Dr. Mark Stegall, Kidney and Pancreas Transplant Surgeon at Mayo Clinic in Rochester, MN, discusses antibody barriers to successful kidney transplantation.
In some instances, kidney transplant candidates have antibodies in their bloodstream that can attack a new kidney transplant. This can lead to antibody-mediated rejection or even loss of the transplant. The two major types of antibodies are antibodies against the donor blood type (when incompatible) and antibodies against the donor tissue types (called HLA types or anti-HLA antibodies).
ABO incompatible kidney transplants
Blood group antibodies occur naturally. For example, a blood group O recipient (their cells have no blood group on their surface) commonly will have antibodies against both blood group A and B. Thus, if a blood group O recipient has antibodies that can reject a blood group A donor kidney. While this is a barrier to transplantation, it is relatively easy to overcome and the long-term success of these transplants is quite good. Recently, paired donation has become another option for these donor/recipient combinations.
Anti-HLA Antibodies: “Sensitized Patients”
HLA are “tissue types” that we talk about when we refer to a donor kidney “matching” the recipient. Anti-HLA antibodies can be a significant barrier to transplantation and be a major contributor to both early and chronic kidney transplant loss. Due to prior transplants, pregnancy and blood transfusions, about 30 percent of kidney transplant candidates have some type of anti-HLA antibodies. This is even more common patients undergoing their second transplant. Patients with anti-HLA antibodies are called “sensitized patients.”
I you have anti-HLA antibodies, you have several options. You can be placed on the deceased donor list, but commonly the chance of transplantation is only about 5 percent per year. A better option may be to be entered into our active paired donor program. In this program that includes all 3 Mayo Clinic locations, patients with antibodies against their donor can be paired with donors against whom they have little or no antibodies. This makes the antibody barrier to transplant much easier to overcome.
In some instances, a paired donor cannot be found and we will recommend performing the kidney transplant even if there is a significant amount of anti-HLA antibody. Over the past 14 years, Mayo Clinic Rochester has developed expertise in the development of new medicines that control antibody production or alter its impact on the transplant. Thus, the success of these transplants are constantly improving and may be your best option for a transplant.
Options for Patients with antibodies against their donor:
• Deceased donor waiting list
• Paired donor program.
• Plasma exchange — Reduces antibody levels
• Take special medications that reduce the risk of rejection
With our expertise in transplanting sensitized patients, we can give patients a wide variety of options and help you make the best decision.
If you would like more information on this topic or would like to schedule an appointment, you may contact the Mayo Clinic Transplant Program at 1-866-249-1648 or visit our website. http://www.mayoclinic.org/kidney-transplant/
Mechanisms of alloantibody production in sensitized renal allograft recipients
Deciphering antibody-mediated rejection: new insights into mechanisms and treatment.
Clinical management of renal transplant patients with donor-specific alloantibody: the state of the art
Baseline donor-specific antibody levels and outcomes in positive crossmatch kidney transplantation
Sensitized renal transplant recipients: current protocols and future directions