The goal of this clinical trial is to learn if mini-pool intravenous immunoglobulin (IVIG) is a safe and effective treatment for children with persistent immune thrombocytopenia (ITP). ITP is a condition that causes low platelet levels and increases the risk of bleeding. The main questions this study aims to answer are: Can mini-pool IVIG raise platelet levels in children with persistent ITP? Can it reduce bleeding episodes and hospital visits? What side effects, if any, are seen with this treatment? There is no comparison group in this study. All participants will receive mini-pool IVIG, which is made from small pools of donated plasma using a cost-effective process. Participants will: Receive one dose of mini-pool IVIG through a vein over 6 to 8 hours Receive follow-up doses every 2 to 4 weeks for up to 5 doses, based on their platelet count Have regular blood tests and checkups during the study and for 6 months after treatment Report on bleeding episodes, physical activity, school attendance, and side effects