The role of inflammation in the development of chronic lung disease in neonates.

Chronic lung disease (CLD) has been associated with chorioamnionitis and upper respiratory tract colonisation with Ureaplasma urealyticum. The aim of this review is to describe the increasing evidence that inflammation plays a critical role in the early stages of CLD of the neonate. Ongoing lung damage in the premature infant may be caused by failure to downregulate and control this inflammatory response. Tumour necrosis factor alpha (TNF-alpha), interleukin-6 (IL-6) and IL-8 are important pro-inflammatory cytokines of which IL-8 is an important chemotactic factor in the lung. Data suggest that preterm newborns with lung inflammation may be unable to activate the anti-inflammatory cytokine IL-10. Therefore, early post-natal anti-inflammatory therapy could help in preventing development of CLD. Prophylactic dexamethasone therapy cannot yet be recommended. There are a number of potential interactions between surfactant and cytokine effects on the preterm lung which have not been evaluated. Surfactant protein A may be an important modulator of the immune response to lung injury. The role of high-frequency ventilation in the prevention of CLD still remains unclear. Many aspects of the pathogenesis of the inflammatory response in the development of chronic lung disease remain to be elucidated. Further research to identify preterm infants at highest risk for the development of this multifactorial and complex disease is needed.