[A familial case of summer-type hypersensitivity pneumonitis possibly associated with bird breeder's lung diagnosed by bronchoalveolar lavage fluid].

Case 1: A 32-year-old woman had cough and exertional dyspnea in August 2002, and chest computed tomographic scan revealed diffuse centrilobular nodules. Bronchoalveolar lavage fluid (BALF) showed a high proportion of lymphocytes with a decreased CD 4/CD 8 ratio. Transbronchial lung biopsy (TBLB) specimens showed alveolitis. Summer-type hypersensitivity pneumonitis was diagnosed on the basis of positive findings of anti-Trichosporon antibodies in the serum. Case 2: A 64-year-old man, the father of Case 1, also had cough and exertional dyspnea in August 2003. He had been in close contact with pigeons. Chest computed tomographic scan revealed bilateral map-like ground-glass opacities predominantly in the upper lobes. BALF showed a high proportion of lymphocytes with a decreased CD 4/CD 8 ratio. TBLB specimens showed alveolitis, granuloma and Masson body in the air spaces. Specific IgG and IgA antibodies against Trichosporon asahii, IgA antibodies against Trichosporon mucoides, and IgA antibodies against pigeon dropping extracts were found only in the BALF but not in the serum. Although a positive finding of returning-home provocation test was definitive in diagnosing summer-type hypersensitivity pneumonitis, he was also suspected of having bird fancier's lung.