Analysis of cytokine/chemokine levels in bronchoalveolar lavage fluids from patients with acute respiratory distress syndrome

Abstract

Bronchoalveolar lavage (BAL) was performed in 5 patients with acute respiratory distress syndrome (ARDS; ARDS group hereafter) and 2 patients with respiratory failure (non-ARDS group hereafter) within 3 hours of intubation before ARDS treatment other than mechanical ventilation. ARDS was diagnosed based on the criteria defined by the American-European Consensus Conference. BAL fluid (BALF) and sera samples were obtained on the same occasion. The presence of 17 cytokines/chemokines in these specimens was simultaneously determined using a Bio-Plex^® Suspension Array System. The levels of these cytokines/chemokines in BALF and sera samples were compared between the ARDS group and the non-ARDS group. The levels of chemokine granulocyte colony-stimulating factor (G-CSF), monocyte chemoattractant protein-1 (MCP-1) (monocyte chemoattractant factor), and macrophage inflammatory protein-1β (MIP-1β) in the BALF samples were significantly higher in the ARDS group than in the non-ARDS group. The level of pro-inflammatory cytokine interleukin (IL)-6 in BALF was also higher in the ARDS group than in the non-ARDS group. In contrast, the levels of IL-1β and IL-8 in BALF were higher in the non-ARDS group than in the ARDS group. The levels of these cytokines in BALF were higher than the corresponding sera levels in both groups. These results indicate that severe initial alveolar injury significantly activates chemokines in patients with ARDS caused by direct lung injury (such as pneumonia), unlike the increased levels of the inflammatory cytokines IL-1β and IL-8 in BALF of patients with early ARDS.