| Research Abstract |
We studied the etiologic agent and pathogenesis of summer-type hypersensitivity pneumonitis (HP). Our results were as follows.
i. Studies on the etiologic agent of summer-type HP When the incidence of fungi in patients' homes were compared with that in homes of control subjects, extensive distribution of trichosporon cutaneum, an arthro-spore forming yeast, war observed in home environments of patients with summer-type HP but not in homes of normal control subjects. The isolated t. cutaneum demonstrated high reactivity to the patients' sera. almost all patients responded to the inhalation challenge with the culture filtrate antigen of t. cutaneum. These results clearly indicate that T. cutaneum is an etiologic agent of summer type HP. HP induced by T. cutaneum is a new disease of HP groups.
ii. Studies on the pathogenesis of summer-type HP. Environmental study revealed that summer-type HP tended to occur in the resident of old wooded houses, and that T. cutaneum grew on old damp wood, floor mats, bed clothes, or budgeriger droppings in their houses during muggy summer season following the rainy season. In other words, summer-type HP in Japan is a sick-house syn-drome. The phenotype of the major histocompatibility complex, loci A, B, C, DR, and DQ, was studied in 66 patients with Japanese summer-type HP induced by T. cutaneum, and the results were compared to those obtained from 472 normal healthy subjects. Our results showed an increase of the frequency of HLA-DQW3 in the patients, suggesting the importance of the host factors for the generation of this disease.
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