[Case report of Farmer's lung disease in siblings in Kagoshima Prefecture]

Two cases of farmer's lung disease in siblings are reported. A 54-year-old male farmer, who had been engaged in stock work for 20 years, presented to our clinic for the second episode of fever, productive cough and shortness of breath. Chest roentgenogram revealed diffuse micronodular pattern, and mild hypoxemia was recognized on arterial blood gas analysis. Cytology obtained from BALF showed lymphocytosis, with especially increased OKT3, OKT4 positive cells and OKT4/8 ratio. The diagnosis was confirmed by highly positive reaction of precipitins to Thermoactinomyces vulgaris and granulomatous interstitial pneumonitis on histopathological examination. The second case was a 51-year-old female patient, the sister of the first case, who also worked as a stock farmer of another farm for 20 years. She presented with an episode of similar symptoms to the first case, one and a half years after the onset of her brother's symptoms. The findings of roentgenogram, BALF analysis, precipitins to T. Vulgaris and pathology were similar to those of the first case. The finding of high OKT4/8 ratio on BALF analysis in both cases is characteristic of formers lung disease, in contrast to the summer-type hypersensitivity pneumonitis which usually shows low OKT4/8 ratio in BALF. To our knowledge, this is the first report of farmer's lung disease in an area other than the northern part of Japan. Thus we conclude that farmer's lung disease may occur in Japan under any environmental conditions, and that some genetic factor may take part in the onset of this disease.