Abstract 129

Objective: To evaluate the contribution of airway infection with Ureaplasma urealyticum (Uu), and bacteria to the extent of pulmonary inflammation in preterm infants at risk for BPD.

Methods: Concentrations of interleukin-1 (IL-1) and interleukin-8(IL-8) were sequencially analyzed on days 1-10 of postnatal age by ELISA in tracheobronchial aspirate fluid (TAF) within the following subgroups: (1) controls (n=14): neonates without severe RDS (FiO2 <0.4), sterile TAF, no BPD. (2) neonates with RDS (FiO2 ≥0.4,n=9), sterile TAF, no BPD. (3) RDS-BPD-group (n=9): neonates with RDS leading to BPD or death due to respiratory failure, sterile TAF (4) neonates with perinatal airway infection with Uu (n=19) (5) neonates with bacterial airway infection at birth, (n=7), and (6) neonates with bacterial or fungal nosocomial airway colonization or infection, with or without RDS (n=17).

Results. Tracheal aspirates of 75 ventilated, consecutively born neonates (birth weight 861 ± 182 g, mean ± SD) were analyzed. Neonates with developing BPD (n=24) exhibited significantly increased mean and maximum levels of interleukin-1 and interleukin-8 in TAF compared to patients without BPD. Concentrations of IL-1 and IL-8 were significantly increased in groups 2,3,4,5 and 6 compared to controls. Neonates with airway infection (groups 4,5,6) had increased mean and maximum levels of IL-1, but not of IL-8 compared neonates with respiratory disease without airway infection (groups 2,3). Conclusion: Pulmonary inflammation of neonates with developing BPD is related both to an infectious and a non-infectious origin. Elevated levels of IL-1 are predominantly associated with airway infection, whereas IL-8 is elevated both in infection and non-infection-related inflammation.