title: A comparison of methods for the detection of the r'(s) haplotype.
abstract: BACKGROUND
  The r'(s) haplotype is found in 5% to 15% of individuals of African descent. Persons with this haplotype have a partial C antigen and weakened e and can produce anti-C or other "e-like" alloantibodies. Thus, for these chronically transfused patients, accurate detection of the r'(s) haplotype is important for selection of matched units.
  
  
  METHODS
  African-American donors were genotyped using the human erythrocyte antigen (HEA) microarray. Samples (n = 125) identified as "possible r'(s) " were then tested by IDCORE XT and RHD and RHCE microarrays. DNA sequencing was used to resolve discordant samples. The genotyping results were compared to serologic testing using a monoclonal anti-C reagent (Clone MS24).
  
  
  RESULTS
  Of the 125 possible r'(s) samples identified by HEA, only 94 (75%) were confirmed by both RHD and RHCE microarrays. The IDCORE XT accurately detected 93 of 94 (99%) of the confirmed r'(s) and had no false positives. DNA sequencing of the one discordant sample revealed the presence of a compound heterozygote with RHD* DIII.4/RHCE*ceVS.02 as one haplotype and r'(s) Type 2 as the other. The 31 unconfirmed r'(s) samples carried RHCE*ceVS.03 not linked to the hybrid RHD-CE-D. This occurred most often with RHD*DIIIa (55%) or RHD*01 (19%) and rarely with DIII.4, DIII.6, DAU3, and weak D Type 14. Serologic testing with anti-C gave 100% concordance with the r'(s) samples.
  
  
  CONCLUSIONS
  The predominant type of r'(s) in African-Americans is Type 1, which can be detected either by a reagent anti-C containing Clone MS24 or by IDCORE XT. However, serology cannot differentiate between a normal C allele and the hybrid.
authors.affiliation: John J. Moulds Scientific Support Services, LifeShare Blood Centers, Shreveport, Louisiana.
authors.forename: Joann M
authors.initials: JM
authors.lastname: Moulds
authors.affiliation: John J. Moulds Scientific Support Services, LifeShare Blood Centers, Shreveport, Louisiana.
authors.forename: Ghislain T
authors.initials: GT
authors.lastname: Noumsi
authors.affiliation: John J. Moulds Scientific Support Services, LifeShare Blood Centers, Shreveport, Louisiana.
authors.forename: Katrina L
authors.initials: KL
authors.lastname: Billingsley
mesh_terms: D001741:Black or African American / Q000235:genetics; D000483:Alleles; D001789:Blood Group Antigens / Q000235:genetics / Q000276:immunology; D004912:Erythrocytes / Q000276:immunology / Q000378:metabolism; D060005:Genotyping Techniques / Q000379:methods*; D006239:Haplotypes; D006650:Histocompatibility Testing / Q000379:methods*; D006801:Humans; D007518:Isoantibodies / Q000235:genetics / Q000276:immunology; D008969:Molecular Sequence Data; D020641:Polymorphism, Single Nucleotide; D012204:Rh-Hr Blood-Group System / Q000235:genetics*
chemical_list: D001789:Blood Group Antigens; D007518:Isoantibodies; C066468:RHCE protein, human; D012204:Rh-Hr Blood-Group System; C026410:Rho(D) antigen