Human leukocyte antigens (HLA) are highly polymorphic tissue antigens that constitute the major immunologic barrier to platelet transfusion and transplantations. Antibodies that recognize mismatched epitopes on HLA molecules are the primary cause of platelet refractoriness and transplant rejection. The traditional approach to HLA matching at the antigen or allele level does not capture the full picture of HLA disparity at the epitope level.
Recent clinical studies have highlighted the benefit of using epitope-based HLA matching to guide platelet product selection and to risk stratify patients undergoing allogeneic transplantations. In this session, we will first introduce the concept and process of HLA epitope matching, followed by a critical review of the evidence for epitope-based matching for platelet transfusion in HLA-alloimmunized patients. Next, we will present the current understanding of the role of epitope mismatch in the development of de novo donor-specific HLA antibodies after kidney transplantation. We will also discuss the potential of optimizing the transplant outcome by considering epitope matching in kidney allocation and personalized immune suppression. Finally, we will discuss the differential impact of epitope mismatch directed toward the graft or host in haploidentical hematopoietic stem cell transplantation.
List the key elements of human leukocyte antigen (HLA) epitope matching.
Evaluate the evidence for epitope-based approach to platelet transfusion refractoriness.
Incorporate epitope matching into the risk stratification of patients undergoing kidney and hematopoietic stem cell transplantations.
Director of Clinical Laboratories,
University of Vermont Medical Center
Washington University In St. Louis