Evidence that Aspergillus fumigatus growing in the airway of man can be a potent stimulus of specific and nonspecific IgE formation.

Serum IgE levels in patients with allergic bronchopulmonary aspergillosis are elevated but the degree of elevation varies markedly. Serum IgE levels in patients with aspergillomas may be strikingly elevated or normal. Absorption of serums with antigens of Aspergillus fumigatus combined with a solid phase radioimmunoassay technic demonstrated that both immunoglobulin E (IgE) and immunoglobulin G (IgG) antibody activity against A. fumigatus were markedly reduced without a parallel reduction in serum total IgE. These results indicate that the very high levels of serum IgE found in allergic bronchopulmonary aspergillosis and aspergilloma are not all specific IgE. These results are similar to those observed in rats infested with Nippostrongylus brasiliensis. An explanation for the elevations of IgE levels in infestations with A. fumigatus may be analogous to the postulate that parasite-produced materials may result in T cell stimulatory factors for IgE-producing cells. Alternatively, A. fumigatus organisms may produce materials that inhibit T suppressor lymphocytes.