Key to stem cell transplant success is tricking immune system

Tricking the body's immune system into ignoring stem cells will be the key to successful stem cell transplants, according to Professor Maggie Dallman, Imperial College London, speaking this week at the BA Festival of Science.

Professor Dallman is investigating how to trick the body into producing regulatory cells, which prevent the body's immune system from attacking its own molecules, at the site of a stem cell transplant. If they were present when stem cells were introduced into the body, the regulatory cells would inhibit the body's natural response to 'foreign' cells, meaning the stem cells would be accepted.

Drug therapies can prevent traditional organ grafts from being destroyed in the short term but organ transplants typically fail after a number of years as the body's immune system rejects the new tissue. Scientists are hopeful that harnessing regulatory cells would prevent stem cell transplants from facing similar rejection.

Professor Dallman, from Imperial's Division of Cell and Molecular Biology, explains: "Stem cell transplants will offer fantastic possibilities for helping people with any disease where there is tissue damage or degeneration. It is vital to work out how to prevent these transplants from being rejected.

"We know from over 50 years of experience with transplants that a major issue affecting the success of such procedures is the immune system's rejection of grafted tissue. Our recent experiments suggest that we could use regulatory cells to stop the immune system responding to foreign transplants, whilst leaving the rest of the immune system intact", she adds.

Cloning stem cells using a patient's own cells is another option for preventing the rejection of stem cell transplants. This would have a low risk of rejection since cloned cells would contain the patient's own DNA. However, the cost and intricate nature of this procedure means that it may not prove to be a practical option for widespread use, according to Professor Dallman.