Platelet surface expression of activation markers in controls and ITP patients at days 0, 7, and 28 of eltrombopag treatment with no added agonist and in response to low and high dose ADP and TRAP stimulation. (A) Activated GPIIb/IIIa (PAC-1), (B) P-selectin, and (C) GPIb. C indicates healthy controls; D0, ITP patients pretreatment with eltrombopag; and D7 and D28, 7 and 28 days after initiation of eltrombopag treatment in ITP patients. Black-capped bars indicate unpaired (ITP at baseline vs controls) and gray bars indicate pairwise comparisons (ITP patients at different study days). Data are mean ± SEM (*P < .05; **P < .02; ***P < .001).