Anti-inflammatory cytokine release by alveolar macrophages in pulmonary sarcoidosis

Sarcoidosis is a systemic, granulomatous disorder with a high rate of spontaneous remission indicating the presence of antiinflammatory mechanisms. Antiinflammatory mediators such as interleukin-10 (IL-10) and transforming growth factor-beta (TGF-beta) should be able to induce spontaneous remission of sarcoidosis. By measuring the release of both mediators in culture supernatants of bronchoalveolar lavage (BAL) cells, we investigated their relevance in the spontaneous remission of sarcoidosis. No spontaneous IL-10 release was observed by BAL cells of sarcoid patients. In supernatants of BAL cells of seven patients found retrospectively to be free of any interstitial lung disease, we found 612 +/- 261.2 pg/ml (mean +/- SEM) TGF-beta. TGF-beta release was recorded in 20 of 39 patients with active disease. Patients with active disease without TGF-beta release in BAL cell culture either required therapy (n = 21; 677 +/- 159 pg/ml) or showed evidence of persisting disease (n = 6; 762 +/- 419 pg/ml). Patients with active disease without indications for therapy and with significantly increased TGF-beta release (n = 12; 1,422 +/- 215 pg/ml; p < 0.004 in all comparisons) had a spontaneous remission within 6 mo. Increased TGF-beta release (1,560 +/- 353 pg/ml) was observed in five of five patients receiving therapy. We conclude that TGF-beta is a regulator of the inflammatory process in sarcoidosis.