B-Lymphocytic Leukemia, Chronic

Background: Chronic lymphocytic leukemia (CLL),small lymphocytic lymphoma (SLL) and B-cell acute lymphoblastic leukemia or lymphoma (ALL) are blood cancers that affect certain white blood cells. Advanced forms of these diseases are difficult to treat. CD19 is a protein often found on the surfaces of these cancer cells. Researchers can modify a person's own immune cells (T cells) to target CD19. When these modified T cells are returned to the body-a treatment called anti-CD19 chimeric antigen receptor (CAR) T cell therapy-they may help kill cancer cells. Objective: To test anti-CD19 CAR T cell therapy in people with CLL or SLL and ALL. Eligibility: People aged 18 years and older with CLL or SLL and ALL that has not been controlled with standard drugs. Design: Participants will be screened. They will have imaging scans and tests of their heart function. If a sample of tissue from their tumor is not available, a new one may be taken; the sample will be tested for CD19. Participants will receive a drug to reduce the leukemia cells in their blood. Then they will undergo apheresis: Blood will be taken from the body through a needle. The blood will pass through a machine that separates out the T cells. The remaining blood will be returned to the body through a different needle. The collected T cells will be gene edited to make them attack cells with CD19. Participants will take drugs to prepare them for treatment for 3 days. These drugs will start 5 days before the treatment. Then their own modified CAR T cells will be returned to their bloodstream. Participants will stay in the hospital for at least 9 days after the treatment. Follow-up visits will continue for 5 years.