Component-Resolved and Complementary Tests in the Diagnosis of Occupational Allergy: Advantages and Limitations

Abstract

Enhancing the repertoire of in vitro methods together with the development of recombinant technology in the field of allergy diagnosis brought tremendous advances in understanding allergens, allergic reactions, and patients’ care. This review is focusing not only on component-resolved diagnosis with occupational allergens, complementary methods, their advantages to improve the in vitro diagnosis for occupational allergy but also their limitations. Up to now, the number of occupational asthma sensitizers characterized on the molecular level and their availability for routine diagnosis is very low. One exception, however, is Hevea brasiliensis latex as an important occupational allergen source. H. brasiliensis latex is an excellent model for the useful application of recombinant single allergens for improvement of routine diagnostics. Despite the many efforts and excellent research in the field of baker’s asthma to characterize the occupationally relevant allergens the results are highly diverse. No major allergen can be identified and the IgE-sensitization profile of each baker showed great inter-individual variation. Therefore, for routine diagnosis of baker’s asthma, the assessment of allergen-specific IgE with the whole wheat (and/or rye) flour extract is still recommended. Unfortunately, no wheat allergens relevant for baker’s asthma are commercially available, although they might help to discriminate between wheat-induced food allergy, grass pollen allergy, and baker’s asthma. In particular cases with discrepancy between different diagnostic tests, the determination of basophil activation test is a recommended option. Flow cytometry determination of CD63 or CD203c on basophils induced by stimulation with the relevant allergen is a good clinically validated test and also useful for the diagnosis of occupational allergy. It is still necessary to increase the knowledge of occupational allergen molecules and include standardized tools into routine diagnostic. For the future, combination of new diagnostic tools and biomarkers, platforms, and complementary methods in occupational allergy and asthma diagnosis is a promising option. In addition, integration of these possibilities in workplace-related allergy and asthma studies is helpful to understand the complex interaction between work-related exposure, individual susceptibility and health outcome.