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Transfusion strategy for weak D Type 4.0 based on RHD alleles and RH haplotypes in Tunisia
Author(s) -
Ouchari Mouna,
Srivastava Kshitij,
Romdhane Houda,
Jemni Yacoub Saloua,
Flegel Willy Albert
Publication year - 2018
Publication title -
transfusion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.045
H-Index - 132
eISSN - 1537-2995
pISSN - 0041-1132
DOI - 10.1111/trf.14411
Subject(s) - allele , haplotype , genetics , biology , rh blood group system , population , gene , coding region , genotype , antibody , medicine , environmental health
BACKGROUND With more than 460 RHD alleles, this gene is the most complex and polymorphic among all blood group systems. The Tunisian population has the largest known prevalence of weak D Type 4.0 alleles, occurring in one of 105 RH haplotypes. We aimed to establish a rationale for the transfusion strategy of weak D Type 4.0 in Tunisia. STUDY DESIGN AND METHODS Donors were randomly screened for the serologic weak D phenotype. The RHD coding sequence and parts of the introns were sequenced. To establish the RH haplotype, the RHCE gene was tested for characteristic single‐nucleotide positions. RESULTS We determined all RHD alleles and the RH haplotypes coding for the serologic weak D phenotype among 13,431 Tunisian donations. A serologic weak D phenotype was found in 67 individuals (0.50%). Among them, 60 carried a weak D Type 4 allele: 53 weak D Type 4.0 , six weak D Type 4.2.2 (DAR), and one weak D Type 4.1 . An additional four donors had one variant allele each: DVII , weak D Type 1 , weak D Type 3 , and weak D type 100 , while three donors showed a normal RHD sequence. The weak D Type 4.0 was most often linked to RHCE*ceVS.04.01 , weak D Type 4.2.2 to RHCE*ceAR , and weak D Type 4.1 to RHCE*ceVS.02 , while the other RHD alleles were linked to one of the common RHCE alleles. CONCLUSIONS Among the weak D phenotypes in Tunisia, no novel RHD allele was found and almost 90% were caused by alleles of the weak D Type 4 cluster, of which 88% represented the weak D Type 4.0 allele. Based on established RH haplotypes for variant RHD and RHCE alleles and the lack of adverse clinical reports, we recommend D+ transfusions for patients with weak D Type 4.0 in Tunisia.