Edited Donor Immune Cells Cause Long Term Leukemia Remission

In an experimental treatment of 2 infants in the UK, an infusion of donor T-cells that have been genetically modified has proved highly promising

CAR-T cell therapy is one of the most exciting branches of immunotherapy today, and normally involves essentially editing a patient's own T-cells (a type of immune cell that can hunt down cancer). This makes these cells more active; better able to pick up on and attack any rogue cells around the body. While it comes with a range of severe side effects in some cases, it's proving phenomenally successful in particular patients. A remaining problem however is securing a sufficient source of these cells for treatment if the patient has a limited number already.

Fighting leukemia

2 killer T-cells attacking. Credit: Wellcome Images

 This is especially true in patients with leukemia, and so in an experimental venture in the UK scientists decided to edit donor T-cells instead, before injecting them into 2 babies suffering from acute lymphoblastic lymphoma. These cells were altered to both prevent the host's immune system recognising foreign cells and triggering complications, and to specifically target the leukemia cancer cells. An additional change was also made to reduce the likelihood of graft versus host disease (in which the foreign cells attack the body). These changes were made using the TALEN gene editing system (transcription activator-like effector nuclease). This is a (slightly) older type of editing technology than CRISPR and requires more effort but is perhaps more accurate and reliable. 

What was the result? 

Both an 11 and 15 month old child were injected with these cells at the same time as chemotherapy. They also later underwent a bone marrow transplant to replenish their depleted immune system. One unfortunately developed graft versus host disease, but this was quickly resolved safely. The overall result is that both remain in remission after a year has passed. 

These results are hopeful, and could give a lifeline to those in desperate need of a more experiment treatment. We shouldn't expect this kind of approach to be approved anytime soon however for more general use. It was only approved in this case as all other options had been exhausted. 

Read more at MedicalXpress