Desensitization (Solid Organ Transplant)
Understanding Desensitization (Solid Organ Transplant)
Prior to transplantation, testing is necessary to determine if the recipient of the organ has human leukocyte antigen (HLA) sensitization. HLA sensitization means the recipient has HLA antibodies which will increase the risk of rejecting the transplanted organ. HLA antibodies are acquired via pregnancy, transfusion, or prior transplant. Desensitization is the process of decreasing antibodies the organ recipient may have that increases the risk of rejection after transplant.
Symptoms of Desensitization (Solid Organ Transplant)
There are no symptoms, rather just a need to assess for HLA antibodies and provide treatment to minimize these antibodies prior to transplant.
Diagnosis of Desensitization (Solid Organ Transplant)
Diagnosis is based on the presence of HLA antibodies prior to transplant. This includes a blood test called a Panel Reactive Antibodies (PRA). This test measures the amount of HLA antibodies an organ recipient may have. A PRA result may range from zero to 100% and tests organ recipient cells against various samples of other people. Zero means there are no alloantibodies, and the risk of rejection goes down; 100% means the recipient would react with 100% of any potential donors and, therefore, significantly decreases the chance of a successful transplant. Anyone with a PRA of 20% is considered highly sensitized and is a candidate for desensitization therapy. Having a PRA greater than 20% can have a significant impact on wait times for a compatible donor.
Treatment of Desensitization (Solid Organ Transplant)
Desensitization therapy may vary depending on the transplant center, and may involve steroids, plasmapheresis, immune globulin therapy and/or other drugs. Immune globulin therapy, administered into the blood stream intravenously (IVIG), is used to suppress the immune response and is known as immunomodulation. The mechanism of action of IVIG in this manner is not clearly understood. IVIG is essentially antibodies from a variety of human donors. This large variety of antibodies is thought to suppress the immune response, thereby decreasing alloantibody production and ultimately lowering PRA levels. Plasmapheresis (also known as apheresis, plasma exchange, or “plex”) is a medical procedure where a device separates whole blood into the cellular components and plasma. The plasma is then discarded and replaced with a colloid fluid, combined back with the cellular components, and returned to the same patient.
- Jordan SC, Vo A, Tyan D, Toyota M. Desensitization therapy with intravenous gammaglobulin (IVIG): applications in solid organ transplantation. Trans Am Clin Climatol Assoc. 2006;117:199-211; discussion 211. PMID: 18528474; PMCID: PMC1500934.
Resources for people undergoing a kidney transplant:
- National Kidney Foundation
- United Network for Organ Sharing
- Transplant Living, a division of UNOS
- Kidney School
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