TLR4 and acute respiratory distress syndrome: Although our work and previous studies have shown the positive effects of TLR4 inhibition in preventing the inflammatory reaction and fibrosis in ALI induced by endotoxins of a Gram-negative bacillus,[9] it was also reported in non-Gram-negative bacteria[22,25,33] or even non-infectious factors[34] induced ALI animal models, the absence or inhibition of TLR4 expression could lead to aggravation of inflammatory injury and increased animal mortality.