Unrelated donor hematopoietic cell transplantation: marrow or umbilical cord blood?

The changing role of stem cell transplantation in childhood

“…13 Mainly because of HLA polymorphism and the limits of conventional techniques for HLA-typing, increased difficulties for engraftment and augmented incidence of both acute and chronic GvHD have been initially reported in recipients of an unrelated donor HSCT, this leading to a final outcome of patients inferior to that reported using a compatible sibling as a donor. 14,15 At that time, recourse to this type of transplant for patients in whom HSCT does not represent a life-saving procedure (that is, thalassemia) did not meet consensus.…”

Selection of cord blood unit(s) for transplantation

“…Higher degrees of HLA matching was associated with improved engraftment and transplant outcome compared to 5/6 or 4/6 matches (Table 2) but the impact is relatively small. 5,37,38 This is because of the confounding impact of cell dose on engraftment and HLA mismatch on GVL effect. As yet, there is no consensus as to which specific HLA mismatches are better tolerated.…”

“…CB transplants are being performed with approximately a log fewer hematopoietic progenitors than other stem cell sources. 5 The adult donor grafts are delivering cell numbers well above the engraftment threshold so that a loss of even half of the product would likely not have a major impact on the transplant. CB as a donor source is not as forgiving.…”

“…The outcome of CB transplants, particularly in children, is similar to those unrelated donor transplants using BM cell or mobilized PBPC. [5][6][7][8] Early experience in adult CB transplantation (CBT) was hampered by poor engraftment and immune recovery. [9][10][11] Recent experience with better risk patients, double CB unit transplants and submyeloablative preparative regimens have been more encouraging.…”

Outcome following unrelated cord blood transplant in 136 patients with malignant and non-malignant diseases: a report from the Australian and New Zealand children's haematology and oncology group

“…[1][2][3][4]6,[8][9][10][11] It has been estimated that more than 95% of patients are able to find at least one potential 4 of 6 HLA matched cord blood unit on the National Marrow Donor Registry, with the majority finding a potential five of six match. 12 The known advantages of unrelated UCB over unrelated BM are well documented and include increased speed of availability, 13 absence of risk to the donor, reduced transmission of viral illnesses such as CMV, tolerance of HLA disparity between the donor and recipient, 9,14,15 better minority representation in UCB banks and reduced risk and severity of acute GVHD when compared to BM grafts. 1,2,[4][5][6]9,10,14,16,17 When compared to BM, however, cord blood results in less optimal engraftment kinetics with higher rate of graft failure and slower haematopoietic recovery time.…”