IL1B and essential thrombocythemia: Nevertheless, we had previously reported that some humoral factors such as endogenous toll-like receptor 4 (TLR4) ligands HSP70 and HMGB1 or other inflammatory cytokines, might participate in the activation of B cells in ET patients because peripheral B cells of ET patients could be stimulated by ET patients’ sera to cause IL-1beta and IL-6 production [23].