Increasing testing for Rh and Kell phenotypes could reduce the risk of adverse transfusion reactions and hemolytic disease of the fetus and newborn (HDFN), according to a study recently published in Cureus.
The authors aimed to assess the prevalence of the different Rh and Kell phenotypes in a tertiary center in Jamnagar, India, in order to create a database that facilitates transfusions in alloimmunized patients.
“Understanding the prevalence of Rh subgroups and Kell antigens within a population can help create a donor database, reduce the risks of alloimmunization and improve transfusion outcomes,” the authors wrote.
Learn more about HDFN testing and diagnosis
The study included over 1000 voluntary donors. The least common Rh antigen among RhD negative donors was E (18%,) followed by C (15%) and e (65%). In RhD positive donors, E and C were the most rare antigens, at 56% and 18% respectively.
Regarding the Kell antigens, the results showed that the k antigen was present in 100% of the population, while the K antigen was present in 2% of the population.
“The findings, consistent with other studies in India, highlight the need for comprehensive donor registries,” the authors wrote. “Such registries would improve blood transfusion management, reduce alloimmunization, decrease the incidence of hemolytic disease in newborns, and prevent transfusion reactions.”
Understanding Rh subtypes
The Rh blood group system is complex. Although the D antigen (RhD) is the primary antigen of the system, other antigens like the C, e, and E can also be clinically relevant. Furthermore, the D antigen can be subclassified into weak D and partial D.
The presence of any of those antigens can complicate transfusion practices, as there can be antigen expression differences between RhD positive individuals, and there are reported cases of HDFN due to RhCE alloimmunization.
In many countries, antigen testing is typically limited to ABO and RhD. Therefore, studies such as these and the creation of large regional databases is vital to ensure safe transfusions for alloimmunized patients.
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