The study of RHD gene mutation in weak D

Lim, Chae Seung; Kim, Chang Hyun; Kim, Il Tae; Ma, Kyung Ran; Kim, Young Kee; Lee, Kap No; Kim, Dae Chul

Abstract

BACKGROUND
The weak D is characterized serologically by a weak or negative agglutination reaction with polyclonal anti-D in an immediate-spin test and agglutination is enhanced in the indirect antiglobulin test. Weak D has a lower number of D antigen or weaker antigen density than are normal D positive red cells. Here we studied the cause of weak D antigenicity at genetic level and compared to that of normal D RBCs.
METHODS
The amplification of RHD gene and RHCcEe gene site was done in normal D(n=20), weak D(n=8), D negative group(n=20) by polymerase chain reaction and by based on D typing in these individuals compared to that of serologic D typing. In addition, to detect RHD gene mutation and nucleotide sequence difference of weak D group compared to normal D RBCs, single stranded conformational polymorphism PCR was simultaneuosly perfomed in two group by RHD amplified product(189 bp). We analysis the correlation RHD genotyping and serological phenotyping, and also analysis the difference of nucleotide sequence between two group in genetic level.
RESULTS
The RHD genotyping was completely matched normal D(n=20), D negative group(n=20) but weak D group(n=8) showed same genotype of normal D RBCs. In single stranded conformational polymorphism PCR, weak D phenotypes does not show any abnormalities at the genomic level when compared to the RHD gene in normal D phenotypes.
CONCLUSIONS
RHD PCR showed good correlation with conventional serologic test but weak D genotype was same as that of normal D RBCs. The weaker immunogenicity of weak D is not explained by genomic DNA difference itself.