Issue link: https://viewer.e-digitaledition.com/i/138456
AbO-Incompatible living Donor Kidney Transplantation by Kenneth J. Woodside, mD, faCS, and James a. Schulak, mD, faCS K IDNEY TRANSPLANTATION IS the gold standard for treatment of end-stage renal disease (ESRD), as both the quality of life and survival are significantly better than is generally achieved with dialysis. However, the number of patents listed for deceased donor kidney transplantation has increased much more rapidly than the number of deceased organ donors. Consequently, wait times for deceased donor kidneys can exceed five years. For many patients (approximately 6,000/year), voluntary living kidney donation has mitigated this shortage and, in fact, has better outcomes than transplants from deceased donors. However, ABO blood type compatibility is necessary in order to prevent irreversible humoral graft rejection. Unfortunately, many potential recipients do not have an ABO blood type compatible voluntary kidney donor. For patients with incompatible donors, a match may be found through participation in a kidney paired donor (KPD) exchange program. In KPD programs, an ABOincompatible donor-recipient pair can be matched with an oppositely mismatched 12 | Cleveland/Akron/Canton MD News pair, such that each recipient receives the other recipient's donor kidney. This exchange, which is sometimes expanded into longer chains, allows for each recipient to benefit from an ABO-compatible living donor kidney transplant. Because blood type O recipients have preformed anti-A and anti-B antibodies that prevent acceptance of kidneys from other blood types, their successful participation in KPD programs is more limited. Some blood type A donors are in the A2 subtype, which has a much lower expression of the A antigen — allowing for successful use of an A2 donor organ in blood type B and O recipients. Over the last two decades, the immunological basis of humoral immunity has become better understood to the point that safer and more effective modulation of this response is now feasible. Consequently, patients with an A or B blood type incompatible (but HLA-crossmatch negative) potential living donor, it is possible to desensitize the potential recipient to the blood type of the donor by removing the anti-A or anti-B antibodies immediately before the transplant. ■ MDNEWS.COM ■ JULY-AUGUST 2013 Early protocols involved plasmapheresis, splenectomy, and anti-CD20 mAb (rituximab, an anti-B lymphocy te monoclona l antibody). With added experience, splenectomy and mAb treatment are now thought to be unnecessary for most patients, as adequate antibody titers can be achieved with plasmapheresis alone. Determination of the initial antibody titer of the potential recipient must be performed, because patients with high titer are difficult to desensitize. Typically, recipients undergo preoperative plasmapheresis treatments coupled with IVIG therapy until a target titer level of 1:8 is reached. Immunosuppression is given for two to four weeks prior to transplant in order to further reduce the risk of humoral rejection. For those with an initial titer of 1:8 or lower, plasmapheresis may not be required at all. Postoperative management is similar to those undergoing ABO-compatible donation. Routine plasmapheresis is not required. However, careful attention is given to postoperative anti-ABO