Desensitization Strategies in Immunized Heart Transplant Recipients

Allosensitization, defined as the presence of anti-HLA antibodies before transplantation, prolongs the waiting list time and increases the waiting list mortality in patients awaiting heart transplantation. Treatment protocols have been developed to reduce the load of preformed anti-HLA antibodies (pfDSAs), defined as desensitization, and allow safe transplantation across the anti-HLA antibody barrier. Aim of this review was to give an overview on the actual desensitization strategies in heart transplantation.

Desensitization can be performed before transplantation or at the time of transplantation when a donor offer becomes available. Treatment protocols should include drugs and interventions that clear pfDSA, target antibody production, and mitigate antibody-mediated graft damage. By now, several transplant centers have developed their own protocols, with optimal graft survival, freedom from antibody-mediated rejection and from coronary allograft vasculopathy, without any significant adverse events. The evolution of the immunoassays for pfDSA detection has allowed a better precision in pfDSA characterization, such as measurement of titer and complement-binding capacity. These refinements have permitted crossing acceptable pfDSA without any need of desensitization.

Crossing the HLA barrier is feasible and safe in heart transplantation. The complexity and redundancy of the immune pathways requires the identification of the appropriate therapy for each patient. Desensitization protocols should include more than one drug and intervention.