Receiving an organ transplant is a trying experience for anyone. Often times, they are the result of an organ failure or a traumatic health event. The surgeries required to do the transplant are often costly and risky to perform.
Not only do patients that require an organ transplant face many risks when undergoing the surgery, they also will face difficulties for a large portion of their lives. The immune system does not naturally allow a transplanted organ to work freely. It detects the organ is foreign, and often attacks it.
Patients who receive organ transplants will be forced to take drugs that suppress the immune system for the remainder of their lives. These drugs do not promise results either. Many times after a person’s immune system has been tolerant for many years, the organ will suddenly be rejected.
A new study published in Nature Communications has discovered that it may be possible for patients that a patient’s rejection of an organ may not be permanent as once previously thought.
Scientists previously believed that if a patient rejected an organ that they were inherently intolerant to any type of organ transplantation. Many doctors and scientists believed that the immune system would remember the previous intolerance of an organ and refuse to accept another.
In a small number of patients, suppressing the immune system can allow for this state of transplanted organ acceptance to continue. For many, a bacterial infection can trigger the immune system to reject the organ. After this is done, it was widely accepted that the immune system would not accept another transplanted organ.
The study conducted at the University of Chicago challenged the previously held views by conducting a study in mice that looked at the potential for immune system suppression to be achieved even after a bacterial infection. They performed heart transplants on mice and then induced immune system tolerance. After the mice were stable for two months with the immune tolerance and the new hearts, the team forced the mice to reject the hearts by creating an infection.
After this rejection, they then implanted a second heart in the mice, but made some changes to the mice’s immune system. The team added a large amount of “T-Cells” to the mice’s immune systems. These cells are found in mice and humans naturally. The team was able to successfully take the immune system back to a state of suppression and allow the mice to accept the second transplant.
The team believes that these T-Cells work similarly to brakes in a car. They slow down the immune systems response to the transplant and allow for the organ to establish itself in the body. When the team reduced the number of T-Cells in the mice, they rejected the organs once again.
“The methods for achieving transplantation tolerance differ between mice and humans, but the mechanisms that maintain it are likely shared,” said Marisa Alegre, one of the co-authors of the study. “Our results imply that tolerant patients who experience rejection could be treated with short-term immunosuppressive medications to protect the transplant, and then weaned off once tolerance returns.”
This new method could offer hope to the numerous patients that are left without many options after an organ is initially rejected and save many lives.