Profiles of inflammatory cytokines in bronchoalveolar lavage fluid from premature infants with respiratory distress disease.

In view of cytokine's effects in promoting or inhibiting inflammation, the objective of this study was to explore the characteristics of the proinflammatory cytokine, interleukin-8 (IL-8), and the inhibitory cytokine, interleukin-10 (IL-10), in the bronchoalveolar lavage (BAL) fluid of premature infants suffering from respiratory distress disease. Eighteen premature neonates with respiratory distress disease with gestational age (GA) ranging from 24 to 37 weeks were recruited for study. BAL fluids were collected following endotracheal intubation during an episode of hypoxemia or dyspnea. A series of BAL samples were obtained on day 1, 2, 4 and 7 after intubation for measuring IL-8 and IL-10 levels. The results indicate that premature infants with GA ranging from 24 to 32 weeks had a higher level of IL-8 (p = 0.029), but not level of IL-10 (p = 0.109), in the BAL obtained during the first intubation compared to premature infants with GA ranging from 33 to 37 weeks. The administration of exogenous surfactant did not influence the profiles of IL-8 and IL-10, as compared to those in-patients without treatment. Levels of IL-8 were correlated with IL-10 levels (r = 0.613, p = 0.007) in BAL fluid samples obtained on the day of intubation. The level of IL-8, but not IL-10, was significantly correlated with the duration of intubation. IL-8 and IL-10 levels in BAL fluid samples collected on the day of intubation were correlated with the development of chronic lung disease (CLD). The results suggest that extreme prematurity tends to have increased IL-8 and IL-10 levels in BAL fluid compared to premature infants with older GA, and that these increased levels are associated with the development of CLD.