INTERLEUKIN-8 EXPRESSION IN BRONCHOALVEOLAR LAVAGE CELLS IN THE EVALUATION OF ALVEOLITIS IN IDIOPATHIC PULMONARY FIBROSIS

Interleukin-8 (IL-8) is a neutrophilic chemotactic factor which may ha ve a prominent role in the attraction of neutrophils to the lung in id iopathic pulmonary fibrosis (IPF), The objective of this study was to investigate the usefulness of IL-8 expression in bronchoalveolar lavag e (BAL) cells in the evaluation of alveolitis in IPF. We analysed the BAL cell expression of IL-8 by immunocytochemistry in 19 patients with IPF (six smokers, three ex-smokers and ten non-smokers) and in a cont rol group composed of 14 individuals (six smokers, eight non-smokers). In IPF, BAL was performed on both the pulmonary lobe with the most ex tensive involvement and the one less extensively involved on high-reso lution computed tomography (HRCT) scans, The percentages and absolute numbers of BAL IL-8(+) macrophages from lobes with the most extensive HRCT scan involvement (36 +/- 6% and (6 +/- 2 x 10(4) ml(-1)) (SE) and from those less extensively involved [26% +/- 4% and (6 +/- 1)x 10(4) ml(-1)] were significantly higher with respect to both those from hea lthy smokers [17% +/- 6% and (7 +/- 4) x 10(4) ml(-1)] and those from non-smokers [2% +/- 1% and (1 +/- 0.3) x 10(4) ml(-1)] (P=0.005 and P= 0.001, respectively), without differences between the two lobes. In co ntrast, both the proportions and the absolute numbers of BAL neutrophi ls in IPF were significantly higher in lobes with the most extensively involved HRCT scan in comparison with lobes with the least extensive involvement [13% +/- 3%, (3 +/- 1) x 10(4) ml(-1) vs. 8% +/- 2%, (1 +/ - 0.3) x 10(4) mil(-1), P=0.05], Moreover, the numbers of BAL neutroph ils, but not those of IL-8(+) macrophages, correlated with the extent of total pulmonary HRCT scan abnormalities in the most involved lobe ( r = 0.64, P = 0.04). A correlation between neutrophils and IL-8(+) cel ls was not observed. The results of this study suggest that, in IPF. B AL neutrophilia offers a better description of the disease inflammator y process than the expression of IL-8 in BAL cells.