A comparison of methods for the detection of the r′s haplotype. Issue 6 (15th December 2014)

• Record Type: Journal Article
• Authors: Moulds, Joann M.; Noumsi, Ghislain T.; Billingsley, Katrina L.
• Is Part Of: Transfusion. Volume 55:Issue 6(2015)Part 2
• Page Start: 1418
• Page End: 1422
• Publication Date: 2014-12-15
• Subjects: Hematology -- Periodicals; Blood -- Transfusion -- Periodicals; Blood Group Antigens -- Periodicals; Blood Preservation -- Periodicals; Blood Transfusion -- Periodicals; 615
• DOI: 10.1111/trf.12956
• Languages: English
• ISSNs: 0041-1132

Abstract

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. Study Design and 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.