Legorreta Center for Clinical Transplant Tolerance

The kidneys are important for your health, helping to clean the blood by removing waste as urine and keeping water, salts, and minerals balanced. They also help control blood pressure and make new red blood cells. While most people have two kidneys, it is possible to live with just one. For people with kidney failure, or end-stage kidney disease, wherein the kidneys’ function is severely impaired, treatments like dialysis or a kidney transplant are needed. 

Following transplant surgery, patients typically require lifelong immunosuppressant medications to stop the immune system from attacking and, ultimately, rejecting the new organ. This rejection process naturally occurs as the immune system's main function is to protect the body from harm by identifying foreign cells and tissues—such as a virus or bacteria. It perceives these foreign “intruders” as a threat and mounts an immune response to attack them. It unfortunately also recognizes transplanted organs as foreign and targets them. Immunosuppressive medications reduce this immune response after transplant surgery to prevent organ rejection.

Transplant tolerance refers to the body’s ability to accept a transplanted organ as its own, reducing or removing the need for immunosuppressant drugs after transplant. At the MGH CCTT, tolerance induction makes immunosuppression-free transplants possible.

Immunosuppressants, or antirejection medications, are drugs that weaken the body’s ability to attack a transplanted organ. This defense system is known as the immune system.

In this animation, learn more about what happens in the body during organ rejection, an injurious immune response that may result in damage or loss of a transplanted organ.

While these medications are globally considered the standard of care for long-term transplant success, they are associated with significant side effects and don’t always prevent a slow form of organ rejection called chronic rejection. The impact of these medications on a patient’s quality of life can be significant and can increase the chance of infections and other complications, like cancer, heart disease, diabetes, and other metabolic diseases.

To initiate tolerance after transplant surgery, the Legorreta Center for Clinical Transplant Tolerance at Mass General uses clinically tested treatments that combine donor bone marrow or blood stem cell transplantation with organ transplantation, which allows for the slow reduction of immunosuppressive medications after surgery. This is called simultaneous tolerance.

Our expert team infuses donor bone marrow or blood stem cells into the patient’s body at the same time as they transplant the organ. In the weeks following surgery, the cells expand and train the immune system to recognize the new organ and accept it as its own rather than attack it.

While immunosuppressive medications are still required immediately following surgery, they will be carefully and intentionally reduced over 9-18 months—sometimes, until no medication is needed at all.

In this animation, learn more about how transplant tolerance aims to re-educate the immune system after transplant surgery to prevent organ rejection without the use of medication.

We also aim to eliminate the need for lifelong immunosuppression in patients who underwent kidney transplant surgery in the past. Our preclinical studies have proven that this is possible, and we are currently enrolling patients into an FDA-approved clinical trial for “Delayed Tolerance.”

This approach is possible as long as the bone marrow or blood stem cells from the original kidney donor are available. For those who received their new organ through the deceased donor waitlist, we can use the donor’s bone marrow cells if they were stored at the time of the original transplant surgery. For recipients who received their new organ through living donation, the delayed tolerance treatment is available anytime as long as their original living donor is willing and medically cleared to provide bone marrow or blood stem cells.

By completing the e-questionnaire, cctt.mghlivingdonors.org, we can start the process to determine a patient's eligibility for either the simultaneous tolerance or the delayed tolerance protocols.

While delayed tolerance treatment at Mass General is currently only available for kidney transplant patients, our team is working to expand this option to include other organ recipients in the future.

You will need to be a kidney transplant candidate to qualify for the transplant tolerance protocol. If you are a kidney transplant patient, request an appointment using our secure online form.