Relative release of interleukin-1β and interleukin-1 receptor antagonist by alveolar macrophages: A study in asbestos-induced lung disease, sarcoidosis, and idiopathic pulmonary fibrosis

Abstract

We examined the influence of untreated interstitial lung disease (ILD) on the in vitro release of interleukin-1β (IL-1β) and interleukin-1 receptor antagonist (IL-1ra) from alveolar macrophages (AM); AM were harvested from normal volunteers, ILD patients, and patients with asbestos-related pleural disease but no ILD. AM were cultured for 24 h and assays for IL-1β and IL- 1ra were done using sensitive and specific enzyme-linked immunosorbent assay. A greater amount of IL-1β was detected in AM supernatants from asbestosis, sarcoidosis, and IPF patients than in those from normal subjects. The IL- 1β:IL-1ra ratio (IL-1β activity index [IL-IAI]) was significantly lower in supernatants of normal macrophages compared with macrophage supernatants from individuals with ILD. The IL-1AI correlated with bronchoalveolar lavage cellularity, a marker of disease activity. Current smoking was associated with lower IL-1β and IL-1ra release in ILD. The IL-1AI is a convenient method for comparison of IL-1β activity between patient populations.