Detection of IgE reactivity to fungus antigens by immunoblotting in allergic diseases in children.

BACKGROUND

Fungi are well-known as sources for allergens that cause allergic rhinitis and allergic asthma. The aim of this study was to evaluate the prevalence of sensitization to airborne fungi in allergic diseases in children.

METHODS

The presence of IgE antibodies to common allergens in serum samples from 77 atopic and 5 non-atopic children was determined by multiple allergosorbent (MAST) chemiluminescent assay. The allergic extracts, Penicillium notatum, Penicillium oxalicum, and Aspergillus fumigatus, were prepared. IgE-binding fungal components were identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE)-immunoblotting, using sera from the above-mentioned patients.

RESULTS

The MAST data demonstrated that 62 (81%) of the 77 sera tested showed IgE antibodies to both Dermatophagoides pteronyssinus and Dermatophagoides farinae. Only 2 and 1 of the 77 atopic sera were positive to Penicillium and Aspergillus, respectively. However, 13 (17%) sera showed positive IgE-immunoblotting. Eight and 6 of them demonstrated IgE antibodies to more than 10 different components of P. notatum and P. oxalicum respectively. Ten of the 13 sera showed IgE-immunoblot reactivity to A. fumigatus, and only 1 of the 10 positive samples showed a positive MAST of class I to Aspergillus. All the other sera showed negative results in the MAST test to Aspergillus. The discrepancy observed between the results of IgE-immunoblotting using self-prepared extracts and the commercial MAST test of the serum samples tested may be due to the variations in the fungal strains and the allergenic extracts used, and the different assay systems employed.

CONCLUSIONS

The results confirmed the importance of airborne fungi in association with allergic disorders in children.