The modified T-cells then carry chimeric antigen receptors, proteins which allow them to recognize and kill multiple cancer cells.
3. Chemotherapy kills any remaining T-cells in the patient. The doctors don't want un-modified T-cells impeding the new ones.
4. The modified T-cells are returned to the patient. Within the patient the newly re-programmed T-cells proliferate.
"The patient becomes a bioreactor," said June.
5. Over the next few weeks the patient develops a temperature, chills, shakes, low blood pressure, and other flu-like symptoms. The symptoms are caused by chemicals called cytokines produced by the T-cells.
The flu-like symptoms also mean the cancer is on the run. After the ordeal, doctors estimated that two pounds of cancer cells had died off in one patient, William Ludwig.
"I have my life back," Ludwig said in a New York Times article.
Six months after treatment Ludwig's cancer was still in remision and he still had the modified T-cells in his blood stream, ready to fight a resurgence of the leukemia.