PROS1 and autoimmune thrombocytopenic purpura: In addition, we showed that Iloprost concentration‐dependently inhibits platelet apoptosis by elevating PKA activity, which inhibits dephosphorylation of proapoptotic protein BAD at Ser155, reducing caspase‐3 activity, resulting in inhibition of platelet apoptosis, and markedly elevates peripheral platelet counts in GPIbα antibody‐induced ITP.