title: Determination of an unrelated donor pool size for human leukocyte antigen-matched platelets in Brazil.
abstract: BACKGROUND
  Successful transfusion of platelet refractory patients is a challenge. Many potential donors are needed to sustain human leukocyte antigen matched-platelet transfusion programs because of the different types of antigens and the constant needs of these patients. For a highly mixed population such as the Brazilian population, the pool size required to provide adequate platelet support is unknown.
  
  
  METHODS
  A mathematical model was created to estimate the appropriate size of an unrelated donor pool to provide human leukocyte antigen-compatible platelet support for a Brazilian population. A group of 154 hematologic human leukocyte antigen-typed patients was used as the potential patient population and a database of 65,500 human leukocyte antigen-typed bone marrow registered donors was used as the donor population. Platelet compatibility was based on the grading system of Duquesnoy.
  
  
  RESULTS
  Using the mathematical model, a pool containing 31,940, 1710 and 321 donors would be necessary to match more than 80% of the patients with at least five completely compatible (no cross-reactive group), partial compatible (one cross-reactive group) or less compatible (two cross-reactive group) donors, respectively.
  
  
  CONCLUSIONS
  The phenotypic diversity of the Brazilian population has probably made it more difficulty to find completely compatible donors. However, this heterogeneity seems to have facilitated finding donors when cross-reactive groups are accepted as proposed by the grading system of Duquesnoy. The results of this study may help to establish unrelated human leukocyte antigen-compatible platelet transfusions, a procedure not routinely performed in most Brazilian transfusion services.
authors.affiliation: Hospital Israelita Albert Einstein, São Paulo, SP, Brazil. Electronic address: carolina.bub@einstein.br.
authors.forename: Carolina Bonet
authors.initials: CB
authors.lastname: Bub
authors.affiliation: LIG Laboratório de Imunogenética, São Paulo, SP, Brazil.
authors.forename: Margareth Afonso
authors.initials: MA
authors.lastname: Torres
authors.affiliation: LIG Laboratório de Imunogenética, São Paulo, SP, Brazil.
authors.forename: Maria Elisa
authors.initials: ME
authors.lastname: Moraes
authors.affiliation: Hospital Israelita Albert Einstein, São Paulo, SP, Brazil.
authors.forename: Nelson
authors.initials: N
authors.lastname: Hamerschlak
authors.affiliation: Hospital Israelita Albert Einstein, São Paulo, SP, Brazil.
authors.forename: José Mauro
authors.initials: JM
authors.lastname: Kutner
keywords: Donors; HLA; Platelet transfusion; Refractoriness