Immune Tolerance: Could A Transplant Become Just Another Operation?
Two things differentiate transplantation from every other type of surgery. One is the reliance on another human being, living or deceased, to donate an organ. The other is the transplanted patient’s continual need for immunosuppressive medications, which leave the recipient vulnerable to a host of chronic and serious illnesses.
Now, however, researchers are looking for ways to eliminate a transplanted patient’s need for immunosuppression, a goal the medical community has worked toward since research began in the early years of transplantation. Recent breakthroughs in immune tolerance research have led transplant physicians and surgeons to test clinical approaches to decreasing and eliminating transplant recipients’ need for medications. While researchers in Europe studied why neonatal mice were able to accept foreign antibodies as their own and how a transplant recipient could be weaned from immunosuppression, doctors in the United States explored chimerism, the mechanism that allows a donor’s antigens to migrate to the transplant recipient’s lymph glands and be accepted.
Current medical thinking holds that pre-conditioning a transplant candidate prior to surgery may play a key role in this process. In addition, it is believed that low doses of immunosuppression administered immediately after the transplant may allow the fighter cells to attack, become exhausted and eventually enable the body to accept the foreign organ as its own.
Physicians, surgeons and scientists from the United States, Canada and Europe are collaborating through the Immune Tolerance Network, a coalition of experts. Although the exact mechanism of immune tolerance is not yet fully understood, the development of tests to monitor, induce and maintain tolerance is in progress. Further investigation is underway to identify ways to save a patient when tolerance fails and the organ is being rejected. Besides kidney transplantation, this work will benefit islet cell transplantation, which is performed to treat diabetes.
