abo incompatibility and hematopoietic stem cell transplantation outcomes

the increased risk of hemolytic reactions and erythrocyte recovery delay in abo incompatible hematopoietic stem cell transplantation (hsct) is well established. effects of abo incompatibility on transplantation outcomes is evaluated in this study. we prospectively followed 501 patients undergoing allogeneic stem cell transplantation according to abo compatibility groups of minor, major and bidirectional mismatch and match groups for a median time of 34.7 months. mean survival time (os) was lower in minor mismatch group (p value= 0.017). minor and bidirectional mismatch groups received significantly more packed cell units than match group (p value < 0.0001 and p value =0.002 respectively). mean number of platelet unit infusion was more in major mismatch recipients than match group significantly (p value=0.031). death rate was much more than expected in minor mismatch group. two cases of prca (pure red cell aplasia) were found in major mismatch group.  acute gvhd, chronic gvhd, time to neutrophil recovery, relapse free survival, non-relapse mortality and relapse rate did not show statistically significant difference in compared groups. considering that unfavorable outcomes such as decrease in os and more need to transfusion are statistically significant in abo incompatible sct, we suggest that if possible, choosing abo compatible donors would improve outcomes of the transplantation.