Allogeneic peripheral blood stem cell transplantation using reduced‐intensity conditioning in an outpatient setting in ABO ‐incompatible patients: are survival and graft‐versus‐host disease different?

Background Graft‐versus‐host disease ( GVHD ) is a major cause of morbimortality after allogeneic hematopoietic stem cell transplantation (allo‐ HSCT ). Minor ABO incompatibility has been associated with an increased risk of GVHD . We analyzed the impact of ABO matching on patient outcome after peripheral blood, reduced‐intensity allo‐ HSCT in an outpatient setting, and its relationship with GVHD . Study Design and Methods Data of 121 patients were included. All patients received allo‐ HSCT from HLA ‐identical siblings as outpatients using a reduced‐intensity conditioning regimen. Influence of ABO matching as a risk factor for the development of GVHD and survival was analyzed using logistic regression and C ox proportional hazards regression, respectively. Results Median age was 36 years (range, 1‐71 years); 88 patients were ABO identical: 13 presented major mismatch and 20 minor mismatch, with an ABO incompatibility rate of 27.3%. The median follow‐up period was 54 months (range, 0.3‐120 months). Minor ABO incompatibility patients presented the highest rate of acute GVHD (aGVHD; 25%), in comparison with ABO ‐identical (20.5%) and major ABO incompatibility patients (15.4%; p = 0.79). The highest incidence of chronic GVHD ( cGVHD ) occurred in the context of minor ABO incompatibility (35%), in contrast to ABO ‐identical (30.8%) and major ABO incompatibility (15.4%). Survival was higher for patients in the minor ABO mismatch group; however, there was no significant correlation between ABO matching status and survival (p = 0.45). Conclusion Using this type of peripheral blood stem cell transplantation, minor ABO ‐mismatched allo‐ HSCT was associated with a higher incidence of aGVHD and cGVHD and with increased survival, albeit with no significance.