Donor-reactive HLA antibodies in renal allograft recipients: considerations, complications, and conundrums

Whether sensitized patients wait for a compatible crossmatch with a deceased donor, enter a paired exchange program with the hope of finding a compatible living donor, or go through a desensitization protocol depends on a number of factors, not the least of which is the overall philosophy of the transplant center. Centers such as ours take the position that donor-directed antibodies detected by solid phase assays (even those that are "weak") present an unacceptable risk factor to the patient. This philosophy is predicated on the biologic role of the immune system, specifically that antibodies were generated in response to a non-self (allo) antigen and that a successful immune response eliminates that which caused its stimulation. Although obviously an oversimplification, this philosophy mandates a comprehensive evaluation of HLA antibodies in sensitized recipients. This article addresses the challenges and conundrums associated with human leukocyte antigen antibody identification.