of the gastrointestinal tract. IgE mediated responses to wheat can be related to wheat ingestion (food allergy) or wheat inhalation (respiratory allergy). A food allergy to wheat is more common in children and can be associated with a severe reaction such as anaphylaxis and wheat-dependent, exercise-induced anaphylaxis. An inhalation induced IgE mediated wheat allergy can cause baker’s asthma or rhinitis, which are common occupational diseases in workers who have significant repetitive exposure to wheat flour, such as bakers. Non-IgE mediated food allergy reactions to wheat are mainly eosinophilic esophagitis (EoE) or eosinophilic gastritis (EG), which are both characterized by chronic eosinophilic inflammation. EG is a systemic disease, and is associated with severe inflammation that requires oral steroids to resolve. EoE is a less severe disease, which can lead to complications in feeding intolerance and fibrosis. In both EoE and EG, wheat allergy diagnosis is based on both an elimination diet preceded by a tissue biopsy obtained by esophagogastroduodenoscopy in order to show the effectiveness of the diet. Diagnosis of IgE mediated wheat allergy is based on the medical history, the detection of specific IgE to wheat, and oral food challenges. Currently, the main treatment of a wheat allergy is based on avoidance of wheat altogether. However, in the near future immunotherapy may represent a valid way to treat IgE mediated reactions to wheat.

Specific immunotherapy and biological treatments for occupational allergy

PURPOSE OF REVIEW

Occupational allergy represents a substantial health, social, and financial burden for the society. Its management is a complex task that, in selected cases, may also include allergen-specific immunotherapy. The purpose of this article is to review clinical data on allergen immunotherapy and biological treatments applied to occupational allergy in 2013.

RECENT FINDINGS

Immunotherapy in occupational allergic diseases has been scarcely used, and only for a few sensitizers, such as latex, flour, and Hymenoptera venom, partly due to the lack of standardized extracts. The recent use of the molecular diagnosis can improve the indication and selection of suitable allergens for preparing new standardized and powerful extracts for immunotherapy. Some recent reports suggest a beneficial role of treatment with omalizumab in workers with occupational asthma who continue to be exposed to the causal agent.

SUMMARY

Although scarce, available data suggest that immunotherapy and biological treatments may allow allergic workers to continue their work activity, but further studies are needed to standardize extracts and to evaluate the cost-effectiveness of these treatments, when exposure at the workplace cannot be avoided.