Impact of Donor-specific Anti-human Leukocyte Antigen Antibodies in Haploidentical Hematopoietic Stem-cell Transplantation: A Single-center Retrospective Study.

Introduction: While donor-specific anti-human leukocyte antigen (HLA) antibodies (DSA) have been implicated in graft rejection in solid organ transplantation, their role in hematopoietic stem-cell transplantation (HSCT) remains unclear. Aim: The aim of this study is to study the role of DSA for proper donor selection and its effect in the setting of allogeneic HSCT. Methodology: HLA A, B, C, DRB1, and DQB1 high-resolution typing, and DSA cross match (XM) of patients (n = 73) and their prospective donors (n = 74) were assessed. A case--control study was designed retrospectively to evaluate the effect of pre- existing DSAs on engraftment. Thirty-five cases with 5/10 HLA alleles mismatches and 38 cases with full HLA matched, these two controls were selected for comparison. These were matched for disease, graft type, conditioning regimen, age, gender, blood group, and sensitizing events. DSAs were tested with solid-phase assay (Luminex 100/200 platform). Results: DSAs were detected in six of 35 patients (17%); however, donors selected for transplantation were all negative for DSA crossmatch. These six patients who underwent haploidentical (HI) transplants had antibodies against Class I and II. One patient carried antibodies against both classes. A patient who experienced primary graft failure had a second HI transplant. No other known factors that could negatively influence engraftment were associated with the development of graft failure in this patient. Conclusions: DSAs are not associated with graft rejection in patients undergoing HI stem-cell transplantation. Anti-HLA sensitization should be evaluated routinely in HSCT with HLA mismatched donors for a better outcome. [ABSTRACT FROM AUTHOR]