Anti-interleukin-8 autoantibody in the tracheobronchial aspirate of infants with chronic lung disease

Background: A high concentration of interleukin (IL)-8 has been observed in the tracheobronchial aspirate of infants with chronic lung disease (CLD), although the pattern varies depending on the type of CLD. Alveolar fluid fr om patients with adult respiratory distress syndrome (ARDS) also contains a n elevated level of IL-8. Recently, the presence of anti-IL-8 autoantibody was demonstrated in the alveolar fluid from patients with ARDS. Methods and Results: The concentration of anti-IL-8 autoantibody in the tra cheobronchial aspirate of infants with CLD was measured in order to discove r whether there was any correlation with the concentration of IL-8. Similar to IL-8 concentration, the anti-IL-8 IgM antibody concentration in all inf ants with CLD following intrauterine infection was already high during the first 48 h. However, the concentration in infants with CLD following respir atory distress syndrome began to increase after 11 days of life, in contras t with the rise in IL-8 between 48 h after birth and day 5. Conclusions: The presence of anti-IL-8 autoantibody may provide a mechanism that limits the bioavailability of free IL-8 in the lungs. In addition, th e time lag between the increase in IL-8 and anti-IL-8 IgM autoantibody demo nstrated in the present study could be used to estimate the time when the i nflammation begins, even if the IL-8 concentration is already high.