TLR3 and COVID-19: Interestingly, exposure to polyI:C diminished the production of IL-6, IL-1β, TNFα, and IL-12 of COVID-19 PBMCs when compared to healthy PBMCs, suggesting a partial blockade of TLR3, MDA5, and RIG-I-associated signaling pathways (Figure S2A), which aligns with the recently described impaired proinflammatory response of COVID-19 pDCs to polyI:C and R848 cocktail [26].