317: Impact of Prophylactic Red Blood Cell Exchange for Prevention of Severe Immune Hemolysis in Pediatric Minor ABO-Mismatched Allogeneic Peripheral Blood Progenitor Cell Transplantation

Abstract

The presence of minor ABO incompatibility between donor and recipient is common in allogeneic hematopoietic stem cell transplantation (allo-HSCT). Delayed severe immune hemolysis due to donor-derived passenger lymphocytes has been reported in minor and/or bidirectional ABO-mismatched transplants. To evaluate the impact of RBC exchange procedure in pediatric patients on the morbidity and outcome we analyzed 29 pediatric cases undergoing minor ABO-incompatible allo-HSCT from January 2000 to January 2007. First group (RBC exchange) included sixteen patients who underwent prophylactic red cell exchange. Six patients received grafts from HLA identical siblings, ten patients – from HLA matched unrelated donors. Eleven patients received bone marrow transplant (BMT), five patients received peripheral stem cell transplant (PBSC). Patient's age was 10 ± 5.3 years old.Second group (No – RBC exchange) included thirteen patients who did not undergo prophylactic red cell exchange, but the stem cell product was plasma depleted according to the institutional guidelines. Six patients received grafts from HLA identical siblings, three patients from HLA matched unrelated donors, and four patients form unrelated cord blood. Four patients received BMT, five patients received PBSC, four patients received cord blood transplant. Patient's age was 7.6 ± 5.4 years old.No incidence of immune mediated hemolysis was documented in both groups. No patients developed pure red cell aplasia. RBC engraftment was not different in both groups (23.2 ± 4.2 vs. 22 ± 4.2 days). Neutrophil engraftment was similar in both groups (21.0 ± 5.4 vs. 21.02 ± 4.0 days). No significant difference was found among the groups in the incidence of acute graft vs. host disease (GVHD). The incidence of chronic GVHD was insignificantly higher in patients with no RBC exchange (72% vs. 60%). The relapse rate and overall outcome were not influence.In conclusion these results suggest that RBC exchange does not have a significant impact in pediatric patients. Further investigations are required to identify the best clinical transfusion practice in pediatric patients with minor ABO incompatibility. The presence of minor ABO incompatibility between donor and recipient is common in allogeneic hematopoietic stem cell transplantation (allo-HSCT). Delayed severe immune hemolysis due to donor-derived passenger lymphocytes has been reported in minor and/or bidirectional ABO-mismatched transplants. To evaluate the impact of RBC exchange procedure in pediatric patients on the morbidity and outcome we analyzed 29 pediatric cases undergoing minor ABO-incompatible allo-HSCT from January 2000 to January 2007. First group (RBC exchange) included sixteen patients who underwent prophylactic red cell exchange. Six patients received grafts from HLA identical siblings, ten patients – from HLA matched unrelated donors. Eleven patients received bone marrow transplant (BMT), five patients received peripheral stem cell transplant (PBSC). Patient's age was 10 ± 5.3 years old. Second group (No – RBC exchange) included thirteen patients who did not undergo prophylactic red cell exchange, but the stem cell product was plasma depleted according to the institutional guidelines. Six patients received grafts from HLA identical siblings, three patients from HLA matched unrelated donors, and four patients form unrelated cord blood. Four patients received BMT, five patients received PBSC, four patients received cord blood transplant. Patient's age was 7.6 ± 5.4 years old. No incidence of immune mediated hemolysis was documented in both groups. No patients developed pure red cell aplasia. RBC engraftment was not different in both groups (23.2 ± 4.2 vs. 22 ± 4.2 days). Neutrophil engraftment was similar in both groups (21.0 ± 5.4 vs. 21.02 ± 4.0 days). No significant difference was found among the groups in the incidence of acute graft vs. host disease (GVHD). The incidence of chronic GVHD was insignificantly higher in patients with no RBC exchange (72% vs. 60%). The relapse rate and overall outcome were not influence. In conclusion these results suggest that RBC exchange does not have a significant impact in pediatric patients. Further investigations are required to identify the best clinical transfusion practice in pediatric patients with minor ABO incompatibility.