TLR4 and COVID-19: The crosstalk between RAGE and TLR4 in response to DAMPs is underlined by the fact that RAGE-positive, TLR4 KO peritoneal macrophages produced almost no proinflammatory cytokines in response to HMGB1 [12], suggesting the existence of a HMGB1/RAGE/TLR4 axis in mediating inflammation in COVID-19.