THBD and COVID-19: In liver autopsy samples from patients who died because of COVID-19 complications, PC activation signaling receptors were significantly decreased compared with control as follows: 2.7-fold for S1PR1, 2.5-fold for F2R and 1.7-fold for THBD (p < 0.001), and less than 5% of cells expressed these genes (Table 1; Figure 2C,D).