CD19-targeted CAR T Cell Autotransfusion for the Treatment of Recurrent/Refractory B-cell Acute Lymphoblastic Leukemia/Lymphoblastic Lymphoma in Children With CD19+

This study tests a CAR T-cell therapy — a cutting-edge treatment that re-engineers the patient's own immune cells to attack cancer — for children with relapsed or treatment-resistant B-cell acute lymphoblastic leukemia (ALL) or lymphoblastic lymphoma that expresses the CD19 protein. **You may be eligible if...** - You are between 3 and 18 years old with a diagnosed relapsed or treatment-resistant B-cell leukemia or lymphoma - Your cancer has returned after chemotherapy, or did not go into remission after at least 2 rounds of standard treatment - Your cancer cells test positive for CD19 (and/or CD20 or CD22) - Your Lansky score (a measure of physical activity in children) is 60 or above - Your heart, liver, and kidney function meet the required levels - Your expected survival is more than 3 months from the time of consent **You may NOT be eligible if...** - Your cancer cells do not express CD19, CD20, or CD22 - Your organ function does not meet the required thresholds - Your physical condition falls below the minimum score Talk to your doctor to see if this trial is right for you.