Anti-interleukin 8 autoantibody : interleukin 8 complexes in the acute respiratory distress syndrome - Relationship between the complexes and clinical disease activity

Increased levels of interleukin 8 (IL-8) are found in bronchoalveolar lavag e (BAL) fluids from patients with the acute respiratory distress syndrome ( ARDS). However, IL-8 is not an efficient predictor of the course of ARDS. O ur prior studies demonstrated that IL-8 present in lung fluids from patient s with ARDS is associated with anti-IL-8 autoantibodies (anti-IL-8:IL-8 com plexes). These data led us to hypothesize that the complexes might better p redict the development of acute lung injury. Accordingly, we measured conce ntrations of free and complexed IL-8 in BAL fluids from 19 patients at risk and 45 with established ARDS on Days 1, 3, 7, 14, and 21 after the onset o f ARDS, The concentrations of antiIL-8:IL-8 complexes in patients with ARDS on Day 1 were significantly higher than in patients at risk (p < 0.05). Th ere was a significant association between anti-IL-8:IL-8 complex concentrat ions and the onset of ARDS (p = 0.03). Similarly, anti-IL-8:IL-8 complex co ncentrations were significantly higher in patients on Day 1 of ARDS who lat er died (p < 0.05), and the association between high anti-IL-8: IL-8 comple x concentrations and the probability of dying was significant (p = 0.03). T he presence of anti-IL-8:IL-8 complexes in BAL fluids of patients with ARDS is an important prognostic indicator for the development and outcome of AR DS.