title: Genomic analyses of RH alleles to improve transfusion therapy in patients with sickle cell disease.
abstract: BACKGROUND
  Red cell (RBC) blood group alloimmunization remains a major problem in transfusion medicine. Patients with sickle cell disease (SCD) are at particularly high risk for developing alloantibodies to RBC antigens compared to other multiply transfused patient populations. Hemagglutination is the classical method used to test for blood group antigens, but depending on the typing methods and reagents used may result in discrepancies that preclude interpretation based on serologic reactivity alone. Molecular methods, including customized DNA microarrays, are increasingly used to complement serologic methods in predicting blood type. The purpose of this study was to determine the diversity and frequency of RH alleles in African Americans and to assess the performance of a DNA microarray for RH allele determination.
  
  
  METHODS
  Two sets of samples were tested: (i) individuals with known variant Rh types and (ii) randomly selected African American donors and patients with SCD. Standard hemagglutination tests were used to establish the Rh phenotype, and cDNA- and gDNA-based analyses (sequencing, PCR-RFLP, and customized RHD and RHCE microarrays were used to predict the genotype).
  
  
  RESULTS
  In a total of 829 samples (1658 alleles), 72 different alleles (40 RHD and 32 RHCE) were identified, 22 of which are novel. DNA microarrays detected all nucleotides probed, allowing for characterization of over 900 alleles.
  
  
  CONCLUSIONS
  High-throughput DNA testing platforms provide a means to test a relatively large number of donors and potentially prevent immunization by changing the way antigen-negative blood is provided to patients. Because of the high RH allelic diversity found in the African American population, determination of an accurate Rh phenotype often requires DNA testing, in conjunction with serologic testing. Allele-specific microarrays offer a means to perform high-throughput donor Rh typing and serve as a valuable adjunct to serologic methods to predict Rh type. Because DNA microarrays test for only a fixed panel of allelic polymorphisms and cannot determine haplotype phase, alternative methods such as Next Generation Sequencing hold the greatest potential to accurately characterize blood group phenotypes and ameliorate the clinical course of multiply-transfused patients with sickle cell disease.
authors.affiliation: Laboratory of Immunochemistry, New York Blood Center, 310 East 67th Street, New York, NY 10065, USA. Electronic address: mreid@nybloodcenter.org.
authors.forename: Marion E
authors.initials: ME
authors.lastname: Reid
authors.affiliation: Laboratory of Immunochemistry, New York Blood Center, 310 East 67th Street, New York, NY 10065, USA. Electronic address: christine.hipsky@roche.com.
authors.forename: Christine
authors.initials: C
authors.lastname: Halter Hipsky
authors.affiliation: Laboratory of Immunochemistry, New York Blood Center, 310 East 67th Street, New York, NY 10065, USA. Electronic address: khue-roye@nybloodcenter.rg.
authors.forename: Kim
authors.initials: K
authors.lastname: Hue-Roye
authors.affiliation: Department of Hematology/Oncology, Children's Hospital & Research Center Oakland, 747 52nd Street, Oakland, CA 94609, USA. Electronic address: CHoppe@mail.cho.org.
authors.forename: Carolyn
authors.initials: C
authors.lastname: Hoppe
mesh_terms: D000483:Alleles; D000755:Anemia, Sickle Cell / Q000235:genetics* / Q000628:therapy; D001803:Blood Transfusion; D017707:Erythrocyte Transfusion; D005787:Gene Frequency; D014644:Genetic Variation; D023281:Genomics / Q000379:methods; D005838:Genotype; D059014:High-Throughput Nucleotide Sequencing; D006801:Humans; D012204:Rh-Hr Blood-Group System / Q000235:genetics*; D016896:Treatment Outcome
chemical_list: C066468:RHCE protein, human; D012204:Rh-Hr Blood-Group System; C026410:Rho(D) antigen
keywords: Blood groups; Compatibility testing in sickle cell disease; DNA testing to predict blood groups; RH blood group system; RH genotype matching