Molecular Characteristics of the Serological Weak D Phenotype in Koreans

Abstract

Serological weak D is a reaction of 2+ or less to anti-D reagent and includes weak D and partial D phenotypes. Although identifying the RhD subtype is important for transfusion safety, serological tests are insufficient for defining the RhD subtype, and molecular tests are needed. To analyze the molecular characteristics of D variants in Koreans to facilitate the formulation of individualized transfusion strategies, molecular tests such as RhD genotyping using real-time polymerase chain reaction (PCR) and partial-D and/or weak-D sequence-specific amplification (SSP) were performed on 105 Korean Rare Blood Program (KRBP) patients exhibiting serological weak D. In total, 58 out of 68 serologically determined weak D KRBP patients were typed as having weak D or partial D phenotypes via RhD genotyping. In detail, eight (13.8%) were typed as partial DVa or DBS, nine (15.5%) as weak D type 15, and four others (6.8%) as partial DVI, partial DVII, weak D type 2, or weak D type 41 or 45, whereas the rest (n = 37, 63.8%) was typed as having either weak D or partial D. This suggests that serological weak D Koreans who require transfusion should be treated as D-negative.

Serological and molecular characterisation of the most prevalent weak D variants in Croatian population

“…Routine serological reagents are differently selected by laboratories testing blood donors or patients due to how they detect certain D variants and this may result in the named inconsistencies. Serological weak D is characterised by a reaction of 2+ or less at the initial direct D typing 8 . When determining the patient's D type, it is extremely important, especially in women of childbearing age, to distinguish weak and partial D variants.…”

“…Serological weak D is characterised by a reaction of 2+ or less at the initial direct D typing. 8 When determining the patient's D type, it is extremely important, especially in women of childbearing age, to distinguish weak and partial D variants. Namely, an expert opinion suggests that people with weak D type 1, 2 and 3 who make up to 90% of all weak D variants, and weak D type 4.0 and 4.1 do not produce anti-D antibodies and can be transfused with RHD positive blood products, while pregnant females do not need to receive RhIg.…”

RHD*DNT (RHD*38) Showing D-Positive Reactivity on Rhesus D Typing and Forming Anti-D Antibody

“…All anti-D reagents showed 4+ reactivity in both tube and column agglutination technology methods. Antibody screening using DiaCell I+II, Dia Positive (Bio-Rad, Glattbrugg, Switzerland) and antibody identification using ID-DiaPanel (Bio-Rad) with dithiothreitol-treated cells excluded anti-LW and confirmed anti-D. Real-time PCR and melting curve analysis revealed the presence of RHD , and PCR using sequence-specific primers (SSP) with BAGene RH-TYPE, Partial D-TYPE, and/or Weak D-TYPE SSP Kits (BAG Health Care GmbH, Lich, Germany) revealed partial D, suggesting RHD*DIIIc ( RHD*03.03 ) or other alleles harboring N512T [ 6 , 7 ]. Sanger sequencing of all 10 RHD exons and flanking regions of RHD confirmed RHD*DNT (method protocol available from the KRBP reference laboratory on request) [ 2 ].…”