title: HLA matching in allogeneic stem cell transplantation.
abstract: OBJECTIVE
  The success of unrelated hematopoietic cell transplantation (HCT) is influenced by the degree of HLA compatibility between the donor and patient. The goal of this review is to summarize new findings in the field of immunogenetics and HCT from unrelated donors using myeloablative conditioning regimens.
  
  
  RESULTS
  Molecular typing methods can discriminate unique alleles encoded by HLA class I and II genes. Incompatibility of donor-recipient HLA alleles increases posttransplant complications including graft rejection, acute and chronic graft-versus-host disease, and mortality. These posttransplant risks increase with increasing numbers of HLA mismatches. The identification of permissible HLA mismatches may be aided by the use of functional assays. Nongenetic factors, including the stage of disease at the time of transplantation, may influence the effect of HLA mismatching on survival.
  
  
  CONCLUSIONS
  HLA alleles are functionally relevant. Unrelated HCT can be optimized by comprehensive and precise donor-recipient allele matching. For patients with high-risk diseases who lack matched donors, use of donors with a single HLA mismatch may permit early treatment before disease progression.
authors.affiliation: University of Washington School of Medicine, Fred Hutchinson Cancer Research Center, Division of Clinical Research, Seattle, Washington 98109, USA. epetersd@fhcrc.org
authors.forename: Effie W
authors.initials: EW
authors.lastname: Petersdorf
mesh_terms: D006680:HLA Antigens; D018380:Hematopoietic Stem Cell Transplantation; D006648:Histocompatibility; D006650:Histocompatibility Testing; D006801:Humans; D014019:Tissue Donors; D019172:Transplantation Conditioning; D014184:Transplantation, Homologous
chemical_list: D006680:HLA Antigens