Materials and Methods
Seventeen patients with HP, including five cases of summer-type HP which is a unique type of HP in Japan, five cases of bird fanciers lung, one case of isocyanate HP, and six cases of HP of unknown cause were investigated. The diagnosis was based on history, clinical evaluation, and radiologic patterns, including provocation tests or home challenge tests. All patients except one with summer-type HP, bird fanciers disease, and isocyanate HP had specifc antibodies in BAL fluids and serum against the relevant antigens, ie, Trichosporxm cutaneum, pigeon dropping extracts, and toluene diisocyanate, respectively. The one exception was a case of bird fanciers disease that was diagnosed by history and positive provocation test against pigeon dropping extracts.
Hypersensitivity pneumonitis of unknown cause was diagnosed by the clinical course, especially improvement during hospitalization and deterioration during home challenge tests, and histologic examinations. Sera and BAL fluids obtained from HP of unknown cause showed nondiagnostic but fairly positive antibody activities against Cladosporium sphaemspermum, Bsnicillium fnequentas, and Scopulariopsis species. Possibilities of sarcoidosis and idiopathic pulmonary fibrosis were carefully excluded in all cases of this report. Antigen-specific antibodies were estimated in serum and BAL fluid by enzyme-linked immunosorbent assay. The antigens employed for the assays included pigeon dropping extracts, T cutaneum, Aspergillus fumi-gatus, Micropolyspora faeni, Thermoactinomyces vulgaris, Ther-moactinomyces Candidas, С sphaerospermum, P frequentas, Scopulariopsis species, and toluene diisocyanate-human serum albumin.