Pathophysiology of ITP and key therapeutic targets. AMR, Ashwell-Morell receptor; BAFF, B-cell activating factor; BCR, B-cell receptor; BLyS, B lymphocyte stimulator; BTK, Bruton's tyrosine kinase; FCR, Fc receptor; FcRn, neonatal Fc receptor; IgG, immunoglobulin; mTOR, mammalian target of rapamycin; Tc, cytotoxic T cell; Th, helper T cell. Drugs in light orange boxes are FDA approved for ITP and not discussed in this article but are shown for completeness; they include fostamatinib and TPO-RAs, thrombopoietin receptor agonists. Rituximab is shown and has sufficient literature to support its use, although it does not have FDA or other regulatory indication for use in ITP.