Extrinsic allergic alveolitis after Aspergillus fumigatus inhalation. Evidence of a type IV immunologic pathogenesis.

Three weeks after a massive inhalation of mold present on infected oats, a farmer's wife had extrinsic allergic alveolitis. Aspergillus fumigatus was cultured from the moldy oats and from deep bronchial washings obtained at fiberoptic bronchoscopy. Spores and hyphae characteristic of Aspergillus species were demonstrated within granulomas in the pulmonary tissue obtained by transbrochial biopsy. Serum precipitins, delayed (48 hour) cutaneous hypersensitivity and in vitro lymphocyte transformation to A. fumigatus were demonstrated. The findings in this case suggest that a type IV immunologic response and subsequent (lymphocyte-mediated) tissue inflammation may underlie the pathogenesis of this and other forms of hypersensitivity pneumonitis.