the research performed by the ITP study group in 2006[15] studying the efficacy of single dose IV-Rhesus antibodies (Anti-D) "50 ug/kg or 75 ug/kg" compared to the single dose IVIG "800 mg/kg"; that study revealed that both have a similar therapeutic effect. that study suggest to compare the single high dose of Anti-D withthree consecutive doses of Methyl-prednisolone in respect of: 1- Time of platelet recovery 2- The continuity of mediation effect throughout ( 6 months) 3- Side effects, hospitalization and cost.