BACKGROUND: Sarcoidosis is a systemic granulomatous disorder of unknown origin and characterized by accumulation of T cells and macrophages. Various cytokines may play crucial roles In the activation of T cells and macrophages, and thereby in the formation of granulomas. However, little is known about the balance between proinflammatory cytokines and antiinflamatory cytokines in the development of sarcoid granulomas and disease activities. In the present study, we measured IL-6, IL-8 and IL-10 in the bronchoalveolar lavage fluid(BALF) from patients with pulmonary sarcoidosis 13 find out whether there is an imbalance between proinflammatory cytokines and antiinflammatory cytokines in the lung. METHODS: Fourteen subjects with the diagnosis of sarcoidosis and six healthy volunteers were included. BALF was concentrated ten-fold by pressure ultrafiltration and each cytokine levels were measured by ELISA method. Active sarcoidosis was defined by major organ involvement or clinically progressive diseases. RESULTS: The mean IL-6 love]s in the BALF of the active sarcoidosis group were significantly increased than in controls or inactive sarcoidosis group(p < 0.05). Meanwhile, the IL-8 levels were increased and IL-10 levels were decreased in the active sarcoidosis group than in controls or inactive sarcoidosis group without significance(p>0.05). In active pulmonary sarcoidosis patients, the IL-6 love]s in BALF correlated with the BALF CD4/CD8 ratio(r=0.768, p < 0.05) and IL-8 levels(r=0.564, p < 0.05). CONCLUSIONS: The data presented showed that proinflammatory cytokine IL-6 is important in the pathogenesis of sarcoidosis and decreased tendency of anti-inflammatory cytokine IL-10 might also be involved in the development of granulomatous inflammation in sarcoidosis.