Summary:Cord blood (CB) is an alternative to other sources of stem cells for transplantation. However, the impact of including CB in the initial strategy of unrelated graft search in a cohort of patients has been the object of limited analysis. Here, we report the results of such a strategy in 91 consecutive children. Absence of mismatch was required for adult donors, and up to two mismatches were allowed for CB grafts, with a nucleated cell dose over 2.5 Â 10 7 cells/kg. A graft was found for 84 of the 85 children who remained available for a 3-month search. In all, 64 patients were transplanted, 36 with CB and 28 with bone marrow (BM). Primary graft failure, acute grade II-IV and extensive chronic graft-versus-host disease occurred in five, five and zero CB, and in three, one and two BM patients, respectively. The 3-year survival was 59% in CB and 57% in BM patients. Accepting CB as a source of stem cells offers a graft to almost every child in need of an unrelated transplantation, with a probability of survival similar to that of unrelated BM transplantation. Advantages of unrelated cord blood (CB) over unrelated bone marrow (BM) include less stringent requirements for HLA compatibility between the donor and recipient, resulting from a lower risk of graft-versus-host disease (GVHD). 1,2 CB viral contamination rate is very low, which may be especially important in pediatric patients who are often cytomegalovirus (CMV) and Epstein-Barr virus (EBV) negative. Further, CB units from banks are more rapidly available than BM volunteer donors from international registries. 3 Accepting CB transplant as a first-line alternative to BM transplant for patients in need for an unrelated transplantation is expected to increase the probability of finding a suitable graft. However, the results of such a search strategy have not been reported to date. It carries two major risks. First, the increase in the pool of donors may be marginal. Second, if CB transplantation outcome is worse, waiting for an unrelated BM donor may be preferable to early CB transplantation. Also, in the absence of an identified HLA-compatible BM donor, other therapeutic options are also available, such as haplo-identical grafts.To randomize patients in a study comparing unrelated CB and BM transplantation, each patient would need a CB and a BM donor available. Conducting such a study has so far not been possible. One has thus to rely on registries or single-institution studies. Clinical reports comparing outcomes for patients undergoing unrelated CB and BM transplantation recipients point to delayed time to hematopoietic recovery, and sometimes to a higher treatmentrelated mortality. [4][5][6][7][8][9] One pediatric registry survey demonstrated a slightly better outcome after unrelated BM transplantation when compared with CB. 8 In this survey, the mean number of CB transplantations for each center was 2.6. A single-institution pediatric study, analyzing 63 CB transplantations, reported a similar outcome after unrelated CB and BM transplantation. 9 In a l...
