Abstract
Heart transplantation can be a lifesaving option for patients with end-stage heart failure. However, implanting recipients with an organ or tissue from a donor presents immunologic challenges. Sensitized recipients are at risk for hyperacute rejection because of the presence of preformed antibodies. Immune modulation with cyclophosphamide, plasmapheresis, and intravenous gamma globulin are methods used to desensitize transplant candidates with preformed anti-HLA antibodies to achieve successful transplantation.
HEART transplantation can be a lifesaving treatment option for patients with end-stage heart failure. Since transplantation involves implanting recipients with an organ or tissue from a donor with different immune proteins, transplantation presents many immunologic challenges. This article discusses the case of an immunologically sensitized patient before transplantation and will include information about transplant immunology and sensitization, implications for transplantation, and the methods used to desensitize heart transplant candidates to achieve successful transplantation.
Rejection is a leading cause of graft failure following cardiac transplantation. Rejection is a complex, multifactorial immune response that occurs when a transplant recipient is exposed to an immunologically different transplanted heart. Hyperacute rejection, which usually causes graft loss, occurs within minutes to hours after transplantation. This form of rejection is related to the presence of preformed antibodies in the recipient that react to antigens in the transplanted tissue. Blood group incompatibility between donor and recipient will also result in hyperacute rejection. The vessels of the graft become occluded, resulting in immediate death of the organ. 1 In heart transplantation, since there is no life-saving alternative other than immediate retransplant, hyperacute rejection is a catastrophic event. The incidence of hyperacute rejection is less than 1% 2 due to pretransplant screening of recipients for preformed antibodies. Finding a donor appropriate for a transplant candidate with high levels of preformed antibodies is difficult. Incompatibility with any organ donor is likely, therefore, finding an acceptable donor may take a long time and may even be impossible. A sensitized candidate may experience worsening heart failure and succumb to the disease before a donor becomes available. Thus, the transplant team is challenged to find ways to reduce the recipient's preformed antibody levels to achieve successful transplantation.