Cell therapy promises revolutionary new therapeutic treatments for cancer and other serious diseases and injuries. For example, T-cell therapy response rates of >50% and durable complete response rates of 20% have been reported in patients with metastatic melanoma who had failed other therapies (1). In another example, sustained remissions of up to a year were achieved among a small group of advanced chronic lymphocytic leukemia patients upon treatment with autologous T-cells expressing an anti-CD19 chimeric antigen receptor (2). Numerous other…