title: Future HLA matching strategies in clinical transplantation.
abstract: BACKGROUND
  HLA matching has shown to be beneficial in clinical transplantation. Due to the enormous polymorphism of the HLA system, however, it is not feasible to select a completely HLA-matched donor for every potential recipient. Only for patients with frequently occurring HLA phenotypes is it realistic to expect a well-matched donor within a reasonable waiting time. The majority of patients will be transplanted with a partially mismatched donor. In order to select the optimal donor for this category of patients, it is important to take advantage of the differential immunogenicity and thus differential importance of mismatched HLA antigens.
  
  
  METHODS
  Based on retrospective analyses of graft survival data and in vitro tests measuring T-cell alloreactivity, the relative importance of different mismatches was evaluated.
  
  
  RESULTS
  It has been possible to define acceptable or permissible mismatches with a low immunogenicity, which are associated with a good graft survival, versus taboo mismatches with a high immunogenicity and a poor graft survival.
  
  
  CONCLUSIONS
  Further developing this new line of permissible versus taboo mismatches, a new strategy will emerge for future HLA matching, which will not only suit a rare number of patients with frequent haplotypes but a great percentage of all patients. This principle of different immunogenicity of different mismatches can not only be applied to T-cell alloreactivity as shown here, but also to B-cell alloreactivity, where a recently developed computer algorithm (HLA matchmaker) can be instrumental in selecting donors with HLA mismatches, which do not lead to alloantibody formation.
authors.affiliation: Department of Immunohaematology and Blood Transfusion, Leiden University Medical Center and Europdonor, Leiden, The Netherlands. fhjclaas@lumc.nl
authors.forename: Frans H J
authors.initials: FH
authors.lastname: Claas
authors.forename: Dave L
authors.initials: DL
authors.lastname: Roelen
authors.forename: Machteld
authors.initials: M
authors.lastname: Oudshoorn
authors.forename: Ilias I N
authors.initials: II
authors.lastname: Doxiadis
mesh_terms: D001402:B-Lymphocytes / Q000276:immunology; D003315:Cornea / Q000276:immunology; D016039:Corneal Transplantation; D006085:Graft Survival / Q000502:physiology; D006680:HLA Antigens / Q000276:immunology; D006650:Histocompatibility Testing / Q000379:methods*; D006801:Humans; D013601:T-Lymphocytes / Q000276:immunology; D014019:Tissue Donors
chemical_list: D006680:HLA Antigens