Illustration of the different mechanisms of action of ITP medications. Immunosuppressive agents are also listed. Ab, antibody; BTK inh, BTK inhibitor; c-MpL, thrombopoietin receptor; IL, interleukin; MMF, mycophenolate mofetil; PC, plasma cell; Plt, platelets; Th, helper T cell; TLR-4, Toll-like receptor-4; TNF-α, tumor necrosis factor-α; Treg, regulatory T cell.