This prospective, case-controlled, study for adult ITP patients between the ages of 18-60 years who requiring splenectomy who have failed to respond to multiple first and second line therapies. The goal is to assess their immune system and to determine how this changes post-splenectomy. Patients would be required to have their splenectomy performed as part of the study. Their platelet count will be raised to a safe level for the procedure. Blood for analysis will be collected at various points before and after surgery in addition to analyzing a small amount of tissue from the spleen taken during surgery, which will be matched with healthy donors. Individuals with secondary ITP will be excluded.