Clinical and immunologic significance of Aspergillus fumigatus in the sputum.

The importance of air-borne fungal spores as allergens in man is being increasingly recognized. Of the fungi, the Aspergillus genus, and in particular A. fumigatus, was first reported by V. Leeuwen (1) and subsequently by others, including Hansen (2), as perhaps the most important fungal cause of respiratory tract allergic disorders in their respective countries. In more recent years the Aspergillus genus has been ranked. high in the list of inhaled fungal spore allergens by Feinberg (3) and Maunsell (4). Aspergillus fumigatus may, however, produce infections in man, animals, and birds. In their report on pulmonary infection in man, entitled bronchopulmonary aspergillosis, Hinson and others (5) described incidents of transient lung shadows with eosinophilia in the peripheral blood, which they attributed to hypersensitivity, although limited skin testing did not provide evidence for this. The spores of A. fumigatus like those of the other Aspergillus species are ubiquitous in their distribution and are present perennially. They are probably frequently inhaled and expectorated by the population at large, so that culture of A. fumigatus from the sputum cannot, by itself, be taken as proof of a causal relationship to the clinical manifestations. The purpose of this investigation is to assess the possible relationship of the Aspergillus species to various respiratory disorders.