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 developm ent of chronic lung disease (CLD) in neonates following an episode of respiratory distress syndrome (RDS), Serial and simultaneous measureme nts of the concentration of IL-8 and granulocyte elastase alpha(1) pro teinase inhibitor complex (E-alpha(1) PI) in the tracheobronchial aspi rate of very low birthweight infants with RDS were conducted. The conc entration 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 concen tration of IL-8 between 48 h of life and day 5 was significantly corre lated to the fraction of inspired oxygen concentration (FiO2) within 4 8 h of age, but not to the mean airway pressure. Interleukin 8 seemed to stimulate neutrophils to release granulocyte elastase which, in tur n, caused lung tissue injury, resulting in the development of CLD. It is suggested that high FiO2 is an important factor causing IL-g produc tion in the lung.