TPO and autoimmune thrombocytopenic purpura: Our data suggests that the mechanism by which ZDF promotes platelet proliferation and improves coagulation in patients with ITP may be as follows: on the one hand, ZDF reduces serum TPO concentration and inhibits Ras/ERK signaling pathway activation, so that downstream GM-CSF and S1P expression decreases, resulting in reduced platelet activation and increased platelet proliferation.