TLR8 and COVID-19: The immunoblotting results revealed that the levels of COVID-19 EV-induced NETs-associated proteins [e.g., myeloperoxidase (MPO), peptidylarginine deiminases 4 (PAD4), and citrullinated histone H3 (citH3)] were inhibited completely in TLR8 knockdown cells (Fig. 2E), which was consistent with IFA data.