Dictionary of Allergies .. Aspergillus fumigatus

Aspergillus fumigatus, is a mould of major allergologic importance. It is found in plant debris, fertile soil, such as compost heaps and stacks of hay and strow, decaying vegetable matter, floors, swimming pool water, in damp old houses, basements, bedding house dust and raw textile materials. Vinegar and soy sauce is made by a non-toxic Aspergillus strain. Aspergillus thrives at 40o C whereas most other moulds require more moderate temperatures [3] The peak concentrations of the spores are during the autumn and winter.

At this period the patients experience allergic symptoms after the inhalation of the spores. According to the immune response of each patient it can be experienced: Allergic asthma, hypersensitivity pneumonitis, allergic bronchopulmonary aspergillosis, Aspergilloma (fungus ball). Cross-reactivity among the different Aspergillus species is assumed but unique antigens have been identified. rAsp f 3 represents a major allergen of A. fumigatus.

It is recognized by 84% of asthmatic individuals sensitized to the fungus and elicits specific type I skin reactions. The skin test outcome strictly depends on the presence of rAsp f 3-specific IgE and the lack of false positive or false negative results comparing skin test outcome with specific serum IgE levels determined by ELISA or rAsp f 3-ImmunoCAP suggests the possibility to rely on serological data obtained with recombinant allergens to diagnose sensitization to A. fumigatus [1]. Allergic bronchopulmonary aspergillosis (ABPA) is a complex disease, triggered by a hypersensitivity reaction to the allergens of Aspergillus fumigatus, a fungus that opportunistically colonizes the lungs of patients with asthma. The diagnosis of ABPA is difficult.

A major problem is the lack of standardized allergens used in the determination of specific IgE, but the use of recombinant allergens has been proposed to overcome this. Serum titers of IgE against rAsp f 1, rAsp f 2, rAsp f 3, rAsp f 4 and rAsp f 6 can be determined [2]. Although fungal spores have been recognized as triggers of respiratory allergy and asthma, only two allergenic fungal cell wall components have so far been described. A cell wall protein of the phialides of A. fumigatus was identified as a major allergen. Asp f 34 belongs to the Aspergillus-specific proteins of the phiA family and has relevant potential for a specific diagnosis of Aspergillus sensitization[4]. M3 is the symbol for Aspergillus fumigatus in RAST. (See Allergic Bronchopulmonary Aspergillosis).

References

1. Hemmann S, Ismail C, Blaser K, Menz G, Crameri R. Skin-test reactivity and isotype-specific immune responses to recombinant Asp f 3, a major allergen of Aspergillus fumigatus. Clin Exp Allergy. 1998 Jul;28(7):860-7

2. de Oliveira E, Giavina-Bianchi P, Fonseca LA, França AT, Kalil J. Allergic bronchopulmonary aspergillosis' diagnosis remains a challenge. Respir Med. 2007 Nov;101(11):2352-7. Epub 2007 Aug 3.

3. Karr, R.M., et al: An approach to fungal antigen relationships by radioallergosorbent test inhibition. J. Allergy Clin. Immunol. 1981:67:194-198.

4. Glaser AG, Kirsch AI, Zeller S, Menz G, Rhyner C, Crameri R. Molecular and immunological characterization of Asp f 34, a novel major cell wall allergen of Aspergillus fumigatus. Allergy. 2009 Mar 23.