Acceptable mismatching at the class II epitope level: the Canadian experience.

PURPOSE OF REVIEW: To summarize the evidence concerning human leukocyte antigen (HLA) epitope mismatch analysis as a means to predict donor-specific antibody (DSA) development and allograft survival.

RECENT FINDINGS: HLA epitope mismatch analysis outperforms traditional whole molecule antigen mismatch for predicting the risk of de-novo DSA development. By analyzing the number of epitope mismatches for a given donor-recipient pair, thresholds have been identified to stratify patients into those at high or low risk of de-novo DSA development. Epitope specificity assignment in patients who develop de-novo DSA compared with controls who do not provides an opportunity to study the relative immunogenicity of mismatched HLA epitopes.

SUMMARY: Recognizing that de-novo DSA is a major cause of graft loss, HLA epitope mismatch analysis is a strategy to minimize de-novo DSA development and improve long-term graft survival.