Kidney transplantation in the hyperimmunized patient.

Individuals who have developed anti-HLA class I and II antibodies are said to be immunized or sensitized. High levels of donor specific anti-HLA antibodies present at the time of transplantation frequently result in early allograft loss due to humoral rejection. Lower levels of donor specific anti-HLA antibodies (DSA) are also associated with poor outcome. Technological advances in tissue typing permit the detection of low levels of DSA not seen with standard cytotoxicity cross-match tests. These tests which previously were used to screen patients to avoid transplantation of donor-immunized patients are now being used to stratify patients based on their degree of donor alloreactivity. New protocols have been developed which permit successful transplantation despite the presence of DSA. These protocols utilize intravenous immunoglobulin infusions prior to transplantation, either alone or in combination with plasmapheresis to block or remove DSA. Using these protocols many persons previously considered essentially nontransplantable are now able to successfully receive transplants. Improved recognition of the clinicopathological characteristics of humoral rejection have allowed earlier diagnosis and treatment of antibody-mediated allograft injury and improved the outcome. Although these advances have improved the outlook for highly immunized kidney transplant candidates, more study is needed to delineate the optimal approach to transplantation in this population.