Interleukin-1β in the bronchoalveolar lavage fluid of premature neonates: a marker for maternal chorioamnionitis and predictor of adverse neonatal outcome

Abstract

Objective: To determine whether the presence of the proinflammatory cytokine interleukin (IL)-1β in the lungs of preterm infants immediately after birth was associated with maternal inflammationand could predict adverse neonatal outcome.Study design: Prospective evaluation of serially obtained tracheal aspirates for the presence of IL-1β in 25 preterm infants (birth weight 595-1700g; gestational age 24-32 weeks) with respiratory distress syndrome. The initial tracheal aspirate was obtained within 1 h after delivery.Results: An initial tracheal aspirate positive for IL-1βhad a highly significant correlation with documented maternal chorioamnionitis for the given patient. In addition, the presence of IL-1β correlated significantly with elevated total cell count (2.62vs. 0.96 × 106/ml, p = 0.0097), granulocyte count (2.12 vs. 0.22 × 106/ml, p = 0.001), macrophage count (0.28 vs. 0.01 × 106/ml, p= 0.02) and the presence of proinflammatory cytokines IL-6, IL-8 and tumor necrosis factor (TNF)-α. Preterm neonates positive for IL-1β in their initial sample were on prolonged assisted ventilation(38 vs. 16 days, p = 0.013) and oxygen supplementation (62 vs. 40.5 days, p = 0.0462) and required prolonged hospitalization (69 vs. 46 days, p = 0.0165).Conclusions: Theconcentration of IL-1β in the initial tracheal aspirate obtained from the lungs of preterm infants within the first hour of life may serve as a marker of antenatal/perinatal inflammation, probablydue to maternal chorioamnionitis, and could predict an adverse clinical course and short-term outcome.