Transplanting the sensitized patient

Clinical relevance of pretransplant human leukocyte antigen donor-specific antibodies in renal patients waiting for a transplant: a risk factor

The use of highly sensitive solid-phase antibody detection assays, including x-MAP multiple bead-based technology (Luminex), has greatly enhanced our ability to accurately detect and define very low levels of HLA antibodies. These developments have led to patients having increasing lists of antibody specificities (which may not be clinically relevant), resulting in a new "technological barrier" to transplantation in sensitized patients. Alloantibodies play a major role in all types of solid organ rejection; the presence of low-titer donor-specific antigen (DSA) identified pretransplant is associated with an increased risk of antibody-mediated rejection (AMR). However, these low-titer antibodies do not represent an absolute contraindication to transplant. Improvement in the diagnosis and treatment of AMR will allow sensitized patients with DSA to be successfully transplanted in the short term, but extended follow-up is required to ensure acceptable long-term graft survival in this group. These factors must be integrated into the decision algorithms for immunosuppressive treatment in patients at immunologic risk.

Tools for human leukocyte antigen antibody detection and their application to transplanting sensitized patients

In recent years there have been major advances in the technology for the detection and definition of human leukocyte antigen antibodies. In this overview we describe the evolution in laboratory technology, the techniques currently available and consider their application in antibody specificity definition and in understanding a patient's sensitization profile. We discuss the importance of antibody specificity definition in facilitating efficient national organ allocation and informing clinical discussion regarding the appropriate pathway for sensitized patients awaiting renal transplantation.