There may be new hope down the road for heart transplant patients. A new study performed on monkeys has shown that injections of certain proteins may prevent the body’s rejection of transplanted organs without the use of immune suppression drugs. Transplant patients currently must take immune suppression drugs for their entire lifetime to ensure that their bodies do not reject the transplanted organ. Furthermore, there must be a close tissue match between the patient and the transplanted organ. Scientists declare this finding a breakthrough that may someday enable the transplantation of organs that are not completely compatible with the recipient’s tissue.

The injected proteins (CTLA4-IG and 5C8) turn off a function of T-cells (lymphocytes) that protect the body from foreign substances. The injections block one of the processes performed by T-cells, and actually teach the immune system to accept the transplanted organ. The treatment does not appear to interfere with the body’s ability to fight infection.

The study included 12 monkeys that had been given kidneys that were not compatible with their body tissue. The monkeys that received the protein injections for the longest period of time (28 days) were in good health after 150 days, and did not reject the new kidneys. The four control monkeys that did not receive the proteins rejected the transplants within eight days.

Scientists confirmed that more research needs to be done before human trials can be undertaken. The study was conducted by Capt. David Harlan and Lt. Commander Allan Kirk of the U.S. Naval Medical Research Institute in Bethesda, Maryland, and was published in The Proceedings of the National Academy of Sciences.

HeartInfo Editorial Comment:
Organ transplant is lifesaving for many people with kidney, liver, heart, or lung failure, but it carries significant risks. One of the major risks is that of long-term immunosuppression with certain drugs. The results of this study suggest that the time is coming in which rejection of transplanted organs might be prevented by injection of specialized proteins at critical times around the time of transplant. Although more studies are required, this approach shows promise.