Immunosuppression

Immunosuppression is a natural act or medical treatment that reduces the activation or efficacy of the natural immune system in humans and animals. Generally, immunosuppression is a result of viral activity (such as human immunodeficiency virus [HIV]) or other natural causes. In some cases, immunosuppression is an unwanted side effect of treatment for particular diseases or conditions. In recent years, this process been very important in allowing people to accept transplants such as kidneys which might otherwise be rejected by the natural immunities of the patient.

There have long been particular conditions that lower the response of the human immune system, with the most wellknown in recent years being HIV. In fact, suffering from many illnesses and medical conditions may weaken a person, and as a result, lower the activation of their immune system, making them [Page 886]more susceptible to other illnesses or diseases. This phenomenon has been observed since ancient times. Often, when someone is suffering from a particular condition, others with any type of potentially infectious disease—even the common cold—are prevented from visiting to help ensure that the patient avoids additional illnesses, an even made more possible due to the patient's compromised immune system.

Additionally, some diseases and conditions are best treated by methods that can further reduce or compromise the patient's immune system. For this reason, people who are having or have recently had treatment by chemotherapy are often advised not to visit friends or relatives in hospitals; as their immune system has been suppressed by treatment, exposure to other conditions may result in infection or additional serious complications.

The immune system often reacts to the transplantation of new organs by attempting to reject the organ as if it were an infection or disease. For this reason, the recipient is often treated with immunosuppressive drugs. The first of these to be identified was cortisone, but it had many side effects that limited its use. In 1959, azathiprine was produced and found to be far more specific in its treatment of organ donor recipients. The discovery of cyclosporine in 1970 as an effective immunosuppressive drug changed the nature of kidney transplantation, allowing it to become a far more common practice for using organs from donors who did not perfectly matched those of recipients. Since then, this drug has been used successfully for liver transplants, lung transplants, pancreas transplants, and heart transplants.

Some of the pioneering research in the field of immunosuppression was conducted by Dr. Joseph E. Murray, professor of surgery at Harvard Medical School since 1970, who was the chief plastic surgeon at the Chil-dren's Hospital, Boston, from 1972 until 1985. In 1990, he was awarded the Nobel Prize in Physiology or Medicine for his work; Dr. Murray and his team were credited with the first successful kidney transplant, which took place at Peter Bent Brigham Hospital in Boston on December 23, 1954. Eight years later, he conducted the first kidney transplant with a kidney from a donor unrelated to the patient; immunosuppressive drugs were key to the success of the operation.

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