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 pathophysiolog y of the disease. High numbers of inflammatory cells and their products are present in the airways of ventilated neonates with respiratory distress sy ndrome and precede the development of CLD. This article reviews the mechani sms underlying neutrophil recruitment in the lungs of ventilated preterm in fants with respiratory distress syndrome and the injurious effects that the se cells can produce on lung parenchyma with special emphasis on the develo pment of CLD. The role of granulocyte colony-stimulating factor and granulo cyte-macrophage colony-stimulating factor is stressed as a pivotal mechanis m of neutrophil recruitment and activation.