Matched Sibling Versus Matched Unrelated Allogeneic Hematopoietic Stem Cell Transplantation in Children with Severe Acquired Aplastic Anemia: Experience of the Polish Pediatric Group for Hematopoietic Stem Cell Transplantation

Abstract

In the study, 48 children with severe acquired aplastic anemia (SAA) transplanted from matched sibling donor (MSD) between 1991 and 2009, and 38 children with SAA transplanted from matched unrelated donor (MUD) between 2000 and 2009 were evaluated. Engraftment was achieved in 45 (93.75 %) patients after MSD-hematopoietic stem cell transplantation (HSCT) and in 33 (86.8 %) after MUD-HSCT. Transplant-related mortality rate after MSD-HSCT was 8 %, while 37 % after MUD-HSCT. After MSD-HSCT 44 (91.7 %) patients are alive for 1-216 months (median: 85 months), while after MUD-HSCT 24 (63.2 %) patients for 1-84 months (median: 16 months). The 5-year probability of event-free survival after MSD-HSCT and MUD-HSCT was 87 and 53 %, respectively, while 5 years of overall survival was 91 and 64 %, respectively. It was concluded that MSD-HSCT as the first line treatment for children with SAA is a safe therapeutic approach with a low rate of treatment failures and excellent outcome. Results of MUD-HSCT in pediatric patients with SAA who failed to respond to immunosuppressive therapy are still inferior than those of MSD-HSCT. Treatment failures of MUD-HSCT are mainly related to infectious complications and graft failure. It seems, however, that HLA-matching of unrelated donors at allelic level along with early MUD-HSCT after FCA (FLUDA, low-dose cyclophosphamide, and anti-thymocyte globulin) conditioning, perhaps using lower Thymoglobulin dose could enable further improvement of long-term results in children with SAA who lack MSD.

Association Between Donor Leukocyte Telomere Length and Survival After Unrelated Allogeneic Hematopoietic Cell Transplantation for Severe Aplastic Anemia

“…17–20 Previous studies suggest that optimal donor selection is a key parameter for improving survival in those patients. 21,22 In our study, longer donor leukocyte telomere length was associated with a higher overall survival probability in severe aplastic anemia patients who underwent allogeneic unrelated HCT (5-year OS=56% vs. 40%, in the long vs. short donor leukocyte telomere length group, respectively).…”

Effect of Recipient Age and Stem Cell Source on the Association between Donor Telomere Length and Survival after Allogeneic Unrelated Hematopoietic Cell Transplantation for Severe Aplastic Anemia

“…Patients who lack a matched sibling donor or those older than 40 years typically receive at least 1 round of immunosuppression therapy before considering alternative donor HCT [4]. Despite advances in HLA-typing techniques and therapeutic strategies for HCT, long-term survival after unrelated donor HCT for SAA is still unsatisfactory [5-8]. Recipient age, stem cell source, and time between SAA diagnosis and HCT are the strongest risk factors for poor survival in both matched sibling and unrelated donor HCT for SAA [9-12].…”

Allogeneic Bone Marrow Transplants for Pediatric Severe Aplastic Anemia: Real‐world Data comparing Matched Related and Unrelated Donors in a Developing Country. Retrospective study on behalf of the Pediatric Hematopoietic Stem Cell Transplant Working Group of the Brazilian Bone Marrow Transplantation Society (SBTMO) and the Brazil‐Seattle Consortium (Gedeco)

“…Graft failure represents an important complication of BMT in patients with SAA. In our study, primary graft failure was observed in five patients, all of whom undergoing BMT from a URD, as previously reported . Eleven additional patients had secondary graft failure.…”