TLR4 and COVID-19: Finally, WARS1, which has been reported to boost the innate immune response as a ligand of toll-like receptors TLR2 and TLR4 (73), has been identified as a factor involved in several biological processes associated with COVID-19 severity and has been described to be downregulated on the mRNA-level upon SARS-CoV-2-infection (74, 75).