Sayeh Parkhideh - Hematopoietic Stem Cell Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
Farzaneh Tavakoli - Hematopoietic Stem Cell Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
Sina Salari - Hematopoietic Stem Cell Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
Elham Roshandel - Hematopoietic Stem Cell Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran

Background and Aim: Allogeneic hematopoietic stem cell transplantation(aHSCT) is a proper option for treatment of patients with a variety ofmalignant hematological. In previous studies, have been reportedthat ABO incompatibility between donor and recipient is seen inapproximately 25%-50% of patients who undergo acute graft-versushostdisease (aGVHD). Also, it has been observed that transplantationswith ABO incompatibility enhance the chance of (aGVHD) incidenceand mortality rate in allo-HCT patients. Therefore, this study aimed toinvestigate the role of ABO incompatibility on aGVHD incidence andoverall survival (OS) in allo-HCT patients.Methods: We retrospectively assessed 149 patients who underwentallo-HSCT at Taleghani hospital, Tehran, between 2008 and 2017.Patients received peripheral blood stem cells (PBSCs) after myeloablative(MA) conditioning regimens and nonmyeloablative (NMA) regimens.We analyzed the impact of major, minor, and bidirectional ABOincompatibility on the incidence of aGVHD and overall survival rate inallo-HCT patients.Results: Analysis of our data showed that the incidence of aGVHD washigher in bidirectional ABO incompatibility patients compared to ABOmatchedpatients (hazard ratio: 1.86, P value: 0.006 and confidenceinterval:1.19 – 2.93). Also, we found a significantly lower overall survivalin ABO-mismatched HSCT compared to ABO-matched allo-HSCT(hazard ratio: 2.3, P value: 0.0008 and confidence interval: 1.5–5.1).However, major and minor ABO-incompatibility did not have an impacton aGVHD incidence and overall survival of allo-HCT patients (P value:0.1).Conclusion: There are different reports from the correlation betweenABO-incompatibility and GVHD incidence in allo-HSCT patients.Our data revealed that only bidirectional ABO incompatibility hasa significant impact on aGVHD incidence and survival outcomes inpatients who undergo allo-HSCT; So, these results are agreement withsome of the previous reports. But, in another study has been reported inaddition to the bidirectional ABO-incompatibility, major and minor ABOincompatibility influence aGVHD. Moreover, other factors that influenceaGVHD incidences such as human leukocyte antigen (HLA) disparity,donor and recipient age etc should be considered.

Allogeneic hematopoietic stem cell transplantation; Acute graft-versus-host disease; HSCT patients