[A case of isocyanate-induced hypersensitivity pneumonitis and a compression-air mask thought to be effective in its prevention].

A 41-year-old paint sprayer, who had worked with polyurethane paint since the spring of 1989, developed exertional dyspnea and dry cough and entered hospital on December 4, 1989. Plain chest X-ray film and a computed tomogram of the lung revealed diffuse micronodular shadows in both lower lung fields. DLco was shown to be significantly decreased in a pulmonary function test. A sample of bronchoalveolar lavage fluid showed increased T lymphocytes and a decreased CD4/8 ratio. A lung biopsy specimen revealed alveolitis, but neither Masson body nor granulomas were seen. Serum antibody specific to TDI-HSA was detected, and an environmental provocation test was positive. From these results, the patient was diagnosed as having isocyanate-induced hypersensitivity pneumonitis. We advised him to wear a compression-air mask when he worked, because he did not want to quit his job. Respiratory symptoms have not been seen since then, but careful observation was thought to be necessary. The involvement of type III humoral and type IV cellular immunity was suspected in this case.