I. Sander

Baker's asthma : Still among the most frequent occupational respiratory disorders

BACKGROUND Bakers asthma and rhinitis are among the most frequent occupational respiratory disorders. OBJECTIVE The aim of the study was to evaluate the frequency of work-related symptoms and the clinical relevance of sensitization to allergens in screened and symptomatic bakers. METHODS Eighty-nine bakers participating in a screening study and 104 bakers filing a claim for compensation were examined with regard to occupational and clinical case history, lung function parameters, and sensitization to bakery allergens by skin prick tests, specific IgE analyses, and inhalative challenge tests. RESULTS A high prevalence of respiratory disorders, abnormal lung function parameters, and sensitization to bakery allergens exists. Most frequently, bakers with workplace-related respiratory symptoms showed sensitization to wheat flour (64%), rye flour (52%), soy bean flour (25%), and alpha-amylase (21%). The correlation between these sensitizations and asthma case history and inhalative challenge test responses was significant. However, approximately 29% of the bakers with respiratory symptoms showed no sensitization to these bakery allergens, whereas 32% of the sensitized bakers in the screening group had no workplace-related symptoms. Atopic status defined by skin prick test sensitization to common allergens or elevated total IgE levels was found to be a risk factor for the development of sensitization to bakery allergens and respiratory symptoms. On the other hand, there is evidence for an increased frequency of elevated total IgE as the result of occupational allergen exposure because respective findings were observed in bakers without symptoms. CONCLUSION Sensitization to bakery allergens seems to be the main cause of bakers asthma and rhinitis but cannot explain the asthma case history in each case. Further methods are required to objectively assume irritative pathomechanisms. Our findings indicate the necessity for an improved primary prevention of exposure to inhalative noxae in bakeries.

Quantitative analysis of immunoglobulin E reactivity profiles in patients allergic or sensitized to natural rubber latex (Hevea brasiliensis)

Background Characterized native and recombinant Hevea brasiliensis (rHev b) natural rubber latex (NRL) allergens are available to assess patient allergen sensitization profiles.

Multiple wheat flour allergens and cross-reactive carbohydrate determinants bind IgE in baker’s asthma

To cite this article: Sander I, Rozynek P, Rihs H‐P, van Kampen V, Chew FT, Lee WS, Kotschy‐Lang N, Merget R, Brüning T, Raulf‐Heimsoth M. Multiple wheat flour allergens and cross‐reactive carbohydrate determinants bind IgE in baker’s asthma. Allergy 2011; 66: 1208–1215.

Allergen content of grass pollen preparations for skin prick testing and sublingual immunotherapy.

Background:  The allergen content of diagnostics and immunotherapeutics is crucial for effective diagnosis and treatment. The aim of this study was to quantify and compare the allergen content of different grass pollen preparations for skin prick testing and sublingual immunotherapy (SLIT).

A New Method to Bind Allergens for the Measurement of Specific IgE Antibodies

Background: Detection of allergen-specific IgE antibodies in patients’ sera plays a key role for the diagnosis of IgE-mediated allergy. If no validated test system is available, diagnostic tools must be developed, usually by coupling or binding the allergens to a solid phase. Streptavidin ImmunoCAP™ is a new solid phase for binding of allergens which can be used in the Pharmacia CAP® system. Objective: It was the aim of this study to assess the diagnostic validity of Streptavidin ImmunoCAP. Methods: Biotinylation and allergen concentration for binding to Streptavidin ImmunoCAP were optimized and IgE obtained with natural rubber latex, obeche wood, wheat and rye flour Streptavidin ImmunoCAP were compared with the results of ImmunoCAP™ and Enzyme Allergo-Sorbent Test (EAST) using sera from patients complaining of workplace-related respiratory symptoms. Results: While the relation of biotin-label and protein was critical (best results were obtained with a 5- fold molar excess), labelled protein for coupling to streptavidin ImmunoCAP was applicable in a wide concentration range. On average, IgE values with streptavidin ImmunoCAP were as high as with ImmunoCAP but considerably higher than values obtained by EAST. Conclusion: Streptavidin ImmunoCAP is a valuable tool for sensitive and specific measurement of IgE binding to new allergens superior to cellulose disk-based methods.

Allergy to Aspergillus-derived enzymes in the baking industry: Identification of β-xylosidase from Aspergillus niger as a new allergen (Asp n 14)

BACKGROUND Aspergillus-derived enzymes are used in dough improvers in bakeries. Some of these enzymes are identified as causing IgE-mediated sensitization in up to 25% of bakers with workplace-related symptoms. OBJECTIVE The aim of this study was to compare the frequency of sensitization to Aspergillus xylanase, cellulase, and glucoamylase with the sensitization to alpha-amylase (Asp o 2) and to identify IgE-reactive proteins in enzyme preparations. METHODS Sensitization to Aspergillus-derived enzymes and cross-reactivity were retrospectively studied by enzyme allergosorbent test (EAST) and EAST-inhibition experiments. IgE-reactive proteins were detected by electrophoretic separation and immunoblotting. Liquid chromatography with electrospray ionization mass spectrometry and Edman degradation of tryptic protein fragments were used for the biochemical identification of an unknown IgE-binding protein. RESULTS Twenty-three percent of 171 tested bakers had specific IgE to alpha-amylase, 8% reacted to glucoamylase, 13% reacted to cellulase, and 11% reacted to xylanase. Xylanase and cellulase preparations, each containing at least 6 different proteins, showed cross-reactivity in the range of 80%. The main IgE-binding protein in the xylanase preparation recognized in 7 of 8 xylanase-positive subjects was a protein of about 105 kd. This protein was identified as beta-xylosidase by peptide mass spectrometric fingerprinting. The identification was confirmed by matching 12 peptide sequences obtained by N-terminal and mass spectrometric sequencing to this protein. CONCLUSIONS Beta-Xylosidase from Aspergillus niger is an occupational allergen present in currently used baking additives, which causes sensitization in at least 4% of symptomatic bakers. According to the International Union of Immunological Societies nomenclature, we suggest the term Asp n 14 for this allergen.

Isolation and denomination of an important allergen in baking additives : α-amylase from Aspergillus oryzae (Asp o II)

Abstract. The commercially available α‐amylase from Aspergillus oryzae which is widely used as a baking additive was compared with a highly purified enzyme preparation. We used enzyme allergosorbent test (EAST), EAST inhibition, sodium dodecyl sulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE), isoelectric focussing, immunoblotting, and N‐terminal amino acid sequencing to characterize the causative allergen. Our screening comprised 89 partially selected bakers. Forty‐three (48%) of them had work‐related respiratory symptoms; 14 (32%) of whom were sensitized to the baking additive. Significant immunological differences could not be found between crude and purified sample with the exception that the latter one produced nearly twice as high antibody values. Iodine starch staining demonstrated that the component which was exclusively or predominantly bound by IgE antibodies of symptomatic bakers represents the active α‐amylase. According to the International Union of Immunological Societies (IUIS) nomenclature, the term Asp o II is suggested for this important occupational allergen.

Overview on denominated allergens.

Type I allergy is a heightened or altered reactivity ofthe immune system in response to external substances involving immunoglobulins of the IgE class. More than 15% of the population in industrial countries suffer from immediate-type allergic symptoms [1]. Tn recent years, allergy research into the immunological, biochemical and structural characterization of allergens has led to an enormous progress alTecting diagnostics and therapeutics. This article summarizes important aspects of allergy research work on purified allergens. Characterized and denominated allergens have been listed. These data include biochemical and structural allergen characteristics as well as research results on human histocompatibility leucocyte antigens (HLA) restriction of ihe immune response, Tand B-cell epitopes and recombinant allergen expression. Allergens were isolated from a variety of dilTerent species. The taxonomy and relationship of dilTerent vertebrate, invertebrate as well as plant species from which allergens are isolated are also shown.

Prediction of challenge test results by flour-specific IgE and skin prick test in symptomatic bakers.

Background:  Wheat and rye flours are among the most important allergens causing occupational asthma. Usually, the diagnosis of baker’s asthma is based on inhalation challenge tests with flours.

Monitoring of occupational and environmental aeroallergens - EAACI Position Paper Concerted action of the EAACI IG Occupational Allergy and Aerobiology & Air Pollution

Exposure to high molecular weight sensitizers of biological origin is an important risk factor for the development of asthma and rhinitis. Most of the causal allergens have been defined based on their reactivity with IgE antibodies, and in many cases, the molecular structure and function of the allergens have been established. Significant information on allergen levels that cause sensitization and allergic symptoms for several major environmental and occupational allergens has been reported. Monitoring of high molecular weight allergens and allergen carrier particles is an important part of the management of allergic respiratory diseases and requires standardized allergen assessment methods for occupational and environmental (indoor and outdoor) allergen exposure. The aim of this EAACI task force was to review the essential points for monitoring environmental and occupational allergen exposure including sampling strategies and methods, processing of dust samples, allergen analysis, and quantification. The paper includes a summary of different methods for sampling and allergen quantification, as well as their pros and cons for various exposure settings. Recommendations are being made for different exposure scenarios.