Managing patients with hemolytic disease of the fetus and newborn (HDFN) and related conditions required accurate knowledge of blood group variants, such as the Asian-type DEL, according to results from a study preprint published recently in The Lancet.
This study from Malaysia revealed a 25% prevalence of Asian-type DEL in Malay serologically D-negative blood donors, a figure exceeding most East Asian populations. These results suggested that individuals with this blood variant could often be treated as Rh-positive, streamlining transfusion protocols and reducing unnecessary interventions.
“Our study contributes to the growing understanding of D-negative phenotypes and their molecular underpinnings in Southeast Asian populations, such as the Malay ethnic group,” this study’s authors said. “Incorporating molecular testing into routine blood donor screening exemplifies the principles of precision medicine, where individualized genetic information can guide more accurate and safer transfusion practices.”
Blood group compatibility plays a vital role in safe transfusions, particularly for individuals with rare Rh phenotypes. This research analyzed Rh phenotyping records of 33,829 blood donors from Terengganu, Malaysia, between January 2020 and July 2024. Among these donors, 0.53% were serologically D-negative, with the highest prevalence of 5% among Indian donors. Further genetic screening revealed that 25% of Malay serologically D-negative donors carried the Asian-type DEL, as did 21% of serologically D-negative Malay patients.
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This study used advanced genetic techniques, including real-time PCR and sequencing, to identify the Asian-type DEL variant. This variant, though serologically D-negative, behaves functionally as Rh-positive, meaning individuals are unlikely to develop alloantibodies when exposed to Rh-positive blood. This discovery holds significant implications for pregnant women and other patients requiring RhIG, a preventive treatment to avoid allo-immunization.
By revising management guidelines for Asian-type DEL individuals, healthcare providers could conserve scarce Rh-negative blood supplies and reduce costs associated with unnecessary RhIG injections. This is particularly important in East and Southeast Asia, where Rh-negative blood is exceedingly rare, representing less than 0.5% of donors in this study.
For pregnant women, adopting D-positive management for those with Asian-type DEL could simplify care while maintaining safety. This approach would ensure more accurate matching of red cell resources and reduce the burden on blood banks, benefiting both patients and the healthcare system.
This study emphasized the need for integrating genetic screening into transfusion practices across Southeast Asia. As the prevalence of Asian-type DEL in Malays surpasses previous estimates, implementing these findings could transform transfusion safety and efficiency, improving outcomes for patients with rare blood types.
