*Minimum dose permitted on trial at all Dose levels is ≥5 x 106 CD19CAR T-cells (plus 20% for thawing losses) The study will evaluate ATIMP safety and efficacy and the duration of disease response in adults with high risk / relapsed CD19+ B-ALL. After completing the interventional phase of the study all patients, irrespective of whether they progressed or responded to treatment, will enter long term follow up until 5 years post-CD19CAR T-cell infusion.