[Relationship between severity of farmer's lung and the level of soluble interleukin 2 receptors in serum].

A 54-year-old woman was admitted to Nayoro City Hospital because of a suspicion of farmer's lung (FL). She had been working on her farm for the previous 16 years. Every April she experienced fever, coughing, and dyspnea. Fine crackles were audible over both lung fields. On admission, arterial blood gas analysis showed hypoxemia, and pulmonary-function testing revealed restrictive lung disease and a low diffusing capacity. A chest X-ray film revealed radio-opacity throughout the lower lung fields. A 67Ga scintigram showed abnormal uptake in the lungs. Examination of bronchoalveolar lavage fluid revealed an abnormally high number of lymphocytes and a high CD4/CD8 ratio in the lymphocytes. Histological examination of a specimen obtained by transbronchial lung biopsy revealed interstitial pneumonitis. A precipitation test was positive for anti-Micropolyspora faeni antibody. After admission, symptoms resolved with no treatment. FL was diagnosed from anamnesis and the results of examinations. On admission, the level of soluble interleukin 2 receptor in serum was twice the upper limit of the normal value, and it decreased over time, a long with the severity of the disease. Serial measurements of levels of this receptor are clinically important for detecting the progression of adult T cell leukemia. This case suggests that they can also be useful for evaluating the severity of FL.