Kidney transplantation or renal transplantation is the organ transplant of a kidney into a patient with the end-stage renal disease. Kidney transplantation is typically classified as deceased-donor (formerly known as cadaveric) or living-donor transplantation depending on the source of the donor organ.
Living-donor renal transplants are further characterized as genetically related (living-related) or non-related (living-unrelated) transplants, depending on whether a biological relationship exists between the donor and recipient.
Exchanges and chains are a novel approach to expand the living donor pool. In February 2012, this novel approach to expand the living donor pool resulted in the largest chain in the world, involving 60 participants organized by the National Kidney Registry. In 2014 the record for the largest chain was broken again by a swap involving 70 participants.
In general, the donor and recipient should be ABO blood group and crossmatch (human leukocyte antigen — HLA) compatible. If a potential living donor is incompatible with their recipient, the donor could be exchanged for a compatible kidney.[clarification needed] Kidney exchange, also known as “kidney paired donation” or “chains” have recently gained popularity.
In an effort to reduce the risk of rejection during incompatible transplantation, ABO-incompatible and desensitization protocols utilizing intravenous immunoglobulin (IVIG) have been developed, with the aim to reduce ABO and HLA antibodies that the recipient may have to the donor.
In the 1980s, experimental protocols were developed for ABO-incompatible transplants using increased immunosuppression and plasmapheresis. Through the 1990s these techniques were improved and an important study of long-term outcomes in Japan was published. Now, a number of programs around the world are routinely performing ABO-incompatible transplants.
The level of sensitization to donor HLA antigens is determined by performing a panel reactive antibody test on the potential recipient. In the United States, up to 17% of all deceased donor kidney transplants have no HLA mismatch. However, HLA matching is a relatively minor predictor of transplant outcomes. In fact, living non-related donors are now almost as common as living (genetically)-related donors.