Increased interleukin-8 and monocyte chemoattractant protein-1 concentrations in mechanically ventilated preterm infants with pulmonary hemorrhage.

Pulmonary hemorrhage (PH) is a serious complication causing acute respiratory distress in the premature infant, and it is associated with significant mortality and morbidity. The role of inflammatory mediators in this condition is largely undefined. Serial tracheal aspirates (TA) were obtained at intervals from 65 mechanically ventilated infants with birth weights less than 1,250 g during the first 21 days of life. Clinically significant PH developed in 15 infants. TA concentrations of interleukin-8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1) were determined by enzyme-linked immunosorbent assay (ELISA).PH was associated with an increased risk of death, bronchopulmonary dysplasia, intraventricular hemorrhage, and prolonged need for mechanical ventilation and supplemental oxygen. TA aspirate concentrations of IL-8 and MCP-1 (P = 0.001, ANOVA) were significantly increased in infants with PH compared to infants who did not develop this condition. TA cytokine concentrations were also significantly increased in infants who developed bronchopulmonary dysplasia (BPD). Peak TA concentrations of IL-8 and MCP-1 were significantly higher in infants with poor outcome (BPD or death). TA MCP-1 but not IL-8 concentrations were significantly higher in infants who were oxygen-dependent at 36 weeks postconceptional age. These data suggest a pathogenic role for IL-8 and MCP-1 in the development of adverse pulmonary outcome in preterm infants with clinically significant PH.