Production of IL-12, IL-18 and TNF-alpha by alveolar macrophages in hypersensitivity pneumonitis
Chen, B.; Tong, Z.; Nakamura, S.; Costabel, U.; Guzman, J.
Sarcoidosis Vasculitis and Diffuse Lung Diseases Official Journal of Wasog 21(3): 199-203
2004
ISSN/ISBN: 1124-0490 PMID: 15554076 Document Number: 570137
Hypersensitivity pneumonitis (HP) is characterized by a macrophage-lymphocyte alveolitis and granuloma formation. A wide range of cytokines have been implicated in the pathophysiology and development of granulomas in HP, but there is no information about the production of interleukin-12 (IL-12) and IL-18 by alveolar macrophages (AM) in human HP. We evaluated whether the production of IL-12, IL-18 and tumor necrosis factor-alpha (TNF-alpha) is locally increased in HP, and whether there is a correlation between these cytokines, as well as with the cellular profile of bronchoalveolar lavage (BAL) fluid in HP. AM from 11 patients with HP and 10 control subjects were cultured for 24h in 10% RPMI medium alone, or with RPMI medium and lipopolysaccharide (LPS) (100 ng/ml). Cytokines in the culture supernatants were assayed by ELISA. The production of IL-18 and TNFalpha was increased in patients with HP in either absence or presence of LPS compared with controls. Although the spontaneous production of IL-12 was low, with LPS stimulation it was significantly elevated in HP. The concentration of the LPS-stimulated IL-12 production positively correlated with the percentage of lymphocytes (r = 0.72, p = 0.011), and negatively correlated with the percentage of macrophages (r = -0.88, p < 0.001). These observations suggest that IL-12, IL-18 and TNFalpha may be involved in the pathogenesis of HP.