Interleukin 8 and granulocyte elastase alpha 1 proteinase inhibitor complex in the tracheobronchial aspirate of infants with chronic lung disease following respiratory distress syndrome.

In order to elucidate the role of interleukin 8 (IL-8) on the development of chronic lung disease (CLD) in neonates following an episode of respiratory distress syndrome (RDS), serial and simultaneous measurements of the concentration of IL-8 and granulocyte elastase alpha 1 proteinase inhibitor complex (E-alpha 1 PI) in the tracheobronchial aspirate of very low birthweight infants with RDS were conducted. The concentration of IL-8 and E-alpha 1 PI in infants with CLD was low in the first 48 h of life, but dramatically increased after 48 h. The concentration of IL-8 between 48 h of life and day 5 was significantly correlated to the fraction of inspired oxygen concentration (FiO2) within 48 h of age, but not to the mean airway pressure. Interleukin 8 seemed to stimulate neutrophils to release granulocyte elastase which, in turn, caused lung tissue injury, resulting in the development of CLD. It is suggested that high FiO2 is an important factor causing IL-8 production in the lung.