Effects of ABO incompatibility in allogeneic hematopoietic stem cell transplantation.
INTRODUCTION
The impact of ABO mismatch on outcomes following allo-HSCT remains controversial. In this study, our aim is to define the effect of ABO mismatch on post-transplant outcomes, engraftment kinetics and complications in a large cohort.


PATIENTS AND METHODS
We retrospectively identified 1000 patients who underwent allo-HSCT from either bone marrow or peripheral blood stem cells at our center between 1988 and 2016. P<0.05 was considered statistically significant.


RESULTS
Five hundred and ninety (59%) patient-donor pairs were ABO matched, 164 (16.4%) were ABO major mismatched (MM), 191 (19.1%) were ABO minor MM, and 55 (5.5%) were ABO bi-directionally MM. ABO matched pairs were more common in transplants from related donors (P<0.001) and using bone marrow as a stem cell source (P<0.001). In minor ABO MM transplantations, mild delayed hemolytic reaction occurred more frequently compared to major and bidirectional ABO MM transplantations (47% vs 35% and 18%, P<0.001). Neutrophil engraftment was slightly delayed in ABO MM patient-donor pairs when compared ABO matched donor pairs according to median engraftment time in all group (167/410, 41% vs 204/590, 35%, P=0.046). Pure red cell aplasia was diagnosed in 6 patients (1%). Higher risk of death was shown in ABO MM transplants compared to ABO matched transplants in overall survival (OS) analysis (HR:1.201, 95% CI:1.004-1.437, P=0.045). The non-relapse mortality (P=0.546) and cumulative incidences of acute graft versus host disease (aGVHD) and chronic (c) GVHD were comparable between ABO MM and ABO matched patient-donor pairs (for aGVHD, P=0.235; for cGVHD, P=0.137).


CONCLUSION
ABO MM transplants were associated with decreased OS and slightly delayed neutrophil engraftment. NRM and the risk of GVHD were not related to ABO incompatibility.
['Ataca Atilla|P|P|', 'Akkus|E|E|', 'Atilla|E|E|', 'Gokmen|N|N|', 'Civriz Bozdag|S|S|', 'Kocak Toprak|S|S|', 'Kurt Yuksel|M|M|', 'Ozcan|M|M|', 'Demirer|T|T|', 'Ilhan|O|O|', 'Beksac|M|M|', 'Akan|H|H|', 'Arslan|O|O|', 'Topcuoglu|P|P|', 'Gurman|G|G|']
D000017:ABO Blood-Group System D000293:Adolescent D000328:Adult D000368:Aged D001787:Blood Group Incompatibility D016026:Bone Marrow Transplantation D018572:Disease-Free Survival D005260:Female D006085:Graft Survival D006086:Graft vs Host Disease D018380:Hematopoietic Stem Cell Transplantation D006461:Hemolysis D006801:Humans D053208:Kaplan-Meier Estimate D008297:Male D008875:Middle Aged D009369:Neoplasms D010976:Platelet Count D012189:Retrospective Studies D014184:Transplantation, Homologous D016896:Treatment Outcome D055815:Young Adult
Allogeneic hematopoietic stem cell transplantation ABO mismatch Outcome Graft versus host disease ABO non compatible Hémolyse L’allogreffe de cellules souches hématopoïétiques Maladie du greffon contre l’hôte Résultats hemolysis