NF-kappa B, in tracheal lavage fluid from intubated premature infants: association with inflammation, oxygen, and outcome

Objectives: To determine if tracheal lavage concentrations of the transcription factor NF-kappa B, which is activated by risk factors associated with bronchopulmonary dysplasia (BPD) and induces expression of cytokines associated with BPD, is related to BPD in premature infants. Design: Serial tracheal lavage samples from intubated premature infants were analysed for cell count and concentrations of interleukin (IL)8 and NF-kappa B, corrected for dilution by secretary component concentrations. Setting: Level III university hospital neonatal intensive care unit. Patients: Thirty three intubated infants (mean (SD) birth weight 903 (258) g, median gestation 27 weeks (range 24-31)) in the first 14 days of life. Main outcome measures: Tracheal effluent NF-kappa B, IL8, and cell counts, corrected for dilution by secretary component measurement. Results: Square root transformed NF-kappa B concentrations were significantly related to signs of inflammation (cell count, p = 0.002; IL8, p = 0.019) and to simultaneous fraction of inspired oxygen in samples from the first 3 days of life (r = 0.512, p < 0.003). Of the 32 subjects with samples in the first 3 days of life, the half who either died or had BPD had higher NF-kappa B concentrations than those without BPD (square root concentration 0.097 (0.043) v 0.062 (0.036) mu g/mu g protein/mu g secretary component, p = 0.018). Conclusions: Tracheobronchial lavage NF-kappa B concentrations are related to lung inflammation, oxygen exposure, and pulmonary outcome in intubated preterm infants. NF-kappa B activation may be an early critical step leading to BPD.