Donor-specific HLA Antibodies in Solid Organ Transplantation: Clinical Relevance and Debates

Early outcomes following solid organ transplantation have markedly improved in recent years. Antibody-mediated rejection caused by donor specific anti-human leukocyte antigen antibodies (HLA-DSA) is widely recognized to be a risk factor for rejection episode, graft loss and decreased graft survival. The presence of HLA-DSA before transplantation and the appearance of these antibodies after transplantation can induce a wide spectrum of allograft injuries, ranging from the absence of allograft lesions with normal biopsy histopathologies to indolent subclinical processes to acute rejection with early allograft loss. However, the interpretation of the current DSA results is not easy and has led to many discussions and controversies. Current challenges exist in identification of pathologic DSA, monitoring and diagnostic algorithms, appropriate risk stratification, minimization for preformed or de novo DSA by proper use of immunosuppression. This article summarizes recent advances concerning the impact of preformed and de novo DSA in solid organ transplantation, with a focus on the clinical significance of DSA and available treatment modalities. Areas requiring further investigation are also identified.