Sustained high levels of circulatory interleukin-8 are associated with a poor outcome in patients with adult respiratory distress syndrome

Neutrophils are reported to be a major factor in the pathogenesis of the adult respiratory distress syndrome (ARDS). We measured serial levels of circulatory interleukin (IL)-8 and neutrophil elastase in 16 patients with ARDS at the onset, on day 3 and on day 7 and studied the relationship of these levels to the clinical course. Circulatory IL-8 levels of all the patients at the onset were significantly elevated compared with controls, mean+/-SE, 30.0+/-6.7 pg/ml and 3.3+/-0.3 pg/ml, respectively. There was a significant correlation between IL-8 and neutrophil elastase levels at the onset (r=0.65, p<0.01). In nonsurvivors circulatory IL-8 levels were significantly higher than those of survivors throughout the study. There were significant differences in oxygenation, as reflected by PaO2/FIO2 ratios, between survivors and nonsurvivors at day 7, mean+/-SE, 208.5+/-21.9 and 113.5+/-9.6, respectively. In conclusion, we have shown that the level of circulatory IL-8 is elevated in patients with ARDS, and sustained high levels of circulatory IL-8 might be correlated with a poor outcome.