[Molecular Mechanism of Reduced RhCE Antigen and Precision Transfusion]

To analyze the RH genotype and molecular mechanisms of weakened RhCE antigens in 10 cases, and to investigate the impact of genetic variations on Rh antigen expression.

A total of 10 cases with weak expression samples in Rh typing initial tests who visited Guiyang Maternal and Child Health Care Hospital from January 2023 to December 2024 were selected. Two different manufacturers' monoclonal antibodies were used for further RhCE serological typing via tube method. The human red blood cell RHCE blood type gene typing kit was used to detect the RH gene fluorescence typing of the samples. PCR technology was used to sequence the exons of the RHCE exons. The modeling analysis of the RhCE protein was performed using Swiss-Model. The impact of mutations on protein function was predicted using PolyPhen-2 software.

The serological results of RhCE in the blood samples of 10 patients showed that patients 1 to 8 had varying degrees of weakened RhC antigen expression (±～2+); patients 9 and 10 exhibited weakened expression of Rhc (1+) and Rhe (2+) antigens, respectively. The fluorescence PCR method detected RHCE typing, and the results of fluorescence typing were consistent with the Rh blood type serology. Sanger sequencing revealed a total of 8 variant sites, namely c.48G>C in exon 1, c.150C>T, c.178C>A, c.201A>G, c.203A>G, c.307C>T in exon 2, c.375C>G in exon 3, and c.676G>C in exon 5. According to the PolyPhen-2 platform, it is predicted that the p.Trp16Cys mutation is benign and the p.Ile125Met mutation is probably damaging.

This study is the first to correlate homozygous c.48G>C with markedly weakened RhC expression and suggest a damaging role for p.Ile125Met in Rhe antigenicity. Genotyping clarifies the molecular basis of weak antigen expression, supporting precision transfusion medicine.