Sequential Treatment With CD20/CD22/CD10-CART After CD19-CART Treatment Base on MRD in Relapsed/Refractory B-ALL

This trial is testing a sequence of specially engineered immune cell therapies (called CAR-T cell therapy) in patients with a type of blood cancer called B-cell acute lymphoblastic leukemia (B-ALL) that has not responded to or has come back after standard treatment. **You may be eligible if...** - You have B-cell acute lymphoblastic leukemia (a type of blood cancer) that came back or did not respond to treatment - Your cancer did not go into remission after 2 rounds of standard chemotherapy, or it came back after treatment - You are not able to receive or do not want a stem cell transplant from a donor - Your cancer cells carry certain proteins (CD19 and CD20/CD22/CD10/CD70) on their surface - Your expected survival is more than 3 months - You are willing to participate and have signed a consent form **You may NOT be eligible if...** - Your cancer has disappeared (MRD negative) but the specific cell markers are absent - You have serious organ problems or infections - You have other conditions that would make participation unsafe Talk to your doctor to see if this trial is right for you.