Postnatal Cytokine Trajectories in Very Preterm Infants

Inflammation often accompanies preterm birth and contributes to poor neurodevelopment in preterm infants. The purpose of this study was to describe postnatal cytokine trajectories among non-infected very preterm infants during the first weeks of life. Blood samples for cytokine analysis were collected weekly from infants born between 28 and 31 weeks post-menstrual age. We used linear mixed models to calculate slopes for each cytokine and allowed the slopes to differ by infant biological sex and post-menstrual age at birth. Levels of interleukin-6, interleukin-8, and interleukin-1 receptor antagonist decreased, on average, during the neonatal period. Monocyte chemoattractant protein-1 levels increased over time, and tumor necrosis factor-alpha levels were stable. Interleukin-6 and interleukin-8 slopes differed by post-menstrual age at birth but were unaffected by infant sex. Knowledge of average cytokine trajectories may be useful in identifying infants with unresolving inflammation that increases their risk for poor neurodevelopment.