CCL2 and acute respiratory distress syndrome: To assess the initial changes of circulating inflammatory cytokine profiles after LPS-induced ALI, serum concentrations of interleukin (IL)-6, tumor necrosis factor-α (TNF-α), monocyte chemoattractant protein-1 (MCP-1), IL-1β, and IL-8 were measured at 6 h after LPS challenge (Figure 2).