Phase I/IIA Study of CART19 Cells for Patients With Chemotherapy Resistant or Refractory CD19+ Leukemia and Lymphoma

This is a study for children who have been previously treated for Leukemia/Lymphoma. In particular, it is a study for people who have a type of Leukemia/Lymphoma that involves B cells (a type of white cell), which contain the cancer. This is a new approach for treatment of Leukemia/Lymphoma that involves B cells (tumor cells). This study will take the subject's white blood cells (T cells) and modify them in order to target the cancer. The subject's T cells will be modified in one or two different ways that will allow the cells to identify and kill the tumor cells (B cells). Both ways of modifying the cells tells the T cells to go to the B cells (tumor cells) and turn "on" and potentially kill the B cells (tumor cells). The modification is a genetic change to the T cells, or gene transfer, in order to allow the modified T cells to recognize your tumor cells but not other normal cells in the subject's body. These modified cells are called chimeric antigen receptor 19 (CART19) T-cells.