The goal of this clinical trial is to learn if anti-CCR9 CAR T cells (which will be made using the patient's own blood cells) are safe and which dose should be used in children and adults with T cell leukaemia and lymphoma.
Participants will:
* have T cells collected from their blood and these T cells will be used to make the CAR-T cells in a specialized laboratory.
* be admitted at the hospital a week before the CAR T cells infusion to receive a short course of chemotherapy drugs which prepare the body to receive the CAR T cells.
* be given the CAR T cells into their vein.
* stay in the hospital for a minimum of 2 weeks to be closely monitored
* following discharge, participants will come to the clinic for check-ups (approximately 12 visits in the first two years)
* during screening, treatment and follow up visits, participants will have physical examination, collection of blood samples and bone marrow biopsies and/or imaging tests (CT/PET-CT scans) depending on their type of T-cell cancer.