PRIMING OF ALVEOLAR MACROPHAGES FOR INTERLEUKIN-8 PRODUCTION IN PATIENTS WITH IDIOPATHIC PULMONARY FIBROSIS

We evaluated the contribution of interleukin-8 (IL-8) to the pathogene sis of idiopathic pulmonary fibrosis (IPF) by studying bronchoalveolar lavage fluid (BALF) in eight patients with IPF in the chronically pro gressive phase, five patients with IPF in the subacutely progressive p hase, eight patients with sarcoidosis (SAR), and eight control (CTL) s ubjects. IL-8 levels were not increased in the BALF of the patients wi th IPF in the chronic phase (11.3 +/- 8.8 pg/ml), nor in that of the S AR patients (13.8 +/- 7.8 pg/ml), whereas they were increased in the B ALF of patients with IPF in the subacutely progressive phase (1.93 +/- 1.10 ng/ml). We then investigated extracellular and cell-associated I L-8 in lipopolysaccharide (LPS)-stimulated BALF cells to determine the IL-8-producing potential of alveolar macrophages (AM). Following LPS stimulation of BALF cells from patients with IPF in the chronic phase, both the extracellular IL-8 in culture fluid and the cell-associated IL-8 in AM were increased as compared with those for the CTL subjects (p < 0.05 and p < 0.05, respectively). These results suggest that AM o f patients with IPF are primed for IL-8 production. We conclude that I L-8 may play a role in neutrophilic alveolitis, especially during the subacute phase of IPF.