title: Is current serologic RhD typing of blood donors sufficient for avoiding immunization of recipients?
abstract: BACKGROUND
  Avoiding immunization with clinically important antibodies is a primary objective in transfusion medicine. Therefore, it is central to identify the extent of D antigens that escape routine RhD typing of blood donors and to improve methodology if necessary.
  
  
  METHODS
  We screened 5058 D- donors for the presence of the RHD gene, targeting Exons 5, 7, and 10 with real-time polymerase chain reaction. Samples that were positive in the screen test were investigated further by adsorption-elution, antibody consumption, flow cytometry, and sequencing of all RHD exons with intron-specific primers. Lookback was performed on all recipients of RBCs from RHD+ donors.
  
  
  RESULTS
  We found 13 RHD+ samples (0.26%). No variants or chimeras were found. Characterization of DNA revealed a novel DEL type (IVS2-2 A>G). In the lookback of the 136 transfusions with subsequent antibody follow-up, of which 13 were from DEL donors, one recipient developed anti-D. However, in this case, a competing and more likely cause of immunization was the concurrent transfusion of D+ platelets. Eleven recipients were immunized with 13 antibodies different from anti-D, of which five were anti-K.
  
  
  CONCLUSIONS
  In our laboratory, serologic RhD typing was safe. We detected all D variants and only missed DEL types. In assessing the immunization risk we included a DEL donor, found previous to this study, that did immunize a recipient with anti-D. We conclude that inadvertent immunization with D antigens in our setting was rare and in the order of 1.4 in 100,000 D- transfusions.
authors.affiliation: Department of Clinical Immunology, Copenhagen University Hospital, Copenhagen, Denmark. grethe.risum.krog@rh.regionh.dk
authors.forename: Grethe Risum
authors.initials: GR
authors.lastname: Krog
authors.forename: Frederik Banch
authors.initials: FB
authors.lastname: Clausen
authors.forename: Adela
authors.initials: A
authors.lastname: Berkowicz
authors.forename: Lone
authors.initials: L
authors.lastname: Jørgensen
authors.forename: Klaus
authors.initials: K
authors.lastname: Rieneck
authors.forename: Leif Kofoed
authors.initials: LK
authors.lastname: Nielsen
authors.forename: Morten Hanefeld
authors.initials: MH
authors.lastname: Dziegiel
mesh_terms: D000328:Adult; D001782:Blood Donors; D001788:Blood Grouping and Crossmatching; D005838:Genotype; D006801:Humans; D012203:Rh Isoimmunization / Q000517:prevention & control*; D012204:Rh-Hr Blood-Group System / Q000235:genetics*
chemical_list: D012204:Rh-Hr Blood-Group System; C026410:Rho(D) antigen