Infection, neutrophils, and hematopoietic growth factors in the pathogenesis of neonatal chronic lung disease.

Continued definition of the biochemical and molecular mechanisms underlying the development of chronic lung disease (CLD) has persuaded investigators that inflammatory cells and mediators are key factors in the pathophysiology of the disease. High numbers of inflammatory cells and their products are present in the airways of ventilated neonates with respiratory distress syndrome and precede the development of CLD. This article reviews the mechanisms underlying neutrophil recruitment in the lungs of ventilated preterm infants with respiratory distress syndrome and the injurious effects that these cells can produce on lung parenchyma with special emphasis on the development of CLD. The role of granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor is stressed as a pivotal mechanism of neutrophil recruitment and activation.