Clinical science
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In bronchoalveolar lavage (BAL) fluid from ventilated patients, cytotoxic oxidant activity is correlated with neutrophil activation. The aim of the present study was to investigate the hypothesis that BAL fluid induces activation of the transcription nuclear factor-kappaB (NF-kappaB) in human alveolar cells, in correlation with inflammatory mediators. We measured endotoxin, inflammatory cytokines [interleukin-1beta (IL-1beta), IL-8], nitrated proteins and the activity of myeloperoxidase (MPO) in BAL fluid from ventilated patients developing bronchopneumonia ( n =19 samples) or with acute respiratory distress syndrome (ARDS) ( n =14), and from ARDS/infection-free patients ( n =11). ⋯ The level of NF-kappaB activity induced by the BAL fluid was correlated with levels of IL-1beta ( P <0.001), IL-8 ( P <0.005) and MPO ( P <0.002), and with the neutrophil count ( P <0.002), and was higher for BAL fluid from the bronchopneumonia group. NF-kappaB activation by MPO was also demonstrated. The activation of NF-kappaB by BAL fluid, especially that from bronchopneumonia patients, suggests that a similar phenomenon may occur in vivo, leading to potential amplification of the inflammatory reaction.