Sensitization to different species of Aspergillus in bakery workers and general atopic population

Six species of Aspergillus predominant in the bakery environment--Aspergillus flavus, A. fumigatus, A. nidulans, A. ochraceous, A. sydowi and A. versicolor--were studied for their role in causing Type 1 hypersensitivity among bakery workers and atopic patients from the general population (PGP). Antigenic extracts from the above species were prepared for in vivo and in vitro studies. The IEF, SDS-PAGE, skin test, ELISA and immunoblot techniques were performed to detect the biochemical- and clinico-immunological characteristics of these species. Among those tested, the important fungal sensitizers among the bakery workers and patients from the general population were A. sydowi, A. fumigatus, A. nidulans and A. ochraceous. The protein fractions of different species were in the acidic region (pI 3.0-6.5) and in the molecular weight range of 13.0-91.0 kDa. The protein fraction of 44.0 kDA of A. flavus and 20.0 and 70.0 kDa for A. fumigatus showed IgE binding in the sera of bakery workers only. Significantly, raised IgG antibodies to different species were recorded among the bakery workers as compared to the PGP group. The study showed that different species of Aspergillus are of potential allergenic significance in bakery workers and the general atopic population.