title: Generation of HLA-deficient platelets from hematopoietic progenitor cells.
abstract: BACKGROUND
  Exposure to allogeneic blood products often leads to the development of human leukocyte antigen (HLA) antibodies. Refractoriness to platelet (PLT) transfusion caused by alloimmunization against HLA Class I antigens constitutes a significant clinical problem.
  
  
  METHODS
  We developed an RNA interference (RNAi)-based approach to silence the expression of HLA Class I molecules on PLTs derived from CD34+ progenitor cells. A lentiviral-based system was used to express short-hairpin RNA (shRNA) targeting β2-microglobulin (β2m) transcripts in CD34+ progenitor cells. Differentiation to PLTs was performed by incubating progenitor cells in the presence of thrombopoietin and interleukin-3.
  
  
  RESULTS
  The transduction of RNAi cassettes containing the sequences for shRNAs targeting β2m caused up to 85% reduction of progenitor cells HLA Class I antigen expression, which was maintained in the culture-derived PLTs. The HLA-deficient PLTs derived from HLA-silenced CD34+ cells proved to be fully functional in in vitro tests when compared to peripheral blood-derived PLTs.
  
  
  CONCLUSIONS
  Our data show that in vitro generating HLA Class I-deficient PLTs from hematopoietic progenitor cells prove to be feasible. As malignancy risks associated with insertional mutagenesis are not to be expected in anucleated PLTs, provision of HLA-deficient PLTs from large-scale production units may become reality in the management of patients suffering from PLT transfusion refractoriness.
authors.affiliation: Institute for Transfusion Medicine, Hannover Medical School, Hannover, Germany.
authors.forename: Constança
authors.initials: C
authors.lastname: Figueiredo
authors.forename: Lilia
authors.initials: L
authors.lastname: Goudeva
authors.forename: Peter A
authors.initials: PA
authors.lastname: Horn
authors.forename: Britta
authors.initials: B
authors.lastname: Eiz-Vesper
authors.forename: Rainer
authors.initials: R
authors.lastname: Blasczyk
authors.forename: Axel
authors.initials: A
authors.lastname: Seltsam
mesh_terms: D020868:Gene Silencing; D006412:Hematopoietic Stem Cells / Q000166:cytology*; D015395:Histocompatibility Antigens Class I / Q000502:physiology*; D006801:Humans; D008533:Megakaryocytes / Q000276:immunology*; D017713:Platelet Transfusion; D034622:RNA Interference; D001613:beta 2-Microglobulin / Q000037:antagonists & inhibitors
chemical_list: D015395:Histocompatibility Antigens Class I; D001613:beta 2-Microglobulin