title: The RHD(1227G>A) DEL-associated allele is the most prevalent DEL allele in Australian D- blood donors with C+ and/or E+ phenotypes.
abstract: BACKGROUND
  Red blood cells (RBCs) with D antigen levels only detected by anti-D adsorption-elution and an antiglobulin test express a DEL phenotype. For two DEL types, including RHD(1227G>A), immunization of D- recipients has been reported. This study's aim was to measure the prevalence of DEL-associated RHD alleles in a cohort of Australian D- donors to develop a model to estimate alloimmunization risk.
  
  
  METHODS
  D-, C+ and/or E+ blood donors were screened for RHD exons using quantitative polymerase chain reaction. Donors with RHD signals were DEL phenotyped with MCAD6 anti-D. RHD alleles were characterized via single-nucleotide polymorphism array or sequencing. Extended DEL phenotyping was performed with an anti-D panel.
  
  
  RESULTS
  Among 2027 donors, 39 carried RHD alleles that have been previously reported to associate with either the DEL or the weak D phenotype. An additional five donors carried previously unreported RHD alleles and exhibited the DEL phenotype: RHD(IVS2-2delA), RHD(IVS1+5G>C), RHD(ex9:del/CE), and RHD(ex8:del/CE) represented twice. In total, DEL/weak D-associated RHD alleles were detected in 44 of 2027 donors or 2.17% (95% confidence interval, 1.54%-2.81%). The RHD(1227G>A) DEL allele was the most frequent (n = 16). The risk of transfusing D- females not more than 40 years of age with an RHD(1227G>A) DEL RBC unit (when managed as D-) is estimated to be one in 149,109 transfusions (range, 100,680-294,490).
  
  
  CONCLUSIONS
  DEL/weak D-associated RHD alleles were found in 2.17% of Australian D-, C+ and/or E+ blood donors. This differs from previous European reports in that the clinically significant RHD(1227G>A) DEL allele is the most prevalent.
authors.affiliation: Research and Development, Australian Red Cross Blood Service, Brisbane, Australia.
authors.forename: Stacy A
authors.initials: SA
authors.lastname: Scott
authors.forename: Lisa
authors.initials: L
authors.lastname: Nagl
authors.forename: Louise
authors.initials: L
authors.lastname: Tilley
authors.forename: Yew-Wah
authors.initials: YW
authors.lastname: Liew
authors.forename: Jenny
authors.initials: J
authors.lastname: Condon
authors.forename: Robert
authors.initials: R
authors.lastname: Flower
authors.forename: Catherine A
authors.initials: CA
authors.lastname: Hyland
mesh_terms: D000328:Adult; D000483:Alleles; D001315:Australia; D001483:Base Sequence; D001782:Blood Donors; D001787:Blood Group Incompatibility / Q000235:genetics / Q000517:prevention & control; D017707:Erythrocyte Transfusion; D005260:Female; D005787:Gene Frequency; D006801:Humans; D008297:Male; D008957:Models, Genetic; D017354:Point Mutation; D015995:Prevalence; D012204:Rh-Hr Blood-Group System / Q000235:genetics*; D017384:Sequence Deletion
chemical_list: D012204:Rh-Hr Blood-Group System; C026410:Rho(D) antigen