TLR4 and acute respiratory distress syndrome: The functional relevance of the amplification in TLR4-induced TLR3 expression in AMΦ was demonstrated by a marked increase in the expression of the chemokines and cytokines, including macrophage inflammatory protein-2 (MIP-2), macrophage chemoattractant protein-1 (MCP-1), tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6), in the ALI mouse model.