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Introduction: Allogenic hematopoietic stem cell transplantation (HSCT) is the only curative treatment for hematologic malignancies. Nowadays, usually, haploidentical stem cell transplant is performed across the ABO blood group barrier; however, the effect of ABO incompatibility on haploidentical hematopoietic stem-cell transplantation is still uncertain. Methodology: Retrospective analysis of data of patients who underwent haploidentical hematopoietic stem-cell transplantation at our hospital was performed. The patient cohort was classified in to two arms: ABO compatible and ABO-incompatible haploidentical stem cell transplantation. ABO-incompatible was further categorized as major mismatch, minor mismatch and bidirectional mismatch. The average follow-up period was 6 months posttransplant for which the following parameters were studied: (a) engraftment kinetics for white blood cell (WBC) and platelets, (b) graft rejection, (c) overall graft survival, (d) graft-versus-host disease (GVHD), and (e) clinical variation in outcome for patients receiving peripheral blood stem cell/bone marrow harvest (BMH) as the source of stem cells. Results: The median age of recipients for both ABO compatible and ABO incompatible was 24 years and most of them were parent-offspring transplants. A total of 39 patients underwent haploidentical stem cell transplantation during the study period. Our cohort consisted of 23 ABO-compatible patients and 17 ABO incompatible patients. Out of these 17, 6 were major mismatch, 11 were minor mismatch and none were bidirectional mismatch. Of these 39 patients, 82% (32/39) engrafted within the normal expected time frame. The average days to WBC and platelet engraftment in these subgroups were noted to be as follows: Major - 12 and 18 days, compatible - 9 and 17 days, and minor - 10 and 17 days, respectively. Graft failure was observed in 20% (8/39) of patients, of which 4 patients had undergone ABO-compatible transplants while 4 patients had undergone minor ABO incompatible transplants. In this study, we observed that major ABO incompatibility had severe risk of GVHD (17%) compared to compatible (39%) and minor (27%) blood group mismatch. The overall survival rate in 6 months was equal (70%) in both arms. 5/39 patients, i.e., 12% received BMH as the source of stem cells, of these 80% are alive. Conclusion: Haploidentical transplants done in patients with ABO-incompatible donors had outcomes comparable to the ABO-compatible group. The risk of severe GVHD did not increased in the ABO mismatch group. Recipient of BMH had a marginally better graft survival. [ABSTRACT FROM AUTHOR]

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]