Studies on cytokines produced by alveolar macrophages in the patients with sarcoidosis

The role of cytokines produced from alveolar macrophages (AMs) in the compartmentalized T-cell activation in pulmonary sarcoidosis is poorly understood. Herein, we demonstrate the production of Interleukin-6 (IL-6) and tumor necrosis factor (TNF-α) by alveolar macro-phages from 36 patients with sarcoidosis and 26 normal subjects. Non-stimulated AMs from sarcoidosis patients spontaneously produced IL-6, as well as TNF-α. The spontaneous produc-tion of IL-6 was significantly increased in the patients with sarcoidosis than in the normal subjects, but not that of TNF-α. Furthermore, the amount of TNF-α and IL-6 produced from AMs stimulated by Propionibacterium acnes (P. acnes) or lipopolysaccharide was significantly increased in patients with asrcoidosis compared to the normal subjects. TNF-α production from AMs stimulated by P. acnes closely correlated to the IL-6 production from AMs stimulat-ed by P. acnes correlated to thr proportion of lymphocytes in the bronchoalveolar lavage fluid. These findings suggest that AMs are activated in sarcoidosis and that those cells produre IL-6 and TNF-α, which are responsible for T-cell activation