Korean J Blood Transfus.  2021 Aug;32(2):91-101. 10.17945/kjbt.2021.32.2.9 1.

The Experience of RHD Genotyping in D-negative Blood Donors

• Kim T
• Park Y
• Shin L
• Jung YS
• Youn M
• Kim Y

• KMID: 2519477
• DOI: http://doi.org/10.17945/kjbt.2021.32.2.9 1

Abstract

Background
There have been some domestic and overseas cases of anti-D alloimmunization caused by the transfusion of serologically D-negative blood. However, it is difficult to distinguish between true D-negative and DEL variants using conventional serologic typing. Therefore, we established the RHD genotyping algorithm for the detection of DEL variants and applied this algorithm to serologic D negative donors who voluntarily consented to testing.
Methods
From September 2016 to December 2020, 216 RHD negative donors who were C＋ and/or E+ in previous serologic typing were recruited. The screening test was PCR amplification of the RHD exons 4, 7, 10, and a promotor. Based on the results of PCR screening, true D-negative samples and RHD variants (including DEL) were discriminated. When the result was a RHD variant, exon 9 was sequenced to identify the nucleotide changes. Full sequencing was performed if no mutations were detected at exon 9.
Results
Among the 216 participants, 39 cases with the C−E−c＋e＋ phenotypes that did not meet the recruitment criteria were excluded from data analysis. Among the remaining 177 samples, 68 cases (38.4%) were RHD total deletions, 35 cases (19.8%) were RHD-CE-D hybrids, and 74 cases (41.8%) were RHD variants. Among the cases of RHD variants, 73 cases (98.6%) had c.1227G＞A substitutions and were confirmed as Asian-type DEL.
Conclusion
Seventy-four cases of serologic D negative donors were reclassified as RHD variants by RHD genotyping. This is believed to have contributed to the improvement of transfusion safety by lowering the risk of anti-D alloimmunization in D-negative patients.

Keyword

RHD genotyping; DEL; D negative blood donors