Interleukin-10 secretion by alveolar macrophages and monocytes in sarcoidosis

Background: Alveolitis and the production of proinflammatory cytokines are known features of sarcoidosis, Because of the usually spontaneous resolutio n of alveolitis despite local secretion of mediators causing inflammation a nd granuloma formation, we hypothesized that downmodulating mechanisms such as anti-inflammatory cytokines might be involved in this process. Objectiv e: Investigation of the secretion of the macrophage deactivating cytokines interleukin-10 (IL-10) and transforming growth factor-beta (TGF-beta) by al veolar macrophages in untreated sarcoidosis of the lung. Methods: Fourteen consecutive and untreated patients with pulmonary sarcoidosis and 18 volunt eers underwent bronchoscopy, Alveolar macrophages (AM) were obtained by bro nchoalveolar lavage and the secretion of IL-10 and TG F-P was studied. Resu lts: Spontaneous IL-10 production by AM was found in 6 of 14 patients and i n 2 of 18 controls. The IL-10 level of lipopolysaccharide-stimulated AM was significantly higher in patients. Monocytes secreted significantly more IL -10 than AM, but there was no difference between sarcoid and control monocy tes, No difference was found in the secretion of TGF-beta between patients and controls. Conclusion: Increased local secretion of IL-10- but not TGF-b eta-may represent a downmodulating mechanism involved in the spontaneous re solution of alveolitis in sarcoidosis, Copyright (C) 2000 S. Karger AG, Bas el.