[Serological and Molecular Biological Detection of RhD Variants].

Abstract

Objective: To analyze the RHD genotyping and sequencing results of RhD serology negative samples in the clinic, and to further explore the laboratory methods for RhD detection, in order to provide a basis for clinical precision blood transfusion.

Methods: A total of 27 200 whole blood samples were screened for RhD blood group antigen using microcolumn gel card method.Serologic RhD-negative confirmation tests were performed on blood samples that were negative for RhD on initial screening using three different clonal strains of IgG anti-D reagents. The 10 exons of the RHD gene on chromosome 1 were also analyzed by PCR-SSP to determine RHD genotyping.When the PCR-SSP method did not yield definitive results, the RHD gene of the sample was analyzed by the third-generation sequencing.

Results: The results of the initial screening test by the microcolumn gel card method showed that 136 of the 27 200 samples were RhD-negative, of which 86 underwent RhD-negative confirmation testing and RHD genotyping, 88.37% (76/86 cases) of the RhD-negative confirmation test results were negative for the three anti-D reagents, and the results of RHD genotyping showed that 67.44% (58/86 cases) of the cases had a complete deletion of 10 exons, and the remaining 28 cases were RHD*711delC (1 case), RHD*D-CE(1-9)-D (1 case), RHD*D-CE(2-9-)D (2 cases), RHD*D-CE(3-9)-D (4 cases), RHD*DEL1 (c.1227G >A) mutation (16 cases), RHD*weak partial 15(845G >A) mutation (3 cases), and a mutation of c.165C >T base was found in 1 sample by three-generation sequencing.

Conclusion: RHD genotype testing of samples that are serologically negative for RhD antigen shows that some of the samples have RHD gene variants, not all of which are total deletions of RHD, suggesting that there are some limitations of the serologic method for RhD detection. Due to the polymorphism of the RHD gene structure, different RhD variants present different serologic features, which need to be further detected in combination with molecular biology testing, especially for the identification of Asian-type DELs, which is important for clinical precision blood transfusion.