Unrelated Umbilical Cord Blood Transplants Could Boost Treatment Options For Children With Leukemia

Dr John Wagner, Division of Pediatric Haematology/Oncology and the Blood and Bone Marrow Transplant Programme, University of Minnesota, Minneapolis, USA, and colleagues studied 503 children under 16-years with acute leukaemia who had undergone transplantation with umbilical cord blood, and compared their outcomes with 282 children who had received bone marrow transplants.

The researchers found after transplants of umbilical cord blood HLA-mismatched for one or two antigens that survival rates for children after five years were similar to children who had received an allele-matched bone-marrow transplant.

For matched umbilical cord blood, survival rates appear greater – but although statistically significant, the number of children studied was small, and further study is required to confirm this finding.

They also concluded that early transplant-related mortality was more than twice as high in children who had been given umbilical cord blood HLA-mismatched for two antigens, regardless of the cell dose of blood given. For blood HLA-mismatched for one antigen, mortality rate was lower if higher cell doses were transplanted.

The authors conclude: “Our findings support the need for even greater investment in cord blood because of the importance of HLA matching and cell dose on survival. These data also support the practice of simultaneously searching accredited cord-blood banks and bone-marrow donor registries for all children with acute leukaemia who are eligible for transplantation of haemopoietic stem cells from unrelated donors. “

They conclude: “In the absence of a randomised trial, we cannot definitively state the relative efficacy of bone-marrow and blood-cord grafts, but the data support the use of cord-blood grafts in children with acute leukaemia.”

In an accompanying comment, Dr Vanderson Rocha and Dr Eliane Gluckman, Bone Marrow Transplant and Research Unit and Clinical Research Laboratory on Cell Therapy and Department of Haematology, Hôpital Saint Louis, Paris, France, say: “Wagner and colleagues data emphasise that an umbilical cord-blood graft should be searched for together with an unrelated allele-matched bone marrow. The decision to transplant cord blood or bone marrow is dependent on the time spent finding a suitable cord-blood graft or HLA-matched bone marrow, on the basis of cord-blood cell dose and HLA.

“Therefore, based on this study and others, we propose an algorithm to search for an alternative haemopoietic stem-cell donor.” (Please see full comment for algorithm)