Interesting article from wsoctv.com in Charlotte, South Carolina.

Organ Transplants In The U.S.

Organ transplantation is the removal of a diseased organ and replacement with an organ from a deceased donor. In some cases, like kidney transplants or partial liver transplants, the organs can come from healthy donors.

Last year, the Organ Procurement and Transplantation Network says 28,112 organ transplants were performed in the U.S. Nearly 2,300 were done so far this year. But there aren't nearly enough donor organs available to meet the requests of those who need them. As of May 31st, there were 92,271 candidates on the waiting list for an organ transplant. The Coalition on Donation estimates about 18 people die each day due to a lack of suitable donor organs. The organs of highest demand are the kidneys, liver, lung, heart and pancreas.

Surviving an Organ Transplant

Survival rates after an organ transplant are increasing. For heart transplants, for example, 86.4 percent of male recipients and 84.6 percent of female recipients are alive after one year. For five years, survival rates are 72.1 percent for males and 68.5 percent for females. Survival rates are even higher for kidney transplants - 95.3 percent of males and 96 percent of females at one year and 84.6 percent of males and 86 percent of females at five years.

One of the biggest advances in the survival of transplanted organs is the use of immunosuppressive drugs. Normally, when a person receives a transplant, the recipient's immune system perceives the donor organ as "foreign" tissue and mounts an attack against the invader. Ultimately, that can lead to a rejection or destruction of the new organ. In 1983, doctors began using cyclosporine, a new drug to suppress the immune system, and hopefully prevent rejection of transplanted organs. Since that time, several other immunosupressive medications have been developed. Doctors may use one or more drugs to prevent rejection of a transplant.

Downside of Immunosuppressive Medication

While immune-suppressing medications are life-saving treatments for many transplant patients, the drugs come with a price. Cyclosporine can raise blood sugar levels, cholesterol and blood pressure. It can also cause kidney problems, swollen gums, headache and excessive growth of body hair. Other immunosuppressants can cause similar problems plus bone loss, weight gain, acne, mood changes, fever, sleep problems, anemia, diarrhea and nausea. And since the drugs suppress the immune system, patients are at increased risk for infection and some types of cancer.

Building Tolerance for Donor Organs

Some transplant patients are able to stop taking immune suppressing medications and show no signs of rejection. Researchers say these patients have developed a "tolerance" for the new organ. Transplant tolerance doesn't mean the body has necessarily accepted the donor organ. Instead, the recipient's immune system has chosen not to initiate a destructive response to the transplant.

Scientists don't know why a few patients develop transplant tolerance. However, it would be an ideal goal for all transplants because patients could avoid the side effects of immune suppressing drugs.

At Baylor Transplant Institute, researchers are studying the role of dendritic cells in the development of immune reactions to organ transplants. Dendritic cells are specialized immune cells that identify foreign substances and signal the release of other immune cells to destroy the invader. In the current study, patients are given strong medications prior to the transplant to destroy most of the body's immune system. The transplant is done with the immune system in a weakened state, hopefully reducing the body's ability to react to the donor organ. As the body rebuilds its immune system, doctors are hopeful the new organ will be more likely accepted as an "original" body part. Patients continue to take lower doses of immune suppressing medications after the transplant. Eventually, doctors hope to completely wean the patient from immune suppressing medication.

Doctors will measure the immune response through a blood test. A drop of blood is placed in a special machine (called a microarray machine) which looks at the activity levels of 50,000 different genes. The gene activity is displayed on a graph showing bars of different colors, creating a "signature," or pattern, of immune system activity. Depending upon which patterns show up, doctors can determine if the immune system is starting to reject an organ or mount a defense against an infection or cancer - all before the patient shows any signs of problems. The blood test will also show doctors which patients may not need to take immunosuppressive medications (because the immune system shows no activity against the organ).

Researchers say less than one-third of organ transplant patients are able to eventually stop taking immune suppressing medications. But monitoring immune response may help doctors find clues that can help them develop ways to increase the number of those who become tolerant to their transplants. Even if patients can't stop taking the medications, some may be able to at least reduce their dosages, and hopefully lower the risk of side effects from the drugs. The blood test may also be useful to help doctors identify patients in early stages of rejection - when they may be able to take steps to halt the process and save the organ. That may reduce the number of patients who experience chronic rejection and require another transplant - making more organs available for those who need an initial transplant.

For general information on organ transplantation:

Coalition on Donation
Organ Procurement and Transplantation Network
United Network for Organ Sharing (UNOS)