TLR4 and hemorrhage: It was reported that TLR4 expression at mRNA and protein levels significantly increased at around 2 to 6 hours after intracerebral haemorrhage, peaked at day 3, declined at day 5, while remained elevated compared with baseline even on day 7.28 In another study, exposure to LPS can enhance TLR4 mRNA expression after 1 hour in autologous human alveolar macrophages and monocytes, with a subsequent decrease in TLR4 mRNA level after 24 hours,29 suggesting that LPS can differentially affect TLR4 abundancy in alveolar macrophages.