Mould allergens: Where do we stand with molecular allergy diagnostics?

The official WHO/IUIS database (www.allergen.org) currently lists 77 mould allergens from a variety of protein families. To date, only eight recombinant single allergens from three mould species are available for molecular allergy diagnosis of mould sensitization. These include rAlt a 1, the major allergen in Alternaria alternata-sensitized individuals, and enolase rAlt a 6 with it potential cross-reactivity to mould, food and natural latex allergens. rAsp f 1, 2, 3, 4 and 6 from Aspergillus fumigatus are available for diagnostic purposes; specific IgE to rAsp f 2, 4 and 6 is often positive in allergic bronchopulmonary aspergillosis (ABPA). The dehydrogenase rCla h 8 is considered a major allergen of Cladosporium herbarum with possible cross-reactivity to other dehydrogenase allergens. The narrow range of commercially available individual mould allergens should be expanded to include marker allergens typical for mould (e.g., serine proteases). In addition, standardization of total extracts needs to be improved in the future to guarantee valid mould products with defined allergen content for diagnostic and therapeutic purposes.