nAsp o 21 alpha-amylase

Code: k87
Latin name: Aspergillus oryzae
Source material: nAsp o 21 is purified from a alpha-amylase extract
Non-cereal additives such as the starch-degrading enzyme alpha-amylase from Aspergillus oryzae are today regularly present in baking flours.

Allergen Exposure

Baker's asthma caused by flour dust exposure is a classic example of occupational asthma. To improve industrial processes and product quality, several non-cereal additives are today regularly present in baking flours. The starch-degrading enzyme alpha-amylase from Aspergillus oryzae and soybean flour (Glycine max) are examples of such additives that, together with the cereal components, are responsible for sensitization and IgE-mediated symptoms in bakers and others exposed to baking flours (1).

Potential Cross-Reactivity

Alpha-amylase hypersensitivity with positive skin tests and specific IgE antibodies was also observed in millers (12). Fungi naturally growing on stored cereal grains were assumed to be the source of the sensitization. This assumption is supported by the observation of common epitopes in amylase and extracts of Aspergillus oryzae (13).

Clinical Experience

Sensitization to enzymes in bakeries is a common cause of occupational asthma (2, 3) and may also result in contact dermatitis (4). The prevalence of sensitization to alpha-amylase in symptomatic bakers is about 25% (5-7). Epidemiologic studies have shown that alpha-amylase exposure is strongly associated with enhanced risk of sensitization of bakery workers (8, 9). Bread made from flour containing alpha-amylase from Aspergillus oryzae can trigger allergic reactions in sensitized subjects (16-17). Clinical reactions after ingestion of baked bread do not occur frequently in those sensitized to Aspergillus fumigatus (18).
 
Review
Baker's asthma caused by flour dust exposure is a classic example of occupational asthma. To improve industrial processes and product quality, several non-cereal additives are today regularly present in baking flours. The starch-degrading enzyme alpha-amylase from Aspergillus oryzae and soybean flour (Glycine max) are examples of such additives, that together with the cereal components are responsible for sensitization and IgE-mediated symptoms in bakers and others exposed to baking flours (1). Sensitization to enzymes in bakeries is a common cause of occupational asthma (2, 3) and may also result in contact dermatitis (4). The prevalence of sensitization to alpha-amylase in symptomatic bakers is about 25% (5-7). Epidemiologic studies have shown that alpha-amylase exposure is strongly associated with enhanced risk of sensitization of bakery workers (8-9).

Work-related respiratory symptoms in small bakeries were significantly associated with specific IgE to alpha-amylase (10). In a study of 83 pharmaceutical-industry workers, sensitization was demonstrated in 26 workers by skin testing. Specific IgE antibodies were found in 24/26 of the workers with positive skin tests. No amylase-specific IgE antibodies were detected in non-exposed controls (11). Alpha-amylase hypersensitivity with positive skin tests and specific IgE antibodies was also observed in millers (12). Fungi naturally growing on stored cereal grains were assumed to be the source of the sensitization. This assumption is supported by the observation of common epitopes in amylase and extracts of Aspergillus oryzae (13).

The enzyme alpha-amylase, also referred to as allergen Asp o 2, loses its enzyme activity when heated. However, it has been shown to retain some allergenic activity even at 200° C (14-15) and bread made from flour containing alpha -amylase from Aspergillus oryzae can trigger allergic reactions in sensitized subjects (16-17). Clinical reactions after ingestion of baked bread do not occur frequently in those sensitized to Aspergillus fumigatus (18). 

References

  1. Baur X, Weiss W, Sauer W, et al. Backmittel als Mitursache des Bäckersasthmas (Baking ingredients as a contributory cause of baker's asthma). Dtsch Med Wochenschr 1988;113:1275-8.
  2. Blanco Carmona JG, Juste Picón S, Garcés Sotillo M. Occupational asthma in bakers caused by sensitivity to a-amylase. Allergy 1991;46:274-6.
  3. Moneret-Vautrain DA, Kanny G, Lagrange A. L'Asthme professionnel aux produits organiques (Occupational asthma caused by organic substances). Rev Med Interne 1994;15 Suppl 2: 216s-25s.
  4. Morren MA, Janssens V, Dooms-Gossens A, et al. a-Amylase, a flour additive: an important cause of protein contact dermatitis in bakers. J Am Acad Dermatol 1993;29:723-8.
  5. Baur X, Chen Z, Sander I. Isolation and denomination of an important allergen in baking additives: a-amylase from Aspergillus oryzae (Asp o II). Clin Exp Allergy 1994;24:465-70.
  6. Baur X, Degens PO, Sander I. Baker's asthma: still among the most frequent occupational respiratory disorders. J Allergy Clin Immunol 1998;102:984-97.
  7. Baur X, Posch A. Characterized allergens causing baker's asthma. Allergy 1998;53:562-6.
  8. Houba R, Heederik DJ, Doekes G, van Run PE. Exposure-sensitization relationship for a-amylase allergens in the baking industry. Am J Respir Crit Care Med 1996;154:130-6.
  9. Houba R, van Run P, Doekes G, et al. Airborne levels of a-amylase allergens in bakeries. J Allergy Clin Immunol 1997;99:286-92.
  10. Jeffrey P, Griffin P, Gibson M, Curran AD. Small bakeries - a cross-sectional study of respiratory symptoms, sensitization and dust exposure. Occup Med (Lond) 1999;49:237-41.
  11. Losada E, Hinojosa M, Quirce S, et al. Occupational asthma caused by a-amylase inhalation: clinical and immunological findings and bronchial response patterns. J Allergy Clin Immunol 1992;89:118-25.
  12. Moneo I, Alday E, Gonzales-Muños M, et al. a-Amylase hypersensitivity in non-exposed millers. Occup Med (Oxf) 1994;44:91-4.
  13. Quirce S, Cuevas M, Díez-Gómez M, et al. Respiratory allergy to Aspergillus-derived enzymes in baker's asthma. J Allergy Clin Immunol 1992;90:970-8.
  14. Baur X, Sander I, Jansen A, Czuppon AB. Sind Amylasen von Backmitteln und Backmehl relevante Nahrungsmittelallergene? (Are amylases in bakery products and flour potential food allergens?). Schweiz Med Wochenschr 1994;124:851-6.
  15. Baur X, Czuppon AB, Sander I. Heating inactivates the enzymatic activity and partially inactivates the allergenic activity of Asp o 2. Clin Exp Allergy 1996;26:232-4.
  16. Baur X, Czuppon AB. Allergic reaction after eating a-amylase (Asp o 2)-containing bread. Allergy 1995;50:85-7.
  17. Kanny G, Moneret-Vautrin DA. a-Amylase contained in bread can induce food allergy. J Allergy Clin Immunol 1995;95:132-3.
  18. Cullinan P, Cook A, Jones M, et al. Clinical responses to ingested fungal a- amylase and hemicellulase in persons sensitized to Aspergillus fumigatus? Allergy 1997;52:346-9.

 

As in all diagnostic testing, the diagnosis is made by the physican based on both test results and the patient history.