OBJECTIVETo evaluate the status of eight RHD specific exons in 131 Han Chinese blood donors who were classified as RhD-negative by serological methods and explore the genomic structure of RHD gene among the Han Chinese. The Rh blood group system has the highest prevalence of polymorphisms among human blood group systems and is clinically significant in transfusion medicine. The Rh antigens are expressed on polypeptides encoded by two highly homologous genes, RHD and RHCE. Recent molecular studies have shown that the RhD-negative trait could be generated by multiple genetic mechanisms and is ethnic group-dependent.

METHODSThe polymerase chain reaction using-sequence specific primers (PCR-SSP) was used to amplify exons 2, 3, 4, 5, 6, 7, 9 and 10 of RHD gene and exons 1, 2 and 5 of RHCE gene, as well as intron 4 in each of them.

RESULTSThe 131 cases of RhD-negative phenotypes consisted of 60 ccee, 58 Ccee, 5 ccEe, 5 CcEe and 3 CCee. Among them, 83 with the Rh ccee or ccEe phenotypes (63.4%) lacked the eight RHD exons indicated above, while 26 cases with the Rh Ccee, CCee, CcEe phenotypes (19.9%) had all the RHD exons examined. Twenty-two individuals with the Ccee, CCee, CcEe phenotypes (16.8%) carried at least one RHD exon. The phenotypes of the RhD negative individuals carrying the RHD gene were Rh CC or Cc, but not cc.

CONCLUSIONSThree classes of RhD-negative polymorphisms among a population of Han Chinese were observed. Antigen association analysis suggested the existence of a novel class of RhD-negative associated haplotype in Han Chinese. This haplotype consisted of a normal RHCE allele and a nonfunctional RHD gene. It may be beneficial to redefine the RhD-negative blood group among Chinese populations upon clarification of the mechanisms of RHD gene expression and RhD antigen immunization.

Asian Continental Ancestry Group ; China ; Ethnic Groups ; genetics ; Humans ; Phenotype ; Polymerase Chain Reaction ; Polymorphism, Genetic ; Rh-Hr Blood-Group System ; analysis ; genetics

Objective To explore the genomic structure of 8 exons in D gene of RhD(-) Chinese Han population.Methods Polymerase chain reaction-sequence specific primers(PCR-SSP) were used to study genomic DNA from 50 samples of RhD(-) Chinese Han donors. Exons 2,3,4,5,6,7,9,10 of RHD gene and exons 1,2,4,5 of RHCE gene were specifically amplified, also intron 4 of them was amplified. Results Phenotypes of the 50 RhD(-) donors were:22 ccdee, 22 Ccdee, 3 CcdEe, 3 CcdEe. The 8 exons of RHD gene were completely absent in 25 donors with ccdee or ccdEe phenotype, while polymorphisms of D gene exons were found in 25 donors with Ccdee or CcdEe phenotype:the presence of all 8 exons of D gene in 9 donors, the absence of the 8 exons in 7 donors, the presence of exon 2 in 5 donors, the presence of exon 6 in 3 donors and the presence of exons 2,6,10 in 1 donor were demonstrated. Conclusion Polymorphisms of RHD gene exons were present among RhD(-) Chinese Han blood donors. The 8 exons of RHD gene were completely absent in donors with Rhesus cc phenotype, while 5 polymorphisms of RHD gene exons were found in donors with Rhesus Cc phenotype. The discrepancy of the RHD gene in RhD(-) individuals between Chinese Hans and Caucasians indicates that care should be exercised by clinicians in the use of the RhD genotyping results.