TLR4 and essential thrombocythemia: In order to determine the potential contribution of TLRs to platelet activation in ET, we assessed TLR2- and TLR4-mediated platelet thromboinflammatory responses, using the synthetic lipopeptide Pam3CSK4 and LPS, as prototypical TLR2/1 and TLR4 ligands, respectively, and employed classic hemostatic agonists, such as TRAP-6 and thrombin, for comparison.