Serological Identification And RH Gene Analysis Of RhD-Individual

BackgroundRhD--deletion is a rare variant of Rh blood group system on the erythrocytes, whichcharacterized by the expression of D antigen without C, c, E and e antigen. Pregnant with RhD--deletionwill be allergized by Rh antigen and produce antibodies against C, c, E, e which named anti-Rh17antibody(Hr0). Hr0will induce severe hemolytic disease by agglutinating with erythrocyte containing RhCE antigen.Therefore, blood transfusion is always difficult for RhD--deficient pregnant and patients. The study ofRhD--deletion is still in infancy and the mechanism is unknown now. Cases of RhD--deletion abroad aremore common than in China. There are two reasons:(1) Exon of RHCE gene is replaced by RHD genewhich resulted in RhCE antigen deletion;(2) RHD and RHCE gene is integrity, but expression of RhCEantigen is deleted because of reduction of RHCE gene transcription activity. Studies are limited toserological tests early in China, but decade studies show that RhD--deletion may result from RHD andRHCE gene recombination, gene mutation of RHCE gene exon or partial deletion of RHCE gene or D--haplotype genetic from parents.ObjectiveThis study aimed to research the mechanism of Rh blood type variants by studying theserological characteristics, gene type and heredity feature of RhD--deletion individual and family members.Then more gene types and polymorphism data of Chinese will be obtained for improvement of blood typegene research technology. This will be useful for diagnosis, treatment and prevention of related disease inclinical practice.Methods(1) ABO blood type and Rh blood type of RhD--deletion individual and family members wereanalyzed by serological methods. The antigen on the erythrocyte surface and internal antibody wereexamined by the Coombs test, Absorb radiation test and antibody screening test.(2) The polymorphic loci,exons of RHD, RHCE gene and Rhesus box gene of RhD--deletion individuals were amplified bysequence-specific primer polymerase chain reaction (PCR-SSP). Then its gene type and molecular basis, and characteristic of heredity were analyzed.Results(1) The patient’s phenotype is D--with the D antigen on the surface of erythrocytes withoutantigen CE. There is anti-Rh17antibody in patient’s blood, which agglutinate with all other’s erythrocyteexcept her own. Her parents’ phenotypes are DCCee with antigen D, C/c and E/e.(2) Results ofPCR-SSP show that genotype of the patient is RhDCCee, which do not consist with serological results. Herparents’ genotypes are RhDCCee, which consist with serological results. RHD and RHCE exon andthe Rhesus box gene amplified by PCR-SSP, the results showed that both patient and her parents’ RHDexons do not lost. Patient’s RHCE gene exon1, exon3, exon4, and exon7exist, while exon5and exon6lost. Her parents’ RHCE gene exon5lost. Results of Rhesus box gene examination show that the patientand her parents are RH gene homozygous.Conclusions(1) The patient is RhD--deletion phenotype, while her parents are RH gene homozygousindividual.(2) Exon5, exon6of RHCE gene absence can result in RhD--deletion. The fracture of RHCEgene cannot express the corresponding antigen result in RhD--. This result is different from current reportof mechanism of RhD--deletion which concerned race and individual.