title: RHD gene polymorphisms in alloimmunized RhD-negative individuals with high rate of racial admixture.
abstract: BACKGROUND
  The D-negative phenotype is the result of the total RHD gene deletion in almost all Caucasians, but it accounts for only about 20% in Africans and 70% in Asians. In Africans the RHDΨ that is one of the most important causes of the D-negative phenotype. We investigated the RHD polymorphisms in D-negative phenotype mixed Brazilians who have anti-D alloantibody.
  
  
  METHODS
  Blood samples from 130 individuals previously typed as D-negative were phenotyped again using: (a) two tube reagents (Anti-D blend reagent, Cellular line TH-28, MS-26; and Anti-D polyclonal); (b) one gel test ID-Card for Rh subgroups including C(w) and K antigen; and (c) ABO/Rh (Anti-D blend reagent, Cellular line 175-2, LDM3). The method used for RHD screening detected the presence of RHD exon 10 and intron 4. Sequence analysis was performed on PCR products amplified from genomic DNA for all 10 exons RHD gene.
  
  
  RESULTS
  We found that 118/130 (90.8%) of D-negative tested individuals had total RHD gene deletion, while 12/130 (9.2%) showed RHD gene polymorphisms. The RHDΨ was found in 10 (7.7%) individuals, one sample (0.77%) hybrid RHD-CE-D(s) /RHDΨ, and another (0.77%) weak D type 4.2.
  
  
  CONCLUSIONS
  The results showed that the RHD gene was present in 9.2% of racially mixed Brazilians who produced usually clinically significant anti-D alloantibodies. Therefore, the data showed that careful attention is necessary for clinicians in applying RhD genotyping to transfusion medicine in populations with high rate of racial admixture.
authors.affiliation: Disciplina de Hematologia e Hemoterapia, Universidade Federal de São Paulo, São Paulo, SP, Brazil. drfabiomartin@hotmail.com
authors.forename: Fábio O
authors.initials: FO
authors.lastname: Martin
authors.forename: Sidnéia S
authors.initials: SS
authors.lastname: de Menezes
authors.forename: Akemi K
authors.initials: AK
authors.lastname: Chiba
authors.forename: Dante M
authors.initials: DM
authors.lastname: Langhi
authors.forename: Luciano M M
authors.initials: LM
authors.lastname: Nardozza
authors.forename: Carlos S
authors.initials: CS
authors.lastname: Chiattone
authors.forename: José O
authors.initials: JO
authors.lastname: Bordin
mesh_terms: D001741:Black or African American / Q000235:genetics*; D005260:Female; D005838:Genotype; D006801:Humans; D007518:Isoantibodies / Q000235:genetics* / Q000276:immunology; D008297:Male; D011110:Polymorphism, Genetic; D012204:Rh-Hr Blood-Group System / Q000235:genetics* / Q000276:immunology; D018029:Rho(D) Immune Globulin; D044465:White People / Q000235:genetics*
chemical_list: D007518:Isoantibodies; C061961:RHO(D) antibody; D012204:Rh-Hr Blood-Group System; D018029:Rho(D) Immune Globulin