Cells of the immune system are able to fight off infection and to kill cancer cells. Unfortunately, cancer cells frequently develop ways to hide from the immune system and are able to avoid being killed. New results show that immune cells from patients with cancer can be modified and turned into potent killers of cancer cells.
The treatment was used in patients with chronic lymphcytic leukemia (CLL). In CLL, the cancer cells are white blood cells. B cells, a type of white blood cell have a protein on their surface called CD19. This protein helps normal B cells perform their job, the production of antibodies. CD19 is also found on cancerous B cells.
In the treatment, another kind of white blood cell, called T cells, were removed from patients and genetically altered so they could recognize and destroy cells producing CD19. They were then put back into the patients where they reproduced and hunted down the cancer cells. The modified 'killer T cells' can travel all over the body to do their job. One great bonus is that the killer cells reproduce in the body, increasing in number to over 1000 times their original numbers.
The results were extremely positive. A CLL patient who had not responded to other treatments had a great response to this treatment and their cancer was put into remission. The patient had no visible disease ten months after the treatment.
An expected side effect of the treatment is a decrease in the number of normal B cells in the patient (because they also have CD19 on them) and a decrease in the immunity provided by B cells. Researchers are working on ways of adding in a 'suicide gene' that can be turned on after the cancer has been eliminated, ridding the patient of the killer T cells when they are no longer needed.
Bottom Line: T cells from CLL patients were genetically modified to recognize a protein (CD19) on the surface of cancer cells. When put back into patients, the altered T cells were able to reproduce and to kill cancerous B cells. One patient (out of three) was put into remission by the treatment. Side effects were limited and were caused by the death of healthy B-cells.
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