A 44-year-old man was admitted for evaluation of dyspnea on exertion and subcutaneous nodules. The chest X-ray on admission revealed bilateral hilar lymph node swelling and diffuse micronodular shadows throughout both lung fields. Ga scintigram demonstrated diffuse abnormal uptake. Serum angiotensin converting enzyme was elevated significantly (86.6 IU/I). The TBLB specimen confirmed the diagnosis of sarcoidosis. The cell numbers in bronchoalveolar lavage fluid was increased (4.4 x 10(8), the percentage of lymphocytes was elevated (64%) and the ratio of Leu 3a+/Leu 2a+ was very high (16.07). We further evaluated the spontaneous IL-1 release in vitro by alveolar macrophages obtained by bronchoalveolar lavage. The results showed that large amounts of IL-1 alpha and beta were produced spontaneously by alveolar macrophages before therapy, followed by a decrease in production after corticosteroid treatment. Previously, the authors reported that no significant amount of IL-1 alpha and beta was detected in 5 normal volunteers and 6 other active sarcoidosis cases which improved without therapy. Therefore, significant amounts of spontaneous release of IL-1 alpha and beta in vitro from alveolar macrophages in sarcoidosis might be considered as an index for the necessity of systemic corticosteroid treatment.