title: Outcomes of transplantation of unrelated donor umbilical cord blood and bone marrow in children with acute leukaemia: a comparison study.
abstract: BACKGROUND
  Although umbilical cord blood is an accepted alternative to bone marrow for transplantation, allele-matched bone marrow is generally regarded as the preferred graft source. Our aim was to assess leukaemia-free survival after transplantations of these alternatives compared with present HLA-matching practices, and to assess the relative effect of cell dose and HLA match, and their potential interaction on leukaemia-free survival after cord-blood transplantation.
  
  
  METHODS
  Outcomes of 503 children (<16 years) with acute leukaemia and transplanted with umbilical cord blood were compared with outcomes of 282 bone-marrow recipients. All transplantation took place in the USA. Recipients of umbilical cord blood were transplanted with grafts that were HLA-matched (n=35) or HLA-mismatched for one (n=201) or two antigens (n=267) (typing at antigen level for HLA-A and HLA-B, and allele level for HLA-DRB1). Bone-marrow recipients were transplanted with grafts that were matched at the allele level for HLA-A, HLA-B, HLA-C, and HLA-DRB (n=116), or mismatched (n=166). The primary endpoint was 5-year leukaemia-free survival.
  
  
  RESULTS
  In comparison with allele-matched bone-marrow transplants, 5-year leukaemia-free survival was similar to that after transplants of umbilical cord blood mismatched for either one or two antigens and possibly higher after transplants of HLA-matched umbilical cord blood. Transplant-related mortality rates were higher after transplants of two-antigen HLA-mismatched umbilical cord blood (relative risk 2.31, p=0.0003) and possibly after one-antigen HLA-mismatched low-cell-dose umbilical-cord-blood transplants (1.88, p=0.0455). Relapse rates were lower after two-antigen HLA-mismatched umbilical-cord-blood transplants (0.54, p=0.0045).
  
  
  CONCLUSIONS
  These data support the use of HLA-matched and one- or two-antigen HLA-mismatched umbilical cord blood in children with acute leukaemia who need transplantation. Because better HLA matching and higher cell doses significantly decrease the risk of transplant-related mortality after umbilical-cord-blood transplantation, greater investment in large-scale banking is needed to increase HLA diversity.
authors.affiliation: Statistical Center, Center for International Blood and Marrow Transplant Research, Medical College of Wisconsin, Milwaukee, WI, USA.
authors.forename: Mary
authors.initials: M
authors.lastname: Eapen
authors.forename: Pablo
authors.initials: P
authors.lastname: Rubinstein
authors.forename: Mei-Jie
authors.initials: MJ
authors.lastname: Zhang
authors.forename: Cladd
authors.initials: C
authors.lastname: Stevens
authors.forename: Joanne
authors.initials: J
authors.lastname: Kurtzberg
authors.forename: Andromachi
authors.initials: A
authors.lastname: Scaradavou
authors.forename: Fausto R
authors.initials: FR
authors.lastname: Loberiza
authors.forename: Richard E
authors.initials: RE
authors.lastname: Champlin
authors.forename: John P
authors.initials: JP
authors.lastname: Klein
authors.forename: Mary M
authors.initials: MM
authors.lastname: Horowitz
authors.forename: John E
authors.initials: JE
authors.lastname: Wagner
mesh_terms: D000293:Adolescent; D000483:Alleles; D016026:Bone Marrow Transplantation; D002648:Child; D002675:Child, Preschool; D005312:Fetal Blood; D006086:Graft vs Host Disease / Q000517:prevention & control; D018380:Hematopoietic Stem Cell Transplantation; D006650:Histocompatibility Testing; D006801:Humans; D007223:Infant; D015470:Leukemia, Myeloid, Acute / Q000628:therapy*; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000628:therapy*; D017211:Treatment Failure