Cross-allergenicity between Aspergillus restrictus, Aspergillus fumigatusand Alternaria alternatadetermined by radioallergosorbent test inhibition

Aspergillus restrictus, an osmophilic fungus, is abundant in house dust. We have shown previously that the incidence of immediate hypersensitivity to A. restrictusis comparable to that for Aspergillus fumigatusand Alternaria alternatain asthmatic children. Radioallergosorbent test (RAST) inhibition was used to determine whether A. restrictusshares similar allergenic components with A. fumigatusand A. alternata. Mycelial mats of the three species cultivated on completely synthetic media were used for extract preparation. IgE antibodies to each fungus were measured with RAST using a polyvinyl chloride microplate as a solid phase. Analysis of a serum pool obtained from nine asthmatic children with a positive RAST to A. restrictusshowed that A. restrictusinhibited the RAST to A. restrictus, A. fumigatusand A. alternataby more than 80%. Similar results were observed with A. fumigatusand A. alternata. Additionally, when 13 serum samples with a positive RAST to A. restrictuswere tested separately, A. restrictussubstantially inhibited the A. restrictusRAST in all subjects tested. A. fumigatusand A. alternatainhibited the A. restrictusRAST in 10 and 8 of the samples studied, respectively. These findings indicate that A. restrictusshares allergenic components with A. fumigatusand A. alternata. The allergenic cross-reactivity between A. fumigatusand A. alternatawas also demonstrated.