TLR4 and COVID-19: The data in Figure 3 show a significant positive correlation between serum urea and TLR2 mRNA expression (p = 0.000) and a positive correlation between serum CK-MB activity and Troponin I level with the mRNA expression of TLR2 (p = 0.000) and TLR4 (p = 0.000) in the moderate COVID-19 group.